Indices of granulocyte activity in inflammatory bowel disease

Abstract

Under conditions of increased neutrophil production, the serum total vitamin B12 binding capacity (TBBC) is considered to correlate with the blood pool size of neutrophil granulocytes. The serum lysozyme, on the other hand, is a measure of neutrophil (and monocyte) turnover. The mean serum TBBC was significantly raised in 23 patients with ulcerative colitis (range 1.23 to 5.51 ng/ml; mean 2.64 ng/ml) and 26 patients with Crohn's disease (range 1.58 to 9.29 ng/ml; mean 2.93 ng/ml). The elevated values were shown to be due to rises in the granulocyte secreted binding proteins, transcobalamins I and III. The TBBC was shown to rise with increasing activity of disease and to correlate roughly with the blood neutrophil granulocyte count. Patients with inflammatory bowel disease also had a significantly raised mean level of serum lysozyme (range 3.1 to 10.4 μg/ml; mean 6.8 μg/ml), but there was no correlation in individual patients between serum lysozyme and total B12 binding capacity. These results are taken to indicate an enlarged granulocyte pool and increased granulocyte turnover in inflammatory bowel disease.