Extrahepatic manifestations associated with hepatitis C virus infection. A prospective multicenter study of 321 patients. The GERMIVIC. Groupe d'Etude et de Recherche en Medecine Interne et Maladies Infectieuses sur le Virus de l'Hepatite C

The antiphospholipid syndrome and infection

Infectious agents have been implicated in the induction of antiphospholipid (aPL) antibodies and the development of the antiphospholipid syndrome (APS). This review focuses on the types of aPL antibodies detected in infections and addresses whether these antibodies are of clinical importance in patients with infections. Hepatitis C virus (HCV) infection is given special attention because this virus has the propensity to induce various autoimmune phenomena. Several aspects are emphasized that should be considered carefully when interpreting results. Most of the published data agree that thrombophilia is not observed in patients with infections (including HCV) because aPL antibodies are mostly the natural or nonpathogenic type. Thus, we do not recommend routinely testing for HCV in patients with APS. However, not all infection-associated aPL antibodies are cofactor independent. For instance, infections are increasingly recognized as a major precipitating condition of the catastrophic variant of APS, perhaps via mechanisms of molecular mimicry. Therefore, it may be possible to prevent this devastating evolution if the infectious process is promptly recognized and exhaustively treated.

[Sarcoidosis and comorbidity: retrospective study of 32 cases]

PURPOSE

A retrospective study was set up to investigate active pathologic processes associated with sarcoidosis diagnosed in 32 patients.

METHODS

Eighteen patients had two identified granulomatous localizations (56%) and 14 patients had three localizations or more (27%). Comorbidity was noticed in nine patients (28% of cases). Sarcoidosis was associated with an infectious disease five times (hepatitis C virus [HCV] infection three times, including one case after recombinant interferon alpha therapy, and HIV and HCV co-infection two times). The association of sarcoidosis with a chronic immunologic inflammatory disease was noticed four times (lupus erythematosus two times, myasthenia and primary biliary cirrhosis). Finally, in two cases sarcoidosis was associated with a neoplasia (non-Hodgkin's lymphoma in a co-infected HIV-HCV patient, ovarian cystadenocarcinoma in another patient). Sarcoidosis preceded or revealed the comorbidity four times.

The GOR gene product cannot cross-react with hepatitis C virus in humans

GOR (GOR47--1) is an epitope thought to be a host-derived antigen cross-reactive with hepatitis C virus (HCV) since it was isolated from a cDNA library of host animals reactive with sera of HCV-positive patients. An enzyme immunosorbent assay (ELISA) using this epitope as antigen is of sufficient sensitivity and specificity for screening patients with HCV. However, the relationship between GOR47--1 epitope and autoimmune phenomena associated with HCV infection or autoimmune hepatitis is controversial. Here we isolated the human GOR gene and found that the GOR47--1 epitope was not translated in humans due to a single base replacement from chimpanzee. Furthermore, we found some patients who had antibodies against another epitope, which is translated (GOR1--125) in humans, although there was no correlation between the existence of anti-GOR47--1 or anti-GOR1--125 Ab and autoimmune phenomena. Serum IgG levels did not influence the titres of these antibodies. Taken together with the results of several other studies, our finding that the GOR47--1 epitope cannot be translated into a protein suggests that there is little relationship between autoimmunity and the GOR gene product in human beings. We also discuss here the possible mechanism of cross-reactivity between HCV and the GOR gene product.

Hepatitis C virus infection with peripheral neuropathy is not always associated with cryoglobulinaemia

OBJECTIVES

To describe cases of peripheral neuropathy associated with chronic hepatitis C virus infection without mixed cryoglobulinaemia.

METHODS

Four cases of peripheral neuropathy associated with chronic hepatitis C virus infection with persistent negativity of mixed cryoglobulinaemia were found.

RESULTS

All patients had small increases of transaminase levels and a positive viraemia. Liver biopsy showed chronic active hepatitis in all but one case (Knodell 4-9, Metavir A0F0-A3F3). Neuromuscular biopsy showed axonal neuropathy associated with lymphoid infiltrates around small vessels in two cases. Rheumatoid factor was always negative and C4 complement level was always normal. In three patients, neuropathy improved with interferon alpha, interferon alpha + ursodesoxycholic acid, or steroids + plasma exchange.

