Lysozyme in plasma and neutrophilic granulocytes in ulcerative colitis and Crohn's disease.

The concentration of lysozyme in plasma (P) and in neutrophil leucocytes (N) was determined by a turbidimetric method in 32 patients with ulcerative colitis (U.C.), 11 patients with Crohn's disease (C.D.), 9 patients with haemorrhagic proctitis, and 39 healthy volunteers. In active U.C., P was significantly elevated (p less than 0.05), whereas C.D. showed normal values. Corresponding N was significantly reduced in active U.C. (p less than 0.05) but normal in C.D. In calculating the ratio N/P, highly significant lower values were found in active U.C. (p less than 0.001) compared to normal levels in C.D. The high P in active U.C. is presumed to reflect an accelerated destruction of neutrophil leucocytes as well as an intensified turnover rate. The reduced N is probably attributable to an inhibited synthesis. The findings suggest that lysozyme determinations are valuable in be differential diagnosis of active U.C. and C.D.