Cytogenetic follow-up after allogeneic bone-marrow transplantation for Ph1-positive chronic myelogenous leukemia.

Serial cytogenetic studies were carried out on 36 patients with Ph1-positive chronic myelogenous leukemia treated with allogeneic bone-marrow transplantation from unlike sex (21 patients) or like sex (15 patients) donors. Fourteen of the 21 sex-mismatched and 12 of the 15 sex-matched donor marrows were T cell depleted. Disease relapse was documented in 19 of the 26 patients who received T cell-depleted marrow, and in none of the 10 patients who received non-T cell-depleted marrow. In the group of patients with unlike sex donor, a triple donor/normal recipient/Ph1-positive recipient or a double donor/Ph1-positive recipient chimerism was documented during the subsequent months, while on alpha-interferon treatment for relapse. Two of these patients subsequently showed a complete disappearance of the Ph1 chromosome. Unstable and/or stable, clonal or non-clonal chromosome changes were detected in Ph1-positive cells from 12 of the 19 patients who relapsed. Analysis of the identified stable changes showed a non-random distribution of breakpoints with clustering to chromosome nos. 1, 4, 7 and 12.