Chapdelaine, Hugo

RELA-related disease is a rare, autosomal-dominant condition presenting with immune dysregulation and immunodeficiency. RELA encodes the p65 subunit, a component of the canonical NFκB pathway. The underlying pathogenesis, at least in part, involves impaired NFκB activation, increased susceptibility to TNFα-induced apoptosis, and hyperinflammation. To date, only a modest number of cases have been documented worldwide, and the full clinical and functional spectrum of disease remains incompletely defined. This study represents a large global cohort identified with RELA variants, comprising 40 patients from 30 institutions, expanding our previous report of a single large kindred (1). The clinical spectrum includes arthritis, mucocutaneous ulcers, uveitis, dermatitis, irritable bowel disease, recurrent infections, lymphopenia, hypogammaglobulinemia, recurrent fevers, and susceptibility to neoplasia. The patients represent 36 kindreds with 28 unique RELA variants, of which 15 are missense, 7 nonsense, and 6 frameshift variants. Fifteen are in the Rel homology domain, 7 in the transcriptional activation domain, and 6 in the C-terminal region proximal to TAD (Fig. 1). Functional studies assessed the canonical NFκB pathway in 27% of the cohort (n = 11; healthy controls = 40). Patient peripheral blood mononuclear cells (PBMCs) were used to quantify total and phosphorylated p65 (ph-p65, Ser529) by flow cytometry after stimulation with PMA (100 ng/ml) and ionomycin (1 uM). In 8 patients, we assessed the kinetics of IκBα degradation, required for p65 phosphorylation and nuclear translocation of p65/p50. All patients tested had decreased total p65, while 64% had decreased ph-p65 with altered phosphorylation kinetics. Nearly 45% had impaired IκBα degradation. One patient (P4) demonstrated increased IκBα degradation and ph-p65, while a related proband (P1) had decreased ph-p65. Additionally, P4 did not have the same mucocutaneous clinical phenotype as P1 despite sharing the same RELA variant. This could reflect the effect of other genetic modifiers, epigenetic, environmental, or stochastic variations, which could lead to variable expressivity and/or incomplete penetrance. All patients appeared to have haploinsufficiency, as none had normal levels of p65. This study expands the clinical and genetic spectrum of RELA-related disease and provides mechanistic insights into the impact of these variants on p65 phosphorylation and downstream function, resulting in variable expressivity. Figure 1. RelA protein structure. Represents unique variant locations and categories, key domains, and phosphorylation sites. Source: UniProt. Adapted from (2). BioRender.

Introduction Individuals with inborn errors of immunity (IEI) are increasingly reaching reproductive age, yet guidance on fertility preservation, genetic counseling, medication adjustments in pregnancy and breastfeeding, monitoring for complications, and multidisciplinary coordination is lacking. This joint effort between two committees of the Clinical Immunology Society (CIS), the Women of the Clinical Immunology Society (WCIS) and the Adult Immune Deficiency Committee (AID) survey aimed to characterize current reproductive care practices for IEI patients. Methods A survey was disseminated to 809 CIS members. The response rate was 6.43% (52 respondents). The 24-item questionnaire addressed management of pregnancy in IEI, medications adjustment, participation in hematopoietic stem cell transplant (HSCT) care and fertility preservation, and maternal/neonatal outcomes. Results Because survey items were optional, the number of respondents varies by question. Forty-two participants completed core items: 64% (27/42) allergists/immunologists, 71% (30/42) practicing at academic centers, and 48% (20/42) with >50% immunology-focused practices. Most respondents (78%, 41/52) currently or previously cared for pregnant/planning IEI patients. Preconception counseling was common (90%, 37/41), yet only 2% (1/41) have access to a formal reproductive multidisciplinary team. Among clinicians involved in HSCT care, 45% (13/29) referred patients for fertility preservation. More than half, 52% (22/42), observed reduced fertility in IEI patients, and 56% (20/36) observed adverse maternal outcomes. Medication management varied: 61% (24/39) discontinued known teratogenic medications, and 64% (25/39) adjusted dosing during pregnancy. Regarding immunoglobulin replacement therapy, 79% adjusted dosing based on IgG levels and 42% increased dosing by trimester. Conclusions This CIS survey reveals practice variability and notable gaps in reproductive health support for individuals with IEIs. Due to the relatively low response rate, generalizability across providers and practice settings is challenging. However, the results of this survey suggest that although most clinicians provide preconception counseling and manage IgG and immunomodulatory therapy during pregnancy, formal multidisciplinary structures are rare. High rates of reported fertility concerns and maternal complications underscore the need for enhanced collaboration with obstetrics/gynecology and the development of structured, evidence-based, multidisciplinary guidelines for reproductive care in IEI. Tabular data are included as downloadable supplement files.