Blog

Methods Mol Biol. 2026;2970:345-352. doi: 10.1007/978-1-0716-4791-2_22.

ABSTRACT

Optogenetics enables precise and reversible control of receptor activation using light-responsive proteins. In one approach, the first 651 amino acids of the photoreceptor phytochrome B (PhyB) of Arabidopsis thaliana are used as a light-responsive ligand for engineered receptors. These receptors are fused to the PhyB-interacting factor 6 (PIF) and bind to PhyB under red, but not under far-red light. The recombinant biotinylated PhyB ligand can be conjugated either to streptavidin-coated plates or to beads, enabling PIF-fused receptor activation with high valency. This method provides high spatiotemporal precision, offering potential for studying receptor signaling in two-dimensional cell-free interactions. Here, we provide protocols to couple recombinant PhyB to plastic plates or polystyrene beads and validate the coupling using light-dependent stimulation of green fluorescent protein (GFP)-PIF-fused T-cell receptors (TCRs) in primary human T cells.

PMID:41028355 | DOI:10.1007/978-1-0716-4791-2_22

Ocul Immunol Inflamm. 2025 Sep 30:1-15. doi: 10.1080/09273948.2025.2551803. Online ahead of print.

ABSTRACT

PURPOSE: The IL-6 R/JAK/STAT3 signaling pathway is implicated in non-infectious uveitis-associated macular edema, and its inhibition using monoclonal anti-IL-6 receptor therapy has been associated with clinical improvement. However, the underlying pathogenic mechanisms remain unclear. In this study, we investigated the pathological effects of a STAT3 gain-of-function (GOF) variant p.L387R identified in a family with immune dysregulation syndrome and severe retinal vasculitis and macular edema.

METHODS: Primary retinal pigment epithelial (RPE) cells were transduced with STAT3 wildtype (WT), the retinal disease-associated familial STAT3 GOF variant p.L387R, or another pathogenic STAT3 GOF variant (p.Y360C) linked to immune dysregulation without retinal involvement. Cells were subsequently stimulated with IL-6 and IFN-α. RNA sequencing was performed to analyze gene expression differences, particularly related to cytokines, chemokines, and factors associated with RPE barrier permeability. Additionally, the expression of tight junction proteins involved in the blood-retinal barrier integrity was assessed. The efficacy of JAK inhibitors to modulate hyperactivation of the IL-6 R/JAK/STAT3 pathway was also evaluated.

RESULTS: Compared with WT and STAT3 p.Y360C variant-expressing cells, those expressing STAT3 p.L387R variant produced significantly elevated levels of IL-6, CCL2, and VEGF-A, which are known contributors to vascular leakage in retinal endothelial cells. Treatment with JAK1/2 inhibitors effectively reduced SOCS3 overexpression in STAT3 GOF RPE cells.

CONCLUSION: The pathogenic STAT3 p.L387R GOF variant enhances inflammatory cytokine production in human primary RPE cells, potentially exacerbating retinal vascular leakage and macular edema. These effects can be mitigated by JAK1/2 inhibition, highlighting a promising therapeutic strategy for retinal inflammation and associated edema.

PMID:41026879 | DOI:10.1080/09273948.2025.2551803

J Clin Immunol. 2025 Sep 30;45(1):135. doi: 10.1007/s10875-025-01939-2.

ABSTRACT

OBJECTIVE: Mutations in the HOIP gene, encoding Heme-oxidized IRP2 ubiquitin ligase-1 (HOIL-1) interacting protein, a key component of the linear ubiquitination chain assembly complex (LUBAC), affect the activation of the NF-κB pathway and result in autoinflammation and immunodeficiency. To date, only three patients with HOIP mutations have been reported in the English literature. This study aimed to identify the genetic cause in a 1-year-6-month-old boy with early-onset autoinflammation and immunodeficiency.

METHODS: Clinical manifestations and immunological phenotypes were assessed in a Chinese patient with novel compound heterozygous mutations in HOIP. Swiss-PdbViewer was used to predict the pathogenicity of the mutations. HOIP and LUBAC protein levels were evaluated by western blot. Immunological phenotypes and intracellular NF-κB phosphorylation in T and B cells were analyzed by flow cytometry, and the interferon (IFN) signature was assessed using quantitative reverse transcription PCR (RT-qPCR).

