[Cytogenetic studies in hematological diseases. Analysis of 185 cases]

To analyse the chromosomal abnormalities found at diagnosis in patients with malignant blood diseases.

Between june 1988 and january 1992, cytogenetic studies were performed at the Cytogenetics Laboratory of the Abel Salazar Institute for Biomedical Sciences on 185 patients with malignant blood diseases. Bone-marrow and/or peripheral blood cells were used for such studies, two simultaneous cultures being prepared at 24 and 48 hr, plus another one, stimulated with phytohemagglutinin, at 72 hr. Trypsin G-banding techniques were used for chromosome identification. Chromosomes were classified in accordance with the international system, and a clone was judged abnormal whenever two or more metaphases showed identical structural abnormalities or extra chromosome(s) and three or more metaphases lacked the same chromosome(s).

Evaluable mitoses were found in 152 of the 185 cytogenetic studies performed (82.2%), pertaining to chronic myelogenous leukaemia (39/42), acute nonlymphoblastic leukaemia (40/43), myelodysplastic syndromes (10/17), acute lymphoblastic leukaemia (30/36), and chronic lymphoproliferative disorders (10/14). Chromosomal alterations, previously described in each diagnostic variety, were found in 69% of the cases with abnormal karyotype. The remaining patients (31%) had chromosomal abnormalities not reported consistently.

The karyotype should be studied regularly in haematologic disorders since, although lacking precise prognostic implications, it may help gain information with regard to the genetic alterations in different blood diseases.