Skin test and blastogenic responses to Sporotrichun schenckii

In vivo skin testing and in vitro lymphocyte blastogenesis were evaluated in a young adult population as methods for detecting cellular immunity to Sporotrichum schenckii. Similar procedures for Candida albicans and Coccidioides immitis were also investigated. 5 of 143 subjects had positive skin tests and 14 had positive blastogenic responses to S. schenckii. These 14 subjects also exhibited unusually high responses to C. albicans in vitro and 11 of the 14 were female. Data demonstrated a correlation coefficient of 0.89 when comparing the blastogenic assays for S. schenckii and C. albicans, suggesting cross antigenicity. Intact cellular immune mechanisms in combination with exposure to C. albicans may protect the host from systemic infection with S. schenckii. Although a limited number of subjects were studied, as a group, females had more vigorous cellular immune responses to C. albicans than males. The rare occurence of sporothrix infection in females as compared to males may be the result of antigenic stimulation from commonly observed vaginal colonization with C. albicans. The present data indirectly support this hypothesis.