ИСТИНА

Under normal conditions, the number of leukocytes and platelets in the blood is several orders of magnitude lower than the concentration of erythrocytes in the blood, but these cells have important functions such as immune response and blood clots formation. Quantification of the number of leukocytes of different subpopulations (neutrophils, eosinophils, etc.), as well as determination of number of activated and nonactivated platelets per volume is an important clinical test that can reveal abnormalities in functional state of the patient. Leukocytes and thrombocytes counting typically is carried out in vitro using special staining and fluorescent labels using flow-cytometry or conventional wide-field microscopy. Recent studies show that leukocyte counting in vivo can be performed by monitoring the circulation of blood in microvessels [1]. Also, unlike red blood cells, leukocytes have relatively high autofluorescence signal [2]. Thus, the classification of blood cells can be performed in vivo using autofluorecence properties of white blood cells. Here we show how fluorescent properties of different subpopulation of leukocytes and activated and non-activated platelets differ in vitro using single cell fluorescence microscopy. Based on these results, we suggests the method for detecting fluorescent response from leukocytes in the microcapillary vessels of the human papillary dermis in vivo. Our results show to which extent autofluorescence of white blood cells and platelets can be used to observe and classify them in the blood flow both in vivo and in vitro. We believe that these results can be applied in the sphere of in vitro clinical tests and in the non-invasive monitoring of leukocytes and platelets levels in the blood.