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Introduction: Patients with congenital agammaglobulinemia, characterized by a defect in B lymphocyte differentiation causing B alymphocytosis, require life-long IgG replacement. There is scant literature regarding the effectiveness of IgG treatment at preventing mucosal (particularly sinopulmonary tract) infection and whether current management adequately restores "normal" health and quality of life (QoL). We aimed to document infective episodes pre- and post-commencing IgG replacement, determine any change in lung function and structure and assess respiratory status and QoL in a cohort of patients treated in Newcastle., Methods: Clinical data were extracted from medical records of 15 patients identified from the immunology database, focusing on infective episodes, serial chest CT and spirometry results. Thirteen patients completed a selection of standardized and validated questionnaires assessing physical health, respiratory health and QoL., Results: Pediatric patients on IgG therapy suffered fewer infections per patient year (0.74) than adults (2.13). 6/14 patients showed deteriorating respiratory status despite adequate therapy. Health questionnaires revealed a significant burden of respiratory disease on a patient's life., Conclusion: Clinical data showed patients with congenital agammaglobulinemia receiving immunoglobulin therapy retained a higher than average infection rate, most of which affected mucosal barriers. Most patients self-reported worse respiratory symptoms, a lower respiratory-related QoL and a lower general health QoL relative to a healthy population. Most participants had progressive structural lung damage and decreased lung function. These results suggest that current management is not entirely effective at preventing deterioration of respiratory health or restoring QoL.

Purpose: To investigate the clinical and functional aspects of MST1 (STK4) deficiency in a profoundly CD4-lymphopenic kindred with a novel homozygous nonsense mutation in STK4. Although recent studies have described the cellular effects of murine Mst1 deficiency, the phenotype of MST1-deficient human lymphocytes has yet to be fully explored. Patient lymphocytes were therefore investigated in the context of current knowledge of murine Mst1 deficiency., Methods: Genetic etiology was identified by whole exome sequencing of genomic DNA from two siblings, combined with linkage analysis in the wider family. MST1 protein expression was assessed by immunoblotting. The ability of patient lymphocytes to adhere to ICAM-1 under flow conditions was measured, and transwell assays were used to assess chemotaxis. Chemokine receptor expression was examined by flow cytometry and receptor signalling by immunoblotting., Results: A homozygous nonsense mutation in STK4 (c.442C > T, p.Arg148Stop) was found in the patients, leading to a lack of MST1 protein expression. Patient leukocytes exhibited deficient chemotaxis after stimulation with CXCL11, despite preserved expression of CXCR3. Patient lymphocytes were also unable to bind effectively to immobilised ICAM-1 under flow conditions, in keeping with a failure to develop high affinity binding., Conclusion: The observed abnormalities of adhesion and migration imply a profound trafficking defect among human MST1-deficient lymphocytes. By analogy with murine Mst1 deficiency and other defects of leucocyte trafficking, this is likely to contribute to immunodeficiency by impairing key aspects of T-cell development and function such as positive selection in the thymus, thymic egress and immune synapse formation in the periphery.

ICOS encodes the Inducible T-cell Co-Stimulator (ICOS). Deficiency of this receptor in humans causes a common variable immunodeficiency (CVID) characterised by an absence of class-switched memory B cells and hypogammaglobulinemia. Three pathogenic mutations in ICOS have been described to date in a total of 13 cases. Here we report a novel homozygous 10 base pair frameshift deletion in exon 2 discovered by whole exome sequencing of two siblings from a family of Pakistani origin. Both patients presented in early childhood with diarrhea, colitis and transaminitis and one showed defective handling of human herpesvirus 6. Activated patient CD3(+)CD4(+) T lymphocytes demonstrated a complete absence of ICOS expression and, consistent with previous reports, we detected a reduction in circulating T follicular helper cells. Findings in this kindred emphasise the phenotypic variability of ICOS deficiency and, in particular, the variably impaired antiviral immunity that is a poorly understood facet of this rare disorder.

Type I interferon (IFN-α/β) is a fundamental antiviral defense mechanism. Mouse models have been pivotal to understanding the role of IFN-α/β in immunity, although validation of these findings in humans has been limited. We investigated a previously healthy child with fatal encephalitis after inoculation of the live attenuated measles, mumps, and rubella (MMR) vaccine. By targeted resequencing, we identified a homozygous mutation in the high-affinity IFN-α/β receptor (IFNAR2) in the proband, as well as a newborn sibling, that rendered cells unresponsive to IFN-α/β. Reconstitution of the proband's cells with wild-type IFNAR2 restored IFN-α/β responsiveness and control of IFN-attenuated viruses. Despite the severe outcome of systemic live vaccine challenge, the proband had previously shown no evidence of heightened susceptibility to respiratory viral pathogens. The phenotype of IFNAR2 deficiency, together with similar findings in STAT2-deficient patients, supports an essential but narrow role for IFN-α/β in human antiviral immunity., (Copyright © 2015, American Association for the Advancement of Science.)

Background: Mutations in dedicator of cytokinesis 8 (DOCK8) cause a combined immunodeficiency (CID) also classified as autosomal recessive (AR) hyper-IgE syndrome (HIES). Recognizing patients with CID/HIES is of clinical importance because of the difference in prognosis and management., Objectives: We sought to define the clinical features that distinguish DOCK8 deficiency from other forms of HIES and CIDs, study the mutational spectrum of DOCK8 deficiency, and report on the frequency of specific clinical findings., Methods: Eighty-two patients from 60 families with CID and the phenotype of AR-HIES with (64 patients) and without (18 patients) DOCK8 mutations were studied. Support vector machines were used to compare clinical data from 35 patients with DOCK8 deficiency with those from 10 patients with AR-HIES without a DOCK8 mutation and 64 patients with signal transducer and activator of transcription 3 (STAT3) mutations., Results: DOCK8-deficient patients had median IgE levels of 5201 IU, high eosinophil levels of usually at least 800/μL (92% of patients), and low IgM levels (62%). About 20% of patients were lymphopenic, mainly because of low CD4(+) and CD8(+) T-cell counts. Fewer than half of the patients tested produced normal specific antibody responses to recall antigens. Bacterial (84%), viral (78%), and fungal (70%) infections were frequently observed. Skin abscesses (60%) and allergies (73%) were common clinical problems. In contrast to STAT3 deficiency, there were few pneumatoceles, bone fractures, and teething problems. Mortality was high (34%). A combination of 5 clinical features was helpful in distinguishing patients with DOCK8 mutations from those with STAT3 mutations., Conclusions: DOCK8 deficiency is likely in patients with severe viral infections, allergies, and/or low IgM levels who have a diagnosis of HIES plus hypereosinophilia and upper respiratory tract infections in the absence of parenchymal lung abnormalities, retained primary teeth, and minimal trauma fractures., (Copyright © 2015 American Academy of Allergy, Asthma & Immunology. All rights reserved.)

