There are three major categories of antibody deficiencies: (a) defects in early B cell development, (b) hyper-IgM syndromes (also called class switch recombination defects), and (c) common variable immunodeficiency (CVID). Category (b), hyper-IgM syndrome (HIM), represents a group of distinct entities characterized by defective normal or elevated IgM in the presence of diminished IgG and IgA levels. Seventy per cent of the cases are X-linked in inheritance, and others are autosomal recessive. In the autosomal recessive hyper IgM syndromes, the problem lies in the nucleotide-editing enzymes AICD or UNG. These enzymes are only present in the germinal center B cells, and defects in either disrupt B-cell development and antibody production. Patients with these syndromes typically have recurrent bacterial infections and often have lymphoid hyperplasia.
Revy P, Muto T, Levy Y, Geissmann F, Plebani A, Sanal O, Catalan N, Forveille M, Dufourcq-Labelouse R, Gennery A, Tezcan I, Ersoy F, Kayserili H, Ugazio AG, Brousse N, Muramatsu M, Notarangelo LD, Kinoshita K, Honjo T, Fischer A, Durandy A
タイトル
Activation-induced cytidine deaminase (AID) deficiency causes the autosomal recessive form of the Hyper-IgM syndrome (HIGM2).
