Delayed hypersensitivity skin tests (DHST) with recall antigens were investigated as prognostic markers in five different approaches.
In the first study, 42 acquired immunodeficiency syndrome (AIDS) patients (IVb, IVcl, IVd, and IVe; MMWR 3 5 3 4 4 3 9 , 1 9 8 6 ) 26 AIDS-related complex (ARC) patients (IVa and IVc2), and 98 asymptomatic patients (I1 and Ill) were evaluated with candidin, tricophytin, PPD and streptokinase-streptodornase. In the second study, 10 patients (I1 and Ill) were evaluated sequentially with the same antigens. In the third, 45 patients with at least two positive skin tests ("reactors") were followed for one year and evaluated every 6 months with the same antigens. In the fourth, 16 "reactors" were followed and evaluated every 3 months with the same antigens. We measured the interval from the time at which patients first presented with only one or no positive DHST until the development of ARC or AIDS. In the last study, the correlation between absolute number of CD4+ lymphocytes and the number of DHST was studied in 151 patients. We found that the decrease in reactiveness to DHSTcorrelated directly with the progression to AIDS, demonstrating the usefulness of this simple procedure as a valid prognostic marker.