Germline loss-of-function mutations in the transcription factor signal transducer and activator of transcription 3 (STAT3) cause immunodeficiency, whereas somatic gain-of-function mutations in STAT3 are associated with large granular lymphocytic leukemic, myelodysplastic syndrome, and aplastic anemia. Recently, germline mutations in STAT3 have also been associated with autoimmune disease. Here, we report on 13 individuals from 10 families with lymphoproliferation and early-onset solid-organ autoimmunity associated with 9 different germline heterozygous mutations in STAT3. Patients exhibited a variety of clinical features, with most having lymphadenopathy, autoimmune cytopenias, multiorgan autoimmunity (lung, gastrointestinal, hepatic, and/or endocrine dysfunction), infections, and short stature. Functional analyses demonstrate that these mutations confer a gain-of-function in STAT3 leading to secondary defects in STAT5 and STAT1 phosphorylation and the regulatory T-cell compartment. Treatment targeting a cytokine pathway that signals through STAT3 led to clinical improvement in 1 patient, suggesting a potential therapeutic option for such patients. These results suggest that there is a broad range of autoimmunity caused by germline STAT3 gain-of-function mutations, and that hematologic autoimmunity is a major component of this newly described disorder. Some patients for this study were enrolled in a trial registered at www.clinicaltrials.gov as #NCT00001350.

Proteasomes and lysosomes constitute the major cellular systems that catabolize proteins to recycle free amino acids for energy and new protein synthesis. Tripeptidyl peptidase II (TPPII) is a large cytosolic proteolytic complex that functions in tandem with the proteasome-ubiquitin protein degradation pathway. We found that autosomal recessive TPP2 mutations cause recurrent infections, autoimmunity, and neurodevelopmental delay in humans. We show that a major function of TPPII in mammalian cells is to maintain amino acid levels and that TPPII-deficient cells compensate by increasing lysosome number and proteolytic activity. However, the overabundant lysosomes derange cellular metabolism by consuming the key glycolytic enzyme hexokinase-2 through chaperone-mediated autophagy. This reduces glycolysis and impairs the production of effector cytokines, including IFN-γ and IL-1β. Thus, TPPII controls the balance between intracellular amino acid availability, lysosome number, and glycolysis, which is vital for adaptive and innate immunity and neurodevelopmental health., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The Primary Immune Deficiency Treatment Consortium (PIDTC) is a network of 33 centers in North America that study the treatment of rare and severe primary immunodeficiency diseases. Current protocols address the natural history of patients treated for severe combined immunodeficiency (SCID), Wiskott-Aldrich syndrome, and chronic granulomatous disease through retrospective, prospective, and cross-sectional studies. The PIDTC additionally seeks to encourage training of junior investigators, establish partnerships with European and other International colleagues, work with patient advocacy groups to promote community awareness, and conduct pilot demonstration projects. Future goals include the conduct of prospective treatment studies to determine optimal therapies for primary immunodeficiency diseases. To date, the PIDTC has funded 2 pilot projects: newborn screening for SCID in Navajo Native Americans and B-cell reconstitution in patients with SCID after hematopoietic stem cell transplantation. Ten junior investigators have received grant awards. The PIDTC Annual Scientific Workshop has brought together consortium members, outside speakers, patient advocacy groups, and young investigators and trainees to report progress of the protocols and discuss common interests and goals, including new scientific developments and future directions of clinical research. Here we report the progress of the PIDTC to date, highlights of the first 2 PIDTC workshops, and consideration of future consortium objectives., (Published by Mosby, Inc.)

Cord blood transplantation (CBT) is curative for many primary immunodeficiencies (PIDs) but is associated with risks of viral infection and graft-versus-host disease (GvHD). Serotherapy reduces GvHD but potentially increases the risk of viral infection by delaying immune reconstitution. Because many PID patients have pre-existing viral infections, the optimal dose of serotherapy is unclear. We performed a retrospective analysis in 34 consecutive PID patients undergoing CBT and compared immune reconstitution, viral infection, GvHD, mortality, and long-term immune function between high-dose (n = 11) and low-dose (n = 9) serotherapy. Serotherapy dose had no effect on neutrophil engraftment. Median CD3(+) engraftment occurred at 92.5 and 97 days for high- and low-dose serotherapy, respectively. The low-dose serotherapy group had higher CD3(+), CD4(+), and early thymic emigrant counts at 4 months compared with the high-dose group. GvHD severity and number of viral infections did not differ between serotherapy doses. Survival from the transplantation process was 90.9% for high-dose and 100% for low-dose groups. In conclusion, low-dose serotherapy enhanced T cell reconstitution and thymopoiesis during the first year after CBT with no increase in GvHD., (Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Genetic mutations cause primary immunodeficiencies (PIDs) that predispose to infections. Here, we describe activated PI3K-δ syndrome (APDS), a PID associated with a dominant gain-of-function mutation in which lysine replaced glutamic acid at residue 1021 (E1021K) in the p110δ protein, the catalytic subunit of phosphoinositide 3-kinase δ (PI3Kδ), encoded by the PIK3CD gene. We found E1021K in 17 patients from seven unrelated families, but not among 3346 healthy subjects. APDS was characterized by recurrent respiratory infections, progressive airway damage, lymphopenia, increased circulating transitional B cells, increased immunoglobulin M, and reduced immunoglobulin G2 levels in serum and impaired vaccine responses. The E1021K mutation enhanced membrane association and kinase activity of p110δ. Patient-derived lymphocytes had increased levels of phosphatidylinositol 3,4,5-trisphosphate and phosphorylated AKT protein and were prone to activation-induced cell death. Selective p110δ inhibitors IC87114 and GS-1101 reduced the activity of the mutant enzyme in vitro, which suggested a therapeutic approach for patients with APDS.

