Ultrio and Ultrio Plus non‐discriminating reactives: false reactives or not?

Background The low, fluctuating levels of DNA characteristic of occult hepatitis B infection make its detection by nucleic acid testing (NAT) a challenge. Methods Four year’s routine use of the Ultrio and Ultrio Plus assays in blood donations in New Zealand was analysed. Results 0·09% of donations tested with Ultrio and Ultrio Plus assays showed reactivity in the multiplex assay, but non‐reactivity in all three discriminatory assays and relevant mandatory serological assays (anti‐HIV, anti‐HCV, HBsAg). These donations were more likely to be anti‐HBc reactive (Ultrio, 13%; Ultrio Plus, 57%; random donors, 6·8%). Thirty‐four per cent of these anti‐HBc‐reactive donations were also reactive in either an alternate NAT assay or on repeat multiplex testing. Thirteen per cent of the donors of the discriminatory‐negative, anti‐HBc‐reactive donations who had given other Ultrio‐ or Ultrio Plus‐tested donations had at least one other multiplex reactive donation. Conclusion These findings suggest that their HBV DNA levels are around the assay’s limit of detection, that false reactivity cannot be presumed when a donor fails to discriminate and that caution should be applied when deciding whether to continue accepting donations from such donors.     

Significant background rates of HBV and HCV infections in patients and risks of blood transfusion from donors with low anti-HBc titres or high anti-HBc titres with high anti-HBs titres in Japan: a prospective, individual NAT study of transfusion-transmitted HBV, HCV and HIV infections

Background The Japanese Red Cross (JRC) conducted a prospective study to evaluate the frequency of transfusion‐transmitted HBV, HCV and HIV infections to assess the risk of transfusion of blood components routinely supplied to hospitals. Study Design and Methods Post‐transfusion specimens from patients at eight medical institutes were examined for evidence of infection with HBV (2139 cases), HCV (2091) and HIV (2040) using individual nucleic acid amplification testing (NAT). If these specimens were reactive, pre‐transfusion specimens were also examined for the virus concerned by individual NAT. In the event that the pre‐transfusion specimen was non‐reactive, then all repository specimens from implicated donors were tested for the viruses by individual donation NAT. In addition, a further study was carried out to evaluate the risk of transfusion of components from donors with low anti‐HBc titres or high anti‐HBc with high anti‐HBs titres. Results Transfusion‐transmitted HCV and HIV infections were not observed. One case of post‐transfusion HBV infection was identified (rate, 0·0004675; 95% CI for the risk of transmission, 1 in 451–41 841). The background rates of HBV, HCV and HIV infections in patients prior to transfusion were 3·4% (72/2139), 7·2% (150/2091) and 0% (0/2040), respectively. Sixty‐four anti‐HBc‐ and/or anti‐HBs‐reactive blood components were transfused to 52 patients non‐reactive for anti‐HBc or anti‐HBs before and after transfusion (rate, 0; 95% CI for the risk of transmission, <1 in 22). Conclusion This study demonstrated that the current criteria employed by JRC have a low risk, but the background rates of HBV and HCV infections in Japanese patients are significant.     

Incidence of hepatitis B virus infection in young Chinese blood donors born after mandatory implementation of neonatal hepatitis B vaccination nationwide

