The introduction of anti-HTLV testing of blood donations and the risk of transfusion-transmitted HTLV, UK: 2002-2006.

The objectives of the study were to describe the introduction of testing blood donations for antibodies to human T-cell lymphotropic virus (anti-HTLV) and to determine the risk of HTLV potentially infectious donations entering the UK blood supply. The rationale for testing was based on (i) evidence of transmission through transfusion in the UK, (ii) the serious nature of HTLV I-associated morbidity and (iii) evidence of infection in UK blood donors. From mid-2002, all blood donations made at UK blood centres were tested in pooled samples using Abbott-Murex HTLV I/II GE 80/81 enzyme immunoassay (EIA). Surveillance data were used to calculate the incidence and prevalence of anti-HTLV and derive estimates of risk. Between August 2002 and December 2006, 106 donations were confirmed positive for anti-HTLV (95 anti-HTLV I and 11 anti-HTLV II). Prevalence was 10-fold higher among donations from new donors than repeat (4.0 and 0.42 per 100 000 donations), and only one repeat donor had evidence of seroconversion. The risk of an HTLV I potentially infectious donation entering the UK blood supply was estimated at 0.11 per million donations (95% confidence interval 0.06 to 0.18). The current very low observed incidence and prevalence among blood donors reflect the very low estimated risk of an HTLV I-positive donation entering the UK blood supply. A change in either the epidemiology of HTLV in UK blood donors or the length of the window period of the test should prompt further review of the risk and a reassessment of anti-HTLV testing in the UK.

Improvement in the performance of HIV screening kits.

SUMMARY: The aim of this study was to assess the performance of HIV screening kits introduced over a 12-year period. HIV kits used by the National Blood Service (NBS) were assessed in the context of other HIV kits employed by diagnostic and reference laboratories. Thirty-three HIV screening kits were assessed and 13 had the potential to be used by the NBS. Specimens applied to NBS evaluations included 2000 HIV-negative specimens collected from blood donors, 200 HIV-positive specimens and 21 seroconversion panels, with larger numbers applied to the latter two categories prior to implementation of Communauté Européennes (CE) marking. The 33 HIV kits gave repeat reactive rates, based on HIV-negative specimens, of between 0% and 0.8% (and between 0% and 0.2% for kits relevant to the NBS). When examined for diagnostic sensitivity, the 33 kits gave sensitivities between 99.78% and 100%. Kits relevant to NBS gave sensitivities of 100% except one kit, which failed to detect one anti-HIV-2-positive specimen. Twenty-six kits were compared for detection of primary HIV infection. Of these, the 10 combined HIV antigen/antibody kits examined were more sensitive than other formats and have been exclusively adopted by NBS where operational considerations allow. Their added seroconversion sensitivity makes them the screening method of choice for populations at increased risk, e.g. in sexually transmitted infection (STI) clinics. The regular review of evaluation results has demonstrated a continuing improvement over time in the performance of HIV screening kits and contributed to advances in blood safety.

Randomised placebo controlled trial of nebulised corticosteroids in acute respiratory syncytial viral bronchiolitis.

OBJECTIVE: To evaluate short and long term effects of giving nebulised budesonide early in respiratory syncytial viral (RSV) bronchiolitis. DESIGN: A multicentre randomised double blind placebo controlled trial. SUBJECTS: Infants admitted to hospital with their first episode of RSV positive bronchiolitis. INTERVENTION: Randomisation to receive either 1 mg of nebulised budesonide (Bud) or placebo (Pla) twice daily from admission until 2 weeks after discharge. Follow up was for 12 months. MAIN OUTCOME MEASURES: Duration of hospital admission, time taken to become symptom free, re-admission rates, general practitioner consultation rates, and use of anti-wheeze medication during follow up. RESULTS: 161 infants were studied. Both arms were similar with respect to initial clinical severity, age, sex, socioeconomic class, and tobacco exposure. Median time from first nebulisation to discharge: Bud and Pla, 2 days. Median number of days for 50% of infants to be symptom free for 48 hours: Bud, 10 days; Pla, 12 days. Respiratory re-admission rates in the 12 month follow up: Bud, 16%; Pla, 18%; median difference (95% confidence interval (CI)), -2 (-14 to 10). Median respiratory related general practitioner attendances: Bud, 4.0; Pla, 4.5; median difference (95% CI), -1 (-2 to 0). Percentage of infants receiving at least one prescription for anti-wheeze medication during follow up, corticosteroids: Bud, 50%; Pla, 60%; difference (95% CI), -10 (-26 to 6); bronchodilators: Bud, 60%; Pla, 67%; difference (95% CI), -7 (-22 to 8). CONCLUSIONS: There are no short or long term clinical benefits from the administration of nebulised corticosteroids in the acute phase of RSV bronchiolitis.

Low detection rate and maternal provenance of hepatitis B virus S gene mutants in cases of failed postnatal immunoprophylaxis in England and Wales.

