Seroepidemiological studies of transfusion-associated hepatitis

Epidemiology, risk factors, and pathogenesis associated with a superbug: A comprehensive literature review on hepatitis C virus infection

Viral hepatitis is a major public health concern. It is associated with life threatening conditions including liver cirrhosis and hepatocellular carcinoma. Hepatitis C virus infects around 71 million people annually, resultantly 700,000 deaths worldwide. Extrahepatic associated chronic hepatitis C virus accounts for one fourth of total healthcare load. This review included a total of 150 studies that revealed almost 19 million people are infected with hepatitis C virus and 240,000 new cases are being reported each year. This trend is continually rising in developing countries like Pakistan where intravenous drug abuse, street barbers, unsafe blood transfusions, use of unsterilized surgical instruments and recycled syringes plays a major role in virus transmission. Almost 123–180 million people are found to be hepatitis C virus infected or carrier that accounts for 2%–3% of world’s population. The general symptoms of hepatitis C virus infection include fatigue, jaundice, dark urine, anorexia, fever malaise, nausea and constipation varying on severity and chronicity of infection. More than 90% of hepatitis C virus infected patients are treated with direct-acting antiviral agents that prevent progression of liver disease, decreasing the elevation of hepatocellular carcinoma. Standardizing the healthcare techniques, minimizing the street practices, and screening for viral hepatitis on mass levels for early diagnosis and prompt treatment may help in decreasing the burden on already fragmented healthcare system. However, more advanced studies on larger populations focusing on mode of transmission and treatment protocols are warranted to understand and minimize the overall infection and death stigma among masses.

Hepatitis C Infection: A Systemic Disease

It is critical to recognize that hepatitis C virus (HCV) infection is, in fact, a multifaceted systemic disease with both hepatic and extrahepatic complications. It is also important to recognize that the comprehensive burden of HCV should include not only its clinical burden but also its burden on the economic and patient-reported outcomes. It is only through this comprehensive approach to HCV infection that we can fully appreciate its true burden and understand the full benefit of curing HCV for the patient and the society.

Hepatitis C infection: A multi-faceted systemic disease with clinical, patient reported and economic consequences

Hepatitis C virus infection (HCV) affects approximately 170-200 million individuals globally. HCV is one of the primary causes of hepatocellular carcinoma (HCC) and cirrhosis and has been identified as the leading indication for liver transplantation in most Western countries. Because HCV is a systemic disease with hepatic, extrahepatic, economic and patient reported consequences, it is important for healthcare practitioners to understand the comprehensive and multi-faceted picture of this disease. In this context, it is important to fully appreciate the impact of HCV on the individual patient and the society. With the recent advent of the new generation of direct antiviral agents, the long standing goal of eradicating HCV in most infected patients has been accomplished. Therefore, now more than ever, it is critical to assess the total benefits of sustained virological response in a comprehensive manner. This should not be limited to the clinical benefits of HCV cure, but also to account for the improvement of patient reported health and economic outcomes of HCV cure. It is only through this comprehensive approach to HCV and its treatment that we will understand the full impact of this disease and the tremendous gains that have been achieved with the new antiviral regimens.

Transfusion-associated hepatitis before the screening of blood for hepatitis risk factors

BACKGROUND

The true incidence of transfusion-associated hepatitis (TAH) before blood screening is unknown. Our aims were to reevaluate blood recipients receiving unscreened blood and analyze hepatitis viruses circulating more than 45 years ago.

STUDY DESIGN AND METHODS

Cryopreserved serum samples from 66 patients undergoing open heart surgery in the 1960s were reevaluated with modern diagnostic tests to determine the incidence of TAH and its virologic causes.

