The value of the lymphocyte proliferation test with phytohemagglutinin in the immune evaluation of Brazilian HIV-infected patients.

We evaluated phytohemagglutinin (PHA) lymphocyte proliferation and delayed-type hypersensitivity tests in 130 Brazilian HIV-infected patients with the objective of assessing the value of these tests in staging HIV infection. Patients were divided into three groups according to their CD4+ cell counts (cells/mm3): < 200 (n = 28); 200 to 499 (n = 50); and > or = 500 (n = 52). An additional 114 individuals, who had come to the same institution for elective surgeries, were enrolled as controls. Results showed a significant decrease in PHA responses when CD4+ cell counts fell below 500 cells/mm3. This decrease was, however, indistinguishable from that of patients with < 200 cells/mm3. In contrast, skin test anergy to common antigenic preparations was only evident in the group of patients with less than 200 CD4+ cells/mm3. Decreases in PHA responses and in CD4+ cell counts were significantly correlated. Since the introduction of antiretroviral therapy is recommended when CD4+ cell counts are below 500 cells/mm3, the PHA proliferation test, in our conditions, could be useful as an additional parameter to initiate antiretroviral therapy. Further prospective studies are needed to establish the value of this test in HIV-infected patients.