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Abstract Background There has been a marked increase in the number of Caesarean sections in many countries during the last decades. In several countries, Caesarean sections are carried out in more than 20 per cent of births. These high Caesarean section rates give cause for concern, both from an economic and a medical perspective. A general opinion among epidemiologists is that the increase in the number of Caesarean sections during the last decade has been greater than could be expected in relation to medical risk factors. Therefore, other explanations must be sought. We studied one potential explanation; the effect that the increase in hospital revenue per bed during the period 1976-2005 has had on the Caesarean section rate in Norway. During this period, hospital revenue increased by about 260% (adjusted for inflation). Methods The analyses were carried out using data from the Medical Birth Registry 1976-2005 from Norway. The data were merged with data about hospital revenue, which were obtained from Statistics Norway. The analyses were carried out using annual data from 46 hospitals. A fixed effect regression model was estimated. Relevant medical control variables were included. Results The elasticity of the Caesarean section rate with respect to hospital revenue per bed was 0.13 (p < 0.05). This represents an increase in the Caesarean section rate from the basis year 1976 to the final year 2005 of about 35 per cent. Most of the variables measuring characteristics of the health status of the mother and child had the expected effects. Conclusion The increase in hospital revenue explains only a small part of the increase in the Caesarean section rate in Norway during the last three decades. The increase in the Caesarean section rate is considerably greater than could be expected, based on the increase in hospital revenue alone. The strength of our study is that we have estimated a cause and effect relationship. This was done by using fixed effects for hospitals, a lagged revenue variable and by including an extensive set of control variables for the risk factors of the mother and the baby.

Surface expression of the common vertebrate sialic acid (Sia) N -acetylneuraminic acid (Neu5Ac) by commensal and pathogenic microbes appears structurally to represent "molecular mimicry" of host sialoglycans, facilitating multiple mechanisms of host immune evasion. In contrast, ketodeoxynonulosonic acid (Kdn) is a more ancestral Sia also present in prokaryotic glycoconjugates that are structurally quite distinct from vertebrate sialoglycans. We detected human antibodies against Kdn-terminated glycans, and sialoglycan microarray studies found these anti-Kdn antibodies to be directed against Kdn-sialoglycans structurally similar to those on human cell surface Neu5Ac-sialoglycans. Anti-Kdn-glycan antibodies appear during infancy in a pattern similar to those generated following incorporation of the nonhuman Sia N -glycolylneuraminic acid (Neu5Gc) onto the surface of nontypeable Haemophilus influenzae (NTHi), a human commensal and opportunistic pathogen. NTHi grown in the presence of free Kdn took up and incorporated the Sia into its lipooligosaccharide (LOS). Surface display of the Kdn within NTHi LOS blunted several virulence attributes of the pathogen, including Neu5Ac-mediated resistance to complement and whole blood killing, complement C3 deposition, IgM binding, and engagement of Siglec-9. Upper airway administration of Kdn reduced NTHi infection in human-like Cmah null (Neu5Gc-deficient) mice that express a Neu5Ac-rich sialome. We propose a mechanism for the induction of anti-Kdn antibodies in humans, suggesting that Kdn could be a natural and/or therapeutic "Trojan horse" that impairs colonization and virulence phenotypes of free Neu5Ac-assimilating human pathogens. IMPORTANCE All cells in vertebrates are coated with a dense array of glycans often capped with sugars called sialic acids. Sialic acids have many functions, including serving as a signal for recognition of "self" cells by the immune system, thereby guiding an appropriate immune response against foreign "nonself" and/or damaged cells. Several pathogenic bacteria have evolved mechanisms to cloak themselves with sialic acids and evade immune responses. Here we explore a type of sialic acid called "Kdn" (ketodeoxynonulosonic acid) that has not received much attention in the past and compare and contrast how it interacts with the immune system. Our results show potential for the use of Kdn as a natural intervention against pathogenic bacteria that take up and coat themselves with external sialic acid from the environment., (© Crown copyright 2021.)

BCG has been recommended because of its efficacy against disseminated and meningeal tuberculosis. The BCG vaccine has other mechanisms of action besides tuberculosis protection, with immunomodulatory properties that are now being discovered. Reports have shown a significant protective effect against leprosy. Randomized controlled trials suggest that BCG vaccine has beneficial heterologous (nonspecific) effects on mortality in some developing countries. BCG immunotherapy is considered the gold standard adjuvant treatment for non-muscle-invasive bladder cancer. BCG vaccine has also been tested as treatment for diabetes and multiple sclerosis. Erythema of the BCG site is recognized as a clinical clue in Kawasaki disease. BCG administration in the immunodeficient patient is associated with local BCG disease (BCGitis) or disseminated BCG disease (BCGosis) with fatal consequences. BCG administration has been associated with the development of autoimmunity. We present a brief review of the diverse facets of the vaccine, with the discovery of its new modes of action providing new perspectives on this old, multifaceted and controversial vaccine.

Bronchiectasis, the presence of bronchial wall thickening with airway dilatation, is a particularly challenging complication of primary antibody deficiencies. While susceptibility to infections may be the primary factor leading to the development of bronchiectasis in these patients, the condition may develop in the absence of known infections. Once bronchiectasis is present, the lungs are subject to a progressive cycle involving both infectious and non-infectious factors. If bronchiectasis is not identified or not managed appropriately, the cycle proceeds unchecked and yields advanced and permanent lung damage. Severe symptoms may limit exercise tolerance, require frequent hospitalizations, profoundly impair quality of life (QOL), and lead to early death. This review article focuses on the appropriate identification and management of bronchiectasis in patients with primary antibody deficiencies. The underlying immune deficiency and the bronchiectasis need to be treated from combined immunology and pulmonary perspectives, reflected in this review by experts from both fields. An aggressive multidisciplinary approach may reduce exacerbations and slow the progression of permanent lung damage., (Copyright © 2020 Wall, Wisner, Gipson and Sorensen.)

