Journal of Medical Virology 80:1720–1722 (2008)

Immune Suppression Leading to Hepatitis C VirusRe-Emergence After Sustained Virological Response

Amy Lin,1 Anupama Thadareddy,1 Michael J. Goldstein,2 and Gerond Lake-Bakaar1*1Department of Medicine, Division of Gastroenterology-Hepatology, Weill Cornell University Medical College,New York, New York2Department of Surgery, Division of Transplantation, Weill Cornell University Medical College, New York, New York

Sustained virological response SVR is defined asundetectable HCV RNA in plasma 6 monthsafter therapy has been discontinued. Relapseor re-emergence of viremia after SVR is rare.We report two patients that relapsed whenimmune suppressive therapy was given within afew weeks of achieving SVR. Patient 1 receivedprednisone for bronchitis and patient 2 relapsedsoon after immune suppression was started postrenal transplantation. These data suggest that theearly phase of SVR might be associated withincomplete protective immunity. They suggestthat sterilizing immunity with complete elimina-tion of virus is unlikely. The cases also cautionagainst the use of immune suppressive therapy inthe immediate aftermath of SVR. J. Med. Virol.80:1720–1722, 2008. � 2008 Wiley-Liss, Inc.

KEY WORDS: sustained virological response;hepatitis C virus; immunity

INTRODUCTION

Sustained virological response SVR is defined asundetectable HCV RNA in plasma 6 months afterinterferon based therapy has been discontinued. Relapseor breakthrough after SVR is rare [McHutchison et al.,2001; Tsuda et al., 2004; Desmond et al., 2006]. Naturalresolution from acute HCV infection is associated witha broad, multi-specific T-cell response [Lauer et al., 2004;Chung, 2005]. It is followed by the development ofprotective immunity, characterized by mild, short-livedinfection on re-challenge [Bassett et al., 2001; Mehtaet al., 2002; Nascimbeni et al., 2003; Lanford et al.,2004]. Protective immunity can be overcome by immunesuppression’ This is illustrated in the case report of anIVDU that had previously cleared HCV, but developedpersistent chronic HCV infection after becoming HIV-1positive [Mehta et al., 2002].

By contrast, successful interferon based therapyof acute [Rahman et al., 2004; Shoukry et al., 2004;Wiegand et al., 2004; Lauer et al., 2005] and possiblyalso of chronic genotype 1 HCV infection [Kaplan et al.,2005] is associated with progressive reduction of both

cellular and humoral responses. It is less clear whetherinterferon based resolution of HCV infection reflectssterilizing immunity (an immune response that eradi-cates any detectable infection) or protective immunity.

We report two SVR patients that relapsed aftertreatment with immune suppressive therapy wasadministered. We argue that aviremia in the immediateperiod after SVR reflects protective immunity. Immunesuppression should be used cautiously in patients inthe immediate aftermath of SVR.

CASE REPORTS

Patient 1 is a 56-year-old male who presented to ourclinic in April 2003 with a history of untreatedchronic HCV genotype 1b that had been diagnosed in1989 during routine work up for unrelated chest pain.He admitted to intravenous drug abuse in the 1960sand 1970s but had been totally drug free since 1977. Inaddition, he had been exposed to blood and bloodproducts from war injuries sustained while serving inVietnam. A liver biopsy in 2002 showed mild to moderatefibrosis but no cirrhosis. MRI in September 2002 showedhemangiomas. Other significant medical history includ-ed mitral valve prolapse, GERD, and L5/S1 lumbar discsurgery in June 2002. He denied significant alcoholabuse in the past.

He started treatment with PEG-IFN-a-2a 180 mcgweekly and Ribavirin 1,000 mg daily in October 2003.Pre-treatment HCV RNA was 630,400 IU/ml. Genotyp-ing revealed HCV genotype 1b. HCV RNA was measuredusing the Bayer Versant 3.0 branched DNA (bDNA;

Dr. Gerond Lake-Bakaar’s present address is Liver Center,Beth Israel Deaconess Medical Center, Harvard Medical School,Boston, MA 02215.

*Correspondence to: Dr. Gerond Lake-Bakaar, MD, LiverCenter, Lowry Medical Building Room 7-A055, Beth IsraelDeaconess Medical Center, Harvard Medical School, 110 FrancisStreet, Boston, MA 02215. E-mail: glakebak@bidmc.harvard.edu

Accepted 13 May 2008

DOI 10.1002/jmv.21257

Published online in Wiley InterScience(www.interscience.wiley.com)

� 2008 WILEY-LISS, INC.

