Decreased hormone content of immune cells in children during acute lymphocytic leukemia (ALL) - effect of treatment.

Histamine, serotonin and triiodothyronine (T3) content of different circulating lymphocyte subsets of leukemic (acute lymphocytic leukemia, ALL) and non-leukemic (control) children were investigated by multicolor flow cytometry. The hormone contents of the cells were followed from the time of diagnosis till the end of treatment. Each hormone could be detected in every time in the investigated cell types, although the amounts of them changed during the treatment.T lymphocytes: Significantly lower amount of serotonin was found in each T cell subsets (Th, Tc and activated T lymphocytes) of leukemic children compared to the healthy control group at the time of diagnosis and it was permanently low during the maintenance therapy. The decreased amount of serotonin could be demonstrated in Tc and Th cells even at one year after the end of treatment. However, there was no alteration in the histamine and T3 content of T cell subsets in the time of diagnosis, but significant decrease was detected during the maintenance therapy and after treatment.NK cells: The serotonin and T3 contents of NK cells (both NK and NKT subsets) were significantly lower at the time of diagnosis and during the maintenance therapy. Similar decrease was detected in the case of serotonin in B cells. Although there was no difference in the T3 content of B cells at the time of diagnosis, significantly lower amounts could be detected during the therapy compared to the healthy control group. The serotonin concentration remained low for years after the end of treatment, both in B and NK cells. These observations might have diagnostic and prognostic importance.