Specific antibody deficiency (SAD) is defined as the inability to mount an antibody response to purified Streptococcus pneumoniae capsular polysaccharide antigens in the presence of normal immunoglobulin concentrations and normal antibody responses to protein antigens. In this review, we discuss the difficulties in using presently available testing methods to adequately define SAD. The fact that there are different forms of SADs to pneumococcal surface polysaccharides is detailed. The diagnostic and therapeutic implications of recognizing that, in addition to SAD, there are other forms of SAD in the response to S. pneumoniae polysaccharides are described in detail. The conclusion of this review is that assessment of immunity and therapeutic actions to deal with SADs need to be based on clinical evidence rather than solely on arbitrarily defined antibody responses., (Copyright © 2019. Published by Elsevier Inc.)

Streptococcus pneumoniae (S. pneumoniae) strains colonize the nasopharynx and can cause mucosal infections in the upper airway and middle ear, pneumonias, and invasive infections like bacteremia, sepsis, and meningitis. Over 90 serotypes, defined by the structure of their capsular polysaccharides, are known. Twenty-three of these serotypes cause most infections and several of these serotypes can develop antibiotic resistance. Susceptibility factors that increase the susceptibility to S. pneumoniae mucosal and invasive infections include all forms of primary and secondary antibody deficiencies. Many patients affected by one of these deficiencies benefit from the regular administration of human gamma globulin (IgG) preparations. Donors of plasma units used to prepare human IgG have varying concentrations of IgG antibodies against relevant S. pneumoniae serotypes. These antibodies are developed in response to colonization and common subclinical infections and by routine vaccination with S. pneumoniae polysaccharide vaccines. The presence of an adequate concentration of these protective antibodies against all prevalent serotypes needs to be determined to assure the effectiveness of human IgG. All presently available methods to assess IgG antibodies against S. pneumoniae capsular polysaccharides have advantages and pitfalls that are analyzed in this review. In vitro testing does not provide a complete or necessarily accurate measurement of the effectiveness of antibodies in vivo. For regulatory purposes, caution needs to be used in the interpretation of currently available assays that measure pneumococcal antibody levels. Monitoring S. pneumoniae infections in patients treated with IgG and tracing information about IgG lots used to treat these patients should be encouraged., (© 2018 AABB.)

Background: Immunologists are increasingly being asked to assess patients with non-classical and secondary antibody deficiency to determine their potential need for immunoglobulin replacement therapy (IGRT). Immunoglobulin is a limited, expensive resource and no clear guidance exists for this broad patient group. The purpose of this survey is to establish what factors influence the decision to commence IGRT in adult patients, when diagnostic criteria for primary antibody deficiency are not fulfilled., Methods: Under the auspices of the United Kingdom Primary Immunodeficiency Network (UKPIN), a study group was established which circulated an online questionnaire to the consultant body across the UK and Ireland. Results provided a snapshot of the current clinical practice of 71% of consultant immunologists, from 30 centers., Results: In order of importance, factors which influence the decision to commence IGRT include number of hospital admissions with infection, serum IgG level, bronchiectasis, radiologically proven pneumonia, number of positive sputum cultures, number of antibiotic courses, and results of immunization studies. The commonest test vaccine used was Pneumovax 23 with measurement of serotype-specific responses at 4 weeks, with a threshold of 0.35 μg/ml in 2/3 of serotypes measured. Eighty-six percent of patients are treated with a trial of prophylactic antibiotics prior to consideration of IGRT. Efficacy of IGRT trial is assessed at between 6 and 12 months., Conclusions: There was consistency in clinical practice using a combination of clinical history, evidence of infections, and vaccination testing for diagnosis. However, there was some variation in the implementation of this practice, particularly in vaccine choice and assessment of response to vaccination.

The American Academy of Allergy, Asthma & Immunology (AAAAI) and the American College of Allergy, Asthma & Immunology (ACAAI) have jointly accepted responsibility for establishing the "Practice parameter for the diagnosis and management of primary immunodeficiency." This is a complete and comprehensive document at the current time. The medical environment is a changing environment, and not all recommendations will be appropriate for all patients. Because this document incorporated the efforts of many participants, no single individual, including those who served on the Joint Task Force, is authorized to provide an official AAAAI or ACAAI interpretation of these practice parameters. Any request for information about or an interpretation of these practice parameters by the AAAAI or ACAAI should be directed to the Executive Offices of the AAAAI, the ACAAI, and the Joint Council of Allergy, Asthma & Immunology. These parameters are not designed for use by pharmaceutical companies in drug promotion., (Published by Elsevier Inc.)

