T cell subpopulation dynamics following insulin-induced hypoglycaemia in normal subjects

Using monoclonal antibodies OKT3, OKT4 and OKT8, T lymphocyte subpopulations were determined in eight normal male volunteers. One month later, the T cell populations were again measured before and during an insulin stress test. Compared to the month before, there was a statistically significant reduction in the numbers of OKT4 cells (P less than 0.01) in the basal sample. Administration of insulin produced a statistically significant rise in the numbers of total lymphocytes and in each of the T cell subpopulations at 30 and/or 60 min (P less than 0.01) when compared with the basal values. It was also noted that in some of the subjects, the sum of OKT4 and OKT8 cells was greater than the number of OKT3 cells after insulin administration. This suggests that under certain circumstances T cells in circulation may express both the helper and suppressor cell antigen. Insulin stress test is associated with increased production of stress hormones in response to the hypoglycaemia, and the observed lymphocyte changes may be mediated via these hormonal alterations.