Effects of the CCR5-Delta32 mutation on hepatitis C virus-specific immune responses in patients with haemophilia

In hepatitis C virus (HCV) infection antiviral T cells express the CC chemokine receptor 5 (CCR5). Their recruitment to the liver is an important step in the immune response. A 32 base pair deletion in the CCR5 gene leads to reduced expression and total loss of CCR5 in CCR5-n32 heterozygous and homozygous subjects, respectively. However, the role of this mutation for antiviral immunity remains unclear. Here, we analysed proliferation, IFN-gamma and IL-4 secretion (ELISpot) induced by the HCV antigens core, NS3, NS4, and NS5a in 21 anti-HCV-positive haemophiliac patients in relationship to their CCR5 genotypes (CCR5 wildtype n = 10, CCR5-n32 heterozygous n = 5 and CCR5-n32 homozygous n = 6). Furthermore, T cell migration in response to the CCR5 ligands CCL3, -4 and -5 was studied. Overall IFN-gamma responses to HCV proteins were only slightly greater in CCR5 wild-type patients than in CCR5-n32 carriers (0.6 versus 0.24 SFC/10(4) PBMC; p = 0.043). This difference was consistently seen with all tested HCV antigens. In contrast, neither T cell migration, nor PBMC proliferation, nor IL-4 production differed between CCR5 genotypes. Interruption of the CCR5 signalling pathway due to CCR5-n32 may potentially result in subtle reduction of HCV specific IFN-gamma responses in anti-HCV-positive haemophiliac patients.

Hepatitis C virus-induced secretion of inflammatory chemokines preferentially recruits NKG2A+CD8+ T cells

In patients with hepatitis C, a loss-of-function mutation of chemokine receptor CCR5 (CCR5Delta32) has been shown to be associated with spontaneous viral clearance and lower levels of hepatic inflammation. In the present study, we show that CCR5 is coexpressed with the inhibitory NKG2A receptor on CD8(+) T cells. Consequently, CCR5(+) T cells were highly susceptible to NKG2A-mediated inhibition of cytotoxic activity and NKG2A(+) lymphocytes were preferentially attracted by CCR5 ligands induced by hepatitis C virus E2 antigen. Thus, CCR5 is likely to exert immunoregulatory effects in hepatitis C virus infection by preferentially recruiting CD8(+) T cells bearing the inhibitory NKG2A receptor to the liver.

Induction of interleukin-6 by hepatitis C virus core protein in hepatitis C-associated mixed cryoglobulinemia and B-cell non-Hodgkin's lymphoma

PURPOSE

Chronic hepatitis C carries the risk to develop mixed cryoglobulinemia (MC) and B-cell non-Hodgkin's lymphoma (B-NHL), possibly because viral antigens stimulate the host's inflammatory response via extracellular pattern recognition receptors (PRR). To clarify this issue, we studied whether recognition of hepatitis C virus (HCV) proteins by PRR is involved in the pathogenesis of HCV-associated MC or B-NHL.

EXPERIMENTAL DESIGN

Peripheral blood mononuclear cells of patients with HCV-associated B-NHL (n = 12), MC (n = 14), uncomplicated hepatitis C (n = 12), and healthy volunteers (n = 12) were incubated with the recombinant HCV proteins E2, core, and NS3 to study induction of cytokine production, stimulation of B-cell proliferation, and immunoglobulin secretion. In addition, serum levels of interleukin-6 (IL-6) were measured by ELISA.

RESULTS

HCV core was the only studied protein, which induced production of IL-6 and IL-8 in CD14(+) cells. IL-6 induction was mediated via Toll-like receptor 2 (TLR2) and lead to increased B-cell proliferation in vitro. TLR2 expression on monocytes and IL-6 serum concentrations were increased in all groups of HCV-infected patients compared with healthy controls and were highest in MC (P < 0.05).

CONCLUSIONS

Increased secretion of IL-6 via stimulation of TLR2 by HCV core protein may play a role in the pathogenesis of hepatitis C-associated MC and B-NHL.

