The influence of low-power helium-neon laser irradiation on function of selected peripheral blood cells.

The effects of low-level laser light irradiation are debatable and the mechanisms of its action are still unclear. This study was conducted to test the effects of low-level laser irradiation on human blood cells: erythrocytes, granulocytes, and lymphocytes. Whole blood obtained by phlebotomy was irradiated at 632.8 nm by using energy fluences 0.6 J/cm2. An analysis of blood gases revealed an increase in PO2 and SaO2 (P<0.001) in irradiated blood. No shifts in PCO2 and pH were recorded. Spontaneous synthesis of DNA in T and B blood lymphocytes decreased significantly after laser irradiation (P<0.02 and P<0.04, respectively). Phytohemagglutinin (PHA)-induced proliferation of T cells and SAC proliferation of B cells, expressed as a stimulation index, were statistically higher in the samples of irradiated than in non-irradiated blood (P<0.01). Chemiluminescence of fMLP-stimulated granulocytes from irradiated blood increased in comparison with non-irradiated samples (P<0.001). No changes of spontaneous and stimulated chemiluminescence kinetics in irradiated samples were observed. These results reveal the influence of photodynamic reactions on the ability of blood to transport oxygen and on immunomodulatory effects on leukocytes.