RESUMEN
In vitro human lymphocyte culture methodology is well established yet certain confounding factors such as age, medical history as well as individual's blood type may potentially modulate in vitro proliferation response. These factors have to be carefully evaluated to release reliable test report in routine cytogenetic evaluation for various genetic conditions, radiation biodosimetry, etc. With this objective, the current study was focused on analyzing the proliferation response of lymphocytes drawn from 90 individuals (21-29 years) with different blood types. The proliferation response was assessed in the cultured lymphocytes by cell cycle, mitotic index (MI), and nuclear division index (NDI) after stimulation with phytohaemagglutinin (PHA). To investigate the toxic effect on proliferation, MI was calculated in representative samples of each blood type were X-irradiated. The results showed that there was no significant difference among the cell cycle phases of lymphocytes in different blood types (P > 0.05). Similarly, both MI and NDI of lymphocytes derived from different blood types also did not show significant difference ( P > 0.05). The extensive interindividual variation within and among the blood types is likely responsible for the lack of significant difference in lymphocyte proliferation. Although spontaneous proliferation efficiency of lymphocytes of different blood types after PHA stimulation was grossly similar, the MI observed after radiation exposure showed a significant difference ( P < 0.05) indicating a differential proliferation response among the blood types. Our results suggest that the blood types did not have any impact on PHA-induced proliferation; however, a specific differential lymphocyte proliferation observed after radiation exposure needs to be considered.