RESULTS

In this heavily transfused population receiving a mean of 20 units per patient of predominantly paid-donor blood, 30 of 66 (45%) developed biochemical evidence of hepatitis; of these, 20 (67%) were infected with hepatitis C virus (HCV) alone, four (13%) with hepatitis B virus (HBV) alone, and six (20%) with both viruses. Among the 36 patients who did not develop hepatitis, four (11%) were newly infected with HCV alone, nine (25%) with HBV alone, and one (3%) with both viruses. Overall, 100% of patients with hepatitis and 39% of those without hepatitis were infected with HBV and/or HCV; one patient was also infected with hepatitis E virus. The donor carrier rate for HBV and/or HCV was estimated to be more than 6%; contemporaneously prepared pooled normal human plasma was also contaminated with multiple hepatitis viruses.

CONCLUSION

TAH virus infections were a larger problem than perceived 50 years ago and HCV was the predominant agent transmitted. All hepatitis cases could be attributed to HCV and/or HBV and hence there was no evidence to suggest that an additional hepatitis agent existed undetected in the blood supply.

Chronic hepatitis C: the virus, its discovery and the natural history of the disease

The identification of hepatitis A and hepatitis B led to the recognition that a third virus was capable of causing blood-borne hepatitis. The pathogen responsible for this nonA, nonB hepatitis was identified in the late 1980s and subsequently named hepatitis C. Since the discovery of hepatitis C there has been a pandemic of research publications describing the natural history of the infection and it is now known that this virus can cause serious liver damage in a proportion of infected patients. It is now clear that the effects of infection with hepatitis C and alcohol misuse are additive and that there is an increased risk of hepatic complications in infected patients who abuse alcohol.

Expression and identification of hepatitis C virus polyprotein cleavage products

Hepatitis C virus (HCV) is the major cause of transfusion-acquired non-A, non-B hepatitis. HCV is an enveloped positive-sense RNA virus which has been classified as a new genus in the flavivirus family. Like the other two genera in this family, the flaviviruses and the pestiviruses, HCV polypeptides appear to be produced by translation of a long open reading frame and subsequent proteolytic processing of this polyprotein. In this study, a cDNA clone encompassing the long open reading frame of the HCV H strain (3,011 amino acid residues) has been assembled and sequenced. This clone and various truncated derivatives were used in vaccinia virus transient-expression assays to map HCV-encoded polypeptides and to study HCV polyprotein processing. HCV polyproteins and cleavage products were identified by using convalescent human sera and a panel of region-specific polyclonal rabbit antisera. Similar results were obtained for several mammalian cell lines examined, including the human HepG2 hepatoma line. The data indicate that at least nine polypeptides are produced by cleavage of the HCV H strain polyprotein. Putative structural proteins, located in the N-terminal one-fourth of the polyprotein, include the capsid protein C (21 kDa) followed by two possible virion envelope proteins, E1 (31 kDa) and E2 (70 kDa), which are heavily modified by N-linked glycosylation. The remainder of the polyprotein probably encodes nonstructural proteins including NS2 (23 kDa), NS3 (70 kDa), NS4A (8 kDa), NS4B (27 kDa), NS5A (58 kDa), and NS5B (68 kDa). An 82- to 88-kDa glycoprotein which reacted with both E2 and NS2-specific HCV antisera was also identified (called E2-NS2). Preliminary results suggest that a fraction of E1 is associated with E2 and E2-NS2 via disulfide linkages.

Syncytial giant-cell hepatitis. Sporadic hepatitis with distinctive pathological features, a severe clinical course, and paramyxoviral features

BACKGROUND AND METHODS

We describe a new form of hepatitis, occurring in 10 patients over a period of six years, characterized clinically by manifestations of severe hepatitis, histologically by large syncytial giant hepatocytes, and ultrastructurally by intracytoplasmic structures consistent with paramyxoviral nucleocapsids.

