Complex chromosome damages in patients with recurrent acute leukemias after allogeneic hematopoietic stem cell transplantations]

Aim. To study the pattern or complex chromosome damages (CCD) in acute leukemias (AL) and their place in the development of post-transplant recurrences (PTR) of AL. Materials and methods. Cytogenetic and partially molecular biological studies of bone marrow cells were conducted in 10 patients with PTR. Of them, 6 patients were diagnosed as having acute lymphoblastic leukemia (ALL), including T-ALL and Ph-positive ALL in 2 and 4 patients, respectively; and 4 patients had acute non-lymphoblastic leukemia (ANLL), including one case secondarily induced by previous polychemotherapy (PCT) and irradiation. The standard G-band staining technique complemented by multicolor fluorescence in situ hybridization in one of the cases was used. Results. It was shown that CCD had the similar pattern in 4 patients before transplantation and in PTR, progressed in 4 more patients, was absent or unnoticed in the early stage of the disease. The other recurrent chromosomal abnormalities that are worthy of notice are as follows: a) the presence of two Ph chromosomes in the cells of two of the 4 patients with Ph+ ALL; b) the frequent involvement of chromosome pairs 9, 19, 5, and 7 into the numerical and structural rearrangements. Conclusion. The important feature of PTR of AL is cellular CCDs, a portion of which is clearly related to previous PCT and may be of pathogenetic value for the development of recurrences.