RESULTS: The patient experienced recurrent fever, multiple site infections, and chronic diarrhea from the neonatal period, requiring repeated hospitalizations. Targeted gene sequencing identified novel compound heterozygous mutations in HOIP (c.1654 C > T, p.Gln552Ter; c.3038 A > C, p.His1013Pro). These mutations significantly reduced HOIP and LUBAC protein expression and altered the HOIP protein structure. Immunophenotyping revealed a reduction in CD8 + T cells, central memory (CD8 CM) and effector memory (CD8 EM) T cells, and CD4 + T cells. Subset analysis of CD4 + T cells showed decreased T follicular helper cells (Tfh) and increased IL-17-producing T helper (Th17) cells. The patient also exhibited a higher percentage of naïve B cells and a lower percentage of memory B cells, alongside impaired NF-κB phosphorylation in T and B cells upon LPS stimulation. The expression of the patient’s interferon-stimulated gene (ISG) was markedly higher than that of healthy controls.

CONCLUSION: HOIP mutations may lead to multiple immune abnormalities, impaired NF-κB activation, and activation of the type I interferon pathway. These findings highlight the diversity of HOIP mutations and expand the clinical spectrum of associated diseases.

PMID:41026334 | DOI:10.1007/s10875-025-01939-2

J Clin Immunol. 2025 Sep 30;45(1):129. doi: 10.1007/s10875-025-01920-z.

ABSTRACT

PURPOSE: Enteropathy is a non-infectious complication in Common Variable Immune Deficiency (CVID) associated with increased morbidity and mortality. We characterized this group of CVID enteropathy (CVID-E) patients and investigated the effectiveness of immunosuppressive treatments on its clinical course.

METHOD: We identified patients with CVID-E in two academic teaching hospitals and obtained informed consents. Using electronic patient health care records, we retrospectively collected clinical information in the national Primary immunodeficiency disorder database until 01-2023.

RESULTS: We included 39 patients with CVID-E. Bronchiectasis (69.2%) and lymphoproliferation (46.1%) were the most frequent co-occurring symptoms. The most common endoscopy findings concerned inflammation (72.2%) and erythema (69.4%); The most prevalent histopathologic findings were IBD-like inflammation (55.6%), indiscriminate chronic inflammation (47.2%) and indiscriminate active inflammation (38.9%). We assessed 88 events of treatment response in the 25 treated patients. Overall treatment response was poor, however there were 31 events of remission observed, ranging from partial to sustained remission. Of these 26 were the result of tumor necrosis factor inhibitors (TNFi) or thiopurines, either as monotherapy or in combination with other immunosuppressive treatment. 10 patients achieved complete remission.

CONCLUSION: In this study, we describe a cohort of CVID-E patients including related comorbidity, clinical course and response to therapy. CVID-E patients frequently develop other, sometimes severe comorbidities. Our study confirms the alleged heterogeneity regarding endoscopic and histopathological findings, and in one third of patients even multiple distinct abnormalities co-occurred in the same biopsy. We found azathioprine and/or TNFi to be the most effective current treatment.

PMID:41026260 | DOI:10.1007/s10875-025-01920-z

J Clin Immunol. 2025 Sep 30;45(1):139. doi: 10.1007/s10875-025-01938-3.

ABSTRACT

Phosphatidylinositol 3-kinases (PI3Ks) are heterodimeric lipid kinases that are involved in a diverse array of cellular functions such as growth, metabolism, and migration. Mutations in PIK3CD, which encodes an immune-specific catalytic subunit of PI3K, cause both dominant (activating) and recessive (loss of function) immune deficiencies in humans. Here we report a family with three affected children carrying a novel bi-allelic, truncating mutation in PIK3CD. All three patients exhibited chronic diarrhea and recurrent sinopulmonary infections. Immunoblot confirmed loss of protein along with reduced expression of the associated p85α regulatory subunit. Immune phenotyping showed B cell dysregulation with abnormally high levels of naïve cells. In vitro functional testing of CD19 + and enriched naïve B cells revealed impaired proliferation, and reduction in class-switch recombination upon CD40L and IL-21 stimulation. Our data raise the possibility that PI3K-related dysregulation in human B cells may be broader than in mouse models, where class-switch recombination can still occur with external T cell help. Our study substantially increases the limited number of patients known to have immune deficiency due to loss of PIK3CD.