This study was carried out to determine the incidence of hepatitis B virus (HBV) infection in the young generation born after mandatory implementation of hepatitis B vaccination since 1992. Repeat blood donors born between 1992 and 1997 were enrolled, who gave blood at least twice during the past 3 years. Donors were tested for HBV infection markers of HBsAg, anti‐HBc, anti‐HBs and viral DNA by immunoassays (EIAs) and nucleic acid tests (NAT). A total of 14 937 pre‐donation screening qualified young repeat donors aged 18‐23 years were tested with 9 (0.06%) being HBsAg by EIA and 10 (1:1494) HBV DNA positive by Ultrio NAT (10.4 IU/mL), respectively. HBV DNA was further detected in 1:192 (9/1732) anti‐HBc+ repeat donors with Ultrio Plus NAT (3.4 IU/mL). Most cases were identified as occult HBV infection (OBI). Of 14 937 repeat donors, 20.9% were anti‐HBc+ positive, while approximately 50% of 12 024 repeat donors were anti‐HBs negative or had levels <100 IU/L. HBsAg+ or OBI strains were classified as wild type of genotype B or genotype C. Incident HBV infection in repeat donors was approximately 1:18.5 person‐years (1.1%/year) but significantly less frequent in donors with confirmed HBV vaccination (2.4%‐3.3%) than those unsure of vaccination status (10.5%; P = .0023). Hepatitis B virus vaccination appears largely protective of HBV infection, but incidence of infections increases in young adults with mostly undetectable or low anti‐HBs or occasionally high anti‐HBs. A boost of hepatitis B vaccine for adolescents prior to age 18 years may reduce HBV infection, and implementation of more sensitive NAT in blood donation screening may improve HBV safety in blood transfusion.     

Tissue donation and virus safety: more nucleic acid amplification testing is needed

A. Pruss, G. Caspari, D.H. Krüger, J. Blümel, C.M. Nübling, L. Gürtler, W.H. Gerlich. Tissue donation and virus safety: more nucleic acid amplification testing is needed.
Transpl Infect Dis 2010: 12: 375–386. All rights reserved Abstract: In tissue and organ transplantation, it is of great importance to avoid the transmission of blood‐borne viruses to the recipient. While serologic testing for anti‐human immunodeficiency virus (HIV)‐1 and ‐2, anti‐hepatitis C virus (HCV), hepatitis B surface antigen (HBsAg), anti‐hepatitis B core antigen (HBc), and Treponema pallidum infection is mandatory, there is until now in most countries no explicit demand for nucleic acid amplification testing (NAT) to detect HIV, hepatitis B virus (HBV), and HCV infection. After a review of reports in the literature on viral transmission events, tissue‐specific issues, and manufacturing and inactivation procedures, we evaluated the significance of HIV, HCV, and HBV detection using NAT in donors of various types of tissues and compared our results with the experiences of blood banking organizations. There is a significant risk of HIV, HCV, and HBV transmission by musculoskeletal tissues because of their high blood content and the high donor–recipient ratio. If no effective virus inactivation procedure for musculoskeletal tissue is applied, donors should be screened using NAT for HIV, HCV, and HBV. Serologically screened cardiovascular tissue carries a very low risk of HIV, HCV, or HBV transmission. Nevertheless, because effective virus inactivation is impossible (retention of tissue morphology) and the donor–recipient ratio may be as high as 1:10, we concluded that NAT should be performed for HIV, HCV, and HBV as an additional safety measure. Although cornea allografts carry the lowest risk of transmitting HIV, HCV, and HBV owing to corneal physiology, morphology, and the epidemiology of corneal diseases, NAT for HCV should still be performed. If the NAT screening of a donor for HIV, HCV, and HBV is negative, quarantine storage of the donor tissue seems dispensable. In view of numerous synergistic effects with transfusion medicine, it would be advantageous for tissue banks to cooperate with blood bank laboratories in performing virological tests.     

Hepatitis B virus blood screening: impact of nucleic amplification technology testing implementation on identifying hepatitis B surface antigen non-reactive window period and chronic infections

