SOLUBLE INTERCELLULAR-ADHESION MOLECULE-1 (ICAM-1) IN SERUM AND URINE- CORRELATION WITH RENAL EXPRESSION OF ICAM-1 IN PATIENTS WITH KIDNEY-DISEASE

A soluble form of intercellular adhesion molecule-1 (sICAM-1) has been described in serum and other body fluids. In order to determine wheth er sICAM-1 in serum and urine is a useful marker of inflammatory activ ity in kidney diseases we measured sICAM-1 in serum and urine of fifty patients who underwent renal biopsy, and of twenty healthy individual s. Expression of ICAM-1 on proximal tubular epithelial cells was inves tigated by immunohistochemistry. Soluble ICAM-1 in serum did not diffe r between patients and controls (354 +/- 129 ng/ml vs. 305 +/- 52 ng/m l). By multiple regression analysis sICAM-1 correlated with tubular ex pression of ICAM-1 (p <0.01), but not with serum creatinine, infiltrat ing leukocytes, urinary ICAM-1 or proteinuria. In healthy controls mea n urinary ICAM-1/cr was 2.5 +/- 3.0 ng/mg creatinine and differed sign ificantly from that of patients (14.5 +/- 14.9 ng/mg) (p <0.005). Pati ents with minimal-change disease had the highest uICAM-1 levels. The r atio of urinary ICAM-1 and proteinuria was remarkably constant in all patients with 6.0 +/- 0.9 ng/mg. By multiple regression analysis uICAM -1/cr correlated with proteinuria/cr (p <0.001) and sICAM-1 (p <0.005) . These data show that sICAM-1 does to some degree reflect ICAM-1 expr ession in the kidney, whereas uICAM-1 is derived from glomerular filtr ation and closely parallels proteinuria. Both sICAM-1 and uICAM-1 are not useful to estimate ICAM-1 expression and inflammatory activity in the kidney.