Rapamycin Controls Lymphoproliferation and Reverses T-Cell Responses in a Patient with a Novel STIM1 Loss-of-Function Deletion.

PURPOSE: Deficiency of stromal interaction molecule 1 (STIM1) results in combined immunodeficiency accompanied by extra-immunological findings like enamel defects and myopathy. We here studied a patient with a STIM1 loss-of-function mutation who presented with severe lymphoproliferation. We sought to explore the efficacy of the mTOR inhibitor rapamycin in controlling disease manifestations and reversing aberrant T-cell subsets and functions, which has never been used previously in this disorder. METHODS: Clinical findings of the patient were collected over time. We performed immunological evaluations before and after initiation of rapamycin treatment, including detailed lymphocyte subset analyses, alterations in frequencies of circulating T follicular helper (cTFH) and regulatory T (Treg) cells and their subtypes as well as T cell activation and proliferation capacities. RESULTS: A novel homozygous exon 2 deletion in STIM1 was detected in a 3-year-old girl with severe lymphoproliferation, recurrent infections, myopathy, iris hypoplasia, and enamel hypoplasia. Lymphoproliferation was associated with severe T-cell infiltrates. The deletion resulted in a complete loss of protein expression, associated with a lack of store-operated calcium entry response, defective T-cell activation, proliferation, and cytokine production. Interestingly, patient blood contained fewer cTFH and increased circulating follicular regulatory (cTFR) cells. Abnormal skewing towards TH2-like responses in certain T-cell subpopulations like cTFH, non-cTFH memory T-helper, and Treg cells was associated with increased eosinophil numbers and serum IgE levels. Treatment with rapamycin controlled lymphoproliferation, improved T-cell activation and proliferation capacities, reversed T-cell responses, and repressed high IgE levels and eosinophilia. CONCLUSIONS: This study enhances our understanding of STIM1 deficiency by uncovering additional abnormal T-cell responses, and reveals for the first time the potential therapeutic utility of rapamycin for this disorder.

Insights into Patient Experiences with Facilitated Subcutaneous Immunoglobulin Therapy in Primary Immune Deficiency: A Prospective Observational Cohort.

BACKGROUND: Immunoglobulin G replacement therapy (IgRT), intravenous (IV) and subcutaneous (SC) routes, is pivotal in treatment of primary immunodeficiencies (PID). In recent years, facilitated subcutaneous immunoglobulin (fSCIG), a combination of rHuPH20 and 10% IgG has emerged as a delivery method to combine advantages of both IV and SC. METHOD: In an observational prospective cohort, we investigated patient experience with fSCIG in PID patients from 5 PID centers for up to 12 months. We assessed the efficacy and safety of this treatment with patient/caregiver- and physician-reported indicators. Additionally, we analyzed patient treatment satisfaction (TSQM-9) and quality of life (QoL). RESULTS: We enrolled 29 patients (22 pediatric and 7 adults; 14 females and 15 males; (median: 15, min-max: 2-40.9 years) who initiated fSCIG as IgRT-naive (n = 1), switched from conventional rapid-push 10% SCIG (n = 6) or IVIG (n = 22). Among the participants, 19 (65%) exhibited antibody deficiencies, 8 (27%) combined immunodeficiencies, and 2 (7%) immune dysregulations. Remarkably, targeted trough immunoglobulin G levels were achieved under all previous IgRTs as well as fSCIG. No severe systemic adverse drug reactions were documented, despite prevalent local (%86.45) and mild systemic (%26.45) adverse reactions were noted with fSCIG. Due to mild systemic symptoms, 2 patients switched from fSCIG to 10% SCIG. The patient satisfaction survey revealed a notable increase at 2-4th (p = 0.102); 5-8th (p = 0.006) and 9-12th (p < 0.001) months compared to the baseline. No significant trends were observed in QoL surveys. CONCLUSION: fSCIG demonstrates admissable tolerability and efficacy in managing PIDs in addition to notable increase of patients' drug satisfaction with IgRT. The identified benefits support the continuation of this therapy despite the local reactions.

Therapeutic modalities and clinical outcomes in a large cohort with LRBA deficiency and CTLA4 insufficiency.

