Hepatitis studies: IL28B genetics, HCV survival, FibroScan in acute HCV, MSM reinfection and responses to transplantation

1 June 2010. Related: Conference reports, Hepatitis coinfection, CROI 17 (Retrovirus) 2010.

Simon Collins, HIV i-Base

The following studies focused on aspects of hepatitis coinfection.

IL28 predict treatment response to IL28

Some of the most exciting coinfection studies included those elaborating on the recent association between genetic variations in the IL28B gene and both HCV pathogenesis and response rates to PEG-IFN and ribavirin treatment.

Andri Rauch from University Hospital Bern, introduced the HCV coinfection scientific session with an overview lecture of this research, most of which has become clearer within the last six months. [1]

Rauch detailed how several groups have independently screened the human genome for genetic variations associated with HCV immune response linked to spontaneous clearance or to explain the wide range of responses to HCV treatment: important as roughly 50% patients globally are unable to clear the virus. These studies consistently identified genetic variations in interleukin 28B (IL28B) as the strongest predictor of spontaneous clearance and treatment-related clearance, in both monoinfection and HIV/HCV coinfected individuals.

Rauch explained how IL28B on chromosome 19 encodes interferon-lambda, a type III interferon with antiviral activity mediated through the JAK-STAT pathway by inducing interferon-stimulated genes. Several single nucleotide polymorphisms (SNPs) might modulate function or expression of IL28B.

The correlation between allele frequency in different American ethnicities and treatment outcome was also detailed. The rs12979860 SNP is found in approximately 40%, 70% and 95% of those with African, European and Asian decent, which correlates with SVR rates of 25%, 55% ad 75%, respectively.

IFN-lambda is induced by IFN-alpha and encoded by IL28B, and is not known to play an important role though mechanism in yet to be determined. Phase 1b trials show a potential treatment, synergistic to IFN-alpha, but associated with fewer side effects including reduced fever, flu-like symptoms, neutropenia, bone marrow toxicity.

Together, these findings may enable greater understanding of individual response rates to current treatment, potentially developing management strategies based on genetic differences, and also, potential lead to new antiviral HCV treatments.

Julia di Iulio from University Hospital Lausanne and colleagues presented an analysis of the rs8099917 allele, linked to the Type II haplotype family, in a genome-wide association study involving 347 people with spontaneous HCV clearance and 1015 people with chronic HCV. This in turn lead to identification 21 SNPs, and then four potential causal SNPs closer to IL28B, that are associated with chronic HCV and that may be more likely to influence IL28B function or expression. [2]

Norma Rallon and colleagues from Madrid reported on the role of rs12979860 on treatment responses of 198 HIV/HCV coinfected patients (106 with SVR and 92 non-responders). Due to sampling issues, 164 patients were included in final analysis.

The SVR rate was significantly higher in patients with the CC alleles than in those with CT/TT alleles across all HCV genotypes (75% vs 38%, p<0.0001) and by genotype (G1: 65% vs 30%, p=0.001; G-3/4 83% vs 57%, p=0.02). In the multivariate analysis, the rs12979860 CC genotype was a strong predictor of SVR (OR 3.4; 95%CI 1.4–7.9; p=0.006), independent of other well-known predictors such as HCV genotype 3, baseline serum HCV-RNA <600,000 IU/mL and fibrosis <F3-F4.

Jacob Nattermann from the University of Bonn, and colleagues, reported slightly different results to other coinfection cohorts when they looked at whether IL28B SNP rs12979860 affected treatment outcome in 192 co-infected patients (74 acute and 118 chronic). Rates of sustained virological responses (SVR) were compared in patients carrying different genotypes. As comparison, 136 uninfected and 156 HCV mono-infected patients were included as control groups. [4]

IL28B genotype distribution did not differ significantly between the HIV (acute and chronic) and uninfected groups but monoinfected patients had a low rate of the protective C/C genotype (30% vs 41-47%).

While coinfected patients with the C/C genotype had significantly higher SVR rates than patients with C/T and T/T (58.1% vs 40.6%; p=0.041). This effect reached statistical significance only in HIV-positive patients with chronic (50% vs 29%; p=0.04) but not in those with acute (73.3% vs 60%; p=NS) HCV.

