Cytokine responses differ by compartment and wasting status in patients with HIV infection and healthy controls

Inflammatory cytokines are implicated in the loss of lean tissue that occurs in patients with inflammatory and infectious diseases, including HIV infection. However, it is not known whether plasma levels or cellular production of cytokines, or their antagonists, are more closely related to lean tissue loss. We studied whether plasma cytokine analysis could substitute for PBMC production assays in studies of nutrition status and disease state, and if cytokine antagonists could offer an alternative in assessing cytokine status. We used a bout of moderately difficult exercise to perturb cytokine production in 12 adults with HIV without wasting, 10 adults with HIV wasting, and nine healthy controls. Plasma and peripheral blood mononuclear cell (PBMC) production of interleukin-1 beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1ra) and soluble TNF receptor type II (sTNFrII) were measured at baseline and 2, 6, 24 and 168h following exercise. PBMC production of IL-1beta, TNF-alpha and IL-6 were all higher in the HIV-infected patients without wasting than in the controls (P<0.05) or the patients with AIDS wasting (P<0.05). Plasma concentrations of TNF-alpha and IL-6 were higher in the HIV wasted patients than in the controls (P<0.05). Both plasma and PBMC levels of sTNFrII were higher in HIV patients, regardless of wasting, than in controls. These data suggest that the PBMC cytokine compartment is more sensitive to nutritional and metabolic abnormalities than is the plasma compartment. PBMC production of IL-1beta, IL-6 and TNF-alpha best distinguish between HIV patients with and without wasting, while plasma concentrations of IL-6 and TNF-alpha are elevated in AIDS wasting, but do not reliably distinguish patients with wasting from HIV-infected patients without wasting.