EXPRESSION ON LEUKEMIC-CELLS AND SERUM CIRCULATING LEVELS OF INTERCELLULAR-ADHESION MOLECULE-1 (ICAM-1) IN B-CELL CHRONIC LYMPHOCYTIC-LEUKEMIA - IMPLICATIONS FOR PROGNOSIS

Expression of intercellular adhesion molecule-1 (ICAM-1) has been corr elated with clinical and laboratory characteristics of 62 patients wit h untreated CD5+ chronic lymphocytic leukemia (CLL). ICAM-1 was detect ed on B-CLL cells from 19 out of 62 patients (30.6%) and its expressio n did not correlate with the majority of immunological markers. An imp ortant finding of this study was the association between ICAM-1 expres sion and mean fluorescence intensity (MFI) of SIg (r=0.507; P<0.001). As far as correlation with clinical parameters is concerned, a statist ically significant association between Binet clinical stages and ICAM- 1 expression was found (P<0.05). Furthermore, an atypical CLL morpholo gy was more frequently encountered among patients who expressed ICAM-1 (P<0.005). To obtain more information on the role of ICAM-1 in CLL we measured serum levels with a sandwich enzyme immunoassay. In 47 B-cel l CLL patients studied, the mean value of circulating ICAM-1 levels wa s significantly higher (561+/ 201 ng/ml) than that observed in 25 norm al controls (353+/-162 ng/ml; P<0.005); a clear correlation being foun d with Binet clinical stages (P=0.026) and bone marrow (BM) histology (P<0.005). We conclude that circulating ICAM-1 is elevated in CLL and such an increase reflects tumor mass as defined by clinical stages and BM histology, rather than peripheral blood lymphocytosis (r=0.240). E ven if soluble ICAM-1 appears to be less specifically increased than s oluble CD23 serum levels, these circulating molecules were not complet ely independent of each other (r=0.512; P<0.001).