Effect of major burns on early and late activating markers of peripheral blood T lymphocytes.

It is known that lymphocytes immunophenotype is a reflection of the functional level of the immune system. The immunosuppressive effect of major burns is also known for many years. T lymphocytes of 50 major burn patients were analyzed in base line (BL) samples at 24 hours and at 1 week and 2 weeks after burn, using monoclonal antibodies of CD3, CD4, CD8, CD25 (IL2R) and HLA-DR by flow cytometry and β2-microglobulin (β2-m) by ELISA. Recorded values were compared with those of 50 healthy donors. There was statistically significant reduction in absolute number of CD3 positive cells (CD3+) (p<0.000) and CD4/CD8 ratio (p=0.01) in the first 24 hours in comparison with controls. CD25 (IL-2R) shows insignificant upregulation on T lymphocytes after burn with significant upregulation of HLA-DR. The absolute number of CD3+ cells began to increase after 2 weeks (p=0.03) but remained less than controls (p=0.08). CD4/CD8 ratio was more or less same as healthy controls after 2 weeks. Upregulation of CD25 was insignificantly increased and that of HLA-DR was markedly increased after 2 weeks (p=0.001). Significant negative correlations were detected between mean values of β2-m and both absolute numbers of CD3 and CD4 positive cells in BL and one week samples. In addition there was significant correlation between mean values of β2-m and values of CD25 expression in the BL samples. The obtained data is suggestive of persistent activation of T lymphocytes two weeks after major burns whereas early shedding of β2-m is related to activation of lymphocytes increasing their susceptibility to apoptosis, both indicative of altered immune response. Burn intensivists and surgeons should be keen to support the patients' immune system in the first hours following major burns. This support will ensure free-bacteremic blood with a consequent better prognosis.