RESULTS

The patients ranged in age from 5 months to 41 years. The tentative clinical diagnosis before biopsy was non-A, non-B hepatitis in five patients and autoimmune chronic active hepatitis in the others. Five patients underwent liver transplantation; the others died. The diagnosis of syncytial giant-cell hepatitis was established pathologically. The liver cords were replaced in all 10 patients by syncytial giant cells with up to 30 nuclei. In 8 of the 10 the cytoplasm contained pleomorphic particles of 150 to 250 microns, filamentous strands, and particles of 14 to 17 nm with peripherally disposed spikes resembling paramyxoviral nucleocapsids. Structures resembling degenerated forms were found in the other two patients. One of two chimpanzees injected with a liver homogenate from the index patient had an increase in the titer of paramyxoviral antibodies, probably an anamnestic reaction to previous paramyxoviral infection, suggesting that a paramyxoviral antigen but not viable virus was present in the liver homogenate.

CONCLUSIONS

Although further virologic studies will be required for precise classification, we believe that paramyxoviruses should be considered in patients with severe sporadic hepatitis.

Transfusion-transmitted cytomegalovirus infections: significance and control

Cytomegalovirus (CMV) is a herpes virus which can give rise to primary infections, reactivated infections, or reinfections in humans. Seroepidemiologic studies have shown CMV infection to be worldwide with the highest antibody prevalences detected in Third World countries; however, significant regional variations can be seen within a given country. Antibody prevalence varies directly with age and inversely according to socioeconomic status. Numerous prospective studies of blood transfusion recipients carried out since 1966 have shown marked differences in infection rates but relatively little associated disease. Infection rates were highest in seronegative recipients given large amounts of fresh blood. Recently published reports have shown substantially lower infection rates than earlier studies, a change likely to be due to the current practice of transfusing fewer units of older blood. CMV has not been found to play a significant role in the etiology of posttransfusion hepatitis. CMV infections have been found to be an important source of morbidity and mortality in immunocompromised patients. Several studies of transfused, premature infants have shown significant differences in infection rates and disease expression. Seronegative low-birth-weight infants receiving blood from seropositive donors are at greatest risk. Blood from CMV-seronegative donors substantially lowers the risk of infection. Receiving a kidney or heart from a CMV-seropositive donor appears to be a more salient risk factor than blood transfusion in renal and cardiac transplant patients who are also more likely to have symptomatic CMV infections. Leukocyte transfusions have been found to be a significant source of CMV infection and disease in bone marrow transplant patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic non-A, non-B hepatitis: ultrastructural and serologic studies

Liver biopsies from five patients with chronic non-A, non-B (NANB) hepatitis were examined by electron microscopy for hepatocellular alterations. Circular fused membranes were observed within the cytoplasm of hepatocytes of four of the patients. Aggregates of intranuclear particles, measuring 22 +/- 2 nm in diameter, were also seen in two of the biopsies in which fused membranes were identified. Sera of all five patients formed precipitin lines detectable by counterimmunoelectrophoresis when reacted with serum from an individual convalescent from posttransfusion NANB hepatitis. Using this convalescent serum as an antibody source, complexes of 22 +/- 2 nm particles were identified in three of the chronic patient sera by immunoelectron microscopy. These observations suggest that at last one of the agents responsible for NANB hepatitis elicits both nuclear and cytoplasmic modifications. Furthermore, the 22 +/- 2 nm particles circulating in the sera of the chronic NANB patients may represent components related to NANB hepatitis agent.

Circulating immune complexes in non-A, non-B hepatitis. Possible masking of viral antigen

Serial serum samples from 22 patients with transfusion-associated non-A, non-B hepatitis and 2 chimpanzees with the experimentally induced disease were tested for circulating immune complexes by Raji-cell radioimmunoassay. 13 patients (59%) and 1 chimpanzee had circulating immune complexes immediately before, coincident with, or during the return to normal of raised aminotransferase activity. 7 of the 10 patients with chronic non-A, non-B hepatitis had detectable complexes at levels which waxed and waned in parallel with changes in serum aminotransferase activity. Immune complexes may contain and mask viral antigens, and their presence may explain the failure of conventional immunological techniques to detect virus antigens.

