Secretory and serum IgA are inversely altered in AIDS patients

Abstract

It is well-documented that levels of total serum IgA as well as IgA-containing immune complexes are often markedly and selectively increased in patients with AIDS. IgA antibodies specific for HIV have been demonstrated in mucosal secretions. All of these findings indicate a profound involvement of both the systemic and mucosal IgA systems in this disease. The present experiments were initiated to determine if alterations of the secretory component of the IgA system similar to those of its systemic counterpart could be identified. In order to determine if the secretory IgA system was quantitatively affected in a manner similar to that of its serum analogue, whole saliva samples obtained from normal volunteers and from patients with AIDS were assayed by quantitative ELISA for levels of total IgA and IgA subclasses. Total salivary IgA was decreased in the AIDS patients. Levels of salivary IgA1 did not differ significantly in the 2 populations. On the other hand, IgA2 levels were markedly diminished in patients with AIDS. Since a major mucosal (but not serum) IgA isotype is selectively diminished in AIDS (as opposed to often extreme elevations in total serum IgA), we conclude that the systemic and mucosal IgA systems appear to be inversely affected in this disease.