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In addition to the data in co-infected patients reviewed by Rauch, his group has also shown that, as in mono-infected patients, polymorphisms also determine spontaneous clearance rates.  The potential for a genetic mechanism to explain differences in spontaneous clearance and HCV treatment response rates by ethnicity is clearly important given the social aspects of HCV care globally. This suggests perhaps a more accurate marker with, or instead of, early treatment response rates, in order to identify people who risk only toxicity without any likely clinical benefit if they use treatment with pegylated interferon and ribavirin.

Clearly, before these tests are utilised in clinical pathways, we need further studies. Positive- and negative-predictive values for genotype results need to be highly predictive to ensure this is not used as a way to exclude some patients from treatment.  IL28 alayses are likely to be included in future treatment studies. Furthermore, there may be implications for the clinical utility of these tests to identify patients with a low likelihood of response to standard therapy who may be candidates for early treatment with specifically-targeted anti-HCV drugs.

Duration of infectious HCV survival in syringes

Elijah Paintsil and colleagues from Yale School of Medicine presented results of the impact that different gauge syringes and different temperatures has on the duration of HCV infectivity and therefore risk from residual blood. [5]

Syringes with low (2 uL) and high (32 uL) quantities of residual HCV-containing blood after full plunger depression, with 1-cc insulin syringe (permanently attached needle) and 1-cc tuberculin syringe (detachable needle), respectively. Syringes were either immediately tested for viable virus or stored at 4ºC, room temperature and 37ºC, for up to 56 days. Virus was recovered from stored syringes and tested for infectivity in cell culture using relative luciferase activity.

HCV infectivity was not detected in the small syringes beyond day one except for those stored at 4º where HCV remained viable in 5% of syringes up to day 7.

After 7 days of storage, 96% ± 7.5, 71%± 23.1, and 52% ± 20 of 32 uL syringes were HCV-positive at 4º, room temperature, and 37º, respectively. Viable virus was recovered from the 32 uL syringes up to day 56. In general, the infectivity of the recovered virus was inversely related to duration and temperature of storage.

Caution when interpreting FibroScan results from acute HCV infection

A study from the European NEAT coinfection group reported that liver stiffness was elevated during acute HCV infection, probably due to high levels of inflammation and short observation periods, and that early FibroScan results should therefore be interpreted with caution, rather than assume that greater stiffness are a marker of rapid progression. [6]

Fibrosis progression rate (FPR) was calculated dividing the difference in fibrosis units by the time of follow-up. The analysis included 28 HIV-positive men with acute HCV that become chronic (91% MSM sexual exposure risk), or if FibroScan prior to anti-HCV therapy was available. Plotting FPR over follow-up time revealed short observation times being strongly correlated with high fibrosis progression rates. No interaction of risk factors for cirrhosis or HAART exposure with follow-up time was observed.

The authors concluded: Calculated high fibrosis progression rates after acute HCV infection in HIV-positive individuals are probably influenced by short observation periods. Higher liver stiffness in the acute phase of HCV infection may be at least partially explained by higher inflammatory activity that has been shown to increase stiffness leading to overestimation of fibrosis. A linear model for fibrosis progression, as is currently applied in the setting of chronic HCV infection, should be used with caution in the setting of acute HCV infection.

HCV reinfection after spontaneous HCV clearance

A poster on acute HCV infection in HIV-positive MSM in Germany was interesting for two reasons. Firstly, 22% patients spontaneously cleared HCV, and secondly, a high rate of reinfection that was reported (5 patients: 17% of those with a spontaneous or treatment related SVR). [7]

Hans-Jürgen Stellbrink and colleagues reported on 46 cases of acute HCV in MSM since 2001, from an HIV cohort of >4,400 predominantly MSM. Incidence rates per 1000 PYFU increased steadily from 0.15 in 2001/02 to 2.48 in 2007/08. HCV was genotype 1, 2, 3 or 4 in 20 (43%), 1 (2%), 9 (20%) and 16 (35%) cases, respectively.

Of the 34 patients treated with peg-IFN/RBV, SVR was achieved in 20 (65% of the 31 subjects with follow-up after treatment), relapse occurred in 3 (10%), and primary non-response was observed in 8 (26%). Ten patients (22%/46) cleared HCV spontaneously, and 2 (4%) remain untreated with persistent infection.

Re-infection occurred in five individuals (17%) of those who cleared acute hepatitis C infection (three with different genotypes, 1 with the same, 1 with pending genotype). After primary infection with G3, one patient developed severe hepatitis upon second re-infection with G1; this patient cleared HCV all 3 times without therapy.