Background Despite improvements in hepatitis B surface antigen (HBsAg) test sensitivity, post‐transfusion hepatitis B virus (HBV) infection still occurs because HBsAg is undetectable during the early window phase (WP) of the infection, in the convalescence core window phase of the infection, or in serologically silent chronic hepatitis or in mutant forms of HBV. HBV‐DNA screening using high sensitivity nucleic amplification technology (NAT) assays has recently been introduced to reduce the residual risk of transmission of HBV by transfusion of blood components. Materials Over 1 year 75 063 donations were individually screened for HBV‐DNA by the Ultrio Procleix assay on the Tigris platform. The donations were collected in the Latium region, an area of the central Italy, and they accounted for the 40% of the total blood units collected in this area per year. The initial reactive samples were re‐tested and confirmed by the discriminatory HBV assay. Additional HBV serological markers were also performed. Suspected WP infections were followed‐up to monitor the development of the immune response. All HBV‐DNA‐positive donors were called back to check up their infectious status. Results The results of testing the 75 063 donations are: 33 donations HBsAg positive, 31 out of them HBV‐DNA‐positive and two HBV‐DNA negative; 22 donations HBsAg‐negative but HBV‐DNA positive with low viral load. Six of the 22 were found to be consistently HBV‐DNA reactive whereas the remaining 16 donations showed inconsistent results on multiple NAT retesting. One WP infection was confirmed by the follow‐up of the donor for 3 months following the index blood donation. Conclusions In the donor population of the Latium region, NAT screening has revealed a higher than expected number of donors who were HBsAg non‐reactive but HBV‐DNA‐positive with three donors showing HBV‐DNA as the only marker of infection. The adoption of genome screening has increased the safety of the blood supply and has also contributed to the protection of donor health by identifying either WP or clinically silent infections.     

Transfusion‐transmitted hepatitis B virus (HBV) infection from an individual‐donation nucleic acid (ID‐NAT) non‐reactive donor

Lookback was initiated upon notification of an acute HBV infection in a repeat Irish donor, 108 days post‐donation. The donation screened non‐reactive by individual‐donation nucleic acid testing (ID‐NAT) using the Procleix Ultrio Elite multiplex assay and again when the archived sample was retested, but the discriminatory assay for HBV was reactive. The immunocompromised recipient of the implicated red cell component was tested 110 days post‐transfusion, revealing a HBV DNA viral load of 470 IU/ml. Genotype C2 sequences identical across two regions of the HBV genome were found in samples from the donor and recipient.     

Occult hepatitis B virus infection and blood transfusion

Transfusion-transmitted infections including hepatitis B virus(HBV) have been a major concern in transfusion medicine. Implementation of HBV nucleic acid testing(NAT) has revealed occult HBV infection(OBI) in blood donors. In the mid-1980 s, hepatitis B core antibody(HBc) testing was introduced to screen blood donors in HBV non-endemic countries to prevent transmission of non-A and non-B hepatitis. That test remains in use for preventing of potential transmission of HBV from hepatitis B surface antigen(HBs Ag)-negative blood donors, even though anti-hepatitis C virus testshave been introduced. Studies of anti-HBc-positive donors have revealed an HBV DNA positivity rate of 0%-15%. As of 2012, 30 countries have implemented HBV NAT. The prevalence of OBI in blood donors was estimated to be 8.55 per 1 million donations, according to a 2008 international survey. OBI is transmissible by blood transfusion. The clinical outcome of occult HBV transmission primarily depends on recipient immune status and the number of HBV DNA copies present in the blood products. The presence of donor anti-HBs reduces the risk of HBV infection by approximately five-fold. The risk of HBV transmission may be lower in endemic areas than in non-endemic areas, because most recipients have already been exposed to HBV. Blood safety for HBV, including OBI, has substantially improved, but the possibility for OBI transmission remains.     

Factors associated with isolated anti‐hepatitis B core antibody in HIV‐positive patients: impact of compromised immunity

