Absence of detectable hepatitis B virus DNA in sera and liver of chimpanzees with non-A, non-B hepatitis.

The risk of hepatitis B infections has been reduced by screening of blood donors for hepatitis B surface antigen (HBsAg). However, recipients remain at significant risk of developing post-transfusion hepatitis. Studies have shown that non-A, non-B hepatitis virus(es) are responsible for the majority of post-transfusion hepatitis infections. In spite of many efforts, these non-A, non-B hepatitis viruses have not yet been identified. Epidemiological studies, however, suggest that non-A, non-B hepatitis shares many features with hepatitis B. Recently, Wands et al [1982] showed, in chimpanzees infected with non-A, non-B hepatitis agents, the presence of antigenemia or viremia by radioimmunoassay with monoclonal antibodies directed toward distinct determinants of HBsAg and by molecular hybridization analysis. They suggested that non-A, non-B hepatitis agents may be related, but distinct variant(s) of hepatitis B virus (HBV). In this study, five chimpanzees were inoculated with three different agents that have been shown to transmit non-A, non-B hepatitis. The following inocula were used (I) a factor VIII preparation kindly provided by D.W. Bradley, (II) acute phase serum from a chimpanzee infected with the F strain kindly provided by A.J. Zuckerman, and (III) a DS-antigen serum previously shown by us to transmit non-A, non-B hepatitis [Duermeyer et al, 1983]. All chimpanzees developed a rise in transaminase levels between 8 and 10 weeks after inoculation. None of the chimpanzees was positive for any markers of HBV infection. No evidence was obtained of infection with hepatitis A, cytomegalovirus, or Epstein-Barr virus. One chimpanzee developed chronic liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute sporadic non-A, non-B hepatitis in India.

A total of 293 sporadic cases of acute viral hepatitis were identified in Kashmir, India, from April 1979 to December 1981; 44 (15%) were found serologically to be hepatitis A, 94 (32%) hepatitis B, and 155 (53%) non-A, non-B type. The non-A, non-B hepatitis observed was a disease of young adults (29.8 +/- 15 years) with slight male predominance (1.4:1). Six of the 155 non-A, non-B cases had history of prior parenteral exposure, while 51 (33%) had a recent contact with another case of jaundice, suggesting that this form of hepatitis was spread by person-to-person contact. Fulminant hepatic failure occurred in 19 cases, and six (31.5%) of the 19 cases occurred in pregnant women. None of 90 non-A, non-B cases followed up six months later had developed chronic hepatitis. The acute sporadic non-A, non-B hepatitis described in Kashmir resembles epidemic non-A, non-B hepatitis epidemiologically and seems to be distinct from the non-A, non-B hepatitis described in the West.

Diagnosis of acute toxoplasmosis by an enzyme immunoassay for specific immunoglobulin m antibodies.

A recently developed enzyme-linked immunosorbent assay for detection of immunoglobulin M (IgM) class antibodies to Toxoplasma gondii was evaluated with respect to specificity and sensitivity. By using an antibody capture principle and F(ab')2 conjugates, interference of rheumatoid factors was absent. No cross-reactions with anti-toxoplasma IgG occurred, and no interference with antinuclear antibodies was found. A large-scale study with about 1,500 clinical specimens revealed a 100% specificity. By testing 79 sera from patients with acute-phase acquired toxoplasmosis, sensitivity was found to be 97%. In routine clinical practice, the IgM-enzyme-linked immunosorbent assay proved to be a more sensitive tool for diagnosis than the immunofluorescent-antibody test. The course of IgM-enzyme-linked immunosorbent assay antibodies in acute patients was studied; IgM reached peak levels within 1 month after onset of illness, and could be demonstrated up to an average of 8 months after onset.

Characterization of DS-antigen, an antigen related to non-A, non-B hepatitis. I. Physico-chemical properties.

An enzyme-linked immunosorbent assay for an antigen (termed DS-Ag) related to non-A, non-B hepatitis has recently been developed in our laboratory. The DS-Ag was derived from a proven infectious serum obtained from a patient with haemophilia and it was also detected in the acute phase serum of an experimentally infected chimpanzee. The DS-Ag has now been shown to have a buoyant density in CsCl of 1.32 g/cm2 and a sedimentation coefficient of 20 S. The mean molecular weight, determined by gel chromatography on 4% agarose columns, was found to be 0.9 x 10(6). The DS-Ag recovered from acute-phase chimpanzee serum has identical characteristics. The DS-Ag is stable for 1 h at 56 degrees C, at pH 3, in high concentration of CsCl or Nal and in 20% ether. Complete inactivation occurred after 1 min at 98 degrees C, at pH 2, in chloroform (1:1 mixture), in 1 ppm chlorine and in formalin (1:4000, 72 h 37 degrees C). Our studies showed that DS-Ag bears no resemblance to particles related to well-documented forms of viral hepatitis types A and B or other known pathogens. The DS-Ag is a complex substance which forms an antigenic entity related to non-A, non-B hepatitis.