PMID:41026257 | DOI:10.1007/s10875-025-01938-3

Iran J Immunol. 2025 Sep 30;22(3):5. doi: 10.22034/iji.2025.104276.2893.

ABSTRACT

BACKGROUND: Common variable immunodeficiency (CVID) is an inborn error of immunity characterized by a defect in terminal B cell differentiation, resulting in hypogammaglobulinemia and impaired production of specific antibodies. Stimulation via Toll-like receptors (TLRs) has been shown to promote the differentiation and functional maturation of late-stage B cells.

OBJECTIVE: To assess aberrations in TLR2 signaling among patients with CVID and to explore their associations with clinical manifestations and immunological parameters.

METHODS: Sixteen CVID patients and 16 healthy controls were recruited for this individual-matched case-control study. Genetic variants in patients had been previously identified through whole-exome sequencing. TLR2 and TLR4 downstream gene expression were analyzed using qRT-PCR, while cytokine levels were measured by enzyme-linked immunosorbent assay (ELISA). Statistical associations between clinical features and laboratory parameters were analyzed using SPSS software.

RESULTS: Downstream gene expression following TLR2 stimulation was significantly reduced in 25% of CVID patients, while the TLR4 signaling pathway remained largely unaffected. Patients exhibiting TLR2 overexpression demonstrated a later disease onset, presenting with autoimmunity, lymphoproliferation, and atopic manifestations. A consistent immunologic feature among patients with defective TLR2 signaling was the reduction in marginal zone and switched memory B cell populations. Furthermore, Levels of IL-6 and IL-1β following agonist stimulation were significantly lower in CVID patients compared to healthy controls.

CONCLUSION: This study demonstrates that functional impairment of TLR2 signaling influences the clinical presentation, immunologic profile, and cytokine production in patients with CVID. These findings suggest a potential underlying etiology in a subset of patients with unidentified monogenic defects.

PMID:41025473 | DOI:10.22034/iji.2025.104276.2893

BMJ Case Rep. 2025 Sep 28;18(9):e265538. doi: 10.1136/bcr-2025-265538.

ABSTRACT

Deficiency of adenosine deaminase 2 (DADA2) is an autoinflammatory disease caused by autosomal recessive inherited loss of function mutations in the adenosine deaminase 2 (ADA2) encoding gene, which reduces plasma ADA2 concentration levels.ADA2 has a major role in the maturation and differentiation of the immune system. It ensures immune homeostasis with the help of adenosine receptors on the cell surface because ADA2 acts as an extracellular enzyme that has an important role in regulating extracellular adenosine concentration and mediates cellular immune interactions. We report a fatal outcome of an infant with DADA2 as a result of delayed diagnosis and definitive treatment with bone marrow transplantation.

PMID:41022419 | DOI:10.1136/bcr-2025-265538

BMC Immunol. 2025 Sep 29;26(1):74. doi: 10.1186/s12865-025-00761-0.

ABSTRACT

BACKGROUND: Inborn errors of immunity (IEI) are inherited defects of innate or adaptive immune system. Thrombocytopenia is a significant multifactorial complication in IEI patients leading to severe clinical consequences including coagulative disorders and vasculopathies.

METHODS: In the present study, we assessed frequency of thrombocytopenia in the most common IEI including combined immunodeficiency (CID), common variable immunodeficiency (CVID), selective immunoglobulin A deficiency (SIgAD), agammaglobulinemia (AGA), hyper immunoglobulin M (HIGM) syndrome, chronic granulomatous disease (CGD) and congenital neutropenia (CN). Also, we compared demographic, clinical and laboratory data between IEI patients with and without thrombocytopenia.

RESULTS: A total of 890 patients (37% female) were included in this study. The frequency of thrombocytopenia in total IEI was 26.6%. Patients with CID and SIgAD had the highest and lowest frequency of thrombocytopenia (50.9% and 8.7%), respectively. Although rare, thrombocytopenia was more severe (< 50000/ul) among patients with AGA compared to other IEI entities. Notably hepatosplenomegaly and autoimmunity were significantly associated with thrombocytopenia and higher mortality in patients with humoral immunodeficiencies.

