LYMPHOCYTE SUBSETS AND ADHESION MOLECULES EXPRESSION IN HEATSTROKE AND HEAT-STRESS

We examined the specificity of the recently reported alterations in ci rculating lymphocytes in heatstroke by determining lymphocyte subsets in 14 consecutive heatstroke patients before and after cooling and in 7 heat-stressed controls using single-or two-color immunofluorescence flow cytometry. The relationship with catecholamine levels was also st udied. In heatstroke, percentages of T (CD3(+)/CD19(-)), T-helper (CD4 (+)/CD8(-)), T-inactive [CD3+/human leukocyte antigen-DR-], CD11a(+), CD11c(+), and CD44(+) lymphocytes were significantly decreased, wherea s percentages of T-suppressor-cytotoxic (CD8(+)/CD4(-)), natural kille r (NK; CD3(-)/CD16(+) or CD56(+)), CD3(+)/CD16(+) or CD56(+), and CD54 (+) lymphocytes were significantly increased, compared with 11 normal controls. The changes in the absolute numbers of lymphocyte subsets we re in the same direction and were significant for T-helper, T-suppress or-cytotoxic, NK, CD3(+)/CD16(+) or CD56(+), and CD11c(+) lymphocytes. Milder but significant changes in percentages of T-helper, T-suppress or-cytotoxic, CD11c(+), and CD44(+) lymphocytes were seen in heat stre ss. Cooling was associated with partial or complete normalization, fur ther derangement (CD11a(+), CD11c(+)), or overcorrection (NK, T-suppre ssor-cytotoxic, CD11b(+)) of abnormal percentages of lymphocyte subset s. Norepinephrine levels were significantly elevated in heatstroke (4. 7-fold) and heat stress (3.2-fold), but did not significantly correlat e with lymphocyte subsets. We conclude that heatstroke is associated w ith significant changes in percentages and in absolute numbers of a wi de range of circulating lymphocyte subsets that are not related to ele vated catecholamine levels or totally normalized by cooling. Similar, albeit milder, changes are seen in heat stress, suggesting that the tw o syndromes represent a continuum.