Human neonatal thymectomy induces altered B‐cell responses and autoreactivity

An association between T-cell lymphopenia and autoimmunity has long been proposed, but it remains to be elucidated whether T-cell lymphopenia affects B-cell responses to auto-antigens. Human neonatal thymectomy results in a decrease in T-cell numbers and we used this model to study the development of auto-reactivity. Two cohorts of neonatally thymectomized individuals were examined, a cohort of young (1-5 years post-thymectomy, n = 10-27) and older children (>10years,n = 26), and compared to healthy age-matched controls. T- and B-cell subsets were assessed and auto-antibody profiling performed. Early post-thymectomy, a decrease in T-cell numbers (2.75 × 10^9/L vs. 0.71 × 10^9/L) and an increased proportion of memory T-cells (19.72% vs. 57.43%) were observed. The presence of auto-antibodies correlated with an increased proportion of memory T cells in thymectomized children. No differences were seen in percentages of different B-cell subsets between the groups. The auto-antigen microarray showed a skewed auto-antibody response after thymectomy. In the cohort of older individuals, auto-antibodies were present in 62% of the thymectomized children, while they were found in only 33% of the healthy controls. Overall, our data suggest that neonatal thymectomy skews the auto-antibody profile. Preferential expansion and preservation of Treg (regulatory T) cell stability and function, may contribute to preventing autoimmune disease development after thymectomy. This article is protected by copyright. All rights reserved