Background: Chronic granulomatous disease (CGD) is a primary immunodeficiency characterized by serious infections and inflammation. It can be managed conservatively with prophylactic antimicrobial agents or curatively with hematopoietic stem cell transplantation (HSCT). In the United Kingdom and Ireland there are cohorts of children managed both conservatively and curatively., Objectives: This study aimed to compare clinical outcomes (mortality and morbidity) in children managed conservatively and curatively., Methods: Children were identified from specialist centers and advertising through special interest groups. Clinical data were collected from medical records regarding infections, inflammatory complications and growth, other admissions, and curative treatment. Comparisons were made for patients not undergoing HSCT and patients after HSCT., Results: Seventy-three living children were identified, 59 (80%) of whom were recruited. Five deceased children were also identified. Clinical information was available for 62 children (4 deceased). Thirty (48%) children had undergone HSCT. Children who did not undergo transplantation had 0.71 episodes of infection/admission/surgery per CGD life year (95% CI, 0.69-0.75 events per year). Post-HSCT children had 0.15 episodes of infection/admission/surgery per transplant year (95% CI, 0.09-0.21 events per year). The mean z score for height and body mass index (BMI) for age was significantly better in post-HSCT children. Survival in the non-HSCT group was 90% at age 15 years. Survival in the post-HSCT group was 90%., Conclusions: Children with CGD not undergoing transplantation have more serious infections, episodes of surgery, and admissions compared with post-HSCT children. Children undergoing transplantation have better height for age. Survival is good at the end of the pediatric age range and also after HSCT., (Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Chronic granulomatous disease (CGD) is a primary immunodeficiency managed conservatively or with hematopoietic stem cell transplant. Studies have shown people with CGD and those transplanted for primary immunodeficiencies have lower than average cognitive ability. In this study, IQ in children with CGD and those transplanted for it was within the normal range., (Georg Thieme Verlag KG Stuttgart · New York.)

Severe infectious disease in children may be a manifestation of primary immunodeficiency. These genetic disorders represent important experiments of nature with the capacity to elucidate nonredundant mechanisms of human immunity. We hypothesized that a primary defect of innate antiviral immunity was responsible for unusually severe viral illness in two siblings; the proband developed disseminated vaccine strain measles following routine immunization, whereas an infant brother died after a 2-d febrile illness from an unknown viral infection. Patient fibroblasts were indeed abnormally permissive for viral replication in vitro, associated with profound failure of type I IFN signaling and absence of STAT2 protein. Sequencing of genomic DNA and RNA revealed a homozygous mutation in intron 4 of STAT2 that prevented correct splicing in patient cells. Subsequently, other family members were identified with the same genetic lesion. Despite documented infection by known viral pathogens, some of which have been more severe than normal, surviving STAT2-deficient individuals have remained generally healthy, with no obvious defects in their adaptive immunity or developmental abnormalities. These findings imply that type I IFN signaling [through interferon-stimulated gene factor 3 (ISGF3)] is surprisingly not essential for host defense against the majority of common childhood viral infections.

Purpose: Chronic Granulomatous Disease (CGD) is a rare primary immunodeficiency that predisposes to life-threatening infections and inflammation. Haematopoietic stem cell transplant (HSCT) can cure CGD. Chronic illness reduces quality of life. Children with haematological malignancies report improved quality of life post-HSCT. There are no data for children with CGD. This study evaluated quality of life and emotional well-being in CGD children treated conventionally or transplanted., Methods: Parents and children completed the Pediatric Quality of Life Inventory v4.0 (PedsQL) and Strengths and Difficulties Questionnaires (SDQ). Mean scores were compared with published UK norms. Comparisons were made for those that had or had not undergone HSCT., Results: Forty-seven parents completed PedsQL (children aged 3-15). Twenty-one were post-HSCT. Forty-two completed SDQ (children aged 3-15). Nineteen post-HSCT. Median age for non-HSCT group 9 years. Median age for post-HSCT group 10 years. The HSCT group were median 3 years post-HSCT (range 1-9 years). HSCT survival was 90 %-two died without completing questionnaires Parent and self-reported quality of life for non-transplanted children was significantly lower than healthy children. Parents reported increased emotional difficulties compared to published norms. PedsQL and SDQ scores for transplanted children were not significantly different from healthy norms., Conclusions: This study demonstrates the quality of life is reduced in CGD. Transplanted patients have quality of life comparable to levels reported in healthy children. This data will help inform families and clinicians when deciding about treatment and may have relevance for other immunodeficiencies treated with transplant.

Purpose of Review: It is 20 years since the 10 Warning Signs of primary immunodeficiency (PID) were first published and with over 180 PIDs now identified it is timely to evaluate their effectiveness, given the broadening clinical spectrum of PID., Recent Findings: Two recent studies have sought to define the features that best identify patients with PID and compare these with the 10 Warning Signs. They suggest the 10 Warning Signs discriminate poorly between those with and without PID, and that other features identify about one-third of patients with PID in whom none of the 10 Warning Signs was present. Recent literature describes the diverse presenting features that may assist in more accurately identifying those with PID., Summary: Further development and refinement of early warning signs in light of the growing knowledge of how PIDs manifest clinically may allow relatively simple yet effective guidelines targeted at different groups to better detect PID.

Haematopoietic SCT (HSCT) is curative for many children with primary immunodeficiencies or other non-malignant conditions. Outcome for those admitted to intensive care following HSCT for oncology diagnoses has historically been very poor. There is no literature available specifically regarding the outcome for children with primary immunodeficiency requiring intensive care following HSCT. We reviewed our post-HSCT admission to intensive care over a 5-year period. A total of 111 children underwent HSCT. Median age at transplant was 1 year 4 months. The most common diagnosis was SCID. In all, 35% had at least one intensive care admission and 44% survived to be discharged from intensive care. Also, 73% of admission episodes requiring invasive ventilation but no inotropes or renal replacement therapy resulted in survival to discharge. Children undergoing HSCT for immunological diagnoses had a high rate of admission to intensive care. No factors were identified that could predict the need for admission. Invasive ventilation alone has a much better outcome than that in historical series. However, the need for multi-organ system support was still associated with a poor outcome. This information is useful when counselling families of children that have deteriorated and been admitted to intensive care during the HSCT procedure.

