慢性骨髄増殖性疾患における染色体異常

—疾患の独立性と相互性の検討—

抄録

Cytogenetic studies were performed on 60 patients with chronic myeloproliferative disorder (MPD). Chromosome analyses were done with G and Q banding on bone marrow or peripheral blood cells incubated for 24 hr. A clonal chromosomal abnormality was observed in 2 of 26 patients with polycythemia vera (PV), in 4 of 23 with essential thrombocythemia (ET), in 4 of 6 with myelofibrosis, and 4 of 5 with UMPD, that could not be classified into any type of the disease. Structural abnormalities of the long arm of no. 20 were found in 4 patients, and were possibly specific for PV and ET. Moreover, the deletion of chromosomal segment was commonly found compared with the chromosomal translocation.
Chromosomal analysis of a single colony derived from BFU-E or CFU-GM in a patient with ET showed 1q trisomy which was identical to the aberration found in the short term culture of bone marrow cells. This is a cytogenetic evidence for monoclonal origin of the disease.
Rearrangement of the bcr gene was studied in 6 patients; 2 with PV, 2 with ET, and 2 with UMPD. DNA prepared from the bone marrow or peripheral blood cells was digested with the restriction enzyme Bgl II, Bam HI, and HindIII. Southern blot analysis using a 0.6-kb fragment of the bcr gene showed the presence of a rearranged fragmnet in a UMPD patient with Ph¹ translocation, who had not any clinical features of chronic myelocytic leukemia at all. Both cytogenetic and molecular analysis will make it possible not only to elucidate the pathogenesis of UMPD but also to evaluate their clinical features.