A Patient with CTLA-4 Haploinsufficiency with Multiple Autoimmune Presentations: A Case Report

Increased susceptibility to autoimmunity, malignancy, and allergy in addition to recurrent infections are the main characteristics suggesting for the primary immunodeficiency diseases (PID). CTLA-4 is predominantly expressed on activated and regulatory T-cells, which can bind to CD80/CD86 molecules on antigen-presenting cells as a negative regulator. Here, we describe a 24-year-old male born from consanguineous parents with heterozygous CTLA-4 mutation who presented with multiple autoimmune diseases. His past clinical history revealed alopecia areata at four years old and subsequently, he developed Evans syndrome, type 1 diabetes mellitus, hypothyroidism, and chronic diarrhea while chronic rhinosinusitis and cytomegalovirus (CMV) colitis were the only infectious manifestations. Immunologic investigations revealed: low B cell count, abnormal Lymphocyte transformation test (LTT) to phytohemagglutinin (PHA), and hypogammaglobulinemia. Although all available treatments such as Intravenous Immunoglobulin (IVIG) therapy, immunosuppressive drugs, and antibiotic therapy were applied, diarrhea was not controlled due to colitis, which remained challenging. Whole exome sequencing was performed and the result showed heterozygous variant CHR2.204,735,635 G>A in the CTLA-4 gene, which was confirmed by the Sanger method. CTLA4 haploinsufficiency leads to autoimmune disorders, recurrent respiratory infections, hypogammaglobulinemia, lymphoproliferation with organ infiltration, and lymphocytic interstitial lung disease.