Patients with specific antibody deficiency (SAD) have a deficient immunologic response to polysaccharide antigens. Such patients experience sinopulmonary infections with increased frequency, duration, or severity compared with the general population. SAD is definitively diagnosed by immunologic challenge with a pure polysaccharide vaccine in patients 2 years old and older who have otherwise intact immunity, using the 23-valent pneumococcal polysaccharide vaccine as the current gold standard. Specific antibody deficiencies comprise multiple immunologic phenotypes. Treatment must be tailored based on the severity of symptoms. Most patients have a good prognosis. The deficiency may resolve over time, especially in children., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Intravenous immunoglobulin (IVIG) and subcutaneous immunoglobulin (SCIG) are effective in the treatment of patients with primary antibody deficiency disorders (PAD). The purpose of this study was to evaluate Streptococcus pneumoniae (Spn) antibody titres to 14 serotypes in patients receiving IVIG compared to SCIG and to correlate Spn antibody levels to clinical outcome. The doses of immunoglobulin (Ig)G/kg/month were similar in both IVIG and SCIG groups. In 11 patients treated with IVIG, Spn antibody titres were ≥ 1·3 μg/ml to 99·4 ± 2·1% of the 14 serotypes at peak IVIG but decreased to 66·9 ± 19·8% at trough IVIG. Loss of Spn titres ≥ 1·3 μg/ml was most frequent for Spn serotypes 1, 4, 9V and 23. This correlated with lower Spn antibody titres to these serotypes at peak IVIG compared to the other serotypes. In 13 patients treated with SCIG, Spn antibody titres were protective to 58·2 ± 23·3% of the serotypes 3-5 days after infusion, similar to trough IVIG. Similarly, the Spn serotypes with the least protective percentages were the same as the ones observed in trough IVIG. There were no annualized serious bacterial infections (aSBI) in either group. However, there were significantly decreased annualized other infections (aOI) in the SCIG group compared to the IVIG-treated group, 0·8 ± 0·7 versus 2·2 ± 1·2 infections/patient/year (P = 0·004). Breakthrough aOI did not correlate with protective or higher serum Spn antibody titres., (© 2015 British Society for Immunology.)

Primary immunodeficiencies (PID) are genetic diseases that affect the immune system and for the last 20 years, the Latin American Society for Immunodeficiencies (LASID) has been promoting initiatives in awareness, research, diagnosis, and treatment for the affected patients in Latin America. These initiatives have resulted in the development of programmes such as the LASID Registry (with 4900 patients registered as of January 2014), fellowships in basic and clinical research, PID summer schools, biannual meetings, and scientific reports, amongst others. These achievements highlight the critical role that LASID plays as a scientific organisation in promoting science, research and education in this field in Latin America. However, challenges remain in some of these areas and the Society must envision additional strategies to tackle them for the benefit of the patients. In June 2013, a group of experts in the field met to discuss the contributions of LASID to the initiatives of PID in Latin America, and this article summarises the current state and future perspectives of this society and its role in the advance of PIDs in Latin America., (Copyright © 2014 SEICAP. Published by Elsevier Espana. All rights reserved.)

Introduction: Clinical observations in patients with specific antibody deficiency treated for periods of time with IgG infusion have suggested that IgG may have a positive immunoregulatory effect on the production of specific antibodies against pneumococcal polysaccharides. We developed an in vitro model to test the effect of an IgIV preparation on the antibody production in response to a pneumococcal polysaccharide serotype and on the antibody and cytokine production in response to both a protein antigen and a pneumococcal polysaccharide antigen., Methods: We studied 37 consecutive patients referred to our clinics for evaluation of their recurrent respiratory infections. Subjects were divided into two groups: 22 patients without SAD and 15 patients with SAD. PBMCs were left unstimulated or were stimulated with tetanus toxoid or pneumococcal polysaccharide serotype 19, in the presence of human albumin or IgIV. IgG anti-Pn-19 antibody, IL-4 and IFN-γ concentrations in culture supernatants were determined by ELISA., Results: An increase in IgG anti-Pn-19 antibodies, associated with an increase in IFN-γ and a decrease in IL-4 production was observed in cultures stimulated with pneumococcal polysaccharide in the presence of IgIV when patients were analyzed together. The enhancing effect of IgIV was more significant for both IgG anti-Pn19 antibodies and IFN-γ in patients without SAD. In contrast, IgIV caused a significant decrease in IL-4 secretion in patients with SAD, which was associated with an increase in IgG anti-Pn19 antibodies in 3 of 7 of these patients., Conclusions: These results suggest that IgIV has some immunomodulatory effect on the in vitro production of IgG anti-Pn19 antibodies and cytokine production in cell cultures stimulated with Pn-19 antigen and that this modulation may be associated with a Th1/Th2 regulatory mechanism. Further studies at a cellular and molecular level are in progress to examine if the differences in the in vitro modulatory response to IgIV in these two groups of patients may point to a functional defect in patients with SAD.

Antibodies are an essential component of the adaptative immune response and hold long-term memory of the immunological experiences throughout life. Antibody defects represent approximately half of the well-known primary immunodeficiencies requiring immunoglobulin replacement therapy. In this article, the authors review the current indications and therapeutic protocols in the Latin American environment. Immunoglobulin replacement therapy has been a safe procedure that induces dramatic positive changes in the clinical outcome of patients who carry antibody defects., (Copyright © 2012 SEICAP. Published by Elsevier Espana. All rights reserved.)

Purpose: Patients with primary immunodeficiency diseases (PIDD) may present with recurrent infections affecting different organs, organ-specific inflammation/autoimmunity, and also increased cancer risk, particularly hematopoietic malignancies. The diversity of PIDD and the wide age range over which these clinical occurrences become apparent often make the identification of patients difficult for physicians other than immunologists. The aim of this report is to develop a tool for educative programs targeted to specialists and applied by clinical immunologists., Methods: Considering the data from national surveys and clinical reports of experiences with specific PIDD patients, an evidence-based list of symptoms, signs, and corresponding laboratory tests were elaborated to help physicians other than immunologists look for PIDD., Results: Tables including main clinical manifestations, restricted immunological evaluation, and possible related diagnosis were organized for general practitioners and 5 specialties. Tables include information on specific warning signs of PIDD for pulmonologists, gastroenterologists, dermatologists, hematologists, and infectious disease specialists., Conclusions: This report provides clinical immunologists with an instrument they can use to introduce specialists in other areas of medicine to the warning signs of PIDD and increase early diagnosis. Educational programs should be developed attending the needs of each specialty.

