T-lymphocyte subsets and delayed type hypersensitivity as classification parameters for HIV infection among drug-addicts.

HIV selectively infects T helper lymphocytes, which play an essential role in cell-mediated immunity mechanisms. Impairment of these mechanisms can be evaluated, other than by clinical parameters, by testing lymphocytic subsets and cutaneous delayed type hypersensitivity. All these indices are used in the Walter Reed Foundation (WR) staging system, which includes the different stages of HIV infection. In our study we investigated the above mentioned parameters in a series of 180 HIV positive PDAs. A classification of the same patients according to WR's criteria was also designed. Of our patients, 46.1% resulted normoergic, 27.2% hypoergic and 26.7% anergic. Of all normoergic subjects, 83.7% (with more than 400 OKT4+ cells/mmc) could be assigned to the WR2 and 16.3% (with less than 400 OKT4+ cells/mmc) to the WR3 staging group. Among the hypoergic patients, only 34.7% were assignable to the WR4 group, whereas the majority (65.3%) had more than 400 OKT4+ cell/mmc. Even among the anergic group, 62.5% did not fit the WR5 stage, exhibiting an OKT4+ level higher than 400/mmc. In the latter 2 groups (referred to as D and E), T helper lymphocyte counts were performed at regular intervals; however, only the ones followed-up for at least 6 months were evaluated. OKT4+ cells were shown to decrease more frequently and more rapidly in the anergic than in the hypoergic patients, which points to cutaneous anergy as representing an early sign of impairment of cell-mediated immunity.