Distribution and mitogen response of peripheral blood lymphocytes after exertional heat injury

• Published in: Journal of applied physiology (1985) 2003-12, Vol.95 (6), p.2381-2389
• Main Authors: DuBose, David A, Wenger, C. Bruce, Flinn, Scott D, Judy, Thomas A, Dubovtsev, Alexandre I, Morehouse, David H
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Antigens, CD - genetics; Antigens, Differentiation, T-Lymphocyte - genetics; Biological and medical sciences; CD3 Complex - immunology; CD3 Complex - physiology; Cell Division - physiology; Female; Fever - immunology; Fever - physiopathology; Flow Cytometry; Fundamental and applied biological sciences. Psychology; Heat; Heat Exhaustion - blood; Heat Exhaustion - immunology; Humans; Immune system; Injuries; Lectins, C-Type; Lymphocyte Count; Lymphocyte receptors; Lymphocyte Subsets - immunology; Lymphocyte Subsets - physiology; Lymphocytes - immunology; Lymphocytes - physiology; Male; Military Personnel; Mitogens - pharmacology; Phytohemagglutinins - pharmacology
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00039.2003

1 United States Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760; and 2 Naval Hospital, Beaufort, South Carolina 29902 Submitted 14 January 2003 ; accepted in final form 4 August 2003 To determine whether immune disturbances during exertional heat injury (EHI) could be distinguished from those due to exercise (E), peripheral lymphocyte subset distributions and phytohemagglutinin-stimulated CD69 mitogen responses as discriminated by flow cytometry were studied in military recruits [18.7 ± 0.3 (SE) yr old] training in warm weather. An E group (3 men and 3 women) ran 1.75–2 miles. During similar E, 11 recruits (10 men and 1 woman) presented with suspected EHI. EHI (40.4 ± 0.3°C) vs. E (38.6 ± 0.2°C) body temperature was significantly elevated ( P < 0.05). Heat illness was largely classified as EHI, not heatstroke, because central nervous system manifestations were generally mild. Blood was collected at E completion or EHI onset (0 h) and 2 and 24 h later. At 0 h (EHI vs. E), suppressor, natural killer, and total lymphocyte counts were significantly elevated, helper and B lymphocyte counts remained similar, and the helper-to-suppressor ratio was significantly depressed. By 2 h, immune cell dynamics between groups were similar. From 0 to 24 h, T lymphocyte subsets revealed significantly reduced phytohemagglutinin responses (percent CD69 and mean CD69 fluorescent intensity) in EHI vs. E. Thus immune cell dynamics with EHI were distinguishable from E. Because heat stress as reported in exercise or heatstroke is associated with similar immune cell disturbances, these findings in EHI contributed to the suggestion that heat stress of varying severity shares a common pathophysiological process influencing the immune system. leukocytes; lymphocyte subsets; hyperthermia; heat stress; heatstroke; flow cytometry; exercise; phytohemagglutinin Address for reprint requests and other correspondence: D. A. DuBose, Thermal and Mountain Division, USARIEM, 15 Kansas St., Natick, MA 01760 (E-mail: david.dubose{at}na.amedd.army.mil ).