Membranoproliferative glomerulonephritis associated with hepatitis C virus infection

Mooren-type hepatitis C virus-associated corneal ulceration

BACKGROUND

Two patients with bilateral Mooren-type ulcers had underlying chronic hepatitis C virus (HCV) infection. Both patients also had chronic, pruritic dermatitis, which in one patient was diagnosed as hidradenitis suppurativa.

METHODS

Serum from the first patient and serum, conjunctiva, and liver from the second patient were analyzed for HCV genomic RNA using the reverse transcriptase-polymerase chain reaction. Serum anti-HCV antibodies were monitored with a commercially available second-generation test. Liver and conjunctival biopsies were evaluated histopathologically.

RESULTS

Liver biopsy showed severe hepatitis in the first patient, but normal liver tissue in the second. Hepatitis C virus genomic RNA was detected in the serum of both patients. In the first patient, the virus was detected 4 months after completion of interferon alfa-2b treatment for chronic active hepatitis. In the second patient, HCV genomic RNA was detected in serum, but not in conjunctiva or liver tissue. Hepatitis C virus could not be detected in the serum of the second patient after 2 weeks of interferon alfa-2b treatment. Both patients had serum anti-HCV antibodies. In case 1, there was a marked improvement in the corneal disease during and after 6 months of interferon alfa-2b treatment for chronic active hepatitis that paralleled a return of serum liver enzyme levels to the normal range. In the second patient, the corneal disease improved after 6 weeks of interferon alfa-2b treatment, but abruptly worsened when the patient discontinued therapy. The corneal disease improved again after interferon alfa-2b was reinstituted.

CONCLUSIONS

Chronic HCV virus infection is associated with Mooren-type peripheral ulcerative keratitis. All patients with Mooren-type ulcers should be tested for evidence of HCV infection in consultation with a liver specialist. Even when improvement is obtained with interferon alfa-2b treatment, however, continued follow-up is important because relapse is common and repeat treatment may be effective.

Presence of hepatitis C virus (HCV) genomic RNA and viral replicative intermediates in bone marrow and peripheral blood mononuclear cells from HCV-infected patients

The cellular tropism of hepatitis C virus (HCV) was studied in vivo in samples from patients with persistent HCV infection. Plasma, liver, peripheral blood mononuclear cell (PBMC), and bone marrow cell (BMC) samples from 15 subjects positive for anti-HCV antibodies were tested for the presence of HCV RNA sequences by reverse transcription PCR. Virus-specific RNA sequences were found to be present in liver samples from all subjects (100%), in plasma samples from 13 of 15 patients (86.7%), in PBMC samples from 3 patients (20%), and in BMC samples from 9 (60%) of the 15 anti-HCV-positive patients enrolled in this study. The presence of the molecular intermediate of HCV replication (the negative-stranded HCV RNA) was evident in the two of the three PBMC and in five of the nine BMC HCV RNA-positive samples. Finally, we studied the nucleotide sequence of a large portion (-270 to -59) of the 5'untranslated region of HCV amplified from plasma samples of 12 of the 15 patients with and without HCV in BMCs; the degree of heterogeneity compared with the prototype HCV sequence was similar in both groups. The data principally indicate that HCV infection of PBMCs and BMCs is frequent in persistently infected patients, as shown by the occurrence of positive- and negative-stranded HCV RNA, thus suggesting the possibility of extrahepatic replication of HCV.

Management of chronic hepatitis in special populations

Over the last several years, much progress has been made in the treatment of adult patients with chronic viral hepatitis and compensated liver disease in the absence of significant other illnesses. However, the treatment of chronic viral hepatitis in other patient populations is still experimental. These groups include children, patients immunocompromised by human immunodeficiency virus infection or immunosuppression following organ transplantation, those with end-stage renal disease, and patients with extrahepatic manifestations of hepatitis viral infection. Data on the treatment of chronic hepatitis in these special populations are reviewed.

[Hepatitis C]

Hepatitis C virus (HCV), identified in 1989, is the main agent of Non-A, Non-B hepatitis. The number of HCV carriers in France is estimated between 500,000 and 2 millions. The main risk factors for HCV infection are blood products transfusion and i.v. drug abuse. Cirrhosis occurs in 30% of cases with a delay ranging from 10 to 30 years, and hepatocellular carcinoma in 2.5% of cases. Interferon is, for instance, the only effective therapy in patients with chronic hepatitis C; however, prolonged response (in terms of transaminase normalization) after stopping treatment occurs only in 20% of patients.

Etiology of IgA nephropathy syndrome

Since Berger's original paper on mesangial IgA-IgG deposition with hematuria, there have been a number of clinical and pathological studies regarding IgA immune complexes, the mechanisms of glomerular IgA deposition leading to glomerular injury and animal models of IgA nephropathy. During the last quarter of this century, glomerular changes such as IgA nephropathy have also been observed in cases associated with other diseases, such as systemic lupus erythematosus, Schoenlein-Henoch purpura, liver cirrhosis and chronic inflammatory diseases of the lung. This evidence supports the idea of an IgA nephropathy syndrome. On the other hand, IgA is thought to be an important humoral factor at the mucosal immune system and appears to have an antibody function against various etiologic candidates of extrinsic or intrinsic substances at the mucosal and systemic immune system. Glomerular IgA deposition in IgA nephropathy syndrome is thought to result from elevated levels of circulating immune complexes or aggregated IgA due to an overproduction of polymeric IgA as antibodies in the serum and due to the clearance impairment of IgA immune complexes in the hepatic and splenic phagocytic system. The glomerular IgA subclass is not one-sided, but should be evaluated in comparison with the age of patients at renal biopsy; this indicates the approximate age of onset. Cirrhotic IgA glomerulonephritis is not related to Hepatitis B or C virus infection, but to the pathophysiologic condition of liver cirrhosis. Various etiologic candidates such as viral, microbial, dietary antigens or auto-antigens have been listed and experimental models of IgA nephropathy syndrome have provided some clues in understanding the etiology of primary IgA nephropathy. However much still remains to be clarified and some specific epitopes common among these etiologic candidates will have to be identified.

IgM and IgG antibodies to hepatitis C virus in patients with mixed cryoglobulinaemia

To assess the relationship between hepatitis C virus (HCV) infection and essential mixed cryoglobulinaemia (EMC), sera from 23 patients with EMC were tested for IgG and IgM antibodies to HCV antigens and for HCV RNA. Quantitative HCV antibody studies were performed on serum and purified cryoglobulin fractions. HCV antibodies of both IgG and IgM class were found in 22 (96%) patients. Ten of these were also HCV-RNA positives. Higher titres of anti-HCV IgM were present in the 11 patients with evidence of liver damage. Anti-HCV IgG antibodies were shown to be concentrated in the IgG fraction of cryoglobulins in all eight patients studied. These results strongly suggest a role for HCV in the pathogenesis of EMC.