Objectives: To investigate the immunological phenotypes detected in children with recurrent upper and lower respiratory infections that have normal total immunoglobulin concentrations., Methods: A cohort of over 60 children with recurrent respiration infections was evaluated for specific antibody deficiencies (SAD) and for memory B-cell abnormalities. A control group of children without recurrent infections was also evaluated. Evaluation included a detailed history of immunizations with pneumococcal vaccines; determination of IgM, IgG, IgA, and IgE concentrations; measurement of anti-pneumococcal polysaccharide antibody levels by ELISA and expression of CD27, IgD, and IgM on peripheral CD19(+)B cells by flow cytometry to determine the proportions of naive, IgM-memory B cells, and class-switched memory B cells., Results: Patients were classified as having a SAD to either pure polysaccharides (PPV-SAD) or to conjugate polysaccharides (PCV-SAD) based on the number of polysaccharides to which they developed an adequate antibody response. A normal response to only 2 or fewer of 7 PCV or PPV serotypes was considered as evidence of SAD. Forty-one patients without SAD and 26 with SAD were identified. IgM-memory B cells were low in 3 of 41 patients without SAD; in 3 of 5 PPV-SAD patients; and in 10 of 21 PCV-SAD patients. Class-switched memory B cells were low in 19 of 41 patients without SAD; in all 5 patients with PPV-SAD; and in 11 of 21PCV-SAD patients., Conclusions: Patients with recurrent infection with or without SAD may have low IgM- and/or class-switched memory B cells. Ongoing research aims to determine the prognostic implications of these differences in patients with SAD.

A major diagnostic intervention in the consideration of many patients suspected to have primary immunodeficiency diseases (PIDDs) is the application and interpretation of vaccination. Specifically, the antibody response to antigenic challenge with vaccines can provide substantive insight into the status of human immune function. There are numerous vaccines that are commonly used in healthy individuals, as well as others that are available for specialized applications. Both can potentially be used to facilitate consideration of PIDD. However, the application of vaccines and interpretation of antibody responses in this context are complex. These rely on consideration of numerous existing specific studies, interpolation of data from healthy populations, current diagnostic guidelines, and expert subspecialist practice. This document represents an attempt of a working group of the American Academy of Allergy, Asthma & Immunology to provide further guidance and synthesis in this use of vaccination for diagnostic purposes in consideration of PIDD, as well as to identify key areas for further research., (Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)

Primary immunodeficiency diseases (PIDD) are associated with significant morbidity and mortality and result in a significant public health burden. This is in part due to the lack of appropriate diagnosis and treatment of these patients. It is critical that governments become aware of this problem and provide necessary resources to reduce this impact on health care systems. Leading physicians in their respective countries must be supported by their own governments in order to implement tools and provide education and thus improve the diagnosis and treatment of PIDD. The Latin American Society of Primary Immunodeficiencies (LASID) has initiated a large number of activities aimed at achieving these goals, including the establishment of a PIDD registry, development of educational programmes and guidelines, and the introduction of a PIDD fellowship programme. These initiatives are positively impacting the identification and appropriate treatment of patients with PIDD in Latin America. Nevertheless, much remains to be done to ensure that every person with PIDD receives proper therapy., (Copyright © 2011 SEICAP. Published by Elsevier Espana. All rights reserved.)

A large population of patients with recurring infections are undiagnosed or under diagnosed and Primary Immunodeficiency (PI) is more common than had been previously estimated. The results strongly indicate the measurable impact of Physician Education and Public Awareness in identifying patients with an underlying PI. The Jeffrey Modell Centers Network (JMCN) provides the infrastructure for referral, diagnosis and appropriate treatment. All disease classifications and identified defects increased significantly over the study period. Quality of Life for referred and diagnosed patients dramatically improved compared to undiagnosed patients. There is a substantial cost savings for diagnosed patients compared to undiagnosed, even if regular IgG is required. The SPIRIT(®) Software successfully identified patients with PI in a large database and at three pilot sites. The Software was successfully tested for specificity and sensitivity.

Early diagnosis and appropriate therapy are essential for the best prognosis and quality of life in patients with primary immunodeficiency diseases (PIDDs). Experts from several Latin American countries have been meeting on a regular basis as part of an ongoing effort to improve the diagnosis and treatment of PIDD in this region. Three programmes are in development that will expand education and training and improve access to testing facilities throughout Latin America. These programmes are: an educational outreach programme (The L-Project); an immunology fellowship programme; and the establishment of a laboratory network to expand access to testing facilities. This report provides the status of these programmes based on the most recent discussions and describes the next steps toward full implementation of these programmes., (Copyright © 2010 SEICAP. Published by Elsevier Espana. All rights reserved.)