An enzyme-linked immunosorbent assay for an antigen related to non-A, non-B hepatitis and its antibody: partial characterization of the antigen and chimpanzee transmission.

An enzyme-linked immunosorbent assay (ELISA) was developed based on sera from patients convalescent from non-A, non-B hepatitis and haemophilia A patients who had been frequently treated with commercial blood products. Using this ELISA, an antigen was detected which appears to be related to non-A, non-B hepatitis. The antigen is provisionally designated as DS-antigen (DS-Ag). The serum of another patient with haemophilia A, which was strongly positive for the DS-Ag, caused a typical case of non-A, non-B hepatitis in a chimpanzee. DS-Ag could be detected in the serum of the chimpanzee during the acute phase of the infection. The ELISA for DS-Ag reacted with neither hepatitis A or B virus antigens, nor Epstein-Barr virus or cytomegalovirus. The assay was provisionally evaluated using sera from different groups of patients. Out of 17 patients with posttransfusion hepatitis non-A, non-B, 11 were found positive in the ELISA for DS-Ag (65%). As expected, a relatively high prevalence of DS-Ag (9%) was found in patients with haemophilia, who are regularly treated with blood-clotting factor-concentrates. Antibodies to DS-Ag were found in 48% of these patients. The DS-Ag was found in 8 of 1400 (0.6%) volunteer blood donors, and antibody to DS-Ag in 3% of the sera. Remarkably, a high incidence (41%) of antibodies to DS-Ag was found in prostitutes, suggesting that this antigen may be transmitted by a sexual route. The DS-Ag was pelleted by ultracentrifugation for four hours at 100,000g and was found to have a buoyant density of 1.32 g/cm3 in a CsCl gradient.

An enzyme-linked immunosorbent assay for the detection of hepatitis non-A, non-B antigen and antibody.

An enzyme-linked immunosorbent assay (ELISA) was developed, based on sera from patients convalescent from non-A, non-B hepatitis and haemophilia A patients. Using this ELISA an antigen (DS-Ag) was detected which appears to be related to non-A, non-B hepatitis. The serum of another patient with haemophilia A, which was strongly positive for the DS-Ag, caused non-A, non-B hepatitis in a chimpanzee. DS-Ag could be detected in the serum of the chimpanzee during the acute phase of the infection. The ELISA for DS-Ag did not react with either hepatitis A or B virus antigens, or with Epstein-Barr virus or Cytomegalovirus. The assay was provisionally evaluated using sera from different groups of patients. From 17 patients with post-transfusion hepatitis non-A, non-B, 11 were found positive in the ELISA for DS-Ag (65%). A relatively high prevalence of DS-Ag (17%) and -antibodies (20%) was found in patients with haemophilia, who are regularly treated with blood clotting factor concentrates. The DS-Ag was found in 8 of 1400 (0,6%) volunteer blood donors, and antibody to DS-Ag in 3% of the sera. Remarkably, a high incidence (41%) of antibodies to DS-Ag was found in prostitutes, suggesting that this antigen may be transmitted by a sexual route as well. The DS-Ag was pelleted by ultracentrifugation for 4 h at 100.000 xg and was found to have a buoyant density of 1.32 g/cm3 in a CsCl gradient.

Examination of crystalline arrays in non-A, non-B hepatitis.

Individual patients within crystalline arrays found in the endothelial cells of hepatic sinusoids in experimental non-A, non-B hepatitis were examined by the Markham rotation technique. The particles appeared to possess an outer structure with 16-18 divisions. The presence of the crystalline structures is probably a reflection of host cell response to infection.

Pathogenetic aspects of hepatitis A virus infection in enterally inoculated marmosets.

Experimental hepatitis A virus (HAV) infection was studied in marmosets after enteral (intragastric) inoculation with special reference to the primary sites of HAV replication and immunopathology of the disease. The experiment was carried out using 28 Saguinus mystax negative for antibody to HAV (anti-HAV) and with statistically uniform baseline values of serum isocitrate dehydrogenase (SICD) activity. Each animal was infected with 1 ml of a 15% w/v stool suspension that was derived from marmosets infected with the third or fourth passage of the MS-1 strain of HAV. The incubation period measured by the first significant SICD elevation was 32 days in 11 of 13 marmosets. The animals were sacrificed 2, 4, 7, 11, 14, 18, 23, 28, and 32 days after inoculation and 1, 4, 8, 14, 21, 28, and 35 days after SICD elevation. HAV antigen, immunoglobulins, complement, and fibrin were identified in the liver, eight segments of the gastrointestinal tract, lymphoid system, and kidneys. HAV antigen was found only in the cytoplasm of hepatocytes and in gallbladder bile. These findings indicated that the liver was the sole and primary site of virus replication. Combined immunomorphologic and histopathologic observations also revealed that HAV antigen localization was associated with the sites of hepatocellular damage. There was no immunomorphologic evidence for humoral immune clearance of HAV antigen in the liver, lymphoid system, or kidneys.