CONCLUSION

Peripheral neuropathy may be associated with hepatitis C virus infection without mixed cryoglobulinaemia.

Binding of the hepatitis C virus envelope protein E2 to CD81 provides a co-stimulatory signal for human T cells

Chronic hepatitis C virus (HCV) infection frequently develops into liver disease and is accompanied by extra-hepatic autoimmune manifestations. The tetraspanin CD81 is a putative HCV receptor as it binds the E2 envelope glycoprotein of HCV and bona fide HCV particles. Here we show that HCV E2 binding to CD81 on human cells in vitro lowers the threshold for IL-2 receptor alpha expression and IL-2 production, resulting in strongly increased T cell proliferation. HCV E2-induced co-stimulation also enhances the production of IFN-gamma and IL-4 and causes increased TCR down-regulation. This suggests that binding of HCV particles to CD81 on T cells in vivo may lead to activation by otherwise suboptimal stimuli. Therefore, co-stimulation of autoreactive T cells by HCV may contribute to liver damage and autoimmune phenomena observed in HCV infection.

Hepatitis C virus infection mimicking primary Sjögren syndrome. A clinical and immunologic description of 35 cases

Hepatitis C virus (HCV) infection is emerging as an extremely common and insidiously progressive liver disease that is often associated with several extrahepatic manifestations. In 1992, a possible relationship between Sjögren syndrome (SS) and patients with HCV infection was first postulated. Subsequently, several studies demonstrated that a "true" SS, with similar clinical and histologic features to those observed in primary SS, may occur in some patients with chronic HCV infection. We report the clinical and immunologic characteristics of 35 patients with chronic HCV infection and a well-documented diagnosis of SS. Compared with 60 patients with primary SS who tested negative for HCV antibodies, SS-HCV patients showed a higher mean age (65.9 yr versus 61.5 yr, p = 0.04), a lower prevalence of parotidomegaly (17% versus 47%, p = 0.004), and a higher prevalence of liver involvement (94% versus 3%, p < 0.001). Moreover, those patients with HCV-related SS showed a higher prevalence of anti-parietal cell gastric antibodies (31% versus 13%, p = 0.03), antimitochondrial antibodies (14% versus 2%, p = 0.02), cryoglobulinemia (60% versus 10%, p < 0.001), hypocomplementemia (60% versus 8%, p < 0.001), and a lower prevalence of anti-Ro/SS-A (17% versus 38%, p = 0.03). The "true" SS observed in some patients with HCV may be considered 1 of the extrahepatic manifestations of HCV, and we suggest that HCV infection can be considered as an exclusion criterion for the diagnosis of primary SS.

Hepatitis C virus may infect extrahepatic tissues in patients with hepatitis C

AIM: To explore the status of extrahepatic hepatitis C virus (HCV) infection and replication in hepatitis C patients, and its potential implication in HCV infection and pathogenicity.

METHODS: By reverse-transcriptase poly-merase chain reaction (RT-PCR), in situ hybridization (ISH) and immunohistochemistry, HCV RNA, HCV replicative intermediate (minus-strand of HCV RNA), and HCV antigens were detected in 38 autopsy extrahepatic tissue specimens (including 9 kidneys, 9 hearts, 9 pancreas, 5 intestines, 2 adrenal glands, 2 spleens, 1 lymph node, and 1 gallbladder) from 9 hepatitis C patients, respectively; and the status of HCV replication in extrahepatic tissues was studied.

RESULTS: By RT-PCR, all 9 patients were positive for HCV RNA in kidney, heart, pancreas, and intestine, but only 6 (66.7%) patients were positive for HCV replicative intermediate. HCV RNA and HCV antigens were detected in kidney, heart, pancreas, intestine, adrenal gland, lymph node, and gallbladder in 5 (55.6%) and 6 (66.7%) patients by ISH and immunohistochemistry, respectively. HCV RNA and HCV antigens were not detected in these extrahepatic organs in 3 (33.3%) patients, although their livers were positive for HCV. HCV replicative intermediate detected by RT-PCR was consistent with HCV RNA and HCV antigens detected by ISH and immunohistochemistry (Kappa = 0.42-0.75). HCV RNA and HCV antigens were detected in myocardial cells, epithelial cells of intestinal gladular, interstitial cells of kidney, epithelial cells of tubules and glomerulus, pancreas acinar cells and epithelial cells of pancreatic duct, epithelial cells of mucous membrane sinus of gallbladder, cortex and medulla cells in adrenal gland, and mononuclear cells in lymph node. HCV RNA was also detected in bile duct epithelial cells, sinusoidal cells, and mononuclear cells in liver tissues by ISH.

