IL-2 receptor alpha deficiency and features of primary biliary cirrhosis

Congenital immune deficiency states have often been valuable experimental models of nature that have significantly enhanced our understanding of the immune response. The relationship between CD4+, CD25+ and Treg cells in the induction of autoimmunity has attracted significant attention. We report herein a male child of consanguineous parents who developed at six months recurrent infections, and at age 5 years, liver dysfunction with serological expression of primary biliary cirrhosis (PBC), an autoimmune liver disease that usually affects middle-aged women. Histologically, there was intense mononuclear cell lymphoid infiltration of the intrahepatic portal tracts, CD3+ CD4+ T cell lymphopenia in blood and serum antibody to PDC-E2. Peripheral blood lymphocytes were completely deficient of the alpha subunit of the IL-2 receptor (IL-2Rα, CD 25), a marker for regulatory T cells (Tregs). Allogenic stem cell transplantation led to full recovery. This case illustrates the role of deficiency of CD4+ CD25+ Treg cells in causing autoimmunity, and speaks to the potential use of allogenic stem cell transplantation for immunoreconstitution in adult PBC.