Expression of adhesion molecules in chronic serum sickness in rats

Peripheral blood leukocytes infiltrate the kidney in chronic serum sickness (CSS). We therefore studied the expression of CD54 and its ligands CD18 an d CD11b/c in CSS in 10 rats with CSS, 6 rats immunized similarly who did no t developed proteinuria (no-CSS group), and 10 normal rats (control group). Intense (6 to 35 times more than controls) leukocyte infiltration was obse rved in CSS. The CSS group over-expressed CD54 in glomeruli and interstitiu m in association with increments in CD18- and CD11b/c-positive cells rangin g 2.5 to 7 times the number found in controls. 75% of infiltrating leukocyt es expressed CD18 and 87% expressed CD11b/c. The non-CSS group had leukocyt e infiltration and expression of adhesion molecules similar to control grou p. Adherence of CD43-positive cells to renal tissues was 4 times higher in renal tissue from CSS rats than to normal kidney. Pretreatment with corresp onding Mabs reduced adherence by half. We concluded that over-expression of CD54 and its ligands CD18 and CD11b/c in infiltrating leukocytes occur in CSS. Binding experiments suggest the functional relevance of these molecule s, (C) 1999 Academic Press.