Summary. In regions that are hyperendemic for chronic hepatitis B virus (HBV) infection, prevalence of and risk factors associated with isolated anti‐hepatitis B core antibody (anti‐HBc) in HIV‐positive patients are less well described. HIV‐positive patients who were tested for hepatitis B surface antigen (HBsAg), anti‐hepatitis B surface antibody (anti‐HBs) and anti‐HBc at designated hospitals for HIV care in Taiwan were included for analysis. HBV DNA was detected by real‐time polymerase chain reaction in patients with and without isolated anti‐HBc. Of 2351 HIV‐positive patients, 450 (19.1%) were HBsAg positive, 411 (17.5%) were anti‐HBc positive alone and 963 (41.0%) for both anti‐HBs and anti‐HBc. Compared with patients who were positive for both anti‐HBs and anti‐HBc, patients with isolated anti‐HBc were older, less likely to have anti‐hepatitis C virus antibody (anti‐HCV), had lower CD4 lymphocyte counts and higher plasma HIV RNA loads. Older age (adjusted odds ratio, 1.029; 95% confidence interval, 1.015–1.043) and CD4 <100 cells/μL (adjusted odds ratio, 1.524; 95% confidence interval, 1.025–2.265) were independently associated with isolated anti‐HBc by logistic regression, while presence of anti‐HCV and injecting drug use were not. HBV DNA was detectable in 8.3% of 277 patients with isolated anti‐HBc and 14.3% of 56 patients with both anti‐HBs and anti‐HBc (P = 0.160). In a country hyperendemic for HBV infection, HIV‐positive patients at older age and with CD4 <100 cells/μL were more likely to have isolated anti‐HBc, suggesting that compromised immunity plays a role in the presence of this marker.     

Fatal outcome of a hepatitis B virus transfusion‐transmitted infection

Background and Objectives In 2008, hepatitis B virus (HBV) DNA testing was not yet mandatory for the screening of blood donations in Switzerland. At that time, HBsAg was the only specific mandatory marker for HBV. The importance of high sensitivity for HBV NAT screening is shown. Materials and Methods Donor and recipient of a transfusion‐transmitted HBV infection were followed up. Multiple samples were tested for HBV serological and molecular markers. Results At donation, the donor appeared healthy, HBsAg was negative and had a normal ALAT level. Ten weeks later, clinical symptoms suggested acute HBV infection as was confirmed with positive HBsAg, HBeAg, anti‐HBc IgG, anti‐HBc IgM and anti‐HBe. The archived sample from the original donation was negative for anti‐HBc, but positive for HBV DNA (17 IU/ml). A recipient transfused with the red cell concentrate was HBV DNA positive (3100 IU/ml) 3 months post‐transfusion. After five months, HBsAg, HBeAg, anti‐HBc and HBV DNA (1·1 × 10¹¹ IU/ml) were positive. Two weeks later, the patient died from complications associated with HBV infection and his underlying bone marrow disease. Conclusions The present case illustrates the importance of introducing highly sensitive HBV NAT screening strategy to prevent possible HBV transfusion‐transmitted infections from donors with low viral load.     

A new method of concentrating hepatitis B virus (HBV) DNA and HBV surface antigen: an application of the method to the detection of occult HBV infection

Background The risk of post‐transfusion hepatitis B virus (HBV) infection has been reduced after the implementation of HBV nucleic acid amplification technology (NAT). However, the problem of HBV DNA‐positive and HBV surface antigen (HBsAg)‐negative occult HBV infections remains to be solved. This is in part due to the HBV DNA load being too low to detect these occult HBV infections using mini‐pool NAT. In Japan, the assay for the antibody against the HBV core antigen (anti‐HBc) has not completely excluded occult HBV infection. To solve this problem, we have developed a new method of concentrating HBV DNA and HBsAg simultaneously to increase the sensitivity of detection tests. Methods Virus concentration is achieved by the enhancement of the agglutination of viruses using poly‐L‐lysine in the presence of a bivalent metal. Poly‐L‐lysine‐coated magnetic beads are used to shorten the time of each step of the concentration procedure. Seventy‐seven anti‐HBc‐positive and HBsAg‐negative donations were examined. HBsAg and anti‐HBc were tested by enzyme immunoassay (EIA) (AxSYM; Abbott) and haemagglutination inhibition test (Japanese Red Cross), respectively. Results HBV surface antigen and HBV DNA levels were concentrated up to four‐ to sevenfold. Using this method, 35 of the 77 anti‐HBc‐positive and HBsAg‐negative donors were HBV DNA‐positive by individual NAT and a further five donors became HBV DNA‐positive by HBV concentration. Twenty‐seven of 40 occult HBV infections became HBsAg‐positive by HBsAg concentration. Conclusion Our new method of concentrating HBV and HBsAg increased the sensitivities of EIA and HBV NAT, and enabled us to detect 27 of 40 occult HBV infections by HBsAg EIA.     