Bayer Corporation, Tarrytown, NY) signal amplificationdetection assay with a limit of detection of 615 IU/ml.Samples with viral loads below this level were testedusing the Bayer Versant Transcription MediatedAmplification with a limit of detection of 5 IU/ml.Genotyping was performed using the Versant HCVGenotype assay, a line probe assay.

Serum ALT was 88 U/L. Ribavirin was reduced to800 mg/day from week 9 because of hemolytic anemia.HCV RNA was negative by transcription mediatedamplification TMA and serum ALT had normalizedto 28 U/L by week 16 of treatment. Treatment wasstopped in early May 2004. SVR with undetectableviral load and normal ALTs were confirmed at thebeginning of November 2004, 6 months after stoppingtreatment.

At the end of November 2004, more than 6 monthsafter stopping interferon treatment, he was treatedsuccessfully for acute bronchitis, with a short course ofprednisone taper, starting at 60 mg orally over 6 days.Routine HCV by TMA in April 2005 was noted to bepositive. The HCV recurrence was confirmed by HCVRNA in May. In June, serum ALT was 41 U/L and HCVRNA, 458,400 IU/ml. The patient denied high riskbehavior or exposure to HCV. Repeat genotype analysisdemonstrated genotype 1b.

Patient 2 is a 44-year-old male with chronic HCVgenotype 1 infection, originally from Pakistan, with end-stage renal disease ESRD secondary to congenitalpolycystic kidney disease that was managed on hemo-dialysis. He also had hypertension. He denied prior useof intravenous drugs, blood transfusions or tattoos.Liver biopsy during the initial workup in 2002 demon-strated stage 0 and grade 1 disease.

Viral loads estimated during 2002 and 2004 were lowand varied from 6,720 IU/ml to 96,000 IU/ml. HCV RNAin this patient was measured using the Cobas Amplicore(Roche Diagnostics Corp, Indianapolis, IN) with a lowerlimit of detection of 50 IU/ml. Pegylated interferon-a-2amonotherapy 180 mcg weekly was started in April2004 with a viral load of 960 IU/ml at the inceptionof treatment, but only lasted 1 month. Therapy wasrestarted in July 2004. Viral load estimated by tran-scription mediated amplification TMA, 4 weeks afterrestarting therapy was undetectable (rapid virologicalresponse). The patient was monitored at monthly clinicvisits and was treatment compliant throughout. Viralload remained undetectable during the full 48 weeks oftreatment. It was still undetectable in January 2006,6 months after treatment was stopped, which consti-tuted a sustained virological response, SVR.

The patient received a kidney in February 2006. Thedonor was a 59-year-old woman with a 10-year history ofhypertension. She was declared brain dead from a CVA.Her terminal creatinine was 1.0. Organ donors olderthan 60 years of age, and those between 50 and 59 withat least two of the following risk factors: death fromCVA, history of HTN, or terminal Creatinine equal to orgreater than 1.5 are considered an Expanded CriteriaDonor (ECD) by UNOS definition.

The deceased donor renal transplant was hepatitis Cvirus negative by serological testing, as is the currentstandard of care. Due to the time limitations in donorrecovery, off-site assays or assays with slow turn-around time are not available. The patient did not fallinto a risk group for recent HCV infection.

Since the patient was a positive CDC (complementdependent lymphocytoxicity) cross-match, he receivedinduction therapy with rabbit antithymocyte globulinwith rapid corticosteroid withdrawal. Maintenanceimmunosuppression consisted of mycophenilate mofetilbeginning on the day of surgery, and followed by initia-tion of tacrolimus on post-operative day 2. Two daysafter transplant, his HCV RNA PCR was noted to be120 IU/ml. The immunosuppressive regimen was con-tinued. HCV RNA PCR levels rose to 1,191,841 IU/ml inJuly 2006. One year later, the viral load was3,952,430 IU/ml. Liver function tests have remainedwithin the normal range throughout.

DISCUSSION

Several long-term follow up studies of patients whoachieve sustained virological response SVR have clearlydemonstrated that relapse or breakthrough after SVRis rare [McHutchison et al., 2001; Tsuda et al., 2004;Desmond et al., 2006]. However, the immune mecha-nisms that underlie the control (protective immunity) oreradication (sterilizing immunity) of virus after SVR areunclear. Our observation that immune suppressivetreatment starting within a few weeks after SVR maybe associated with virological relapse allows us tospeculate on potential immune mechanisms.

