Antibodies to Pityrosporum orbiculare in patients with tinea versicolor and controls of various ages.

Sera from patients with tinea versicolor and controls of various ages were investigated with the indirect immunofluorescence technique for antibodies against Pityrosporum orbiculare, the etiologic agent of tinea versicolor. No differences in titers were observed between patients and adult controls. Also, there were no differences in antibody titers in the patient group with regard to age and sex, or to duration and distribution of lesions. A statistically significant difference in antibody titers was observed between adult controls and children, particularly the youngest. Antibodies against Candida albicans from randomly selected sera from the same groups showed the same tendency, although only statistically significant when children of 5 years or younger were compared with adult controls. This investigation indicates that although P. orbiculare is capable of inducing antibodies, these are not correlated to tinea versicolor but occur when an individual becomes colonized with the organism.