Acquirement and disappearance of HBsAg and anti‐HCV in an aged population: a follow‐up study in an endemic township

Background: HBsAg and anti‐hepatitis C virus (anti‐HCV) are stable markers and widely used. The seroconversion and seroclearance of HBsAg and anti‐HCV are important for disease control and prognosis of diseases. Aims: To investigate acquirement and disappearance of HBsAg and anti‐HCV in an endemic area. Methods: Seven years after a community screening, 1002 of 2909 residents of Tzukuan Township were recruited. HBsAg, anti‐HCV and alanine transaminase (ALT) were checked in all who participated and hepatitis B virus (HBV) DNA, anti‐HBs, anti‐HBc, HCV RNA, anti‐HDV and upper abdominal ultrasonography were studied in different groups. Results: There were 461 male and 541 female residents with a mean age of 66.7±8.6 years. No new HBsAg carrier was noted and the HBsAg clearance rate was 1.58% per year. One of the 17 cases with HBsAg clearance had positive HBV DNA, three had ALT elevation, two had cirrhosis and seven had anti‐HBs seroconversion. Quantitative of HBsAg and HBV DNA were concordant and 78.1% subjects had low levels of titration. Anti‐HBc alone contributed to 32.1% and was prominent in old age and the anti‐HCV‐positive group. The anti‐HCV seroconversion rate was only 0.74% per year and household transmission was the only risk factor. Only 37.5% of cases with anti‐HCV seroconversion had HCV viraemia and the anti‐HCV seroreversion rate was 0.63% per year. The anti‐HDV seroconversion rate was 0.72% per year and no subject showed anti‐HDV clearance. Conclusions: Much higher rates of HBsAg seroclearance, anti‐HCV seroreversion and anti‐HBc alone were noted in this endemic area and no subject showed anti‐HDV clearance.     

Prevalence of occult hepatitis B & C in HIV patients infected through sexual transmission.

BACKGROUND: Prevalence of Hepatitis B virus (HBV) and Hepatitis C virus (HCV) markers including active and occult infection has not been described in diverse cohorts among HIV-infected patients in India. Earlier studies have explained the role of HBV/HCV co-infection in cohorts of injection drug users (IDUs) but the sexual co-transmission of HBV/ HCV is not completely understood. OBJECTIVE: The objective of this study was to assess the prevalence of occult HBV & HCV infection in HIV positive sexually acquired transmission risk group. MATERIALS AND METHODS: 58 sexually acquired HIV positive patients were taken up for the study of occult HBV/HCV co-infection. Data on demographics, sexual behaviour, sexually transmitted diseases (STD), medical history, laboratory tests viz., serum ALT and CD4 count were recorded. HBV serology included HBsAg, anti HBs, IgG anti HBc and HBV DNA (PCR). HCV serology included anti HCV & HCV RNA (RT-PCR). RESULTS: Occult HBV infection (HBV DNA) was observed in 12.2% (7/58 with HBsAg -ve and IgG anti HBc +ve subjects) while an overall prevalence of HBV DNA was 13.7% (12% occult & 1.7% in HBsAg+ve patients). Out of 58 HIV positive patients 29.3% demonstrated reactivity for any marker of past or current HBV infection. (HBsAg 1.7%, anti HBs 10.3% anti HBc IgG 17.2%). 4/58 (6.8%) revealed anti HCV positivity along with HCV RNA positivity by RT-PCR while 6/58 (10.3%) individuals revealed an occult HCV infection (anti HCV negative). The overall HCV RNA prevalence was 17.2%. 2 out of 58 (3.4%) individuals were positive for occult infection of both HBV DNA & HCV RNA (Triple infection HIV/HBV/ HCV). The HBV/HCV co-infected group (n = 18) showed a significantly high ALT (114.3 + 12.3 U/I) & low CD4 count (202.5 + 33.7 cells/mm3). The percent prevalence of HBV/ HCV co-infection was higher in the illiterate group, in men less than 30 years of age, and in those who were married and exhibited polygamous activity. CONCLUSIONS: The study demonstrated that in HIV infected patients testing only serological viral markers like HBsAg, antiHBcIgG & anti HCV, fails to identify the true prevalence of co-infection with HBV & HCV. Qualitative PCR for HBV DNA & HCV RNA detects co-infection in patients who are negative for serological markers. Also, in subjects who had only a sexual risk factor for parenterally transmitted infections, HIV may enhance the sexual transmission of HBV and HCV.     

