CD79A and Opportunistic infection: Other studies have shown that IgA secretion is decreased in the parotid and palatine tonsils, suggesting that systemic and mucosal immune responses vary in HIV infection.14, 15, 32 In this study, secretory IgA levels are markedly reduced; such a difference between the systemic and mucosal response could contribute to/or explain the reduction in mucosal defenses, which results in opportunistic infections.