Percentage of lymphocytes (A) and monocytes (B) expressing membrane-bound (m)TNFα and mTNFRs (p55- and p75-TNFR) were analyzed by flow cytometry in three different immunologic subgroups of HIV-1–infected patients and 12 healthy controls. The patients were classified in three groups according to their CD4⁺ lymphocyte counts as follows: I, CD4⁺ lymphocyte counts < 199 × 10⁶/L, (n = 11); II, CD4⁺ lymphocyte counts of 50 to 199 × 10⁶/L, (n = 12); III, CD4⁺ lymphocyte counts < 50 × 10⁶/L, (n = 10). *P < .05 versus controls, **P < .01 versus controls, ^ρP < .05 versus CDC group C, ^#P < .01 versus CDC group C. Data are given as medians and 25th to 75th percentiles.