Development of positive DTH reactions to KLH and Candida in the 3 XHM participants who received rCD40L. The patients were administered rCD40L subcutaneously 3 times per week at 0.03 mg/kg for 22 weeks, and after a 12-week drug-free interval, the dose of rCD40L was increased to 0.05 mg/kg for an additional 22 weeks of treatment. Note the absent reactions during the drug-free interval and the posttreatment period, indicating the positive results during rCD40L treatment period were not because of repeated skin testing.