CONCLUSION: The significant association between thrombocytopenia with lymphoproliferation and autoimmunity emphasizes the importance of paying attention to these clinical features for suspecting IEI disorders. Understanding the pathophysiology of thrombocytopenia in various genetic defects associated with IEI is required for the development of proper diagnostic and therapeutic techniques as well as improved quality of life of these patients.

PMID:41023781 | DOI:10.1186/s12865-025-00761-0

Clin Exp Immunol. 2025 Sep 29:uxaf065. doi: 10.1093/cei/uxaf065. Online ahead of print.

ABSTRACT

BACKGROUND: B-cell maturation antigen (BCMA) is a B cell surface receptor that regulates activation, proliferation and survival. BCMA can be cleaved from the cell surface, producing soluble BCMA (sBCMA), which has been studied as a disease biomarker in systemic lupus erythematosus, multiple sclerosis and multiple myeloma. Reduced sBCMA concentrations have been associated with the severity of different primary antibody deficiencies.

AIMS AND METHODS: We explored the relationship between sBCMA concentrations, humoral immune responses to SARS-CoV-2 vaccination and disease complications in 107 individuals with primary and secondary antibody deficiency enrolled in the COVID-19 in Antibody Deficiency (COV-AD) study.

RESULTS: Serum sBCMA concentrations were significantly reduced in primary antibody deficiencies compared to healthy controls and asymptomatic selective IgA deficiency. Individuals with X- linked agammaglobulinemia and common variable immunodeficiency (CVID) demonstrated the lowest serum concentrations of sBCMA. sBCMA concentrations in secondary antibody deficiency were highly variable. Amongst individuals with CVID, peripheral blood CD19 count, but not sBCMA concentrations discriminated SARS-CoV-2 vaccine responders. sBCMA was significantly lower in individuals with CVID and bronchiectasis and outperformed serum IgA and IgM concentrations in discriminating this subgroup. sBCMA was not associated with any other complication of CVID.

CONCLUSION: Our data highlights the potential of sBCMA as biomarker to support the assessment of antibody deficiency. In primary antibody deficiencies, it may contribute to the risk stratification of disease severity and identify those at risk of bronchiectasis. In secondary antibody deficiency, it may identify subgroups that would benefit from intensive monitoring and therapy.

PMID:41017320 | DOI:10.1093/cei/uxaf065

Mutat Res Rev Mutat Res. 2025 Sep 27;796:108564. doi: 10.1016/j.mrrev.2025.108564. Online ahead of print.

ABSTRACT

BACKGROUND: Patients with inborn errors of immunity (IEI) experience severe infectious and non-infectious complications, leading to an increased risk of mortality. Delayed diagnosis or misdiagnosis significantly contributes to the heightened mortality rates observed in IEI patients.

OBJECTIVES: This study systematically reviews the causes of mortality in IEI patients with a meta-analysis to determine the mortality rate among patients with various IEI.

METHODS: Embase, ISI Web of Science, PubMed, and Scopus were searched (up to July 2024) using terms related to IEI and mortality.

RESULTS: A total of 12,581 deceased IEI patients were included, with an overall reported mortality rate of 24.0 % (95 % confidence interval: 23.0-26.0 %) among all published IEI cases. This represents an approximately 27-fold higher mortality rate among IEI patients compared to the mean global mortality rate (24 % vs. 0.874 %). Severe combined immunodeficiency, chronic granulomatous disease, and ataxia-telangiectasia had the highest numbers of reported deceased cases (2304, 962, and 820 cases, respectively). However, familial hemophagocytic lymphohistiocytosis exhibited the highest mortality rate (49.0 %). The most common causes of death were infections, transplant-related mortality and non-infectious pulmonary complications, (3429, 2749, and 1141 cases), respectively. Among infectious causes of death, COVID-19 infection accounted for 10.8 % (370 cases).

CONCLUSION: This study identifies specific types of IEI with the highest mortality rates and numbers, alongside immune component defects most strongly associated with increased mortality. Patients with immune dysregulation, defects in cellular immunity, and phagocyte function were particularly linked to higher mortality rates, underscoring the urgent need for improved management strategies for these IEIs.

PMID:41016093 | DOI:10.1016/j.mrrev.2025.108564