Autoimmunity in patients with inborn errors of immunity: A case series.

Objective: To assess the prevalence of systemic and organ-specific autoimmunity among individuals with human inborn errors of immunity (IEI).

Methods: Retrospective study. We recorded demographic variables, type of immunodeficiency, and systemic and organ specific autoimmunity.

Results: We included 48 patients (54.1% men) with mean age of 32.1 years. The most common IEIs included combined immunodeficiency with syndromic features (31.2%) and predominantly antibody deficiency (20.1%). We observed autoimmunity in 15 patients (31.2%): 12 organ-specific autoimmunity and 5 systemic autoimmunity, not mutually exclusive groups. Organ-specific autoimmunity preceded the onset of IEI in 5 patients, was concurrent in one patient, and developed after the diagnosis of IEI in 6 cases. From the systemic autoimmunity group, we observed polyarteritis nodosa (n = 2), antiphospholipid syndrome (APS) (n = 2), and overlap of limited systemic sclerosis/APS/Sjögren's syndrome (n = 1), and in all cases, this occurred after the IEI diagnosis.

Conclusion: Our findings confirm the coexistence of autoimmunity and IEI. This overlap may be attributed to B and T cell disorders, as well as potential alterations in the microbiota in these patients.