Sister chromatid exchange in lymphocytes in myelodysplastic syndrome.

Sister chromatid exchange (SCE), percentage of first, second, third mitoses, blastic transformation index and mitotic index in patients with myelodysplastic syndrome (MDS) (3 with refractory anaemia, 2 with refractory anaemia with sideroblasts, 1 with refractory anaemia with excess of blasts, 4 with refractory anaemia with excess of blasts in transformation) and in 15 healthy volunteers were estimated. Three types of lymphocytes cultures were set up: first with phytohemaglutinin (PHA), second with PHA and bromodeoxyuridine (BRdU), third with BRdU. In healthy persons the SCE frequency was negatively correlated to proliferating rate index, but in MDS such correlation was not found. The lymphocytes cell cycle duration based on percentage of mitoses was longer in MDS patients than in controls. The results of our studies show the disturbances of lymphocytes during cell cycle division resulting in higher SCE frequency and lower proliferating rate compared to controls.