Role of Skewed X-Chromosome Inactivation in Common Variable Immunodeficiency.

The term common variable immunodeficiency (CVID) encompasses a clinically diverse group of disorders, mainly characterized by hypogammaglobulinemia, insufficient specific antibody production, and recurrent infections. The genetics of CVID is complex, and monogenic defects account for only a portion of cases, typically <30%. Other proposed mechanisms include digenic, oligogenic, or polygenic inheritance and epigenetic dysregulation. In this study, we aimed to assess the role of skewed X-chromosome inactivation (XCI) in CVID. Within our cohort of 131 genetically analyzed CVID patients, we selected female patients with rare variants in CVID-associated genes located on the X-chromosome. Four patients harboring heterozygous variants in BTK (n = 2), CD40LG (n = 1), and IKBKG (n = 1) were included in the study. We assessed XCI status using the HUMARA assay and an NGS-based method to quantify the expression of the 2 alleles in mRNA. Three of the 4 patients (75%) exhibited skewed XCI, and the mutated allele was predominantly expressed in all cases. Patient 1 harbored a hypomorphic variant in BTK (p.Tyr418His), patient 3 had a pathogenic variant in CD40LG (c.288+1G>A), and patient 4 had a hypomorphic variant in IKBKG (p.Glu57Lys) and a heterozygous splice variant in TNFRSF13B (TACI) (c.61+2T>A). Overall, the analysis of our cohort suggests that CVID in a small proportion of females (1.6% in our cohort) is caused by skewed XCI and highly penetrant gene variants on the X-chromosome. Additionally, skewed XCI may contribute to polygenic effects (3.3% in our cohort). These results indicate that skewed XCI may represent another piece in the complex puzzle of CVID genetics.

Kappa free light chains index in multiple sclerosis very long-term prognosis.

Introduction: The role of the kappa-free light chain (kFLC) in the diagnosis of multiple sclerosis (MS) and, to a lesser extent, its role as a medium-term prognostic marker have been extensively studied. This study aimed to explore its potential as a long-term prognostic marker for MS. Methods: We performed an exploratory retrospective observational study by selecting patients systemically followed up in our MS unit with available cerebrospinal fluid and serum samples at the time of initial evaluation. Two groups were defined: benign MS (bMS), defined as patients with Expanded Disability Status Scale (EDSS) ≤ 3 at 10 years of follow-up, and aggressive MS (aMS), defined as patients with EDSS ≥ 6 at 15 years of follow-up. Clinical variables were collected, and the immunoglobulin G (IgG) index, kFLC index, and oligoclonal bands (OCB) were determined for all patients and compared between the groups. Results: Twenty bMS and 15 aMS patients were included in this study. Sixty percent (21/35) were female, and the mean age at the time of the first symptom was 31.5 ± 9.45 years, with no statistical differences between groups. Median follow-up time was 19.8 years (Interquartile range, IQR 15.9-24.6). The median EDSS scores at the last follow-up were 1.5 and 7.5 in the bMS and the aMS group, respectively. No statistically significant differences were found in the kFLC index between the two groups (136.6 vs. 140.27, p=0.59). The IgG index was positive in 62.9% of patients (55% bMS vs. 73.3% aMS, p>0.05), and OCB was positive in 88.6% (90% bMS vs. 86.7% aMS, p>0.05). A significant positive correlation was found between IgG and kFLC indices (rs = 0.85, p<0.001). Conclusion: Given the absence of differences between the two groups with opposite disease courses, it is unlikely that the kFLC index is a reliable and powerful marker of long-term prognosis in MS.

Immunosuppression minimization in kidney transplant recipients hospitalized for COVID-19.

BACKGROUND: Immunosuppressed patients such as kidney transplant recipients (KTs) have increased mortality risk in the setting of coronavirus disease 2019 (COVID-19). The role and management of chronic immunosuppressive therapies during COVID-19 must be characterized. METHODS: Herein, we report the follow-up of a cohort of 47 KTs admitted at two Spanish Kidney Transplant Units, who survived COVID-19. The impact of the management of immunosuppression during COVID-19 on graft function and immunologic events was evaluated. RESULTS: At least one immunosuppressive agent was withdrawn in 83% of patients, with antimetabolites being the most frequent. Steroids were generally not stopped and the dose was even increased in 15% of patients as part of the treatment of COVID-19. Although immunosuppressive drugs were suspended during a median time of 17 days, no rejection episodes or de novo donor-specific antibodies were observed up to 3 months after discharge, and no significant changes occurred in calculated panel reactive antibodies. Acute graft dysfunction was common (55%) and the severity was related to tacrolimus trough levels, which were higher in patients receiving antivirals. At the end of follow-up, all patients recovered baseline kidney function. CONCLUSIONS: Our observational study suggests that immunosuppression in KTs hospitalized due to COVID-19 could be safely minimized.