Experts from six Latin American countries met to discuss critical issues and needs in the diagnosis and management of primary immunodeficiency diseases (PIDD). The diagnosis of PIDD is generally made following referral to an immunology centre located in a major city, but many paediatricians and general practitioners are not sufficiently trained to suspect PIDD in the first place. Access to laboratory testing is generally limited, and only some screening tests are typically covered by government health programmes. Specialised diagnostic tests are generally not reimbursed. Access to treatment varies by country reflecting differences in healthcare systems and reimbursement policies. An online PIDD Registry Programme for Latin America has been available since 2009, which will provide information about PIDD epidemiology in the region. Additional collaboration across countries appears feasible in at least two areas: a laboratory network to facilitate the diagnosis of PIDD, and educational programmes to improve PIDD awareness. In total, these collaborations should make it possible to advance the diagnosis and management of PIDD in Latin America., (Copyright © 2010 SEICAP. Published by Elsevier Espana. All rights reserved.)

The nonhuman sialic acid N-glycolylneuraminic acid (Neu5Gc) is metabolically incorporated into human tissues from certain mammalian-derived foods, and this occurs in the face of an anti-Neu5Gc "xeno-autoantibody" response. Given evidence that this process contributes to chronic inflammation in some diseases, it is important to understand when and how these antibodies are generated in humans. We show here that human anti-Neu5Gc antibodies appear during infancy and correlate with weaning and exposure to dietary Neu5Gc. However, dietary Neu5Gc alone cannot elicit anti-Neu5Gc antibodies in mice with a humanlike Neu5Gc deficiency. Other postnatally appearing anti-carbohydrate antibodies are likely induced by bacteria expressing these epitopes; however, no microbe is known to synthesize Neu5Gc. Here, we show that trace exogenous Neu5Gc can be incorporated into cell surface lipooligosaccharides (LOS) of nontypeable Haemophilus influenzae (NTHi), a human-specific commensal/pathogen. Indeed, infant anti-Neu5Gc antibodies appear coincident with antibodies against NTHi. Furthermore, NTHi that express Neu5Gc-containing LOS induce anti-Neu5Gc antibodies in Neu5Gc-deficient mice, without added adjuvant. Finally, Neu5Gc from baby food is taken up and expressed by NTHi. As the flora residing in the nasopharynx of infants can be in contact with ingested food, we propose a novel model for how NTHi and dietary Neu5Gc cooperate to generate anti-Neu5Gc antibodies in humans.

Defects causing severe combined immunodeficiency (SCID) have been reported in pathways mediating antigen receptor rearrangement, antigen receptor and cytokine signaling, and purine metabolism. Recognizing that the actin regulator Coronin-1A is essential for development of a normal peripheral T cell compartment in mouse models, we identified absence of Coronin-1A in a girl with T-B+NK+ SCID who suffered recurrent infections including severe post-vaccination varicella at age 13 months. Murine Coronin-1A is essential for the release of T cells from the thymus, consistent with the paradoxically detectable thymus in our patient. Molecular analysis revealed a 2 bp deletion in the paternal CORO1A coding sequence paired with a 600 kb de novo deletion encompassing CORO1A on the maternal allele. This genomic region at 16p11.2 is subject to recurrent copy number variations associated with autism spectrum disorders, including attention deficit and hyperactivity, present in our patient. This case highlights the first link between actin cytoskeleton regulation and SCID.

Mice carrying the recessive locus for peripheral T cell deficiency (Ptcd) have a block in thymic egress, but the mechanism responsible is undefined. Here we found that Ptcd T cells had an intrinsic migration defect, impaired lymphoid tissue trafficking and irregularly shaped protrusions. Characterization of the Ptcd locus showed a point substitution of lysine for glutamic acid at position 26 in the actin regulator coronin 1A that enhanced its inhibition of the actin regulator Arp2/3 and resulted in its mislocalization from the leading edge of migrating T cells. The discovery of another coronin 1A mutant during an N-ethyl-N-nitrosourea-mutagenesis screen for T cell-lymphopenic mice prompted us to evaluate a T cell-deficient, B cell-sufficient and natural killer cell-sufficient patient with severe combined immunodeficiency, whom we found had mutations in both CORO1A alleles. Our findings establish a function for coronin 1A in T cell egress, identify a surface of coronin involved in Arp2/3 regulation and demonstrate that actin regulation is a biological process defective in human and mouse severe combined immunodeficiency.

This second article in the miniseries Practical Aspects of Ambulatory Diagnosis and Management of Immunodeficiency Disorders' extends the discussion on evaluation of individuals with suspected humoral immunodeficiency by reviewing the logistics and interpretation of the patient's ability to produce antibodies to polysaccharide antigens, specifically pneumococcal surface polysaccharides. The response to these polysaccharides is important in the evaluation of patients with documented immune abnormalities and those individuals who have normal total immunoglobulin levels. Although profound immune deficiencies, such as X-linked agammaglobulinemia and severe combined immunodeficiency, are always associated with a defect in specific antibody production, some immune disorders may have variable responses, whereas others with persistent IgG or IgG subclass deficiencies may have normal or clearly abnormal antipolysaccharide antibodies. Measurement of the response to pneumococcal polysaccharides is preferred because of the availability of a pure polysaccharide vaccine for antigen challenge and standardized techniques to measure specific antibody responses.

