[Clinical classification of adult T-cell leukemia and its complications]

Since human lymphotropic virus, type 1(HTLV-1) associated adult T-cell leukemia (ATL) has various clinical appearances and courses, it is difficult for the clinician to differentiate acute disease which needs immediate treatment from chronic disease which can be observed with no specific treatment. The Lymphoma Study Group of Japan (1984-87) proposed four clinical subtypes: (1) smoldering type; more than 5% of abnormal T-lymphocytes with less than 4000/microliters of lymphocytes in peripheral blood and few abnormal blood chemistry profiles and ATL infiltration, (2) chronic type; absolute lymphocytosis with T-lymphocytosis of more than 4000/microliters, LDH < 2 times the normal upper limit and no hypercalcemia with possible lymph-node, liver, spleen, skin and lung involvement, (3) lymphoma type; no lymphocytosis with less than 1% of abnormal T-lymphocytes, and histologically-proven lymph-node enlargement, and (4) acute type; the patients not classified into any of the above 3 types. The median survival time (MST) was 6.2 months for acute type, 10.2 months for lymphoma type, and 24.3 months for chronic type; 62.8% of smoldering type was still alive up to 4 years. ATL has a poor prognosis because of life-threatening complications including infections and hypercalcemia. Among infectious complications, cytomegalovirus (CMV) is frequently encountered in autopsy patients. It is important to make an early diagnosis since an anti-CMV agent, ganciclovir is now available for clinical use. It takes 10-14 days to culture CMV in vitro, but now rapid diagnosis can be made by direct immunoperoxidase staining with human monoclonal antibodies against an immediate-early antigen. Another major complication is hypercalcemia. The patients' serum and tumor tissues are found to have parathyroid hormone related protein (PTHrP) associated with hypercalcemia. Serum PTHrP (1-34) is determined by radioimmunoassay and its values seem to be correlated with hypercalcemia and the disease activity. There are still many problems to solve for ATL, but recent advances have been made in clinical subtypes and the above 2 complications.