Hematopoietic stem cell transplantation (HSCT) is now highly successfully curing a widening range of primary immunodeficiencies (PIDs). Better tissue typing, matching of donors, less toxic chemotherapy, better virus detection and treatment, improved supportive care, and graft-versus-host disease prophylaxis mean up to a 90% cure for severe combined immunodeficiency patients and a 70-80% cure for other PIDs given a matched unrelated donor, and rising to 95% for young patients with specific PIDs, such as Wiskott-Aldrich syndrome. Precise molecular diagnosis, detailed data on prognosis, and careful pre-HSCT assessment of infective lung and liver damage will ensure an informed benefit analysis of HSCT and the best outcome. It is now recognized that the best treatment option for chronic granulomatous disease is HSCT, which can also be curative for CD40 ligand deficiency and complex immune dysregulation disorders., (© 2011 New York Academy of Sciences.)

In this retrospective collaborative study, we have analyzed long-term outcome and donor cell engraftment in 194 patients with Wiskott-Aldrich syndrome (WAS) who have been treated by hematopoietic cell transplantation (HCT) in the period 1980- 2009. Overall survival was 84.0% and was even higher (89.1% 5-year survival) for those who received HCT since the year 2000, reflecting recent improvement of outcome after transplantation from mismatched family donors and for patients who received HCT from an unrelated donor at older than 5 years. Patients who went to transplantation in better clinical conditions had a lower rate of post-HCT complications. Retrospective analysis of lineage-specific donor cell engraftment showed that stable full donor chimerism was attained by 72.3% of the patients who survived for at least 1 year after HCT. Mixed chimerism was associated with an increased risk of incomplete reconstitution of lymphocyte count and post-HCT autoimmunity, and myeloid donor cell chimerism < 50% was associated with persistent thrombocytopenia. These observations indicate continuous improvement of outcome after HCT for WAS and may have important implications for the development of novel protocols aiming to obtain full correction of the disease and reduce post-HCT complications.

Background: The 10 warning signs of primary immunodeficiency diseases (PID) have been promoted by various organizations in Europe and the United States to predict PID. However, the ability of these warning signs to identify children with PID has not been rigorously tested., Objective: The main goal of this study was to determine the effectiveness of these 10 warning signs in predicting defined PID among children who presented to 2 tertiary pediatric immunodeficiency centers in the north of England., Methods: A retrospective survey of 563 children who presented to 2 pediatric immunodeficiency centers was undertaken. The clinical records of 430 patients with a defined PID and 133 patients for whom detailed investigations failed to establish a specific PID were reviewed., Results: Overall, 96% of the children with PID were referred by hospital clinicians. The strongest identifiers of PID were a family history of immunodeficiency disease in addition to use of intravenous antibiotics for sepsis in children with neutrophil PID and failure to thrive in children with T-lymphocyte PID. With these 3 signs, 96% of patients with neutrophil and complement deficiencies and 89% of children with T-lymphocyte immunodeficiencies could be identified correctly. Family history was the only warning sign that identified children with B-lymphocyte PID., Conclusions: PID awareness initiatives should be targeted at hospital pediatricians and families with a history of PID rather than the general public. Our results provide the general pediatrician with a simple refinement of 10 warning signs for identifying children with underlying immunodeficiency diseases.

Background: Accumulating evidence implicates T(H)17 cytokines in protection against Candida species infections, but the clinical relevance is not clear. Chronic mucocutaneous candidiasis (CMC) is a heterogeneous syndrome with the unifying feature of selective susceptibility to chronic candidiasis. Different subgroups with distinct clinical features are recognized, including autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), CMC with hypothyroidism, and isolated CMC. Understanding immune defects in patients with CMC will define cellular and molecular mechanisms crucial for protection against Candida species in human subjects., Objectives: We sought to determine whether impaired T(H)17 responses underlie susceptibility to Candida species infections and whether the same defect is present in different CMC subgroups., Methods: We assessed T(H)17 responses of PBMCs to Candida and non-Candida species stimuli by measuring IL-17, IL-22, IL-21, IL-6, IL-23, and IFN-γ cytokine production using cytokine arrays and intracellular cytokine-producing cell numbers and proliferation with flow cytometry. PBMCs from healthy subjects and unaffected family members served as controls., Results: In patients with CMC with hypothyroidism, T(H)17 cells demonstrated decreased proliferation and IL-17 production in response to Candida species. In contrast, in patients with APECED, T(H)17 cell proliferation and IL-17 production were normal unless exposed to APECED plasma, which inhibited both functions in both APECED and normal PBMCs. Candida species-stimulated IL-22 production was impaired in all patients with CMC, whereas IL-6 and IL-23 responses were unaltered., Conclusion: An impaired T(H)17 response to Candida species, although mediated by different mechanisms, was present in all CMC subgroups studied and might be a common factor predisposing to chronic candidiasis., (Copyright © 2010 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Background: Hematopoietic stem cell transplantation remains the only treatment for most patients with severe combined immunodeficiencies (SCIDs) or other primary immunodeficiencies (non-SCID PIDs)., Objective: To analyze the long-term outcome of patients with SCID and non-SCID PID from European centers treated between 1968 and 2005., Methods: The product-limit method estimated cumulative survival; the log-rank test compared survival between groups. A Cox proportional-hazard model evaluated the impact of independent predictors on patient survival., Results: In patients with SCID, survival with genoidentical donors (n = 25) from 2000 to 2005 was 90%. Survival using a mismatched relative (n = 96) has improved (66%), similar to that using an unrelated donor (n = 46; 69%; P = .005). Transplantation after year 1995, a younger age, B(+) phenotype, genoidentical and phenoidentical donors, absence of respiratory impairment, or viral infection before transplantation were associated with better prognosis on multivariate analysis. For non-SCID PID, in contrast with patients with SCID, we confirm that, in the 2000 to 2005 period, using an unrelated donor (n = 124) gave a 3-year survival rate similar to a genoidentical donor (n = 73), 79% for both. Survival was 76% in phenoidentical transplants (n = 23) and worse in mismatched related donor transplants (n = 47; 46%; P = .016)., Conclusion: This is the largest cohort study of such patients with the longest follow-up. Specific issues arise for different patient groups. Patients with B-SCID have worse survival than other patients with SCID, despite improvements in each group. For non-SCID PID, survival is worse than SCID, although more conditions are now treated. Individual disease categories now need to be analyzed so that disease-specific prognosis may be better understood and the best treatments planned., (Copyright (c) 2010 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Cartilage-hair hypoplasia (CHH) is a rare autosomal recessive disease caused by mutations in the RMRP gene. Beside dwarfism, CHH has a wide spectrum of clinical manifestations including variable grades of combined immunodeficiency, autoimmune complications, and malignancies. Previous reports in single CHH patients with significant immunodeficiencies have demonstrated that allogeneic hematopoietic stem cell transplantation (HSCT) is an effective treatment for the severe immunodeficiency, while growth failure remains unaffected. Because long-term experience in larger cohorts of CHH patients after HSCT is currently unreported, we performed a European collaborative survey reporting on 16 patients with CHH and immunodeficiency who underwent HSCT. Immune dysregulation, lymphoid malignancy, and autoimmunity were important features in this cohort. Thirteen patients were transplanted in early childhood ( approximately 2.5 years). The other 3 patients were transplanted at adolescent age. Of 16 patients, 10 (62.5%) were long-term survivors, with a median follow-up of 7 years. T-lymphocyte numbers and function have normalized, and autoimmunity has resolved in all survivors. HSCT should be considered in CHH patients with severe immunodeficiency/autoimmunity, before the development of severe infections, major organ damage, or malignancy might jeopardize the outcome of HSCT and the quality of life in these patients.