Of note, a 24% rate of spontaneous clearance was reported by Bradley Hare and colleagues in a group of 54 HIV-positive MSM in San Francisco and New York. This study also reported 100% response rates in patients who, having achieved undetectable HCV RNA at week 8 or 12, continued treatment with PEG-IFN only (dropping RBV) for the subsequent 12 weeks. [8]

People with haemophilia with HIV/HCV coinfection need earlier referral for liver transplant

Margaret Ragni and colleagues presented results of canditates for liver transplant from the US multicentre study in people coinfected with HIV/HCV, comparing outcomes in men with and without haemophilia. [9]

Of 100 HIV/HCV enrolled candidates, 33 (33%) underwent orthotopic liver transplantation (OLTX), including 8/16 (50.0%) with haemophilia and 25/84 (29.8%) without.

Men with haemophilia were less likely to still be alive, and more likely to have died before transplant (mainly related to sepsis or multi organ failure). Men with haemophilia reached transplant (OLTX) and MELD of 25 marginally faster than non-hemophilic subjects (p=0.09 and 0.06 respectively). Although younger (42 vs 48 years, p=0.004), there were no differences in BMI, CD4, detectable HIV RNA or detectable HCV VL, time to post-OLTX death, graft loss, and treated rejection or 3-year survival. See Table 1.

Table 1: Outcomes from liver transplant in men with and without haemophilia

The authors concluded that in HIV-positive men with hemophilia, “despite early acquisition of HCV, transplant outcomes appear to be similar to those in co-infected individuals without hemophilia. However, pre-transplant mortality appears higher among co-infected hemophilic men. Whether earlier intervention could reverse this finding is not known”.

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Although this was one of the few studies at CROI to mention management issues for people with haemophilia, these results should be interpreted cautiously. With only 16 haemophilia patients in the study who are, by definition, a highly selected group of long-term survivors, the researchers are unlikely to have been able to adjust for the likely differences between the two groups.

References All references are to the 17th Conference on Retroviruses and Opportunistic Infections, 16-19 February 2010, San Francisco. Oral presentations are included in the webcast: Oral Abstracts and Scientific Overview: Hepatitis C: Transmission, Outcomes, and Treatment. 17th CROI, 2010. Friday 09.30am. 1. Rauch A. The interleukin 28B gene and HCV recovery. 17th CROI, 2010. Oral abstract 162. http://www.retroconference.org/2010/Abstracts/39872.htm 2. di Iulio J et al. Association of IL28B haplotypes with chronic HCV infection in HIV/HCV co-infected individuals. 17th CROI, 2010. Oral abstract 163. http://www.retroconference.org/2010/Abstracts/37377.htm 3. Rallon N et al. Strong association of a single nucleotide polymorphism located near the interleukin-28b gene with response to hepatitis C therapy in HIV/HCV co-infected patients. 17th CROI, 2010. Oral abstract 165LB http://www.retroconference.org/2010/Abstracts/39833.htm 4. Nattermann J et al. Genetic variation in IL28B and treatment-induced clearance of HCV in HCV/HIV co-infected patients. 17th CROI, 2010. Oral abstract 164. http://www.retroconference.org/2010/Abstracts/39494.htm 5. Paintsil E et al. Survival of HCV in syringes: implication for HCV transmission among injection drug users. 17th CROI, 2010. Oral abstract 168. http://www.retroconference.org/2010/Abstracts/38965.htm 6. Ref: Vogel M et al. Liver Fibrosis Progression after Acute HCV Infection in HIV+ Individuals. 17th CROI, 2010. Poster abstract 642. http://www.retroconference.org/2010/Abstracts/38914.htm 7. Stellbrink H-J et al. Incidence, Genotype Distribution, and Prognosis of Sexually Transmitted Acute Hepatitis C in a Cohort of HIV-infected Patients. 17th CROI, 2010. Poster abstract 645. http://www.retroconference.org/2010/Abstracts/38606.htm 8. Hare B et al. Kinetically Guided PEG Alfa-2a and RBV Therapy for HIV-+ Adults with Acute HCV Infection. 17th CROI, 2010. Poster abstract 639. http://www.retroconference.org/2010/Abstracts/38114.htm 9. Ragni M et al. Outcomes in HIV/HCV Hemophilic vs Non-hemophilic Transplant Candidates. 17th CROI, 2010. Poster abstract 688. http://www.retroconference.org/2010/Abstracts/39692.htm