SERUM LEVELS OF CIRCULATING ICAM-1 ARE INCREASED IN HODGKINS-DISEASE

The intercellular adhesion molecule 1 (ICAM-1) is the ligand for the l ymphocyte function-associated antigen 1 (LFA-1). The ICAM-1/LFA-1 comp lex mediates cell-cell and cell-matrix interactions and is believed to be crucial for several immunological functions, including non-MHC-res tricted cytoxicity. Recently, a circulating form of the surface ICAM-1 molecule, the 82 kDa cICAM, has been identified. Using enzyme-linked immunosorbent assay (ELISA) we have examined 82 kDa cICAM-1 levels in the sera of 45 age- and sex-matched healthy subjects and 130 consecuti ve patients with Hodgkin's disease (HD). The mean +/- SD concentration of the 82 kDa cICAM-1 was significantly higher (p < 0.001) in HD pati ents (725.6 +/- 141 ng/ml) than in healthy controls (403.5 +/- 54.5 ng /ml). Patients with B-symptoms (n = 66) had higher cICAM-1 levels than patients without systemic symptoms (n = 64) (825.1 +/- 202.9 ng/ml ve rsus 671.7 +/- 164.9 ng/ml; p < 0.001). Serum levels of cICAM-1 were a lso significantly higher (p < 0.05) in patients with disseminated dise ase (stage III and IV) than in those with localized disease (stage I a nd II). The HD patients in stage III and IV with B-symptoms had signif icantly higher (p < 0.001 and p < 0.02, respectively) cICAM-1 levels t hen stage III/IV patients lacking B-symptoms. The increase of cICAM-1 concentrations was positively correlated to increases of soluble recep tors for interleukin-2 (sIL-2R) (r = 0.69; p < 0.001). Since cICAM-1 i s functionally able to bind to LFA-1, increased serum levels of this m olecule could be a mechanism for promoting de-adhesion and inability o f Hodgkin and Reed-Sternberg cells (H-RS) to be recognized by cytotoxi c effector cells, and could thus represent a way for these cells to es cape immunosurveillance and for progression and spreading of disease.