T cell disorders have been poorly understood until recently. Lack of knowledge of underlying molecular mechanisms together with incomplete data on long term outcome have made it difficult to assess prognosis and give the most effective treatment. Rapid progress in defining molecular defects, improved supportive care and much improved results from hematopoietic stem cell transplantation (HSCT) now mean that curative treatment is possible for many patients. However, this depends on prompt recognition, accurate diagnosis and careful treatment planning.This review will discuss recent progress in our clinical and molecular understanding of a variety of disorders including: severe combined immunodeficiency, specific T cell immunodeficiencies, signaling defects, DNA repair defects, immune-osseous dysplasias, thymic disorders and abnormalities of apoptosis.There is still much to discover in this area and some conditions which are as yet very poorly understood. However, with increased knowledge about how these disorders can present and the particular problems each group may face it is hoped that these patients can be recognized early and managed appropriately, so providing them with the best possible outcome.

Most patients with autoimmune polyendocrine syndrome type I (APS-I) display chronic mucocutaneous candidiasis (CMC). We hypothesized that this CMC might result from autoimmunity to interleukin (IL)-17 cytokines. We found high titers of autoantibodies (auto-Abs) against IL-17A, IL-17F, and/or IL-22 in the sera of all 33 patients tested, as detected by multiplex particle-based flow cytometry. The auto-Abs against IL-17A, IL-17F, and IL-22 were specific in the five patients tested, as shown by Western blotting. The auto-Abs against IL-17A were neutralizing in the only patient tested, as shown by bioassays of IL-17A activity. None of the 37 healthy controls and none of the 103 patients with other autoimmune disorders tested had such auto-Abs. None of the patients with APS-I had auto-Abs against cytokines previously shown to cause other well-defined clinical syndromes in other patients (IL-6, interferon [IFN]-gamma, or granulocyte/macrophage colony-stimulating factor) or against other cytokines (IL-1beta, IL-10, IL-12, IL-18, IL-21, IL-23, IL-26, IFN-beta, tumor necrosis factor [alpha], or transforming growth factor beta). These findings suggest that auto-Abs against IL-17A, IL-17F, and IL-22 may cause CMC in patients with APS-I.

Background: The hyper-IgE syndrome (HIES) is a primary immunodeficiency characterized by infections of the lung and skin, elevated serum IgE, and involvement of the soft and bony tissues. Recently, HIES has been associated with heterozygous dominant-negative mutations in the signal transducer and activator of transcription 3 (STAT3) and severe reductions of T(H)17 cells., Objective: To determine whether there is a correlation between the genotype and the phenotype of patients with HIES and to establish diagnostic criteria to distinguish between STAT3 mutated and STAT3 wild-type patients., Methods: We collected clinical data, determined T(H)17 cell numbers, and sequenced STAT3 in 100 patients with a strong clinical suspicion of HIES and serum IgE >1000 IU/mL. We explored diagnostic criteria by using a machine-learning approach to identify which features best predict a STAT3 mutation., Results: In 64 patients, we identified 31 different STAT3 mutations, 18 of which were novel. These included mutations at splice sites and outside the previously implicated DNA-binding and Src homology 2 domains. A combination of 5 clinical features predicted STAT3 mutations with 85% accuracy. T(H)17 cells were profoundly reduced in patients harboring STAT3 mutations, whereas 10 of 13 patients without mutations had low (<1%) T(H)17 cells but were distinct by markedly reduced IFN-gamma-producing CD4(+)T cells., Conclusion: We propose the following diagnostic guidelines for STAT3-deficient HIES. Possible: IgE >1000IU/mL plus a weighted score of clinical features >30 based on recurrent pneumonia, newborn rash, pathologic bone fractures, characteristic face, and high palate. Probable: These characteristics plus lack of T(H)17 cells or a family history for definitive HIES. Definitive: These characteristics plus a dominant-negative heterozygous mutation in STAT3., (Copyright 2010 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Unlabelled: As part of collaborative multi-centre study started in 2000, 7 children in the UK fulfilled the inclusion criteria for treatment with autologous T cell depleted (TCD) haematopoietic stem cell transplantation (HSCT) for severe juvenile idiopathic arthritis (JIA). Here we report on the outcome and transplant-related complications., Outcome: The initial, often dramatic clinical response in all patients was followed in 4 with sustained benefit, including the withdrawal of immunosuppressive and anti-inflammatory treatment, significant catch-up growth and immense improvement of the quality of life during 5-8 years long follow-up. Two patients relapsed within 1-12 months, and one died 4 months post transplant., Complications: Adenovirus reactivation with dissemination was lethal in one patient, whilst Epstein-Barr (EBV) and cytomegalovirus (CMV) reactivation-driven haemophagocytic syndrome responded to antiviral and immunomodulatory treatment in 2 patients. Both the conditioning and the T cell depletion of the graft, leading to severe immunosuppression and prolonged immune system function reconstitution, are the main predisposing factors for potentially life-threatening transplant-related complications., Conclusions: Autologous TCD HSCT for children with severe JIA results in two-phase response. The initial remission seen in all patients is due to immunosuppressive conditioning. This is followed by sustained drug-free remission in over 50% of patients, which is due to 'immunomodulatory' effects of TCD HSCT. The procedure carries a significant morbidity and mortality risk. However, this risk should be balanced against the risks of life-threatening infections occurring in this very selective group of patients on long-term and combined immunosuppressive and anti-inflammatory therapies. How to correctly identify and appropriately assess the patients in need for autologous TCD HSCT, particularly in relation to optimizing the timing for the procedure in regards to the newly available therapies with different biologic response modifiers, are some of the most important questions awaiting answers from this on-going study.

