Acute lymphoblastic leukaemia in adults: immunological subtypes and clinical features at presentation.

In 91 of 106 adult patients with acute lymphoblastic leukemia (ALL) enrolled in the treatment protocol ALL HOVON-5 between May 1988 and October 1991, the immunophenotype of the leukemia was determined and correlated with clinical characteristics at presentation. The immunological marker analysis was performed in ten laboratories, all members of the Dutch Study Group on Immunophenotyping of Leukemias and Lymphomas (SI-HON). Undifferentiated blasts were found in four patients, 67 had B-lineage ALL, 18 had T-lineage ALL, and two had biphenotypic ALL. The age of T-lineage ALL patients was lower (mean 29.3) than that of B-lineage ALL patients (mean 35.5). Tumor mass, as expressed by leukocyte count, organomegaly, and LDH, was more pronounced in T-lineage ALL. Hemoglobin and platelet count was similar in all (sub)types. CD34 was expressed in 58% of the leukemias, but most frequently in the common B-ALL (70%). Thirteen percent of the leukemias expressed one or more markers not associated with their lineage. In this prospective study immunological data were not evaluable for 15 patients. On four of them data were not available because of dry tap, for six patients the typing was technically insufficient, and for four patients the results were unclassifiable; with one patient the marker analysis was not performed.