BACKGROUND: LPS-responsive beige-like anchor (LRBA) deficiency (LRBA-/-) and cytotoxic T-lymphocyte-associated antigen-4 (CTLA4) insufficiency (CTLA4+/-) are mechanistically overlapped diseases presenting with recurrent infections and autoimmunity. The effectiveness of different treatment regimens remains unknown. OBJECTIVE: Our aim was to determine the comparative efficacy and long-term outcome of therapy with immunosuppressants, CTLA4-immunoglobulin (abatacept), and hematopoietic stem cell transplantation (HSCT) in a single-country multicenter cohort of 98 patients with a 5-year median follow-up. METHODS: The 98 patients (63 LRBA-/- and 35 CTLA4+/-) were followed and evaluated at baseline and every 6 months for clinical manifestations and response to the respective therapies. RESULTS: The LRBA-/- patients exhibited a more severe disease course than did the CTLA4+/- patients, requiring more immunosuppressants, abatacept, and HSCT to control their symptoms. Among the 58 patients who received abatacept as either a primary or rescue therapy, sustained complete control was achieved in 46 (79.3%) without severe side effects. In contrast, most patients who received immunosuppressants as primary therapy (n = 61) showed either partial or no disease control (72.1%), necessitating additional immunosuppressants, abatacept, or transplantation. Patients with partial or no response to abatacept (n = 12) had longer disease activity before abatacept therapy, with higher organ involvement and poorer disease outcomes than those with a complete response. HSCT was performed in 14 LRBA-/- patients; 9 patients (64.2%) showed complete remission, and 3 (21.3%) continued to receive immunosuppressants after transplantation. HSCT and abatacept therapy gave rise to similar probabilities of survival. CONCLUSIONS: Abatacept is superior to immunosuppressants in controlling disease manifestations over the long term, especially when started early, and it may provide a safe and effective therapeutic alternative to transplantation.

Evaluation of Clinical and Immunological Alterations Associated with ICF Syndrome.

PURPOSE: Immunodeficiency with centromeric instability and facial anomalies (ICF) syndrome is a rare autosomal recessive combined immunodeficiency. The detailed immune responses are not explored widely. We investigated known and novel immune alterations in lymphocyte subpopulations and their association with clinical symptoms in a well-defined ICF cohort. METHODS: We recruited the clinical findings from twelve ICF1 and ICF2 patients. We performed detailed immunological evaluation, including lymphocyte subset analyses, upregulation, and proliferation of T cells. We also determined the frequency of circulating T follicular helper (cTFH) and regulatory T (Treg) cells and their subtypes by flow cytometry. RESULTS: There were ten ICF1 and two ICF2 patients. We identified two novel homozygous missense mutations in the ZBTB24 gene. Respiratory tract infections were the most common recurrent infections among the patients. Gastrointestinal system (GIS) involvements were observed in seven patients. All patients received intravenous immunoglobulin replacement therapy and antibacterial prophylaxis; two died during the follow-up period. Immunologically, CD4+ T-cell counts, percentages of recent thymic emigrant T cells, and naive CD4+ T decreased in two, five, and four patients, respectively. Impaired T-cell proliferation and reduced CD25 upregulation were detected in all patients. These changes were more prominent in CD8+ T cells. GIS involvements negatively correlated with CD3+ T-, CD3+CD4+ T-, CD16+CD56+ NK-cell counts, and CD4+/CD8+ T-cell ratios. Further, we observed expanded cTFH cells and reduced Treg and follicular regulatory T cells with a skewing to a TH2-like phenotype in all tested subpopulations. CONCLUSION: The ICF syndrome encompasses various manifestations affecting multiple end organs. Perturbed T-cell responses with increased cTFH and decreased Treg cells may provide further insight into the immune aberrations observed in ICF syndrome.

MHC Class II Deficiency: Clinical, Immunological, and Genetic Insights in a Large Multicenter Cohort.

BACKGROUND: Major histocompatibility complex class II deficiency, a combined immunodeficiency, results from loss of HLA class II expression on antigen-presenting cells. Currently, hematopoietic stem cell transplantation stands as the sole curative approach, although factors influencing patient outcomes remain insufficiently explored. OBJECTIVES: To elucidate the clinical, immunologic, and genetic profiles associated with MHC-II deficiency and identify prognostic indicators that affect survival rates. METHODS: In this multicenter retrospective analysis, we gathered data from 35 patients with a diagnosis of MHC-II deficiency across 12 centers in Turkey. We recorded infection histories, gene mutations, immune cell subsets, and surface MHC-II expression on blood cells. We conducted survival analyses to evaluate the impact of various factors on patient outcomes. RESULTS: Predominant symptoms observed were pneumonia (n = 29; 82.9%), persistent diarrhea (n = 26; 74.3%), and severe infections (n = 26; 74.3%). The RFXANK gene mutation (n = 9) was the most frequent, followed by mutations in RFX5 (n = 8), CIITA (n = 4), and RFXAP (n = 2) genes. Patients with RFXANK mutations presented with later onset and diagnosis compared with those with RFX5 mutations (P =.0008 and .0006, respectively), alongside a more significant diagnostic delay (P = .020). A notable founder effect was observed in five patients with a specific RFX5 mutation (c.616G>C). The overall survival rate for patients was 28.6% (n = 10), showing a significantly higher proportion in individuals with hematopoietic stem cell transplantation (n = 8; 80%). Early death and higher CD8+ T-cell counts were observed in patients with the RFX5 mutations compared with RFXANK-mutant patients (P = .006 and .009, respectively). CONCLUSIONS: This study delineates the genetic and clinical panorama of MHC-II deficiency, emphasizing the prevalence of specific gene mutations such as RFXANK and RFX5. These insights facilitate early diagnosis and prognosis refinement, significantly contributing to the management of MHC-II deficiency.