Chronic granulomatous disease (CGD) causes recurrent infection and inflammatory disease. Despite antimicrobial prophylaxis, patients experience frequent hospitalisations and 50% mortality by 30 years. Haematopoietic stem cell transplantation (HSCT) can cure CGD with resolution of infection and colitis. This study reports the survival and long-term outcome in 20 conditioned patients treated between 1998 and 2007, using 10 matched sibling (MSD) and 10 unrelated donors (URD). Age at HSCT, graft-versus-host disease (GvHD), growth, and outcome were analysed. Fourteen had > or = 1 invasive infection, 10 had colitis and seven had growth failure before HSCT. Median age at transplantation was 75 months (range 15 months-21 years). Eighteen (90%) were alive 4-117 months (median 61) after HSCT with normal neutrophil function. Two died from disseminated fungal infection. Two experienced significant chronic GvHD, with continuing sequelae in 1. Colitis resolved within 8 weeks of HSCT. Mean weight and height for age Z scores on recovery from HSCT rose significantly (P < 0.001). HSCT with MSD or URD gave excellent engraftment and survival, remission of colitis and catch-up growth, with low incidence of significant GvHD. Transplant-associated complications were restricted to those with pre-existing infection or inflammation, supporting the argument for early HSCT for more CGD patients with a well matched donor.

Patients with chronic mucocutaneous candidiasis (CMC) have an unknown primary immune defect and are unable to clear infections with the yeast Candida. CMC includes patients with AIRE gene mutations who have autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), and patients without known mutations. CMC patients have dysregulated cytokine production, suggesting that defective expression of pattern recognition receptors (PRRs) may underlie disease pathogenesis. In 29 patients with CMC (13 with APECED) and controls, we assessed dendritic cell (DC) subsets and monocyte Toll-like receptor (TLR) expression in blood. We generated and stimulated monocyte-derived (mo)DCs with Candida albicans, TLR-2/6 ligand and lipopolysaccharide and assessed PRR mRNA expression by polymerase chain reaction [TLR-1-10, Dectin-1 and -2, spleen tyrosine kinase (Syk) and caspase recruitment domain (CARD) 9] in immature and mature moDCs. We demonstrate for the first time that CMC patients, with or without APECED, have normal blood levels of plasmocytoid and myeloid DCs and monocyte TLR-2/TLR-6 expression. We showed that in immature moDCs, expression levels of all PRRs involved in anti-Candida responses (TLR-1, -2, -4, -6, Dectin-1, Syk, CARD9) were comparable to controls, implying that defects in PRR expression are not responsible for the increased susceptibility to Candida infections seen in CMC patients. However, as opposed to healthy controls, both groups of CMC patients failed to down-regulate PRR mRNA expression in response to Candida, consistent with defective DC maturation, as we reported recently. Thus, impaired DC maturation and consequent altered regulation of PRR signalling pathways rather than defects in PRR expression may be responsible for inadequate Candida handling in CMC patients.

Patients with chronic mucocutaneous candidiasis (CMC) suffer persistent infections with the yeast Candida. CMC includes patients with autoimmune regulator (AIRE) gene mutations who have autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), and patients without known mutations. CMC patients have dysregulated cytokine production, and dendritic cells (DCs), as central orchestrators, may underlie pathogenic disease mechanisms. In 29 patients with CMC (13 with APECED) and controls, we generated monocyte-derived DCs, stimulated them with Candida albicans, Toll-like receptor-2/6 ligand and lipopolysaccharide to assess cytokine production [interleukin (IL)-12p70, IL-23, interferon (IFN)-gamma, IL-2, tumour necrosis factor (TNF)-alpha, IL-6, transforming growth factor-beta, IL-10, IL-5, IL-13] and cell-surface maturation marker expression (CD83, CD86, human leucocyte antigen D-related). In both APECED and non-APECED CMC patients, we demonstrate impairment of DC function as evidenced by altered cytokine expression profiles and DC maturation/activation: (1) both groups over-produce IL-2, IFN-gamma, TNF-alpha and IL-13 and demonstrate impaired DC maturation. (2) Only non-APECED patients showed markedly decreased Candida-stimulated production of IL-23 and markedly increased production of IL-6, suggesting impairment of the IL-6/IL-23/T helper type 17 axis. (3) In contrast, only APECED patients showed DC hyperactivation, which may underlie altered T cell responsiveness, autoimmunity and impaired response to Candida. We demonstrate different pathogenic mechanisms on the same immune response pathway underlying increased susceptibility to Candida infection in these patients.

Context: In autoimmune polyendocrinopathy syndrome type I (APS-I), mutations in the autoimmune regulator gene (AIRE) impair thymic self-tolerance induction in developing T cells. The ensuing autoimmunity particularly targets ectodermal and endocrine tissues, but chronic candidiasis usually comes first. We recently reported apparently APS-I-specific high-titer neutralizing autoantibodies against type I interferons in 100% of Finnish and Norwegian patients, mainly with two prevalent AIRE truncations., Objectives: Because variability in clinical features and age at onset in APS-I frequently results in unusual presentations, we prospectively checked the diagnostic potential of anti-interferon antibodies in additional APS-I panels with other truncations or rare missense mutations and in disease controls with chronic mucocutaneous candidiasis (CMC) but without either common AIRE mutation., Design: The study was designed to detect autoantibodies against interferon-alpha2 and interferon-omega in antiviral neutralization assays., Setting and Patients: Patients included 14 British/Irish, 15 Sardinian, and 10 Southern Italian AIRE-mutant patients with APS-I; also 19 other patients with CMC, including four families with cosegregating thyroid autoimmunity., Outcome: The diagnostic value of anti-interferon autoantibodies was assessed., Results: We found antibodies against interferon-alpha2 and/or interferon-omega in all 39 APS-I patients vs. zero of 48 unaffected relatives and zero of 19 British/Irish CMC patients. Especially against interferon-omega, titers were nearly always high, regardless of the exact APS-I phenotype/duration or AIRE genotype, including 12 different AIRE length variants or 10 point substitutions overall (n=174 total). Strikingly, in one family with few typical APS-I features, these antibodies cosegregated over three generations with autoimmune hypothyroidism plus a dominant-negative G228W AIRE substitution., Conclusions: Otherwise restricted to patients with thymoma and/or myasthenia gravis, these precocious persistent antibodies show 98% or higher sensitivity and APS-I specificity and are thus a simpler diagnostic option than detecting AIRE mutations.