Transmissible agent in non-A, non-B hepatitis

Plasma or serum from 4 patients with acute or chronic non-A, non-B post-transfusion hepatitis (P.T.H.) and from a blood-donor implicated in two cases of P.T.H. was inoculated into 5 chimpanzees. Biochemical and histological evidence of hepatitis developed in these 5 chimpanzees but not in a control animal. The mean incubation period in the chimpanzees was 13.4 weeks, compared with 7.7 weeks in the 4 patients with P.T.H. The peak alanine aminotransferase (A.L.T.) levels in the 5 chimpanzees were 265, 212, 219, 70, and 62 I.U./l. Histological changes ranged from mild to conspicuous hepatitis and generally correlated with the degree of A.L.T. elevation. There was no evidence of clinical disease and all animals went on to biochemical and histological recovery. There was no serological evidence of type A or type B hepatitis. Hepatitis was transmitted by serum derived from patients with chronic as well as acute hepatitis, strongly suggesting a chronic carrier state for the agent responsible for non-A, non-B hepatitis. Non-A, non-B hepatitis thus seems to be due to a transmissible agent which can persist and remain infectious for long periods.

Non-A, non-B post-transfusion hepatitis

To clarify the role of hepatitis-A virus (H.A.V.) in the aetiology of post-transfusion hepatitis unrelated to hepatitis-B virus, we have tested and titred pre-transfusion and convalescent serum samples from 32 patients for antibody to hepatitis-A antigen (anti-HA) by quantitative immune adherence haemagglutination. 12 patients had no detectable anti-HA in either pre-transfusion or late convalescent serum; the other 20 had anti-HA in pretransfusion serum and no significant chance in titre during convalescence. This study excludes H.A.V. as the agent responsible for these cases of post-transfusion hepatitis and supports the existence of "non-A, non-B" hepatitis virus(es).

Multiple hepatitis viruses in multiple attacks of acute viral hepatitis

We evaluated the causes of 30 episodes of acute viral hepatitis in 13 patients who had multiple attacks. Two (seven per cent) of 30 bouts were caused by hepatitis A virus, and 12 (40%) by hepatitis B virus. No patient, however, had more than one attack with the serologic characteristics of Type A or Type B disease. Thus, there were 16 bouts (53 per cent) not attributable to either of the two recognized hepatitis viruses. None of these "non-A, non-B" episodes, evaluated for infectious mononucleosis and cytomegalovirus infection, could be ascribed to either. From this evidence, therefore, it appears that the clinical syndrome of viral hepatitis is produced not only by the two viruses (hepatitis A virus and hepatitis B virus) recognized since the 1940's but also, in all probability, by two non-A, non-B agents.

Studies of an outbreak of acute hepatitis A: II. Antibody changes to cytomegalovirus and herpersvirus

The acute and convalescent sera from 14 schoolchildren with acute hepatitis A were tested for antibody changes to 70 viral antigens. Marked decreases were noted in the levels of antibody to cytomegalovirus in 5 of the 14 children and in the levels of antibody to herpesvirus type 1 in 3. No such changes were noted in 9 sex- and age-matched healthy control children from the same classes.

Viral hepatitis--a primer. 2. Prevention and control

The clinical differentiation of hepatitis A from hepatitis B is often impossible, and only a finding of hepatitis B surface antigen in blood allows the presence of hepatitis B to be definitely diagnosed. Heaptitis A is most easily contracted via the fecal-oral route, while hepatitis B is usually transmitted percutaneously, especially by inoculation with contaminated instruments. Because viral hepatitis has a long incubation period, controlling its spread is difficult. Prevention and control have traditionally depended on general public health measures, and for hepatitis A, passive immunization with immune serum globulin. Promising research is now being conducted to develop vaccines for both active and passive immunization against hepatitis B.

