Cutaneous sensitivity and in vitro responsiveness of lymphocytes in patients with disseminated coccidioidomycosis.

Sixty-eight of 74 patients with disseminated coccidioidomycosis demonstrated cutaneous reactivity to intradermal injectionof coccidioidin. Lymphocytes of all patients with positive skin test results underwent blast transformation in vitro in response to coccidioidin. No correlation was found between the size of skin test induration and the magnitude of in vitro lymphocyte response. Six patients with disseminated disease failed to demonstrate cutaneous reactivity to coccidioidin; however, lymphocytes of three of these patients responded with blast transformation in vitro. The lymphocyte reactivity of two of these three patients was abrogated by addition of autologous plasma to the culture medium. Autologous plasma did not block the patient's in vitro response to phytohemagglutinin or allogeneic lymphocytes, and blocking did not appear to be attributable to direct neutralization of coccidioidin.