Heat shock protein (HSP) expression in lymphocytes isolated from 20 patients with HIV disease and 15 age-matched controls was determined. Fold increases in lymphocyte hsp70 expression after heat shock were 4.52 +/- 2.97 in HIV-positive individuals compared with 2.60 +/- 1.29 for HIV-negative controls (P= 0.001). Given clear roles for HSP in the cross-presentation of antigens, alpha-defensin internalization and pro-inflammatory cytokine production, a further investigation of HSP in HIV patients is merited.