An antigen/antibody system specific for an epidemic non-A, non-B hepatitis in patients of a cardiovascular surgical unit

European quality clearance of new microbiological diagnostics

Laboratory-based diagnosis of infectious diseases is evolving quickly. New technologies and new tests are frequently commercialized, and although guidelines for their proper clinical validation do exist, these are often at the national or regional level. Therefore, the guidelines remain open to interpretation, and are not always applied properly. One of the main questions is how a high level of test quality can be maintained by European legislation. How can product quality be reliably and independently assessed and how can the penetration of sub-standard assays in the European market be managed and hopefully prevented? We here propose that local initiatives, including external quality assessment, public health initiatives, and close multidisciplinary collaborations between manufacturers and academic research institutes, may accelerate decision-making. Vigilance in test quality assessment and legal simplification are important key concepts warranting selective use of those diagnostic tests that comply with the highest quality standards.

Demonstration of hepatitis C virus genome in saliva and urine of patients with type C hepatitis: usefulness of the single round polymerase chain reaction method for detection of the HCV genome

The possible transmission routes of hepatitis C virus (HCV) in patients without overt parenteral exposure (sporadic or community acquired form) were examined. Saliva and urine specimens obtained from type C hepatitis patients, whose sera were positive for the HCV genome, were examined by reverse transcription and polymerase chain reaction (RT-PCR). By analyzing the factors that influenced the detection of the HCV genome by PCR, we developed a single round method which enabled semiquantitative detection with higher sensitivity than that obtained with nested PCR. Single round PCR revealed that 34.8% (8 of 23) of saliva and 56.5% (13 of 23) of urine specimens from patients with type C hepatitis contained the HCV genome. The amounts of HCV genome in saliva and urine specimens correlated with those in serum. The relative amounts of HCV genome in serum, saliva, and urine from a chronic type C hepatitis patient were determined by comparing the reciprocal of the smallest volume of the specimens in which the PCR products were visualized in agarose gels (PCR units/ml), and the values were 1 x 10(5), 5 x 10(1), and 3 x 10(1) PCR units/ml for serum, saliva, and urine specimens, respectively.

Seroepidemiological studies on a non-A, non-B hepatitis specific antigen/antibody system (SO-antigen/anti-SO)

The patients and staff members of a haemodialysis unit were examined for their serological responses to SO-antigen, which was isolated from the urine of epidemic type non-A, non-B hepatitis patients at Tohoku University Hospital. To understand how SO-antigen or SO-antigen-related aetiology can be incriminated for the hepatitis found in the haemodialysis unit, the prevalence of SO-antigen/anti-SO system and hepatitis A and B virus-related antibodies was compared in the sera of patients and staff members. Although the SO-antigen was rarely detected in the serum, anti-SO antibody was frequently detected in the sera of patients and staff. A significantly higher prevalence was found in the serum of patients (15%, 54 out of 361) than staff members (7.1%, 13 out of 184) and volunteer blood donors (1%, 3 out of 305). The same prevalence percentages of HBV-related antibodies (either positive for anti-HBs or anti-HBc) and anti-HAV were observed among the patients, staff, and volunteer blood donors, irrespective of whether the sera were anti-SO positive or negative. Among the staff, anti-SO antibody was more frequently found in those with a history of acute hepatitis (16.7%, 3 out of 18) than in those without (6%, 10 out of 166). These prevalence ratios conformed with those of HBV-related antibodies, but the same prevalence ratios of antibody to HAV were observed between the staff with and without a history of acute hepatitis. These results indicate that the SO-antigen/anti-SO system or entity related to this immune system is distinct from HBV or HAV, and this immune system was found widely in the haemodialysis unit where type B and non-A, non-B hepatitis were also found frequently.

AN6520 Ag: an antigen purified from liver with non-A, non-B hepatitis

An extract prepared from the liver of patient with chronic non-A, non-B (NANB) hepatitis was found to produce a precipitin line in immunodiffusion with a serum from a multiply transfused patient and those from patients convalescent from NANB hepatitis. The antigen was purified by gel filtration and density gradient centrifugation. The antigen had a buoyant density of 1.16-1.20 g/cm3 in cesium chloride, a sedimentation coefficient (S20,w) of 51.5, and a molecular weight of larger than 1.5 X 10(6) daltons. Electron microscopic examination revealed particles 29-34 nm in diameter (average 31.5 nm), which could be agglutinated by the specific antiserum. We developed a reverse passive hemagglutination (R-PHA) and a passive hemagglutination (PHA) technique for detection of the new antigen and antibody, respectively, and applied these to human sera. Antibody to the antigen was detected in 19/28 (67.9%) convalescent sera of NANB hepatitis. This prevalence was significantly higher than those found in convalescent sera of type A hepatitis patients (2/17 = 11.8%), type B hepatitis patients (2/15 = 13.3%), and normal blood donors (9/129 = 7.0%) (p less than 0.01); and the prevalence in hepatitis A and B patients did not differ significantly from that of normal donors. Furthermore, most (66.7%) of the cases of NANB hepatitis endemic in Shimizu City, Japan, showed clear seroconversion with respect to this antibody. These results suggest that the new antigen/antibody system is associated with NANB hepatitis.

Demonstration of a transient rheumatoid factor in the acute phase of hepatitis non A, non B

The evaluation of an enzyme-linked immunosorbent assay (ELISA) test designed to detect antigens of hepatitis non A, non B (HNANB) revealed that a rheumatoid factor (RF)-like reaction was interfering. This RF-like reaction was not detectable by routine screening methods for RF, such as latex agglutination or the Waaler Rose test. Testing of sequential sera of chimpanzees with acute HNANB showed that this RF-like reaction was present in the acute phase of HNANB simultaneously with alanine aminotransferase (ALT) elevations. Characterization of this RF-like reaction revealed the presence of an IgM antibody against human IgG that banded in CsCl at 1.3 g/ml and at 19S in sucrose gradients. Absorption with IgG-coated latex particles and anti-human IgM gave further evidence of an RF. By testing sera of patients with different forms of acute viral hepatitis, it was demonstrated that an RF-like factor was also present in seven sera from 9 patients with acute hepatitis A, in two sera from 11 patients with hepatitis B, and seven sera from 11 patients with acute HNANB. The rise of RF in the acute phase of hepatitis A may be an effect of polyclonal stimulation of IgM producing B lymphocytes. The high prevalence of RF in HNANB remains unclear as no polyclonal stimulation of IgM has been observed.