We monitored Streptococcus pneumoniae serotypes causing invasive infections in patients admitted to one hospital in southern Chile during a 10-year period (1994 to 2004). All specimens isolated from patients with invasive S. pneumoniae infections were serotyped at the CDC in Atlanta, GA. A total of 508 isolates belonged to 58 serotypes. There were 95 infections in patients <2 years old, 33 infections in patients 2 to 4 years old, 61 infections in patients 5 to 14 years old, 66 infections in patients 15 to 44 years old, 134 infections in patients 45 to 64 years old, and 120 infections in patients >or=65 years old. The 10 serotypes isolated with the highest frequency in all groups were, in decreasing order, 1, 3, 14, 5, 19F, 6B, 7F, 12F, 23F, and 6A. The 10 most frequent isolates in children under 2 years of age were 1, 6B, 14, 19F, 5, 23F, 6A, 9V, and 7F. In patients >or=65 years old, the most common serotypes were 3, 7F, 1, 14, 19A, 23F, 19F, 35B, 4, and 5. Penicillin resistance was detected in 14 (2.7%) clinical specimens isolated since 1998, with 13 resistant strains identified since 2001. Vaccine coverage for the 7-valent conjugate vaccine was 42% for children <2 years of age. This study is important for the design of vaccines for this region and to evaluate public health measures to decrease pneumococcal infections.

This is the second report on the continuing efforts of LAGID to increase the recognition and registration of patients with primary immunodeficiency diseases in 12 Latin American countries: Argentina, Brazil, Chile, Colombia, Costa Rica, Honduras, Mexico, Panama, Paraguay, Peru, Uruguay, and Venezuela. This report reveals that from a total of 3321 patients registered, the most common form of primary immunodeficiency disease was predominantly antibody deficiency (53.2%) with IgA deficiency reported as the most frequent phenotype. This category was followed by 22.6% other well-defined ID syndromes, 9.5% combined T- and B-cell inmunodeficiency, 8.6% phagocytic disorders, 3.3% diseases of immune dysregulation, and 2.8% complement deficiencies. All countries that participated in the first publication in 1998 reported an increase in registered primary immunodeficiency cases, ranging between 10 and 80%. A comparison of the estimated minimal incidence of X-linked agammaglobulinemia, chronic granulomatous disease, and severe combined immunodeficiency between the first report and the present one shows an increase in the reporting of these diseases in all countries. In this report, the estimated minimal incidence of chronic granulomatous disease was between 0.72 and 1.26 cases per 100,000 births in Argentina, Chile, Costa Rica, and Uruguay and the incidence of severe combined immunodeficiency was 1.28 and 3.79 per 100,000 births in Chile and Costa Rica, respectively. However, these diseases are underreported in other participating countries. In addition to a better diagnosis of primary immunodeficiency diseases, more work on improving the registration of patients by each participating country and by countries that have not yet joined LAGID is still needed.

The majority of children with Down syndrome (DS) tend to have frequent bacterial infections including recurrent respiratory infections. Our objective was to evaluate the production of antibodies to pneumococcal polysaccharide antigens after active immunization in DS subjects. IgG antibodies to pneumococcal serotypes (1, 3, 6B, 9V, and 14) were measured before and 6 weeks after immunization with a 23-valent pneumococcal vaccine (Pneumo23, Pasteur-Merrieux) in 6- to 13-year-old DS children (N = 17) and in aged-matched normal controls (N = 30). An adequate response was defined as a 4-fold increase over baseline or a post-immunization level of specific pneumococcal serotype antibody > or = 1.3 microg/mL. After immunization, all DS children had an increase in post-immunization levels against all serotypes analyzed. A 4-fold or more increase was observed in all DS children concerning serotypes 1 and 14, in 90% of subjects for serotypes 3 and 9V, and in 65% for serotype 6B. Regarding this increase, 8 of the 17 DS children had an adequate response to all serotypes analyzed, 8/17 patients to 4 serotypes and 1/17 to 3 serotypes. However, when we compared post-immunization levels between DS children and controls, we observed lower levels in the former group (P < 0.05) for all serotypes except serotype 3. We conclude that pneumococcal polysaccharide immunization could be beneficial for these DS children.

Angioedema and chronic diarrhea in patients taking immunosuppressants are not always because of side effects and could be a new onset of food allergy. Our aim is to discuss the pathogenesis and treatment of the post-transplant development of food allergies. The first patient was receiving tacrolimus subsequent to heart transplantation and developed angioedema after consumption of dairy products at 12 months after transplantation. He was found to be allergic to multiple foods by both RAST and ImmunoCAP tests. The second patient with argininosuccinic aciduria, post-liver transplant, also received tacrolimus and developed chronic non-mucoid/bloody diarrhea at seven months following transplantation. ImmunoCAP test was positive only for egg white and peanuts. Biopsy showed eosinophilic infiltration of the mucosa from the stomach to the rectum. Elimination diets in both patients resolved the symptoms. These cases suggest a direct relationship between tacrolimus and development of food allergy.

Human immunoglobulin prepared for intravenous administration (IGIV) has a number of important uses in the treatment of disease. Some of these are in diseases for which acceptable treatment alternatives do not exist. In this review we have evaluated the evidence underlying a wide variety of IGIV uses and make specific recommendations on the basis of these data. Given the potential risks and inherent scarcity of IGIV, careful consideration of the indications for and administration of IGIV is warranted.

