Delayed hypersensitivity cross-reactions between Sporothrix schenckii and Ceratocystis species in sporotrichotic patients.

Cutaneous delayed hypersensitivity to antigens prepared from Sporothrix schenckii and several Ceratocystis species, including C. stenoceras, C. ulmi, C. ips, and C. minor, was tested in 14 patients with known cutaneous sporotrichosis. Extensive cross-reactions were observed. Nonsporotrichotic people (controls) did not react to these antigens. The correlation coefficient between antigens of S. schenckii and each Ceratocystis species was calculated from the areas of the cutaneous reactions. Among the Ceratocystis species tested, the correlation coefficient between S. schenckii and C. stenoceras was 0.91.