Hepatitis B virus (HBV) infection occurred despite full passive-active immunoprophylaxis in 20 of 321 infants born to mothers seropositive for hepatitis B e antigen. In 2 (12%) of 17 infected infants, mother-infant DNA sequence mismatches were found in a segment of the HBV S gene coding for antigenic determinants of the HBV surface antigen (HBsAg) amplified from sera by polymerase chain reaction (PCR). Point substitutions occurred in codons 120, 134, and 144 of the HBsAg polypeptide in the variant sequence of 1 infant and in codon 126 in the other; all were missense mutations. Mutant sequences could not be recovered from maternal sera by PCR cloning but were selectively generated using an amplification refractory mutation system. The frequency of potential vaccine escape mutants is therefore low, and these preexist maternally as minor variants.

Evaluation of a combined HIV-1/2 and HTLV-I/II assay for screening blood donors.

A combined immunoassay for the simultaneous detection of antibodies to HIV-1/2 and HTLV-I/II (Bioelisa, Launch Diagnostics) has been evaluated to determine its suitability for routine use in blood screening. 84,222 donations were tested from 76,452 donors. One HIV- and 1 HTLV-1-positive donor were identified. The specificity was 99.7%, and the sensitivity for anti-HIV-1, anti-HIV-2, and anti-HTLV-1 on 173 positive sera was 100%; 2 of 25 anti-HTLV-II-positive sera were non-reactive. Although the specificity of the assay is not as high as that of HIV-1/2 kits currently in UK transfusion use, the information gained about donor HTLV antibody status makes the test an attractive alternative to them.

Use of anti-GOR testing in the screening of blood donors for hepatitis C virus infection.

Sera from 12/1,155 (1%) anti-HCV-negative (Elisa) UK blood donors were found to be anti-GOR positive. None out of 12 of those sera were positive for HCV RNA by the reverse transcriptase/polymerase chain reaction (RT/PCR). In a cohort of 316 anti-HCV Elisa-positive sera, 27/57 RIBA-positive, and 1/188 RIBA-negative sera were anti-GOR positive, resulting in a sensitivity of 47% and a specificity of 99.5% for anti-GOR as a marker for RIBA-confirmed HCV infection. Four out of 71 (6%) of RIBA-indeterminate sera were anti-GOR positive. Donors with anti-GOR reactivity were more likely to have antibodies against each of the individual HCV antigens represented in the RIBA, and those antibodies were of greater intensity, when compared to the anti-GOR negative cohort. Twenty out of 36 (55.6%) of RT/PCR-positive sera were anti-GOR positive, compared to 1/7 (14.3%) of RT/PCR-negative sera (p = 0.09). The usefulness of anti-GOR testing of UK blood donors is discussed in the light of these results.

Coxsackie virus B4 infection of the mouse pancreas: I. Detection of virus-specific RNA in the pancreas by in situ hybridisation.

The pathology of Coxsackie virus B4 (CVB4) infection in a murine model was investigated by in situ hybridisation using a biotinylated cDNA probe derived from CVB4. During the acute phase of infection virus RNA sequences were detected in the exocrine pancreas of 60% of mice infected with a pancreotropic variant of CVB4. A positive hybridisation signal was observed in other organs in some animals including the heart and liver of 1 mouse 28 days after infection. The cellular distribution of virus RNA sequences corresponded well with the histological findings in most tissues. Possible causes for failure of hybridisation in some infected pancreases are discussed in conjunction with potential application of the technique in human pancreas biopsy samples.

Performance characteristics of a novel immunoassay based on hybrid Ty virus-like particles (Ty-VLPs): rapid differentiation between HIV-1 and HIV-2 infection.

Recombinant antigens containing all or parts of the HIV-1 proteins p24, Nef and gp41 and HIV-2 gp36 have been purified and used to develop a rapid immunoassay to detect and differentiate between HIV-1 and HIV-2 antibodies in a single test. The antigens were produced as particulate fusion proteins by exploiting the ability of a protein encoded by the yeast retrotransposon Ty to assemble into virus-like particles (Ty-VLPs). Hybrid HIV: Ty-VLPs carrying each of the antigens were applied to nitrocellulose strips at specified locations in a slot-blot format and then used to detect antibodies present in human serum and plasma samples of diverse geographical origin. Previously confirmed HIV-1- and HIV-2-positive samples were readily and reliably identified. The assay was used to identify a case of HIV-2 infection in an African woman who had been resident in the Oxford region for the last 3 years and to analyse the prevalence of anti-HIV antibodies in a longitudinal study of seroconverting patients. We also demonstrate that the assay works efficiently with whole blood.

Use of betapropiolactone to disinfect fresh tissue without impairing antigenicity: method applicable to human immunodeficiency virus (HIV) positive tissue.

