[Dna comets as markers of cells death]

Unstimulated human peripheral blood lymphocytes gradually underwent death during incubation in vitro. According to morphological criteria, the type of death was identified as apoptosis. After immobilization in agarose, lysis, and electrophoresis, these lymphocytes formed DNA comets, which differed in DNA content, tail length, tail moment, and the fraction of DNA migrating in the comet tail. We classified the comets in 3 groups in accordance with the values of these parameters. There was a good correlation between the fraction of apoptotic cells (morphological data) and the fraction of "apoptotic" DNA comets. The results showed that DNA comets may be adequate markers of cell death (including apoptosis). The use of DNA comets as markers of spontaneous death made it possible to reveal an increased level of apoptosis in vitro lymphocytes from patients with systemic lupus erythematosus.