The objective of this study was to evaluate humoral immunity of allergic respiratory children with chronic/recurrent sinusitis. Twenty-seven allergic respiratory (persistent mild/moderate asthma and persistent allergic rhinitis) children (7-15-year old) with chronic or recurrent sinusitis were evaluated. Patients had symptoms and abnormal computer tomography scan even after two adequate treatments (long-lasting antibiotics, decongestants, and short-term oral corticosteroids). clinical examination, sweat test, total blood cell count, measurement of serum levels of: total and specific IgE, immunoglobulins (G, M, A), IgG subclasses, antibodies to Haemophilus influenza type b (IgG anti-Ps Hib) and pneumococcal serotypes (IgG anti-Ps 1, 3, 5, 6B, 9V, and 14) before and after active immunization (Act-Hib and Pneumo23, Aventis Pasteur SA, Lyon, France), Rubella neutralizing antibody titers and human immunodeficiency virus antibodies. Specific IgE to inhalant allergens higher than class III were observed in 24/27 patients. One patient had IgA plus IgG2 deficiency and other an IgG3 deficiency. Eight and 12 of 27 patients had IgG2 and IgG3 serum levels below 2.5th percentile, respectively. Immunological responses to protein and polysaccharide antigens were normal in all patients. Although our patients have been appropriately treated of their allergic diseases, they persisted with chronic/recurrent sinusitis and 60% of them had a documented osteomeatal complex blockade. In spite of the diagnosis of IgA plus IgG2 deficiency and an isolated IgG3 deficiency, in all patients an adequate response to Ps antigens was observed. Primary and/or secondary humoral immunodeficiency seems not to be the main cause of chronic/recurrent sinusitis in patients with respiratory allergic disease.

The aim of this study was to evaluate the effect of absorption with pneumococcal type 22F polysaccharide on antipneumococcal antibody titers in unimmunized Chilean pregnant women and on antibodies in their offspring at birth and 3, 6, and 12 months of age. Sera from 10 healthy pregnant women and from their offspring at birth and at 3, 6, and 12 months of age were studied. Immunoglobulin G antibodies against serotypes 1, 3, 4, 5, 6B, 9V, 14, 18, 19F, and 23F were measured by a standardized enzyme-linked immunosorbent assay method. All sera were absorbed with polysaccharide C, and aliquots of each serum were absorbed with polysaccharide 22F. Individual results were expressed in mug/ml based on the standard serum pool 89-SF. Absorption with polysaccharide 22F reduced antibody concentrations in all samples and to all 10 serotypes studied. Reduction was highest in maternal sera and in cord blood, but it was also present at 3, 6, and 12 months of age. The percent reduction ranged from 24% for serotype 14 to 50% for serotype 1 in maternal samples and from 20% for serotype 18C to 49% for serotype 4 in cord blood samples. The percentages of transplacental transmission were similar for nonabsorbed and absorbed maternal fetal pairs. Absorption with serotype 22F had a significant impact on antipneumococcal antibody concentrations in unimmunized pregnant women and in their offspring. Our results suggest that absorption with 22F polysaccharide needs to be performed in studies of transplacental transmission of antipneumococcal antibodies.

All clinical S. pneumoniae specimens isolated from patients with invasive or sterile-site infections admitted to one regional general hospital in southern Chile were collected during a 5-year period (February 1994 to September 1999). A total of 247 strains belonging to 50 serotypes were isolated in this survey: 69 in patients under 5 years of age, 129 in patients 5 to 64 years old, and 49 from patients 65 years and older. Eight serotypes were identified in all age groups, while all other serotypes were found exclusively in one age group or in patients over 4 years of age. Serotype 3 was never found in patients under 5 years old, and serotype 14 was not found in patients >64 years of age. There was no difference in the serotypes causing infection in each one of the 5 years of the survey. Our results suggest that both bacterial virulence factors and host factors play an important role in the selection of S. pneumoniae serotypes causing invasive infection. Possible host factors include age-related differences in the immune response. Comparative studies with other areas of the world may help to further understanding of our observations in southern Chile.

We wished to determine whether pneumococcal polysaccharide antigens induce mRNA expression of CD40 ligand (CD40L) and Th1 or Th2 cytokines in unimmunized individuals in vitro and whether immunization with the 23-valent pneumococcal polysaccharide vaccine induces changes in CD40L and cytokine mRNA expression. Children with recurrent respiratory infections were studied before and 4 to 6 weeks after receiving the pneumococcal vaccine. One patient who failed to respond to the polysaccharide vaccine subsequently received a single dose of the experimental 7-valent pneumococcal conjugate vaccine. Unimmunized healthy adults were included as controls. Quantification of mRNA expression of CD40L, interleukin-4 (IL-4), IL-12p40, and gamma interferon (IFN-gamma) was performed by reverse transcription-PCR and enzyme-linked immunosorbent assay (ELISA)-PCR with resting and stimulated peripheral blood mononuclear cells. Serum immunoglobulin G (IgG) anti pneumococcal antibody levels were measured by ELISA. The results showed a significant increase in the expression of mRNAs for CD40L and IL-4, but not IL-12p40 or IFN-gamma, in stimulated cultures from unimmunized individuals. CD40L and IL-4 mRNA expression was significantly higher in postimmunization than in preimmunization samples stimulated with the individual pneumococcal serotypes. These results suggest that pneumococcal polysaccharide antigens specifically up-regulate CD40L expression and induce a Th2 response in vitro which parallels the increase in IgG antipneumococcal antibody levels in serum.

Antibodies have a crucial role in protecting against infections, and antibody deficiencies are the commonest primary and secondary immunodeficiencies. Antibody deficiencies may be the only abnormality present in a patient, or they may be present and aggravate the symptoms of various other conditions. Because the presence of an antibody deficiency is difficult to predict from clinical presentation, physicians should perform an evaluation of antibody-mediated immunity, even knowing that, in many cases, the results are normal. When immunizations are included as a part of the evaluation, many patients experience a benefit from enhanced immunity against common pathogens. Some alternative practical approaches to the evaluation of patients with recurrent infections are outlined in Figure 8. Referral to a clinical immunologist can be based on the presence of recurrent infections, a positive family history without prior evaluation by a pediatrician, or abnormal immunologic findings that require an advanced evaluation. In any case, a close collaboration between pediatrician and immunologist likely will result in an accurate diagnosis and better treatment of patients with antibody-deficiency syndromes and their families.