HBV reactivation in patients with HCV/HBV cirrhosis on treatment with direct‐acting antivirals

Anecdotal reports suggest that patients with chronic hepatitis C virus (HCV) hepatitis and overt or occult hepatitis B virus (HBV) coinfection may reactivate HBV when HCV is suppressed or cleared by direct‐acting antivirals (DAAs). We assessed the prevalence of overt or previous HBV coinfection and the risk of HBV reactivation in patients with HCV cirrhosis treated with DAAs. This was a retrospective cohort of 104 consecutive patients with HCV cirrhosis treated with DAAs. Serum HCV‐RNA and HBV‐DNA were tested at weeks 4, 8 and 12 of DAAs therapy and at week 12 of follow‐up. At the start of DAAs, eight patients (7.7%) were HBsAg positive/HBeAg negative with undetectable HBV‐DNA and low levels of quantitative HBsAg (four on nucleos(t)ide analogues [NUCs] and four inactive carriers), 37 patients (35.6%) had markers of previous HBV infection (25 anti‐HBc positive, 12 anti‐HBc/anti‐HBs positive) and 59 (56.7%) had no evidence of HBV infection. Sixty‐seven patients (64.4%) were HCV‐RNA negative at week 4 and 98 (94.2%) achieved sustained virological response. All four HBsAg‐positive patients treated with NUCs remained HBV‐DNA negative, but three of four untreated patients showed an increase in HBV‐DNA of 2‐3 log without a biochemical flare and achieved HBV‐DNA suppression when given NUCs. During or after DAAs, by conventional assay, HBV‐DNA remained not detectable in all 37 anti‐HBc‐positive patients but in three of them (8.1%) HBV‐DNA became detectable with a highly sensitive PCR. HBV reactivation is likely to occur in untreated HBV/HCV‐coinfected cirrhotic patients when they undergo HCV treatment with DAAs. Pre‐emptive therapy with NUCs should be considered in this setting. Anti‐HBc‐positive patients rarely reactivate HBV without clinical or virological outcomes.     

Donor screening for hepatitis B virus infection in a cell and tissue bank

Abstract: Background and objectives. Hepatitis B virus (HBV) has been transmitted by tissue transplantation. In order to reduce the risk of HBV transmission, testing for antibody to HBV core antigen (anti‐HBc) is used in addition to testing for hepatitis B surface antigen (HBsAg) in many blood centers and tissue banks. Design and methods. We retrospectively analyzed the results of HBV assays in tissue donors. All tissue donors were tested for HBsAg and anti‐HBc. All anti‐HBc positive sera were tested for the antibody to HBsAg (anti‐HBs). From July 2006, an HBV nucleic acid testing (NAT) assay was also performed. Results. A total of 6855 tissue donors from January 1999 till July 2007 were tested for HBV assays: 4756 women and 2099 men. Positive HBsAg was found in 23 (0.36%) living donors, while no multiorgan or cord blood (CB) donor was found to be positive for HBsAg. Positive anti‐HBc was found in 80 multiorgan donors (12.94%), 599 living donors (17.84%), and 103 CB donors (3.57%) (P<0.005), while isolated anti‐HBc was found in 12 multiorgan (1.94%), in 126 living tissue donors (3.75%), and in 8 CB donors (0.28%). A total of 1310 donors were analyzed for single‐sample DNA HBV NAT assay. Discussion. We consider that anti‐HBc and NAT assays must both still be performed in addition to HBsAg assay for HBV screening in tissue donors. All these tests will be useful in order to define an algorithm for safe and efficient management of the tissue bank.     