Interferon controls viral infections principally byinhibition of viral replication and by stimulation of hostadaptive immune responses [Garcia-Sastre and Biron,2006]. The adaptive immune response appears crucialfor the natural resolution from acute HCV infection andseveral studies have linked clearance to the breadth anddepth of host virus specific T-cell response [Lauer et al.,2004; Chung, 2005]. By contrast, interferon therapyinduced resolution of both acute and chronic HCVinfections is associated with progressive reduction,rather than augmentation of the cellular and humoralresponses [Rahman et al., 2004; Shoukry et al., 2004;Wiegand et al., 2004; Kaplan et al., 2005; Lauer et al.,2005]. Thus, the immune mechanisms that underlienatural resolution may differ significantly from inter-feron induced resolution of HCV infection. In naturalresolution, suppression of viral replication by innateimmunity is followed by the development of significantand quantifiable specific adaptive immunity that drivesviremia to undetectable levels. By contrast, chronicinterferon therapy induces prolonged, sustained inhib-ition of viral replication. At these low levels of virus, hostimmunity, though weak, is capable of controlling viralreplication and preventing re-emergence.

Viremia can be maintained at clinically undetectablelevels either protective or sterilizing immunity. In bothhumans and chimpanzees, natural resolution of acute

J. Med. Virol. DOI 10.1002/jmv

HCV Re-Emergence After SVR 1721

HCV infection is associated with the development ofprotective immunity. This is characterized by mild,short-lived infection on re-challenge [Bassett et al.,2001; Mehta et al., 2002; Nascimbeni et al., 2003;Lanford et al., 2004]. Protective immunity can beovercome by immune suppression, well illustrated inan IVDU that had previously cleared HCV, butdeveloped persistent chronic HCV infection after becom-ing HIV-1 positive [Mehta et al., 2002]. Sterilizingimmunity on the other hand is associated with completeeradication of virus and therefore does not relapse withimmune suppression. Reports that HIV-1 infection canlead to relapse after resolution from HCV infection[Mehta et al., 2002] is reminiscent of our two patients,both of whom relapsed after immune suppressivetherapy. The report of HCV relapse several years afterSVR, in relation to corticosteroid therapy [Lee et al.,2005] is also consistent with protective immunity as thebasis of SVR.

Protective immunity implies low levels of persistentHCV replication, undetectable by current conventionalmethods. Ultra sensitive techniques for determining thepresence of HCV RNA using a highly sensitive reversetranscription (RT)-polymerase chain reaction-nucleicacid hybridization (RT-PCR-NAH) assay, detectedHCV RNA in macrophages, lymphocytes or sera in themajority of patients with SVR [Radkowski et al., 2005].

Virological relapse in our two patients may have beenthe result of re-infection. However, disease recurrencewas associated with the identical genotype in both cases;high risk behavior or exposure to ICV was remote inpatient 1; and donor kidney was HCV negative inpatient 2. A probable hypothesis might be that aviremiain the immediate post treatment phase is maintained byprotective immunity and that sterilizing immunity mayfollow as the small numbers of infected target cells areeliminated.

The persistently low levels of viremia in patient 2prior to renal transplant (range 960–96,000 IU/ml)suggest some degree of immune control. One yearafter starting immune suppression with tacrolimusand mycophenilate, viral load had increased to3,952,430 IU/ml. Thus, it may be that the higher viralloads associated with immune deficiency states such asHIV and common variable immune deficiency syndromereflects loss of immune control through either reducedviral clearance from plasma, elimination of infectedcells, or prevention of de novo target cell infection.

Knowledge of the immune mechanism(s) underlyingSVR may be clinically very relevant. Our data areconsistent with protective immunity as a mechanism forcontrolling viremia at the time of SVR. Thus, boostinghost immunity with virus specific antibody [Borgia,2004] or CpG [Jiao et al., 2004] at the end of treatmentmay help to prevent relapse.

In summary, we describe two patients with SVRwho demonstrated virological relapse after immunesuppression. We suggest caution in the use of immuno-

suppressive drugs in chronic HCV patients, at least inthe immediate aftermath of SVR.

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