A prospective study of acute respiratory tract infections among children in a kibbutz: the role of secretory IgA and serum immunoglobulins.

Absolute concentrations of IgA in nasal secretions and concentrations of immunoglobulins in serum were determined in a prospective study of acute respiratory tract infections. The study was carried out in 48 children aged six months to four years liveing in a kibbutz with a homogeneous environment. No correlation was demonstrated between mean base-line levels of secretory IgA or serum IgA and number of episodes of acute resporatory tract infection. However, children who responded to infection by the production of higher levels of secretory IgA had a lower incidence of acute respiratory tract infection than those who did not. Thisfinding supports the hypothesis that the responsiveness of the host in the production of secretory IgA during infection is important in protection against mucosal infections.