Ia+T10+ blast cells in acute lymphoblastic leukaemia are precursors of T+ and B+ cells

Leukaemic blasts isolated from peripheral blood of two patients with non-T, non-B ALL were cultivated for 10-13 days and cell markers were assayed on day 0 and during culture period. Using a panel of cell markers it was demonstrated that the populations of ALL blasts of both patients were composed of T10+Ia+ and "null" blasts. These blasts in the culture differentiated into three cell lines: T and B lymphocytes and myelomonocytic cells. The results thus obtained suggested that within the population of ALL blasts of these two patients there are progenitors of lymphoid and myelomonocytic cells ("null" blasts) and common precursors of T and B lymphocytes (T10+Ia+ blasts). In vitro differentiation of ALL blasts was not affected by LPS and CTPE.