Epidemiology of hepatitis A in Amsterdam, October 1978--December 1979.

The epidemiology of hepatitis A was studied in Amsterdam during a 15 month period from October 1978 through December 1979. 349 cases of viral hepatitis were reported of which 135 were serologically identified as hepatitis A. The diagnosis was established by testing a single acute-phase serum sample with ELISA for the detection of hepatitis A IgM antibodies. Most cases were sporadic; there were no outbreaks involving more than three cases. A seasonal variation was recognized with the highest incidence in later autumn and early winter. The peak attack rate was found in the age group of 5--9 and a smaller peak was noticed in the age group of 30--34. Recent exposure to a known case of hepatitis A or to a jaundiced person was the probable source of infection in 27% of the patients; 23% contracted hepatitis A within 7 weeks of visiting a tropical or subtropical country and in 50% no source was found. 50 patients provided stool specimens within 2 weeks of the onset of jaundice. Specimens were examined for the presence of hepatitis A virus antigen by ELISA and seven patients had positive stools, all within the first week of the onset of jaundice.

Enzyme-linked immunosorbent assay for detection of immunoglobulin M antibodies against Toxoplasma gondii.

A new principle that uses anti-immunoglobulin M-coated polystyrene microtiter plates for the detection of immunoglobulin M antibodies against Toxoplasma gondii by an enzyme-linked immunosorbent assay was developed.

An outbreak of hepatitis A in an institution for the mentally retarded.

From December 1977 until April 1978 a hepatitis A outbreak occurred in an institution for the mentally retarded. The institution housed 311 residents and had a staff of 308. The outbreak was studied by enzyme-linked immunosorbent assays for hepatitis A antigen and antibodies, and by liver function tests in serum. When the investigations started, 13 residents and one staff member were ill and already seropositive; 34 of the 182 residents that were seronegative at that time and 12 of the 223 seronegative staff members subsequently developed disease. Out of the 60 cases 32 were asymptomatic; 19 cases with jaundice were seen. Normal human immunoglobulin was administered to a large part of the seronegative group, but the effect is difficult to interpret as the immunoglobulin was often given after the presumed time of infection and failed to protect. Elevated liver enzyme levels were demonstrated in 38 of 60 patients.

An enzyme-linked immunosorbent assay (ELISA) for PBS Z1, a defective phage of Bacillus subtilis.

The sensitivity, reproducibility and specificity of an enzyme-linked immunosorbent assay (ELISA) for the defective phage PBS Z1 of Bacillus subtilis have been investigated. It was shown that phages in concentrations between 10(8) and 2.5 X 10(10) particles/ml could be assayed with this method. The coefficient of variation for concentrations between 5 X 10(8) and 5 X 10(9) particles/ml was approx. 10%. From some other Bacillus phages tested, only the defective phages resembling PBS Z1 in morphology were detected efficiently with the ELISA for PBS Z1. A comparison is made between ELISA and other assays for PBS Z1.

A new principle for the detection of specific IgM antibodies applied in an ELISA for hepatitis A.

A new test principle for the detection of specific IgM-class antibodies was developed and applied in an Enzyme-Linked Immuno Sorbent Assay (ELISA) for the detection of hepatitis A IgM antibodies. A solid phase coated with anti-IgM was incubated successively with serum sample, specific antigen, and enzyme-labeled F (ab')2 fragments from IgG antibodies against the antigen and enzyme substrate. F(ab')2 fragments were used to avoid interference with rheumatoid factor. Specificity and sensitivity are very high. This test principle appears generally applicable in the diagnosis of infectious and parasitic diseases by testing only one serum sample.

An outbreak of hepatitis A investigated by immune electron microscopy and enzyme-linked immunosorbent assay.

In a small outbreak of hepatitis A among members of a hospital staff, excretion of hepatitis A virus could be detected by immune electron microscopy (IEM) and enzyme-linked immunosorbent assay (ELISA) in 3 out of 3 cases tested. Significant increases in antibody titre could be shown in 4 out of 6 cases (IEM), and development of virus specific IgM was shown in all 6 cases (ELISA). Among these patients IgM could be detected after 3 months, while sera drawn after 10 months were negative.