Daniel S. Fierer

HIV-1 Vpu Antagonism of Tetherin Inhibits Antibody-Dependent Cellular Cytotoxic Responses by Natural Killer Cells

ABSTRACT The type I interferon-inducible factor tetherin retains virus particles on the surfaces of cells infected with vpu-deficient human immunodeficiency virus type 1 (HIV-1). While this mechanism inhibits cell-free viral spread, the immunological implications of tethered virus have not been investigated. We found that surface tetherin expression increased the antibody opsonization of vpu-deficient HIV-infected cells. The absence of Vpu also stimulated NK cell-activating FcγRIIIa signaling and enhanced NK cell degranulation and NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC). The deletion of vpu in HIV-1-infected primary CD4+ T cells enhanced the levels of antibody binding and Fc receptor signaling mediated by HIV-positive-patient-derived antibodies. The magnitudes of antibody binding and Fc signaling were both highly correlated to the levels of tetherin on the surfaces of infected primary CD4 T cells. The affinity of antibody binding to FcγRIIIa was also found to be critical in mediating efficient Fc activation. These studies implicate Vpu antagonism of tetherin as an ADCC evasion mechanism that prevents antibody-mediated clearance of virally infected cells. IMPORTANCE The ability of the HIV-1 accessory factor to antagonize tetherin has been considered to primarily function by limiting the spread of virus by preventing the release of cell-free virus. This study supports the hypothesis that a major function of Vpu is to decrease the recognition of infected cells by anti-HIV antibodies at the cell surface, thereby reducing recognition by antibody-dependent clearance by natural killer cells.

Telaprevir in the Treatment of Acute Hepatitis C Virus Infection in HIV-Infected Men

BACKGROUND There is an international epidemic of hepatitis C virus (HCV) infection among human immunodeficiency virus (HIV)-infected men who have sex with men. Sustained virologic response (SVR) rates with pegylated interferon and ribavirin treatment are higher in these men during acute HCV than during chronic HCV, but treatment is still lengthy and SVR rates are suboptimal. METHODS We performed a pilot study of combination therapy with telaprevir, pegylated interferon, and ribavirin in acute genotype 1 HCV infection in HIV-infected men. Men who were treated prior to the availability of, or ineligible for, telaprevir were the comparator group. The primary endpoint was SVR12, defined as an HCV viral load <5 IU/mL at least 12 weeks after completing treatment. RESULTS In the telaprevir group, 84% (16/19) of men achieved SVR12 vs 63% (30/48) in the comparator group. Among men with SVR, median time to undetectable viral load was week 2 in the telaprevir group vs week 4 in the comparator group, and 94% vs 53% had undetectable viral loads at week 4. Most patients (81%) who achieved SVR in the telaprevir group received ≤12 weeks of treatment and there were no relapses after treatment. The overall safety profile was similar to that known for telaprevir-based regimens. CONCLUSIONS Incorporating telaprevir into treatment of acute genotype 1 HCV in HIV-infected men halved the treatment duration and increased the SVR rate. Larger studies should be done to confirm these findings. Clinicians should be alert to detect acute HCV infection of HIV-infected men to take advantage of this effective therapy and decrease further transmission in this epidemic.

Rare Birds in North America: Acute Hepatitis C Cohorts

In this issue, the Comment from the Editor highlights 8 cohorts of acute hepatitis C patients and the dedicated investigators who are tracking these rarely identified patients in variety of unusual settings— collectively identifying 643 patients since 1996. The identification, enrollment, prospective monitoring and treatment of patients with acute HCV infections require enormous collaborative efforts and networking among individuals and institutions in addition to multiple sources of research funding. Acute hepatitis C provides a critical window of opportunity to understand the early and dynamic host-virus interactions that define the outcome of HCV infection, an opportunity that is lost once HCV persistence or resolution is firmly established. These cohorts continue to provide valuable insights about the natural history, outcome, therapy and immune pathogenesis of acute hepatitis C in various populations while offering important collaborative opportunities.

Rapid Progression to Decompensated Cirrhosis, Liver Transplant, and Death in HIV-Infected Men After Primary Hepatitis C Virus Infection

BACKGROUND We and others have shown that primary hepatitis C (HCV) infection in men infected with human immunodeficiency virus (HIV) causes early-onset liver fibrosis; however, little is known about the long-term natural history of the liver disease in these HIV-infected men. METHODS We followed a cohort of HIV-infected men with primary HCV infection in New York City. RESULTS Four men who were not cured after their primary HCV infection developed decompensated cirrhosis within 17 months to 6 years after primary HCV infection. Three died within 8 years of primary HCV infection, and 1 survived after liver transplant done 2 years after primary HCV infection. Three of the 4 men had AIDS at the time of primary HCV infection, and the most rapid progression occurred in the 2 men with the lowest CD4 counts at the time of HCV infection. Liver histopathology was most consistent with HCV-induced damage even though some had exposures to other potential hepatotoxins. CONCLUSIONS Primary HCV infection resulted in decompensated cirrhosis and death within 2-8 years in 4 HIV-infected men. The rapid onset of fibrosis due to primary HCV infection in HIV-infected men cannot therefore be considered benign. The rate of continued progression to liver failure may be proportional to the degree of underlying immunocompromise caused by HIV infection. More research is needed to better define the mechanisms behind accelerated liver damage.

