Type Two Hyper-IgM Syndrome caused by Mutation in Activation-Induced Cytidine Deaminase

DOI IR
  • Yi Zhu
    Department of Human Ontogeny and Childhood Development, Tokyo Medical and Dental University, School of Medicine, Tokyo, Japan
  • Nonoyama Shigeaki
    Department of Human Ontogeny and Childhood Development, Tokyo Medical and Dental University, School of Medicine, Tokyo, Japan
  • Morio Tomohiro
    Department of Human Ontogeny and Childhood Development, Tokyo Medical and Dental University, School of Medicine, Tokyo, Japan
  • Muramatsu Masamichi
    Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
  • Honjo Tasuku
    Department of Medical Chemistry, Graduate School of Medicine, Kyoto University, Kyoto, Japan
  • Mizutani Shuki
    Department of Human Ontogeny and Childhood Development, Tokyo Medical and Dental University, School of Medicine, Tokyo, Japan

Search this article

Abstract

Thirteen Japanese patients with hyper-IgM syndrome but normal CD40 ligand were characterized. All patients had mutations in AID (activationinduced cytidine deaminase) gene. Five of them had a missense mutation of Arg112His. In all patients, serum IgG, IgA and IgE levels were undetectable, B cells failed to produce detectable amounts of IgE even if cultured them with anti- CD40 and IL-4. Somatic hypermutation (SHM) was also impaired in their peripheral blood B cells. These results suggest that Arg112 is the hot spot of AID mutation and demonstrate that AID plays indispensable roles in class switch recombination (CSR) and somatic hypermutation (SHM) in human B cells. In addition, serum IgM levels in the patients have been continuously high even after proper intravenous immunogloburin infusion (IVIG) and without infection, indicate that AID has the function to induce spontaneous IgM production in B cells.

Journal

Keywords

Details 詳細情報について

Report a problem

Back to top