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Lymphocyte subsets and adhesion molecules expression in heatstroke and heat stress

M M Hammami1, A Bouchama, E Shail

  • 1Department of Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.

Journal of Applied Physiology (Bethesda, Md. : 1985)
|June 6, 1998
PubMed

Insights

Heatstroke significantly alters circulating lymphocyte subsets, with changes not fully reversed by cooling and unrelated to catecholamine levels. Heat stress shows similar, milder immune cell alterations, suggesting a continuum between the conditions.

Area of Science:

  • Immunology
  • Environmental Medicine
  • Physiology

Background:

  • Heatstroke is a severe condition with known physiological impacts.
  • Previous research suggested alterations in circulating lymphocytes during heatstroke.
  • The specific nature and extent of these lymphocyte changes, and their relationship to heat stress, remained unclear.

Purpose of the Study:

  • To investigate the specific alterations in circulating lymphocyte subsets in patients with heatstroke.
  • To compare these changes with those observed in individuals experiencing heat stress.
  • To examine the relationship between lymphocyte subset changes, catecholamine levels, and the effects of cooling.

Main Methods:

  • Single- or two-color immunofluorescence flow cytometry was used to analyze lymphocyte subsets.
  • Blood samples were collected from heatstroke patients (before and after cooling) and heat-stressed controls.
  • Catecholamine levels were measured and correlated with lymphocyte subset data.

Main Results:

  • Heatstroke patients exhibited significant decreases in T lymphocytes (CD3+), T-helper (CD4+), and increases in T-suppressor-cytotoxic (CD8+) and natural killer (NK) cells.
  • Absolute lymphocyte subset numbers showed significant changes in T-helper, T-suppressor-cytotoxic, NK, and CD11c+ cells.
  • Heat stress induced milder but significant changes in T-helper, T-suppressor-cytotoxic, CD11c+, and CD44+ lymphocytes.
  • Cooling resulted in partial normalization or overcorrection of abnormal lymphocyte subsets.
  • Elevated norepinephrine levels were observed in both heatstroke and heat stress but did not correlate with lymphocyte subset alterations.

Conclusions:

  • Heatstroke is characterized by widespread, significant alterations in circulating lymphocyte subsets.
  • These immune changes are not directly related to elevated catecholamine levels and are not fully normalized by cooling.
  • Heat stress presents with similar, though less severe, lymphocyte alterations, indicating a potential continuum between heat stress and heatstroke.

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