SERUM COMPLEMENT LEVELS IN ACTIVE ULCERATIVE COLITIS

Circulating immune complexes in ulcerative colitis.--II. Correlation with serum protein concentrations and complement conversion products

Several serum proteins were quantified in twenty-two patients with active ulcerative colitis, and the findings were related to disease activity and occurrence of circulating immune complexes (IC). Conversion of C3 was significantly more frequent in the IC-positive group (eight patients) as compared to the IC-negative group (fourteen patients). Factor B was demonstrable in fifteen out of the twenty-two patients and seven out of the eight IC-positive patients had detectable levels of factor B. There was no difference between the IC-positive and the IC-negative group as regards serum concentrations of the complement factors C3, C4 and factor B, or serum orosomucoid, albumin, IgM and IgG. In contrast, the serum IgA levels tended to be reduced in the IC-positive group. C3 and factor B were significantly elevated in four patients with severe disease activity. In addition, C3, factor B and C4 concentrations showed a positive correlation to the serum orosomucoid levels. The serum concentrations of orosomucoid and albumin were inversely correlated to each other.

Immune complexes in ulcerative colitis and Crohn's disease

Sera from 156 patients with ulcerative colitis and Crohn's disease were tested for the presence of immune complexes, by the detection of anti-complementary activity and 125I-labelled Clq precipitation. Using aggregated IgG, a comparison between the two tests indicated that the anti-complementary test was most sensitive to aggregates of 11S in size, while the 125I-labelled Clq test detected aggregates over 20S in size. Excess anti-complementary activity was common in patients with active bowel disease, and in those with extra-intestinal manifestations, particularly acute arthritis, ankylosing spondylitis and liver disease. Large complexes were only common in patients with liver disease. Immune complexes in the gut mucosa may play a role in the pathogenesis of these diseases, and the deposition of circulatory immune complexes may explain at least some of the extra-intestinal manifestations.

Serum concentration of 19 serum proteins in Crohn's disease and ulcerative colitis

The serum concentration of 19 serum proteins was determined by electrophoresis in 42 patients with Crohn's disease and 36 patients with ulcerative colitis. The results were compared with 78 healthy persons as matched controls. Distinctive, but similar, changes were present in the two diseases. An increased serum concentration of orosomucoid, alpha(1)-antitrypsin, easily precipitable glycoprotein, alpha(1)-antichymotrypsin, haptoglobin, and haemopexin was present. The serum concentration was decreased for prealbumin, albumin, alpha(2)-HS glycoprotein, caeruloplasmin, alpha(2)-macro-globulin, and transferrin. No significant difference between the two diseases existed as far as the serum protein pattern was concerned. Certain proteins, ;the acute phase reactants' (orosomucoid, alpha(1)-antitrypsin, alpha(1)-antichymotrypsin, and haptoglobin) and the immunoglobulins were clinically useful, since their serum concentration reflected the grade of activity of the disease. A pronounced elevation of haptoglobin compared with that of the other ;acute phase reactants' was present in patients with Crohn's disease complicated by suppurative fistulas or abscesses. Patients with active Crohn's disease who responded favourably to medical treatment had significantly higher immunoglobulin levels than patients not responding. A similar observation, though not statistically significant, was made in patients with ulcerative colitis.

Eosinophilic granuloma of the gastro-intestinal tract

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