ABSTRACT
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.
PIP: During 1993-94, in Sao Paulo, Brazil, clinical investigators used the phytohemagglutinin (PHA) lymphocyte proliferation and delayed-type hypersensitivity tests to determine the stage of HIV infection among 130 adult HIV-infected patients. They aimed to evaluate the value of these tests. 28 (21.5%) patients had CD4+ cell counts of less than 200 cells/sq m. 50 had 200-499 CD4+ cells/sq m. The remaining 52 had at least 500 CD4+ cells/sq m. The researchers compared data on the HIV-positive adults with data on 111 HIV-negative controls. When patients had a CD4+ count of less than 500 cells/sq m, PHA responses were significantly lower than those for a CD4+ cell count of more than 500 cells/sq m and the controls (p 0.01 and p 0.001; respectively). Reductions in PHA responses and in CD4+ cell counts had a significant association. HIV-positive patients with less than 200 CD4+ cells/sq m were less likely to exhibit skin test anergy to common antigenic preparations than other HIV-positive patients (5% vs. 46%; p = 0.003). These findings suggest that the PHA proliferation test could help providers determine at what point in an individual's progression of HIV disease to initiate antiretroviral therapy (i.e., 500 cells/sq m). Further prospective studies are warranted to confirm the value of this test in HIV-positive individuals.
