The mechanism and interrelationships of the flocculation tests

Chronic hepatitis C without anti-hepatitis C antibodies by second-generation assay. A clinicopathologic study and demonstration of the usefulness of a third-generation assay

To study the clinicopathologic features of hepatitis C viremic patients negative for hepatitis C antibodies (anti-HCV) by current second-generation assay, we categorized 139 consecutive histologically verified patients with chronic non-A, non-B hepatitis into three groups: 121 (87%) were positive for second-generation anti-HCV (group A); 10 (7%) were negative for second-generation anti-HCV but positive for HCV RNA (group B); and 8 (6%) were negative for both antibodies and viremia (group C). Six (60%) of group B patients could be, further detected by a new third-generation assay, but none of group C patients was third-generation anti-HCV-positive. The demographic features, mean peak serum alanine aminotransferase levels, HCV genotype distribution, and histologic changes were comparable among the three groups. The study indicates that most patients with chronic hepatitis C in Taiwan could be identified by current second-generation assay, and viremic but antibody seronegative patients were clinicopathologically similar to the seropositives. Most patients of the latter group could be diagnosed by a third-generation assay, indicating the usefulness of this assay.

Isolation of a protective gamma-globulin fraction interfering with the zinc sulphate turbidity test

The serum of a case of hyperglobulinaemia with negative thymol and zinc sulphate turbidity reactions was studied. The serum when added to pathological sera with high turbidity values brought about a marked reduction in the original turbidity values. Also, the serum did not give the usual copper proteinate precipitate when added to copper sulphate solutions. The anomalous protein fraction responsible for the above properties was isolated from the gamma globulins by precipitation at 28% saturation with ammonium sulphate. It was found to be neither a macroglobulin (Waldenstrom's), a cryoglobulin, nor a collagen protein. Its occurrence in the very gamma globulin fraction which is responsible for many of the turbidity reactions is of great significance in the interpretation of these tests. It is suggested that the normal turbidity and flocculation reactions reported in some cases of multiple myelomatosis might be due to some such anomalous proteins.