The aims of this study were to examine the extent of gastroenteric virus contamination in a pediatric primary immunodeficiency (PPI) ward and a general pediatric ward over a winter season and to determine whether changes to hospital infection control interventions would have an impact on environmental contamination levels within pediatric units. Environmental swabs were collected weekly from 11 sites in both wards from 15 December 2005 to 3 March 2006 and examined for the presence of norovirus (NoV), astrovirus, and rotavirus (RV) by reverse transcriptase PCR. Viruses were detected in 17% and 19% of swabs from both wards. Virus contamination for NoV and RV decreased from 20% to 6% and 15% to 10% of swabs, respectively, in the PPI ward from the 2004 study by Gallimore et al. (C. I. Gallimore, C. Taylor, A. R. Gennery, A. J. Cant, A. Galloway, M. Iturriza-Gomara, and J. J. Gray, J. Clin. Microbiol. 44:395-399, 2006). Overall, changes to cleaning protocols were deemed to have reduced the level of environmental contamination with gastroenteric viruses, but contamination still occurred due to a breakdown in infection control procedures indicated by contamination in areas frequented by parents but used only occasionally by staff.

More than 11 genetic causes of severe combined immunodeficiency (SCID) have been identified, affecting development and/or function of T lymphocytes, and sometimes B lymphocytes and natural killer (NK) cells. Deletion of 22q11.2 is associated with immunodeficiency, although less than 1% of cases are associated with T-B + NK + SCID phenotype. Severe immunodeficiency with CHARGE syndrome has been noted only rarely Omenn syndrome is a rare autosomal recessive form of SCID with erythroderma, hepatosplenomegaly, lymphadenopathy and alopecia. Hypomorphic recombination activating genes 1 and 2 mutations were first described in patients with Omenn syndrome. More recently, defects in Artemis, RMRP, IL7Ralpha and common gamma chain genes have been described. We describe four patients with mutations in CHD7, who had clinical features of CHARGE syndrome and who had T-B + NK + SCID (two patients) or clinical features consistent with Omenn syndrome (two patients). Immunodeficiency in patients with DiGeorge syndrome is well recognized--CHARGE syndrome should now be added to the causes of T-B + NK + SCID, and mutations in the CHD7 gene may be associated with Omenn-like syndrome.

The molecular bases of most primary immunodeficiencies (PID) have been discovered. Long-term follow-up of patient cohorts treated with antimicrobial prophylaxis has demonstrated good short-term prognosis but with increasing morbidity and mortality over time. The results of hematopoietic stem cell transplantation (HSCT) for PID have improved incrementally over time, with survival and cure of 90% for some defined diseases. This article examines the advances in HSCT for PID and argues that HSCT should be considered earlier for most patients.

There are no epidemiological studies from the British Isles of chronic granulomatous disease, characterized by recurrent, life-threatening bacterial and fungal infections and inflammatory sequelae. Patients were enrolled in a national registry and medical records were analysed. Of 94 subjects, 69 had X-linked disease, 16 had autosomal recessive disease and nine were unknown. Prevalence was 7.5/million for 1990-99 and 8.5/million for 1980-89. Suppurative adenitis, abscesses and pneumonia presented commonly. Twenty-three of 30 patients who underwent high resolution computerized tomography had chronic respiratory disease. Inflammatory sequelae included bowel stricture and urogenital tract granulomata. Growth failure was common; 75% of those measured were below the population mean. All patients received prophylactic antibiotics and 93% anti-fungal prophylaxis. Interferon gamma was used to treat infection, but rarely as prophylaxis. Despite prophylaxis, estimated survival was 88% at 10 years but 55% at age 30 years. Morbidity remains significant, severe infectious complications common. Curative treatments including stem cell transplantation should be considered for patients with frequent or serious complications.

Objective: Assays based on interferon gamma (IFNgamma) are an exciting new development for screening for latent tuberculosis infection (LTBI) in adults, but there are limited data on their effectiveness in children. Nevertheless new National Institute for Health and Clinical Excellence (NICE) guidelines recommend their use when screening paediatric tuberculosis (TB) contacts. We evaluated the potential effect of the new NICE guidelines on current paediatric practice., Design: Children screened for TB who had had an IFNgamma assay performed (QuantiFERON-TB Gold (QFG)) were included. Actual outcomes from existing guidelines were compared with those that would have been obtained using NICE guidelines., Results: QFG assays were performed on 120 children, 103 as part of TB contact tracing. Six of the 120 (5%) were QFG positive, and seven of the 120 (6%) were indeterminate. Where both Mantoux and QFG results were available, these agreed in 62/104 (60%) of cases. QFG tests were more likely to correlate with a negative Mantoux (98% agreement) than with a positive Mantoux (11% agreement). Management outcomes differed for 23/103 children seen as part of TB contact tracing. Only one (1%) of these had an indeterminate QFG result. 17 (85%) fewer children would have been given LTBI treatment (chemoprophylaxis) and two (2%) children with possible TB would not have been identified using NICE guidelines., Conclusion: New NICE guidelines for the use of IFNgamma-based tests for TB screening will reduce the number of children treated for presumed LTBI. Long-term prospective studies are needed to determine the number of children with positive Mantoux tests but negative IFNgamma results who are not given LTBI treatment yet later develop TB.

Background: Immunodeficiency, centromeric instability and facial dysmorphism (ICF syndrome) is a rare autosomal recessive disease characterised by facial dysmorphism, immunoglobulin deficiency and branching of chromosomes 1, 9 and 16 after PHA stimulation of lymphocytes. Hypomethylation of DNA of a small fraction of the genome is an unusual feature of ICF patients which is explained by mutations in the DNA methyltransferase gene DNMT3B in some, but not all, ICF patients., Objective: To obtain a comprehensive description of the clinical features of this syndrome as well as genotype-phenotype correlations in ICF patients., Methods: Data on ICF patients were obtained by literature search and additional information by means of questionnaires to corresponding authors., Results and Conclusions: 45 patients all with proven centromeric instability were included in this study. Facial dysmorphism was found to be a common characteristic (n = 41/42), especially epicanthic folds, hypertelorism, flat nasal bridge and low set ears. Hypo- or agammaglobulinaemia was demonstrated in nearly all patients (n = 39/44). Opportunistic infections were seen in several patients, pointing to a T cell dysfunction. Haematological malignancy was documented in two patients. Life expectancy of ICF patients is poor, especially those with severe infections in infancy or chronic gastrointestinal problems and failure to thrive. Early diagnosis of ICF is important since early introduction of immunoglobulin supplementation can improve the course of the disease. Allogeneic stem cell transplantation should be considered as a therapeutic option in patients with severe infections or failure to thrive. Only 19 of 34 patients showed mutations in DNMT3B, suggesting genetic heterogeneity. No genotype-phenotype correlation was found between patients with and without DNMT3B mutations.