Background: Advances in immunologic techniques in recent years have led to increased recognition of primary immunodeficiency disorders, with IgA deficiency the most common phenotype reported by most registries. There have also been reports of increased associated incidence of autoimmunity, allergy, and other diseases., Objectives: We wished to determine the percentage of different primary immunodeficiency disorders seen in a pediatric tertiary hospital and to determine the association of primary immunodeficiency disorders with other diseases that are not part of classic immunodeficiency disorders., Methods: We performed a retrospective review of the patients referred to our allergy/immunology clinic for immunologic evaluation of recurrent infections during an 8-year period. We also reviewed pathology reports with postmortem diagnosis of immunodeficiencies not identified while patients were alive., Results: Of the 91 patients with primary immunodeficiency disorders evaluated, the majority had predominantly antibody deficiencies (67%). The most common phenotype was specific antibody deficiency with normal immunoglobulins (23.1%), defined as inability to mount an adequate response to pneumococcal polysaccharides followed by IgG2 subclass deficiency (17.6%). These two phenotypes were diagnosed mostly in the last 2 years of the survey. Associated diseases, found in 40% of patients, were mostly allergic conditions followed by syndromic/chromosomal disorders., Conclusion: The study reveals that specific antibody deficiency with normal immunoglobulins followed by IgG2 subclass deficiency was the most frequently diagnosed primary immunodeficiency disorder in our patient population. It also indicates that immunodeficiency disorders should be considered in patients with other abnormalities like allergic and syndromic/chromosomal disorders that present with recurrent infections.

Background: The hyper-IgE syndrome is a primary immunodeficiency characterized by severe recurrent abscesses, pneumonia with pneumatocele formation, and elevated serum IgE. Eosinophilia, neutrophil chemotactic defects, and marked tissue damage are frequently present in this syndrome., Objective: To study whether functional changes in cytokines, adhesion molecules, and neutrophils might help explain these clinical observations., Methods: The following functions were analyzed in patients with the hyper-IgE syndrome and in controls: (1) production of granulocyte-macrophage-colony-stimulating factor by peripheral blood mononuclear cells by ELISA; (2) respiratory burst and reactive oxygen intermediates production by peripheral neutrophils using the luminol-enhanced chemiluminescense technique; and (3) expression of L-selectin on granulocytes and lymphocytes by flow cytometry., Results: Patients with hyper-IgE syndrome had significantly increased production of granulocyte-macrophage-colony-stimulating factor by resting or stimulated mononuclear cells, increased generation of reactive oxygen intermediates by neutrophils treated with opsonized zymosan, and reduced L-selectin expression on quiescent and activated granulocytes and lymphocytes., Conclusions: Our results suggest that an important feature of the hyper-IgE syndrome is the increased production of granulocyte-macrophage-colony-stimulating factor, which may explain the reduced L-selectin expression, decreased chemotaxis, and increased oxygen radical production and tissue damage in this disease.

Cell-mediated immunity that results in IL-12/IFN-gamma production is essential to control infections by intracellular organisms. Studies in animal models revealed contrasting results in regard to the importance of CD40-CD40 ligand (CD40L) signaling for induction of a type 1 cytokine response against these pathogens. We demonstrate that CD40-CD40L interaction in humans is critical for generation of the IL-12/IFN-gamma immune response against Toxoplasma gondii. Infection of monocytes with T. gondii resulted in up-regulation of CD40. CD40-CD40L signaling was required for optimal T cell production of IFN-gamma in response to T. gondii. Moreover, patients with hyper IgM (HIGM) syndrome exhibited a defect in IFN-gamma secretion in response to the parasite and evidence compatible with impaired in vivo T cell priming after T. gondii infection. Not only was IL-12 production in response to T. gondii dependent on CD40-CD40L signaling, but also, patients with HIGM syndrome exhibited deficient in vitro secretion of this cytokine in response to the parasite. Finally, in vitro incubation with agonistic soluble CD40L trimer enhanced T. gondii-triggered production of IFN-gamma and, through induction of IL-12 secretion, corrected the defect in IFN-gamma production observed in HIGM patients. Our results are likely to explain the susceptibility of patients with HIGM syndrome to infections by opportunistic pathogens.

Antibody deficiency syndromes are an important cause of recurrent infections in children. Today it is possible to perform a complete evaluation of antibody-mediated immunity leading to a definitive diagnosis of either normal or abnormal immunity in most patients. However, the interpretation of the results of IgG subclass determinations and specific antibody responses is still being defined. At this time our recommendation is that patients who meet the criteria for an evaluation of antibody-mediated immunity be referred to subspecialists trained in this evaluation until better criteria for normal have been developed. The possibility that protective amounts of antibodies against pneumococcal serotypes may develop only transiently must be considered in patients with recurrent infections after initial improvement after immunization, especially if IgG2 subclass deficiency is also present. In the future it may be possible to use a faster and more economical approach to evaluate patients with recurrent infections by immunization with pneumococcal vaccine and then measuring IgM, IgG and IgA along with postimmunization specific antipneumococcal antibody titers 4 to 6 weeks later. For this approach to become feasible, further studies comparing the information obtained from the evaluation of pre- and postimmunization antibody concentrations with that obtained from the evaluation of postimmunization concentrations alone are needed.