Estimates of the frequency of HBV, HCV, and HIV infectious donations entering the blood supply in the United Kingdom, 1996 to 2003

Several new tests have been recently introduced by the United Kingdom Blood Services to improve safety. The frequency (or risk) of hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV infectious donations entering the UK blood supply during 1996-2003 has been estimated. These years span the introduction of nucleic acid testing (NAT) for HCV, HIV combination antigen and antibody test and NAT for HIV. The frequency of an infectious donation entering the blood supply due to i) the window period, ii) assay failures and iii) human and technical errors in testing and processing, was estimated. The window period risk was estimated using the incidence of infection in donors and the length of the window period for tests in use, with an adjustment for atypical inter-donation intervals in seroconverting donors. The estimated frequency of infectious donations entering the blood supply during 1996-2003 was 1.66, 0.80 and 0.14 per million for HBV, HCV and HIV respectively. HCV NAT resulted in an over 95% fall in the risk of HCV. Current usage of HIV combined antibody-antigen tests and of HIV NAT reduced the estimated risk of HIV by 10%. Since 1996, the risk of transfusion-transmitted HBV, HCV and HIV infection in the UK has been lowered by several improvements to donation testing, although the absolute reduction in risk has been small. Vigilance for errors and the affects of donor selection may be as or more important than further reductions to window periods of tests for improving blood safety with respect to HBV, HCV and HIV.     

T‐ and B‐cell responses and previous exposure to hepatitis B virus in ‘anti‐HBc alone’ patients

A serologic response to hepatitis B virus (HBV) defined as ‘anti‐HBc alone’ is commonly observed, but its significance remains unclear. This study aimed to define the relationship between ‘anti‐HBc alone’ serostatus and HBV infection, including HBV‐specific T‐ and B‐cell memory responses. We enrolled 31 ‘anti‐HBc alone’ patients. Total HBV DNA and cccDNA were tested by nested polymerase chain reaction (PCR) analysis in liver samples from 22 ‘anti‐HBc alone’ patients vs controls (chronic or resolved HBV infection), followed by HBsAg/HBcAg immunohistochemical (IHC) staining. IFN‐γ secretion by HBV‐specific T cells was compared in individuals who were ‘anti‐HBc alone’ (n = 27), resolved HBV (n = 21), chronic HBV (n = 24) and 12 healthy controls using enzyme‐linked immunospot (ELISpot) assays. An HBsAg‐IgG B‐cell ELISpot assay was performed in ‘anti‐HBc alone’ patients before and after one dose of recombinant HBsAg vaccine. The majority (23/31, 74.2%) of the ‘anti‐HBc alone’ individuals were co‐infected with HCV. Infrequent intrahepatic total HBV DNA (2/22, 9.1%) and cccDNA (1/22, 4.5%) were detected in biopsies; HBsAg and HBcAg IHC staining was negative. HBV‐specific T‐cell responses were similar between ‘anti‐HBc alone’ individuals and HBV resolvers. Circulating HBV‐memory B‐cell responses were detected in all ‘anti‐HBc alone’ individuals, consistent with an HBsAg‐specific memory pool. After one HBV vaccine dose, increased anti‐HBs antibody levels were observed, accompanied by an expansion of HBsAg‐specific memory B cells (P = 0.0226). ‘Anti‐HBc alone’ individuals showed HBV‐specific T‐cell and memory B‐cell responses typical of previous viral exposure and protective memory, suggesting a resolved infection.     

