The impact of background lymphopenia on the reactivity of nonspecific immunity in response to total body cold exposure

Abstract

Lymphopenia is a condition in which there are lower than normal counts of lymphocytes in the blood. Combination of lymphopenia and prolonged exposure to low temperatures leads to a reduction of adaptive resources, increasing risks of chronic inflammatory processes and secondary environmentally induced immunodeficiencies. The aim of the study was to compare characteristics of immune reactivity in response to cold exposure depending on background level of lymphocytes. Changes in hematologic and immunologic parameters in 203 participants before and immediately after short-term cold exposure were studied. Measurements included skin temperature (forehead, backside of palm), blood pressure, heart rate, leukogram, and hemogram. Levels of ferritin, lactoferrin, transferrin, interleukin-6, interleukin-1β, TNFα, erythropoietin, and irisin were determined using the enzyme immunoassay method. Apoptosis and necrosis of lymphocytes were assessed by flow cytometry analysis using AnV/PI double staining assay. Regardless of the background level of lymphocytes in peripheral blood, same-type responses to short-term cold exposure were observed in cardiovascular system as well as in irisin and ferritin levels, providing an evidence of activating thermoregulation and thermal homeostasis mechanisms. Lymphopenia is associated with a decrease in activity of nonspecific defense - in response to cold exposure there were no changes in level and functional activity of circulating neutrophil granulocytes that can increase the risks of chronicization of infectious processes in this group.