Activation-induced deaminase (AID) is required for class switch recombination (CSR) and somatic hypermutation (SHM), which are responsible for secondary diversification of antibodies in germinal centers.
AID initiates these processes by deamination of cytosines on the immunoglobulin (Ig) locus, a potentially mutagenic activity. AID expression is restricted to germinal-center B cells, but the mechanisms that regulate its target specificity are not completely understood.
AID expression is an indicator of an unfavorable prognosis in chronic lymphocytic leukemia/small lymphocytic lymphoma patients.
References
AID protein expression in chronic lymphocytic leukemia/small lymphocytic lymphoma is associated with poor prognosis and complex genetic alterations. Leuenberger M, Frigerio S, Wild PJ, Noetzli F, Korol D, Zimmermann DR, Gengler C, Probst-Hensch NM, Moch H, Tinguely M. Mod Pathol. 2009 Nov 6. PMID: 19898425
A coming-of-age story: activation-induced cytidine deaminase turns 10. Delker RK, Fugmann SD, Papavasiliou FN. Nat Immunol. 2009 Nov;10(11):1147-53. PMID: 19841648
Activation-induced deaminase: light and dark sides. de Yebenes VG, Ramiro AR. Trends Mol Med. 2006 Sep;12(9):432-9. PMID: 16861038