Sofosbuvir Plus Ribavirin Without Interferon for Treatment of Acute Hepatitis C Virus Infection in HIV-1–Infected Individuals: SWIFT-C

Background Historically, acute hepatitis C virus (HCV) infection was treated with shorter durations of interferon-containing therapies. In the era of direct-acting antivirals (DAAs), it is unclear whether the efficacy of treatment achieved in chronic infection can be maintained with abbreviated courses of therapy during the acute phase. Methods The sofosbuvir-containing regimens without interferon for treatment of acute HCV in HIV-1 infected individuals (SWIFT-C) is an open-label, 2-cohort clinical trial in which the first cohort assessed for the safety and efficacy of 12 weeks of sofosbuvir plus ribavirin for the treatment of acute HCV infection in participants with chronic human immunodeficiency virus type 1 (HIV-1) infection. This is a preplanned analysis of the first cohort, which had a planned accrual of 17 participants. Results Seventeen men (11 Hispanic, 6 white, median age 45 years) were enrolled. Most (88%) had HCV genotype-1 infection and few (24%) had the favorable IL28B CC genotype. Median baseline HCV RNA was 2 280 000 IU/mL (interquartile range, 272 000-4 230 000). Ten participants (59%) achieved the primary outcome of SVR12 (90% confidence interval, 36%-78%), failing to establish noninferiority. All treatment failures were due to viral relapse (41%). There were no premature treatment discontinuations. The only factor that differed between participants who achieved SVR vs those who relapsed was ribavirin concentration at the end of treatment. Conclusion Sofosbuvir-ribavirin for 12 weeks for the treatment of acute HCV genotype-1 infection in HIV-1-infected persons results in a high relapse rate. Preliminary studies of DAA combination therapies suggest improved response rates, although the adequate duration of therapy remains unclear. Clinical Trials Registration NCT02128217.

Acute HCV in HIV-infected MSM: modes of acquisition, liver fibrosis, and treatment.

Hepatitis C virus (HCV) is not considered to be efficiently transmitted sexually, but since the early 2000s, HCV infection of HIV-infected men who have sex with men has emerged as an epidemic worldwide. In this review, we discuss the epidemiology of sexually transmitted acute HCV, the growing body of literature regarding risk factors for acquisition, and possible mechanisms of transmission. We also discuss the progression of liver disease in these men and the advances in therapy of acute HCV with interferon-free regimens and put forth our current approach of evaluating and treating these men in New York City.

Early-Onset Liver Fibrosis Due to Primary Hepatitis C Virus Infection Is Higher Over Time in HIV-Infected Men

To the Editor—We were pleased to read the recent report by Vogel et al [1] of their study undertaken in response to our findings of rapid onset fibrosis during primary hepatitis C virus (HCV) infection in human immunodeficiency virus (HIV)–infected men [2]. Their study, plus the recent publication of the liver biopsy results of Bottieau et al [3], seems to cement that this unexpected outcome is a true consequence of primary HCV infection in HIV-infected men. We disagree, however, that their results using transient elastography demonstrate a sharp decrease in the fibrosis progression rate (FPR) to a clinically unimportant level soon after the primary HCV infection period has waned.

Epidemic of Sexually Transmitted Hepatitis C Virus Infection Among HIV-Infected Men

Sexual contact is thought to be an inefficient mode of hepatitis C virus (HCV) transmission. However, reports of sexually transmitted HCV infection among HIV-infected men who have sex with men (MSM) began to appear in 2004. The patients were of early middle age with well-controlled HIV infection, participated in unprotected receptive sex, and frequently used noninjection recreational drugs. Molecular studies showed evidence of clusters of transmission between patients in different countries in Europe. Spontaneous clearance was relatively rare, but treatment with pegylated interferon and ribavirin resulted in cure in about two thirds of patients. Of concern was the finding of moderately advanced fibrosis during the early stages of HCV infection. HIV-infected MSM are a new risk group for HCV infection and so should be screened regularly for HCV infection.

Real-World Sustained Virologic Response Rates of Sofosbuvir-Containing Regimens in Patients Coinfected With Hepatitis C and HIV

BACKGROUND Patients with hepatitis C virus (HCV) with or without human immunodeficiency virus (HIV) achieve high sustained virological response (SVR) rates on sofosbuvir (SOF)-containing regimens in clinical trials. Real world data on patients coinfected with HCV and HIV treated with SOF-based regimens are lacking. METHODS This observational cohort study included HIV/HCV-coinfected adults with genotype 1 HCV who initiated treatment with a SOF-containing regimen between December 2013 and December 2014 (n = 89) at the Mount Sinai Hospital or the Brooklyn Hospital Center. The primary outcome was SVR at 12 weeks after the end of treatment. The secondary outcomes were risk factors for treatment failure, serious adverse events, and side effects. A post hoc per protocol analysis of SVR was performed on patients who completed treatment and follow-up. RESULTS In an intention-to-treat analysis, SVR rates were 76% (31/41) for simeprevir (SMV)/SOF, 94% (16/17) for SMV/SOF/ribavirin (RBV), and 52% (16/31) for SOF/RBV. The SVR rates of SMV/SOF/RBV and SMV/SOF did not differ significantly in this small study (P = .15). However the SVR rate of SMV/SOF/RBV was higher than that of SOF/RBV (P < .01). In a per protocol analysis, SMV/SOF/RBV had a higher SVR rate than SOF/RBV: 100% (16/16) vs 57% (16/28) (P < .01). The most commonly reported adverse effects were rash, pruritus, fatigue, and insomnia. One patient who had decompensated cirrhosis prior to treatment initiation died after receiving SMV/SOF. CONCLUSIONS SMV/SOF ± RBV is an effective option with minimal adverse effects for most HIV-positive patients with genotype 1 HCV. SMV should be used with caution in patients with decompensated cirrhosis.

Shedding of Hepatitis C Virus in Semen of Human Immunodeficiency Virus-Infected Men

HCV was shed into the semen of one-third of HIV-infected MSM with recent or chronic HCV infection. Levels were plausibly sufficient to transmit HCV during unprotected anal intercourse, therefore condoms should be worn to prevent transmission.