Background: Results of treatment of severe T-lymphocyte immunodeficiencies by means of hematopoietic stem cell (HSC) transplantation have improved. T cell-depleted haploidentical transplantations are successful if there is no HLA-identical donor. Methods to remove T lymphocytes include addition of anti-CD52 antibodies and CD34(+) HSC selection., Objective: Assessment of long-term immune function is important after these treatments. We looked at immune reconstitution in 36 survivors for more than 2 years after HSC transplantation for severe T-lymphocyte immunodeficiencies and compared engraftment quality between the 2 T-lymphocyte depletion methods., Methods: Chimerism, T- and B-lymphocyte subsets, immunoglobulin levels, and specific antibody production at last follow-up were examined. The chi(2) (Fisher exact test) and Wilcoxon rank sum analyses were used to compare the groups., Results: Nineteen patients received anti-CD52-treated and 19 anti-CD34-treated HSCs. More anti-CD52-treated patients had full donor myeloid chimerism (P = .025). All patients had full donor T-lymphocyte chimerism. There was no difference in donor B-lymphocyte chimerism, but significantly more anti-CD52-treated patients had class-switched memory B lymphocytes (P = .024), normal IgG levels, and normal responses to tetanus and Haemophilus influenzae type B vaccination. More anti-CD52-treated patients with common gamma chain or Janus-associated kinase 3 severe combined immunodeficiency had donor B lymphocytes., Conclusion: Long-term T-lymphocyte function is good with either treatment method, with a low incidence of graft-versus-host disease. The results imply more incomplete donor chimerism in anti-CD34-treated patients with less B-lymphocyte function.

Wiskott-Aldrich syndrome (WAS) is a rare X-linked immunodeficiency with microthrombocytopenia, eczema, recurrent infections, autoimmune disorders, and malignancies that are life-threatening in the majority of patients. In this long-term, retrospective, multicenter study, we analyzed events that occurred in 96 WAS patients who received transplants between 1979 and 2001 who survived at least 2 years following hematopoietic stem-cell transplantation (HSCT). Events included chronic graft-versus-host disease (cGVHD), autoimmunity, infections, and sequelae of before or after HSCT complications. Three patients (3%) died 2.1 to 21 years following HSCT. Overall 7-year event-free survival rate was 75%. It was lower in recipients of mismatched related donors, also in relation with an older age at HSCT and disease severity. The most striking finding was the observation of cGVHD-independent autoimmunity in 20% of patients strongly associated with a mixed/split chimerism status (P < .001), suggesting that residual-host lymphocytes can mediate autoimmune disease despite the coexistence of donor lymphocytes. Infectious complications (6%) related to splenectomy were also significant and may warrant a more restrictive approach to performing splenectomy in WAS patients. Overall, this study provides the basis for a prospective, standardized, and more in-depth detailed analysis of chimerism and events in long-term follow-up of WAS patients who receive transplants to design better-adapted therapeutic strategies.

Purpose of Review: Umbilical cord haematopoietic stem cell transplantation for primary immunodeficiencies is examined with other developments in treatment. Cord blood biology is reviewed, and advantages and disadvantages of umbilical cord blood stem cell transplantation for primary immunodeficiencies discussed. Clinical outcome data and future developments are reviewed., Recent Findings: Cord blood T lymphocytes become tolerant to host human leukocyte antigen antigens, but retain alloreactivity to other antigens, in part due to immaturity of cord blood T lymphocytes and dendritic cells. Although naïve T lymphocytes can generate herpes virus specificity after transplantation, the risk of viral death is increased within the first 100 days. The clinical success of umbilical cord blood stem cell transplantation for primary immunodeficiencies is reviewed and new methods for expanding the stem cell number or encouraging engraftment with the use of third-party haematopoietic or mesenchymal stem cells examined., Summary: Many advantages make umbilical cord blood an attractive source of stem cells; over 100 umbilical cord blood stem cell transplantations have been performed for primary immunodeficiencies, with low rates of significant graft vs. host disease, despite significant human leukocyte antigen mismatch. Immune reconstitution is as good as for other stem cell sources: use of nascent stem cells in young recipients may have long-term advantages. Stem cell engineering to improve engraftment will expand potential beneficiaries of umbilical cord blood stem cell transplantation to older patients.

A vaccine containing inactivated polio (eIPV) (Pediacel) is now used in the UK. The effect of the eIPV on other components is not well understood. We studied Haemophilus influenzae type b (Hib) and tetanus responses in preterm infants, <32 weeks gestation at birth, immunised with the (then) standard UK primary vaccines and either oral polio vaccine (OPV) or eIPV and analysed the effect showing reduced Hib responses with eIPV.

Pulmonary infection, often insidious, is frequent in primary immunodeficiency (PID) and acquired immunodeficiency. Pulmonary complications are serious obstacles to success of haematopoietic SCT (HSCT) for these conditions. Bronchoalveolar lavage (BAL) permits identification of lower respiratory tract pathogens that may direct specific treatment and influence prognosis. There are no reports about the utility of pre-HSCT BAL for immunodeficient patients. We prospectively studied the value of 'routine' BAL before commencing transplantation in patients undergoing HSCT for severe immunological disease. Routine non-bronchoscopic BAL was performed under general anaesthetic, a few days before commencing pre-HSCT cytoreductive chemotherapy. Patients were categorized as symptomatic or asymptomatic with respect to pulmonary disease or infection. Samples were sent for microbiological processing. Complications arising from the procedure, pathogens isolated and treatments instituted were recorded. Results were available from 69/75 patients transplanted during the study period; 26 (38%) had pathogens identified (six asymptomatic patients), 10 (14.5%) developed complications post-procedure (two asymptomatic patients)-all recovered, 21 had management changes. There was no statistically significant difference in the number of positive isolates from severe combined or other immunodeficient patients, or of symptomatic or asymptomatic patients. Routine non-bronchoscopic BAL is safe in immunodeficient patients about to undergo HSCT, and leads to management changes.