Characterization of HBV DNA+/HBsAg- blood donors in Poland identified by triplex NAT

Nucleic acid testing (NAT) for hepatitis B virus (HBV) has been performed in Poland since 2005 on samples seronegative for hepatitis B surface antigen (HBsAg), anti-hepatitis C virus (anti-HCV), and anti-human immunodeficiency virus (anti-HIV). Tools included 24-donation pool testing (PT) using Cobas Amplicor or in individual donations (ID) by Procleix Ultrio. Seven of 761,666 (1:108,800) and 21/250,191 (1:11,900) HBV DNA-positive donations were identified and confirmed by alternative methods. HBV DNA load ranged between 11.6 and 4.6 x 10(4) IU/mL in 11 samples and could not be quantified in 17 samples. HBV genotypes A (56%) and D (4%) were found. The analysis of combined results from index, follow-up, and look-back samples identified four groups: (1) Two cases tested HBsAg positive with alternative, more sensitive, assays; (2) Four cases were in the pre-seroconversion window period; (3) Eight cases had a fluctuating pattern of HBV DNA and anti-HBs detection (recovered infection); and (4) twelve cases carried anti-HBc without anti-HBs, which might correspond to either chronic or recovered "occult" HBV infection. One donor with no HBV markers in the follow-up was excluded, and another was in the window period preceding anti-HBs. HBV NAT identified more confirmed positive donors than HCV or HIV NAT, and 1:250,000 could not be detected by anti-HBc screening. Serological and molecular studies on follow-up and look-back samples are important to classify donors. In conclusion, further studies are needed to determine whether the considerably higher yield of HBV DNA detection obtained with individual donation screening improves blood safety compared with anti-HBc screening.     

Trends in risk of transfusion-transmitted viral infections (HIV, HCV, HBV) in France between 1992 and 2003 and impact of nucleic acid testing (NAT)

Monitoring trends in residual risk of transfusion-transmitted viral infections is important to assess improvements in blood safety and to adapt the risk reduction policies. These trends were analysed in France over 4 periods of 3 years (1992-1994, 1995-1997, 1998-2000 and 2001-2003). The 2001-2003 estimates were compared to the results of HIV-1 and HCV NAT implemented on all blood donations in July 2001. Due to improvements in donor recruitment and selection, continuing progress in screening assays, and preventive measures taken in the community to control infections, a significant decrease was observed in residual risks for HIV, HCV and HBV between 1992 and 2003. The residual risk is currently extremely low: for the 2001-2003 period, this risk was estimated at 1 in 3.15 million donations for HIV, at 1 in 10 million for HCV and at 1 in 640,000 for HBV. Of the 6.14 million donations screened with NAT between July 2001 and December 2003 in France, 2 HIV-positive and 3 HCV-positive donations were discarded thanks to NAT, representing a yield of 1 in 3.07 million for HIV and 1 in 2.05 million for HCV. These results show the limited benefit of NAT and suggest that its cost-effectiveness is poor.     

Reduced risk of transfusion‐transmitted HIV in Kenya through centrally co‐ordinated blood centres,stringent donor selection and effective p24 antigen‐HIV antibody screening

Background Following a 1994 study showing a high rate of transfusion‐associated HIV, Kenya implemented WHO blood safety recommendations including: organizing the Kenya National Blood Transfusion Service (NBTS), stringent blood donor selection, and universal screening with fourth‐generation p24 antigen and HIV antibody assays. Here, we estimate the risk of transfusion‐associated HIV transmission in Kenya resulting from NBTS laboratory error and consider the potential safety benefit of instituting pooled nucleic acid testing (NAT) to reduce window period transmission. Methods From November to December 2008 in one NBTS regional centre, and from March to June 2009 in all six NBTS regional centres, every third unit of blood screened negative for HIV by the national algorithm was selected. Dried blood spots were prepared and sent to a reference laboratory for further testing, including NAT. Test results from the reference laboratory and NBTS were compared. Risk of transfusion‐associated HIV transmission owing to laboratory error and the estimated yield of implementing NAT were calculated. Findings No cases of laboratory error were detected in 12 435 units tested. We estimate that during the study period, the percentage of units reactive for HIV by NAT but non‐reactive by the national algorithm was 0·0% (95% exact binomial confidence interval, 0·00–0·024%). Interpretation By adopting WHO blood safety strategies for resource‐limited settings, Kenya has substantially reduced the risk of transfusion‐associated HIV infection. As the national testing and donor selection algorithm is effective, implementing NAT is unlikely to add a significant safety benefit. These findings should encourage other countries in the region to fully adopt the WHO strategies.