Search

Background: In 2014, germline signal transducer and activator of transcription (STAT) 3 gain-of-function (GOF) mutations were first described to cause a novel multisystem disease of early-onset lymphoproliferation and autoimmunity. Objective: This pivotal cohort study defines the scope, natural history, treatment, and overall survival of a large global cohort of patients with pathogenic STAT3 GOF variants. Methods: We identified 191 patients from 33 countries with 72 unique mutations. Inclusion criteria included symptoms of immune dysregulation and a biochemically confirmed germline heterozygous GOF variant in STAT3. Results: Overall survival was 88%, median age at onset of symptoms was 2.3 years, and median age at diagnosis was 12 years. Immune dysregulatory features were present in all patients: lymphoproliferation was the most common manifestation (73%); increased frequencies of double-negative (CD4−CD8−) T cells were found in 83% of patients tested. Autoimmune cytopenias were the second most common clinical manifestation (67%), followed by growth delay, enteropathy, skin disease, pulmonary disease, endocrinopathy, arthritis, autoimmune hepatitis, neurologic disease, vasculopathy, renal disease, and malignancy. Infections were reported in 72% of the cohort. A cellular and humoral immunodeficiency was observed in 37% and 51% of patients, respectively. Clinical symptoms dramatically improved in patients treated with JAK inhibitors, while a variety of other immunomodulatory treatment modalities were less efficacious. Thus far, 23 patients have undergone bone marrow transplantation, with a 62% survival rate. Conclusion:: STAT3 GOF patients present with a wide array of immune-mediated disease including lymphoproliferation, autoimmune cytopenias, and multisystem autoimmunity. Patient care tends to be siloed, without a clear treatment strategy. Thus, early identification and prompt treatment implementation are lifesaving for STAT3 GOF syndrome.

Primary Immunodeficiency disease (PIDD) comprise a group of disorders of immune function. Some of the most severe PIDD can be treated with hematopoietic cell transplant (HCT). Hizentra® is a 20% liquid IgG product approved for subcutaneous administration in adults and children greater than two years of age with PIDD-associated antibody deficiency. Limited information is available on use of Hizentra® in children following HCT for PIDD. A multicenter retrospective chart review demonstrated 37 infants and children (median age 70.1 [range 12.0 to 176.4] months) with PIDD treated by HCT who received Hizentra® infusions over a median duration of 31 (range 4-96) months post-transplant. The most common indication for HCT was IL2RG SCID (n=16). Thirty-two patients switched from IVIG to SCIG administration, due to one or more of the following reasons: patient/caregiver (n=17) or physician (n=12) preference, discontinuation of central venous catheter (n=16), desire for home infusion (n=12), improved IgG serum levels following lower levels on IVIG (n=10), and loss of venous access (n=8). Serious bacterial infections occurred at a rate of 0.041 per patient-year while on therapy. Weight percentile increased by a mean of 16% during the observation period, with females demonstrating the largest gains. Mild local reactions were observed in 24%; 76% had no local reactions. One serious adverse event (death from sepsis) was reported. Hizentra® was discontinued in 15 (41%) patients, most commonly due to recovery of B-cell function (n=11). These data demonstrate that Hizentra® is a safe and effective option in children who have received HCT for PIDD.

Optimal management of patients with combined immunodeficiency, especially pertaining to hematopoietic stem cell transplantation (HSCT), remains unclear.To identify factors influencing HSCT and mortality in the population with combined immunodeficiency in North America.We identified 337 participants in the United States Immunodeficiency Network database with diverse forms of combined immunodeficiency and their characteristics, including demographic characteristics, laboratory values, infectious history, comorbidities, and treatment strategies. Univariate analysis was performed using logistic regression, whereas multivariate analysis was performed using multiple Cox proportional hazards.On univariate analysis, disseminated invasive viral infections and variants in STAT3, GATA2, and, DOCK8 were associated with increased odds of HSCT. Mucocutaneous fungal infections and variants in STAT3 were associated with increased odds of survival, whereas disseminated/invasive fungal infections, disseminated/invasive viral infections, and parasitic infections were associated with decreased odds of survival. On multiple variable Cox proportional hazards analysis, variants in ZAP70, nonspecific bacterial, and disseminated/invasive viral infections were associated with increased hazards of transplantation, whereas variants in multiple genes (RMRP, NEMO, DOCK8, CD40L, and CARD9), disseminated/invasive viral infections, autoimmune disease, and higher absolute lymphocyte count were associated with increased hazards of death. Importantly, demographic characteristics, basic lymphocyte subset counts, and absence of genetic diagnosis were not associated with HSCT or mortality.We determined that specific genetic diagnoses and infection burden impacts the decision to undergo HSCT in this cohort. In addition, certain genetic diagnoses and invasive viral infections carry an increased risk of mortality.

Granulomas are organized aggregates of differentiated macrophages and other immune cells that form in response to mycobacterial infection and other persistent stimuli. While the tuberculous granuloma has long been considered a host-protective structure, our recent work in the genetically tractable and optically transparent zebrafish embryo-Mycobacterium marinum model of tuberculosis, has suggested that the early granuloma actually benefits mycobacteria. The mycobacterial RD1 virulence locus, a specialized bacterial secretion system, enhances granuloma formation, which in turn, promotes bacterial expansion and dissemination. Here we present the molecular and cellular details of RD1-induced granuloma formation. RD1-secreted effectors induce host matrix metalloproteinase 9 (mmp9) in epithelial cells neighboring the infected macrophages. By specifically knocking down host mmp9, we have shown that its expression facilitates macrophage recruitment to form granulomas and bacterial expansion. Selective mmp9 induction in immotile epithelial cells neighboring infected macrophages may serve as a mechanism to fix and expand infection foci at optimal sites. Our results provide direct evidence that early granulomas benefit mycobacteria and suggest new tuberculosis therapeutic strategies that target granuloma-promoting host susceptibility determinants like mmp9.