Hepatitis C virus E2 and CD81 interaction may be associated with altered trafficking of dendritic cells in chronic hepatitis C

Dendritic cells (DC) are crucially involved in the induction of immune responses; however, reports on DC functions in chronic hepatitis C are controversial. Function of DC includes proper cell trafficking between sites of infection and lympho-cellular compartments. Thus, we analyzed DC compartmentalization and changes in DC migration in hepatitis C virus (HCV)-infected patients. We found significantly lower numbers of circulating BDCA1+ and BDCA2+ DC in HCV(+) patients (n = 20) than in healthy controls (n = 12) (P < .05). Analyzing liver samples from HCV(+) patients (n = 15), HCV(-) controls (n = 15), and disease controls (n = 10), we demonstrated chronic hepatitis C to be associated with intrahepatic DC enrichment (P < .05). In vitro studies indicated that HCV E2-induced secretion of RANTES efficiently attracts CCR5(+) immature DC. Incubation of DC with sera derived from HCV(+) patients made DC unresponsive to CCL21, the chemokine recruiting DC to lymphoid tissues for T cell priming. Unlike attraction of CCR5+ DCs via RANTES, direct inhibition of DC migration in response to CCL21 was specific for patients with chronic hepatitis C and could be attributed to interaction of HCV E2 with CD81 on DC. In conclusion, migration of DC is markedly affected by interaction of HCV E2 with CD81. Failure of DC to recirculate to lymphoid tissue may be critically involved in impaired T cell priming during HCV infection.

Distribution and effects of polymorphic RANTES gene alleles in HIV/HCV coinfection -- a prospective cross-sectional study

AIM

Chemokines and their receptors are crucial for immune responses in HCV and HIV infection. RANTES gene polymorphisms lead to altered gene expression and influence the natural course of HIV infection. Therefore, these mutations may also affect the course of HIV/HCV coinfection.

METHODS

We determined allele frequencies of RANTES-403 (G --> A), RANTES-28 (C --> G) and RANTES-IN1.1 (T --> C) polymorphisms using real-time PCR and hybridization probes in patients with HIV (n = 85), HCV (n = 112), HIV/HCV coinfection (n = 121), and 109 healthy controls. Furthermore, HIV and HCV loads as well as CD4(+) and CD8(+) cell counts were compared between different RANTES genotypes.

RESULTS

Frequencies of RANTES-403 A, RANTES-28 G and RANTES-IN1.1 C alleles were higher in HIV infected patients than in healthy controls (-403: 28.2% vs 15.1%, P = 0.002; -28: 5.4% vs 2.8%, not significant; IN1.1: 19.0% vs 11.0%, P = 0.038). In HIV/HCV coinfected patients, these RANTES alleles were less frequent than in patients with HIV infection alone (15.4% P = 0.002; 1.7%; P = 0.048; 12.0%; not significant). Frequencies of these alleles were not significantly different between HIV/HCV positive patients, HCV positive patients and healthy controls.

CONCLUSION

All three RANTES polymorphisms showed increased frequencies of the variant allele exclusively in patients with HIV monoinfection. The finding that the frequencies of these alleles remained unaltered in HIV/HCV coinfected patients suggests that HCV coinfection interferes with selection processes associated with these alleles in HIV infection.

Effects of the CCR5-Delta32 mutation on antiviral treatment in chronic hepatitis C

BACKGROUND/AIMS

The CC-chemokine receptor (CCR) 5-Delta32 mutation may predispose to chronic liver disease and high level viremia in hepatitis C. However, it is unclear whether CCR5-Delta32 also affects the response to antiviral treatment.

METHODS

We determined CCR5 genotypes in patients with hepatitis C treated with either interferon-alpha (N=78) or interferon and ribavirin (N=78). In each group, rates of end of treatment responses (ETRs) and sustained virological responses (SVRs) were compared between CCR5-Delta32 carriers and homozygous CCR5 wildtype patients.

RESULTS

ETR and SVR were achieved in 25 and 12 patients with interferon-alpha and in 52 and 45 patients with interferon/ribavirin treatment, respectively. CCR5-Delta32 carriers had significantly lower ETR rates than homozygous CCR5 wildtype patients (10.5 vs. 39.0%; P=0.02), whereas SVR rates only showed a non-significant trend (5.3 vs. 18.6%). Multivariate analysis confirmed CCR5-Delta32 carriage as an independent negative predictor for ETR in interferon-alpha monotherapy (odds ratio: 0.16; 95% confidence limits: 0.032-0.82; P=0.03). In interferon/ribavirin treated patients CCR-Delta32 carriers and CCR5 wildtype patients had similar ETR rates [19.2% vs. 23.1%] and SVR rates [20.0% vs. 21.2%].

