Normal Expression of Cytotoxic T-lymphocyte- Associated Protein4 (CTLA4) in a Lipopolysaccharide- Responsive and Beige-like Anchor Protein (LRBA) Deficient Patient

Biallelic lipopolysaccharide-responsive and beige-like anchor (LRBA) mutations could lead to an immune dysregulation disorder, labeled as LRBA deficiency. A wide spectrum of clinical manifestation was shown to be associated with recurrent infections, enteropathy, hypogammaglobulinemia, and autoimmune complications. Notably, LRBA interacts with cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) by its recycling to the T-cell surface. Accordingly, LRBA deficiency abolishes CTLA4 protein expression. In this study, we presented a case with a homozygous mutation in the LRBA gene as well as a normal level of CTLA4 protein. In this regard, the immunologist assays of this patient revealed low immunoglobulin levels, CD4+ helper T cells, and CD19+ B cells.