CONCLUSION: HCV can infect extrahepatic tissues, and many various tissue cells may support HCV replication; extrahepatic HCV infection and replication may be of “concomitant state” in most of patients with hepati tis C. The infected extrahepatic tissues might act as a reservoir for HCV, and play a role in both HCV persistence and reactivation of infection. HCV as an etiologic agent replicating and expressing viral proteins in extrahepatic tissues itself contributes to extrahepatic syndrome associated-HCV infection in a few patients with chronic HCV infection.

Hepatitis C virus infection mimicking systemic lupus erythematosus: study of hepatitis C virus infection in a series of 134 Spanish patients with systemic lupus erythematosus

OBJECTIVE

To determine the prevalence and clinical significance of hepatitis C virus (HCV) infection in patients with systemic lupus erythematosus (SLE).

METHODS

We investigated 134 consecutive SLE patients (121 women and 13 men; mean age 35 years) who fulfilled the 1982 revised criteria for SLE of the American College of Rheumatology. Two hundred consecutive volunteer blood donors were also studied. Serum from all patients and controls was tested for antibodies to HCV (by third generation enzyme-linked immunosorbent assay and confirmed by third generation recombinant immunoblot assay [RIBA-3]).

RESULTS

Antibodies to HCV were present in 18 patients with SLE (13%) and in 2 (1%) of the blood donors studied. Among the anti-HCV-positive group, HCV infection was confirmed (by RIBA-3 and polymerase chain reaction) in 15 SLE patients (11%) and in the 2 blood donors (1%) (P < 0.001). We observed a lower frequency of cutaneous SLE features (40% versus 76%; P = 0.01) and positivity for anti-double-stranded DNA (anti-dsDNA) (33% versus 81%; P < 0.001), and a higher frequency of hepatic involvement (93% versus 2%; P < 0.001), low C4 levels (73% versus 39%; P = 0.002), low CH50 levels (73% versus 44%; P = 0.03), and cryoglobulins (60% versus 22%; P = 0.02) in SLE patients with HCV infection compared with SLE patients without infection.

CONCLUSION

The prevalence of HCV infection in SLE patients was higher than in blood donors from the same geographic area. SLE HCV-positive patients showed a lower frequency of cutaneous SLE features and anti-dsDNA antibodies, and a higher prevalence of liver involvement, hypocomplementemia, and cryoglobulinemia. HCV testing should be considered in the diagnosis of SLE, especially in patients who lack the typical cutaneous features of SLE or who have low titers of autoantibodies, cryoglobulinemia, or liver involvement.

Immunology of hepatitis C virus infection

Hepatitis C virus (HCV) is known for its ability to establish persistent infection and cause chronic hepatitis in most infected individuals. The pathogenesis of hepatic injury and the precise mechanisms underlying viral persistence are unknown. Accumulating evidence indicates that successful elimination of HCV is associated with the induction and maintaining of strong helper T-cell and cytotoxic T-cell responses against multiple viral epitopes. In contrast, patients who develop chronic HCV infection are characterized by the lack of strong viral-specific helper T-cell responses. The failure to mount and maintain strong HCV-specific T-cell responses may be determined by the genetics, especially the major histocompatibility complex background, of the host. However, it is likely that other host and viral factors are also involved in determining the outcome of HCV infection. Available data suggest that HCV is not cytopathic to hepatocytes and that liver injury associated with chronic HCV infection is likely to be mediated by immune responses against HCV-infected hepatocytes. In addition to hepatitis, HCV infection may also cause breaching of immune tolerance, leading to autoimmune disorders. Although the lack of a small animal model and a tissue culture system has impeded research on hepatitis C virus (HCV) infection, recent studies in humans and chimpanzees have significantly enhanced our understanding of the interaction between HCV and the host's immune system. This review focuses on the most recent advances in our understanding of the immunology of HCV infection. In particular, the possible mechanisms of how HCV establishes chronic infection are discussed. The pathogenesis of liver injury, the immunogenetics of HCV infection, and the effect of HCV infection on host's immune function are also reviewed.