Humoral immunity in nasal mucosa of patients with common variable immunodeficiency.

Humoral immunodeficiency, as reflected by the low serum immunoglobulin (Ig) concentrations in adult patients with common variable immunodeficiency (CVID), was even more severely expressed at the B-cell level in their nasal mucosa. No Ig-producing cells could be detected by immunohistochemistry in 11 of 19 mucosal specimens. The epithelial distribution of secretory component (SC) was normal in all specimens, but a sign of SC-dependent IgM transport was seen in only three. Epithelial IgA was completely lacking. All patients had had recurrent lower respiratory tract infections and 16 had recurrent or chronic infections of the upper respiratory tract. A previous report indicated that the intestinal mucosa is a privileged site for maturation of B cells in patients with CVID; the present study shows that this does not hold true for the nasal mucosa. This difference in B-cell maturation may in part explain the preferential susceptibility to infections in the respiratory tract of patients with CVID.