A method for inactivating viruses in tissues is reported that does not impair the antigenicity of the Coxsackie virus or of some common tissue antigens, a common problem with standard tissue fixation methods. Tissues can be placed briefly in Betapropiolactone before cryostat sectioning without any adverse effect on preservation or antigen expression. It is suggested that use of Betapropiolactone is applicable to tissues harbouring or exposed to the human immunodeficiency virus (HIV). As betapropiolactone has been reported to be carcinogenic in rodents any potential danger can be avoided by basic simple precautions.

HTLV-1, HIV-1, hepatitis B and hepatitis delta in the Pacific and South-East Asia: a serological survey.

Blood samples from 13 locations in the Pacific and South-East Asia were tested for evidence of infection with human T-cell lymphotropic virus type-1 (HTLV-1), human immunodeficiency virus (HIV-1), hepatitis B virus (HBV) and hepatitis delta virus (HDV). No samples were positive for antibody to HIV-1. Antibodies to HTLV-1 were found in samples from five locations, the maximum prevalence being 19%, in Vanuatu. Serological markers of HBV infection were found in all locations, the maximal prevalence being 88%, in Majuro, Micronesia. Antibodies to HDV in HBsAg positive sera were found in six locations with a maximum prevalence of 81% in Kiribati.

PIP: In a serological survey of samples taken throughout the Pacific and South-East Asia for HILV-1, HIV-1, HBV, and HDV infection, 9 of the samples tested positive for antibodies to HIV-1. HTLV-1 antibodies were found in 2 groups. Other findings showed 13 or 81% of HBsAG positive sera when tested for anti-HDV. Of all the locations surveyed, serological markers of HBV infection were noted. The maximum prevalence (88%) of HBV infection was found in Majuro, Micronesia. The greatest evidence of antibodies to HDV in HBsAG positive sera of 6 locations was found in kiribati (84% prevalence). The survey studied haemoglobinopathies from samples taken between May 1985 and February 1986 from New Guinea, Philippines, Vanuatu, French Polynesia, Palau and the Federated States of Micronesia. The survey volunteers were adult blood donors attending ante-natal clinic. Samples were also taken from a Tuvaluan community of immigrant workers in Nauru and from people from Kapingamarangi who have been resettled onto Ponape.

Routine full blood counts as indicators of acute viral infections.

Over a period of three weeks about 9000 full blood counts were analysed on the Technicon H6000 automated haematology machine. From these, 62 patients were identified who had abnormally high numbers of large unstained white cells; these patients were followed up for evidence of viral infection. Seventeen were either lost to follow up or in chronic renal failure; of the remaining 45 patients, 40 had viral infections, 26 of which were due to Epstein-Barr virus. In the presence of a raised number of large unstained white cells, an IgM test for Epstein-Barr virus is recommended, followed by routine serology when necessary.

Abnormal tubular structures associated with the granular endoplasmic reticulum of neocortical neurons in a biopsy from a patient with Alzheimer's disease.

The electron microscope has been used to examine a diagnostic biopsy of frontal neocortex which showed the light microscopic features of Alzheimer's disease. In addition to plaques and tangles, the biopsy showed some neurons which contained abnormal tubular profiles specifically associated with their granular endoplasmic reticulum. In transverse section the profiles consisted of two concentric layers of trilaminar unit membrane with an overall diameter of approximately 75 nm and they appeared to lie within the cisternae of granular endoplasmic reticulum. When cut longitudinally, the structures appeared as elongated tubes lying within the endoplasmic reticulum, but a number of ends were found where the inner membrane formed a closed tube and the outer membrane folded back and was continuous with the membrane forming the outer layer of the sac of endoplasmic reticulum. These profiles do not appear to have been described previously although similarities between their ultrastructure and that of the coat of certain unusual forms of Rhabdovirus are noted.

Screening for antibodies to HTLV-III amongst the semen donors of an AID programme.

This study suggests that, at the present time, AID is not likely to be a significant risk factor in the transmission of AIDS in Britain, particularly in centres which are already practising careful screening of semen donors. New facilities which are becoming available for HTLV-III screening should help to provide reassurance that semen donations are free from the virus.

African Kaposi's sarcoma and AIDS.

16 Zambian patients with Kaposi's sarcoma (KS) were studied to determine whether they had evidence of lymphopenia with decreased T helper/T suppressor (Th/Ts) ratios or previous infection with opportunistic pathogens. Serological tests for viruses commonly associated with the acquired immunodeficiency syndrome (AIDS) were also carried out. 12 patients had a decreased Th/Ts and 2 of these were also lymphopenic. Serological evidence for infection with Toxoplasma and with Pneumocystis was present but this was not significantly more common in KS patients than in controls. All 16 patients had antibodies to cytomegalovirus (CMV), 15 had antibodies to Epstein-Barr virus and 13 to human T leukaemia virus (HTLV) infected cells. 5 patients had evidence of previous infection with hepatitis B virus. African patients with KS seem to have an immunological and virological profile similar to that seen in American patients with AIDS.