Clinical and serological analysis of transfusion-associated hepatitis

Of 108 prospectively followed, multiply transfused, open-heart-surgery patients, 12 (11%) developed hepatitis. Patients received only volunteer donor blood tested for hepatitis-B surface antigen (HBsAg) prior to transfusion by counterelectrophoresis (C.E.P.). 4 of the 12 patients developed hepatitis-B-virus infection. Subsequent testing of donor serums by solid-phase radioimmunoassay (R.I.A.) revealed that an R.I.A.-positive, C.E.P.-negative blood unit was transfused to 3 of the 4 type-B hepatitis cases, but to none of the remaining 104 patients; 3 hepatitis-B cases could probably have been prevented by prescreening of donors by solid-phase R.I.A. 8 hepatitis cases were serologically unrelated to the hepatitis-B virus, the hepatitis-A virus, the cytomegalovirus, or the Epstein-Barr virus. Had R.I.A.-positive donors been excluded, 8 of the 9 residual hepatitis cases (89%) would have represented "non-A, non-B" hepatitis. The existence of previously unrecognised human hepatitis virus(es) is probable.

Hepatitis B antigens in serum and liver of chimpanzees acutely infected with hepatitis B virus

We report the temporal patterns of various immunohistological and serological parameters of acute self-limited hepatitis B virus infection of two chimpanzees, and we provide evidence that the synthesis of hepatitis B core antigen precedes that of hepatitis B surface antigen. Our data suggest that existence of a biphasic hepatitis B virus infection involving a hematogenous reinfection of the liver and indicate that recruitment of liver cells to produce hepatitis B virus may occur in a pattern consistent with a replicative cycle of about 8 days.

Serologic characterization of patients with two episodes of acute viral hepatitis

Since testing for serologic markers of hepatitis B virus (HBV) became routine, we have observed in our hospital 28 patients with two distinct episodes of illnesses, each of which was compatible with acute viral hepatitis. We found no distinctions between the first and second bouts with respect to clinical characteristics, abnormalities of liver function or epidemiologic background. Testing of specimens obtained during each of the two acute episodes, the interval between the two episodes and the period subsequent to the second by sensitive procedures for hepatitis B surface antigens (HBsAg) and their corresponding antibodies (anti-HBs) permitted the following classification: 13 of 28 patients experienced first bouts serologically classifiable as due to HBV; 11 patients had second bouts serologically classifiable as due to HBV; 2 patients had two episodes both which were serologically indeterminate; and 2 patients had two bouts neither of which appeared compatible with HBV infection by present criteria. No patient had a second episode for which the HB2Ag and anti-HBs data suggested HBV recurrence or reinfection. This evidence does not favor the speculation that HBV can account for repeated episodes of acute icteric hepatitis.

Transfusion-associated hepatitis not due to viral hepatitis type A or B

Twenty-two patients who had an episode of transfusion-associated hepatitis not positive for hepatitis B antigen were examined for development of antibody to heaptitis A and B antigens, cytomegalovirus and Epstein-Barr virus. Antibody response to the 27-nm virus-like hepatitis A antigen was measured by immune electron microscopy. In none of the 22 patients studied did serologic evidence of infection with hepatitis A virus develop during the study period. Nine of the 22 patients had antibody responses to cytomegalovirus, but it was difficult to relate these seroconversions to their hepatitis. In addition, all 22 patients had pre-existing antibody to the Epstein-Barr virus. It seems likely that at least a proportion of such antigen-negative transfusion-associated hepatitis is caused by other infectious agents, not yet identified.

Cytomegalovirus antibody production in renal transplant patients

Sera were examined from 50 patients on the renal transplant unit, Cambridge, for antibody against cytomegalovirus by complement fixation and by immunofluorescence for IgG and IgM antibodies.The incidence of antibody on admission was 84% with a possible further 8% so that nearly all had been infected at some time by CMV.43 (86%) patients showed evidence of active infection after admission, 39 by serology and four only from the examination of post-mortem material.Twenty-one patients produced IgM antibody and production was prolonged for years in patients that survived. Antibody production was related both to transplantation and admission to hospital.The evidence indicated that primary CMV infections were rare, that IgM antibody production was the result of active infection and that this could be attributed to reactivation without the need to invoke re-infection as the source although this type of patient is both susceptible and exposed to re-infection.