Patients with autoimmune polyendocrinopathy syndrome type 1 (APS-1) caused by autosomal recessive AIRE deficiency produce autoantibodies that neutralize type I interferons (IFNs)^1,2, conferring a predisposition to life-threatening COVID-19 pneumonia³. Here we report that patients with autosomal recessive NIK or RELB deficiency, or a specific type of autosomal-dominant NF-κB2 deficiency, also have neutralizing autoantibodies against type I IFNs and are at higher risk of getting life-threatening COVID-19 pneumonia. In patients with autosomal-dominant NF-κB2 deficiency, these autoantibodies are found only in individuals who are heterozygous for variants associated with both transcription (p52 activity) loss of function (LOF) due to impaired p100 processing to generate p52, and regulatory (IκBδ activity) gain of function (GOF) due to the accumulation of unprocessed p100, therefore increasing the inhibitory activity of IκBδ (hereafter, p52^LOF/IκBδ^GOF). By contrast, neutralizing autoantibodies against type I IFNs are not found in individuals who are heterozygous for NFKB2 variants causing haploinsufficiency of p100 and p52 (hereafter, p52^LOF/IκBδ^LOF) or gain-of-function of p52 (hereafter, p52^GOF/IκBδ^LOF). In contrast to patients with APS-1, patients with disorders of NIK, RELB or NF-κB2 have very few tissue-specific autoantibodies. However, their thymuses have an abnormal structure, with few AIRE-expressing medullary thymic epithelial cells. Human inborn errors of the alternative NF-κB pathway impair the development of AIRE-expressing medullary thymic epithelial cells, thereby underlying the production of autoantibodies against type I IFNs and predisposition to viral diseases.

Inborn errors of IFN-γ immunity can underlie tuberculosis (TB). We report three patients from two kindreds without EBV viremia or disease but with severe TB and inherited complete ITK deficiency, a condition associated with severe EBV disease that renders immunological studies challenging. They have CD4+ αβ T lymphocytopenia with a concomitant expansion of CD4−CD8− double-negative (DN) αβ and Vδ2− γδ T lymphocytes, both displaying a unique CD38+CD45RA+T-bet+EOMES− phenotype. Itk-deficient mice recapitulated an expansion of the γδ T and DN αβ T lymphocyte populations in the thymus and spleen, respectively. Moreover, the patients’ T lymphocytes secrete small amounts of IFN-γ in response to TCR crosslinking, mitogens, or forced synapse formation with autologous B lymphocytes. Finally, the patients’ total lymphocytes secrete small amounts of IFN-γ, and CD4+, CD8+, DN αβ T, Vδ2+ γδ T, and MAIT cells display impaired IFN-γ production in response to BCG. Inherited ITK deficiency undermines the development and function of various IFN-γ–producing T cell subsets, thereby underlying TB.