CONCLUSIONS

Response rates to interferon-alpha monotherapy are reduced in hepatitis C virus (HCV)-infected patients carrying the CCR5-Delta32 mutation. However, interferon/ribavirin combination treatment may overcome this negative effect of CCR5-Delta32.

[Do polymorphisms of the SDF1 and CCR2b genes modify the course of hepatitis C or HIV/HCV co-infection?]

BACKGROUND AND OBJECTIVE

Complementary to the CCR5-Delta32 mutation polymorphisms in the genes of CCR2b (CCR2b-V64 I) and stromal derived factor (SDF)-1 (SDF-1 3'A) affect the course of the human immunodeficiency virus (HIV) infection. While the CCR5-Delta32 mutation is also increased in chronic hepatitis C virus (HCV) infection it is unclear, whether the CCR2b-V64 I and the SDF-1 3'A polymorphisms also are associated with chronic HCV infection.

METHODS

We analyzed the frequencies of the CCR2b-V64I and SDF1 - 3'A mutation in patients with HIV/HCV coinfection (n = 130), HIV infection (n = 105), HCV infection (n = 153) and 112 healthy blood donors. We stratified each group into homozygous mutations, heterozygous mutations and homozygous wild types, respectively. The resulting subsets were compared with respect to HIV and HCV loads, CD4 and CD8 cell counts.

RESULTS

The mutant SDF1 - 3'A allele was found at 20.3 % frequency in patients with HCV infection and at 20.4 % frequency in patients with HIV/HCV coinfection, respectively. It was present in 27.1 % of the patients with HIV infection and 27.9 % of the healthy controls (not significant). The number of SDF-1 3) A homozygous patients was highest in patients with HIV/HCV coinfection and significantly different compared to the Hardy-Weinberg equilibrium (p = 0.010, chi (2) = 9.15). However, CD4- and CD8-cell counts or viral loads were not affected by this mutation. The frequency of the CCR2b-V64 I allele was similar in all patient groups. However, CCR2b-V64 I heterozygous patients showed HIV loads that were threefold lower than in CCR2b wildtype patients (22.9 x 103 vs. 6.4 x 103 copies/ml, not significant). Furthermore, hepatitis C viral loads were reduced roughly by 30 %.

CONCLUSION

These results suggest that the SDF1 - 3'A and CCR2b-V64I mutations do not affect the course of HCV and HIV/HCV infection in the same manner as does the CCR5-Delta32 mutation.

Frequency of the HIV-protective CC chemokine receptor 5-Delta32/Delta32 genotype is increased in hepatitis C

BACKGROUND & AIMS

A homozygous 32-base pair deletion in the CCR5 gene (CCR5-Delta32) protects against human immunodeficiency virus infection (HIV). However, the role of this mutation in other infections, such as hepatitis C virus (HCV) infection, has not been defined.

METHODS

We determined the frequency of the CCR5-Delta32 mutation by polymerase chain reaction in anti-HCV(+) (n = 153), anti-HIV(+) (n = 102), and anti-HCV(+)/HIV(+) (n = 130) white patients as well as in 102 healthy blood donors. Then, HIV and HCV loads, aminotransferases, and CD4 and CD8 cell counts were compared between the resulting subsets of CCR5-Delta32/wild-type heterozygotes, CCR5-Delta32, and wild-type homozygotes, respectively.

RESULTS

Twelve of 153 (7.8%) anti-HCV-seropositive patients and 1 of 102 (1.0%) healthy blood donors were CCR5-Delta32 homozygous, whereas CCR5-Delta32 homozygosity was absent in anti-HIV(+) and anti-HCV(+)/HIV(+) patients (P < 0.001). The frequency of the CCR5-Delta32 allele was higher in the anti-HCV(+) (16.0%, P < 0.05) and anti-HCV(+)/HIV(+) (12.7%, NS) patients than in healthy blood donors (8.3%) and anti-HIV(+) patients (9.3%), respectively. Anti-HCV(+) CCR5-Delta32 homozygotes occurred 3 times more frequently than expected from the Hardy-Weinberg equation (P < 0.0001) and had significantly higher HCV loads than wild-type patients (P = 0.045).

CONCLUSIONS

The increased prevalence of CCR5-Delta32 homozygosity associated with increased viral loads in patients with chronic hepatitis C suggests that the CCR5-Delta32 mutation may be an adverse host factor in hepatitis C.