Soluble complement receptor type 1 (sCR1) in chronic liver diseases: serum levels at different stages of liver diseases.

Complement receptor type 1 (CR1) is an integral membrane protein of many haematopoietic cells and plays an important role in the clearance of complement-associated immune complexes, favouring their transport to liver and spleen macrophages. A small amount of soluble CR1 (sCR1) is also found in plasma and might originate directly from release of leucocytes and other circulating cells. In previous studies, an increase in serum sCR1 level has been observed in liver cirrhosis and end-stage renal failure. High levels have also been found in patients with some haematologic malignancies. sCR1 serum levels were measured using a specific double sandwich ELISA assay. The present study demonstrates the correlation between mean serum sCR1 concentrations and disease severity in patients with chronic liver disease. In patients with liver cirrhosis, grouped according to the Child-Pugh classification, sCR1 rose as liver function decreased. The presence of neoplastic growth in the liver apparently does not play a role in the increase of sCR1. Serum sCR1 was not elevated in other solid malignancies. Since sCR1 accumulates in liver diseases, evaluation of its serum levels could be useful as a liver function test.