In: Biology
Selective IgA deficiency is been found with frequency of 1 in 600 in Caucasian race. In current definition, if serum level of IgA falls below 0.07 g/lt with normal IgG and IgM levels in individuals above 4 age is considered as to have selective IgA deficiency.
a. Selective IgA deficiency is believed to associated with human leukocyte antigen (HLA)-B8, DR3, DQ2 (8.1) haplotype. Non-Major histocompatibility complex (MHC) genes are also involved autoimmune disorders. These genes are known to involve in several immune functions such as T-cell differentiation, cell activation/signaling and innate immunity. However, the mechanism underlying Selective IgA deficiency still remains elusive.
b. Serum IgA is shown to have both pro and anti-inflammatory activities at mucosal barriers. IgA also involved to control the activities of other immunoglobulin molecules. For example, in the absence of antigen, IgA downregulates the activities of IgG such as phagocytosis, chemotaxis, bactericidal activity, oxidative burst activity and cytokine release. In the absence of IgA in mucosal site. If IgA deficiency occurs, then these regulatory functions of IgA are impaired and hence lead to breach in mucosal barrier.