A 17 year old Caucasian woman in whom disseminated coccidioidomycosis developed with culture positive meningitis during her third trimester of pregnancy was treated with amphotericin B and subsequently with transfer factor prepared from her father's peripheral lymphocytes. Clinical response and in vivo and in vitro immunologic data indicated that this transfer factor afforded a significant contribution to her survival whereas previous therapy with transfer factor from an unrelated donor provided only transient immunologic reactivity. This experience suggests that transfer factor prepared from a related donor with positive responses to C. immitis may be more efficacious than that prepared from an unrelated donor.