Elevated antibody levels to mycobacterial 65-kDa stress protein in patients with superficial candidiasis

Antibody levels to the mycobacterial 65-kDa stress protein (mSP65) were determined by ELISA in sera from patients with chronic atrophic oral candidiasis, vulvovaginal candidiasis, Candida albicans-infected or noninfected oral lichen planus, or recurrent aphthous ulceration and from subjects with clinically healthy oral mucosa. The results showed significantly elevated anti-mSP65 antibody levels in patients with oral or vulvovaginal candidiasis and in patients with Candida-infected lesions of lichen planus when compared with patients with noninfected lichen planus or recurrent oral ulceration and with matched healthy controls (P less than .001). Immunoblot analysis showed that the rabbit antiserum that strongly bound to mSP65 cross-reacted only weakly with a homologous band of a soluble C. albicans extract. Moreover, the binding of antibodies from patients with candidiasis to the mSP65 antigen was not inhibited in the presence of Candida extract. In view of the poor serologic cross-reactivity, it seems plausible that the recall stimulation of anti-mSP65-producing B cells could be induced by helper T cells that cross-react with the structurally homologous protein of C. albicans.