The phenomenon has also been described previously in a case series of three immuno-suppressed HIV-infected individuals (CD4 cell counts 14C266 cells/l) [15], with formation of anti-HCV antibodies following treatment with HAART and resultant immune restoration. had a negative result. After 9 months, 10% of patients had a negative test and 5% remained unfavorable after 1 year. Conclusion/discussion: Delayed seroconversion in HIV-positive individuals with acute HCV may result in delayed diagnosis and treatment. Where there is a clinical suspicion of recent HCV contamination, for example, elevated alanine transaminase levels, HIV-infected patients should be screened for HCV RNA by RTCPCR. Keywords: acute hepatitis C, antibody, HIV Introduction An epidemic of acute hepatitis C contamination in HIV-positive men who have sex Zapalog with men (MSM) has been reported in the UK, France, the Netherlands, Germany and the United States [1-4]. Early diagnosis and treatment of HIV-infected patients with pegylated interferon alpha and ribavirin results in improved sustained virological response (SVR) rates (59% in acutely infected patients versus 40% in chronically infected patients) [1,5], but does not reach the 98% treatment success rate reported in HIV-negative individuals [6]. Antibody testing is the main screening method for HCV contamination in HIV-infected individuals in the UK [7]. However, serological methods in HIV-infected patients might Zapalog not be the optimal screening method for early HCV diagnosis [8]. The objectives of this study were to assess the sensitivity of serology versus reverse transcriptase PCR (RTCPCR) performed on blood samples collected at 1C3 monthly intervals in 43 HIV-positive patients presenting with acute HCV contamination, and to estimate the median time from PCR amplification of HCV sequences to the development of antibodies. Methods Case definition: patients were diagnosed with acute HCV if they had a negative RTCPCR within 8 months of the first positive RTCPCR test, or a preceding unfavorable anti-HCV antibody within 6 months of the first positive RTCPCR, if HIV-negative at this time (two coinfected patients). Spontaneous Zapalog clearance was defined as a negative PCR test 6 months after the last positive PCR. Stored plasma samples collected at 1C3 monthly intervals from 43 HIV-positive Zapalog patients diagnosed with HCV contamination were available for retrospective analysis. The median duration of follow-up was 962 days [interquartile range (IQR) 567C1347 days]. Samples were tested for HCV RNA by qualitative nested RTCPCR, designed to amplify the 5 untranslated region (outer primers HCV-26 5-GTCTAGCCATGGCGTTAG-3, HCV-27 5-GCACGGTCTACGAGACCT-3, inner primers HCV-28 5-GTGTCGTGCAGCCTCCAG-3 and HCV-29 5-GGGGCACTCGCAAGCACC-3, limit of detection <10 copies/ml). Quantitative HCV viral loads were measured by real-time PCR (Abbott, limit of detection <12 IU/ml). Antibodies to HCV core, NS3 and NS4 proteins were assayed by a third-generation enzyme-linked immunosorbent assay (ELISA), according to the manufacturer's instructions (Monolisa Anti-HCV Plus, BioRad, Kent, UK). Seroconversion time was calculated as the time between the first positive PCR and first positive antibody test. A further Zapalog analysis of seroconversion time was carried out using samples from a subgroup of patients, who had samples taken at 4-weekly intervals. MannCWhitney assessments and Spearman’s rank correlation were carried out using STATA 10.0 software. Ethical approval for the study was granted by the Riverside Research Ethics Committee, Charing Cross Hospital, London (05/Q0401/17). Results Forty-three MSM with acute HCV contamination were identified. These patients constitute a part of an emerging outbreak of HCV in HIV-positive men presenting to St Mary’s Hospital, London. The risk factors for contamination were intravenous, intramuscular, intranasal and intrarectal drug use (80%) and recent unprotected anal intercourse (94%). Fifty-three percent of patients were receiving treatment HAART at the time of contamination. The median time SGK2 from the last negative to the first positive RTCPCR was 96 days (IQR 70C119 days). The median HCV viral load was 1 836 595 IU/ml. A variety of HCV genotypes were identified. Genotype 1a was the most prevalent (75%), genotype 4d occurred in 17.5% and genotypes 1b and 3a in 2.5%, respectively. One patient was coinfected with genotypes 1a and 4d. The median CD4 cell count at the time of HCVacquisition was 570 cells/l (Table 1). Patients who cleared.