Interpretation of low reactivity in the Abbott Architect rHTLV I/II assay.

OBJECTIVE: The objective of this study is to reduce donor tissue wastage. AIM: The aim of this study is to determine, in the case of the Abbott Architect rHTLV I/II assay, whether a signal/cut-off (S/CO) ratio higher than the manufacturer's recommendation of 1·0 could be applied to diagnose significant HTLV-1 seroreactivity. BACKGROUND: The detection of human T cell leukaemia virus type 1 (HTLV-1) infection is primarily based on serology often utilising random access platforms. Although current assays have high sensitivity and specificity, in low-prevalence regions, significant numbers of false-positive reactions occur. A comprehensive follow-up is difficult within the time frame of organ donation. This can lead to donor tissue wastage. METHODS: A retrospective analysis of 12 250 samples previously tested on the Abbott Architect rHTLV I/II platform and further tested by confirmatory serology/molecular detection to determine the sensitivity and positive predictive value in the S/CO ratio range was conducted. RESULTS: Where the sample S/CO ratio was >20 (n = 498), HTLV infection was confirmed in all but eight subjects. All of these eight had indeterminate confirmatory results, and none were found to be uninfected. Conversely, in the samples within the S/CO ratio range 1-4 (n = 271), no subject was subsequently found to be HTLV-infected although HTLV infection could not be excluded in all cases, primarily due to lack of follow-up samples (n = 60/271). CONCLUSIONS: Samples with an S/CO ratio of <4·0 on the Abbott Architect rHTLV I/II platform represent a low risk of HTLV infection in the UK, and organs from such donors might reasonably be considered for transplantation, within the context of appropriate risk-benefit assessment.

Recent infection testing algorithm (RITA) applied to new HIV diagnoses in England, Wales and Northern Ireland, 2009 to 2011.

In 2009, Public Health England (PHE) introduced the routine application of a recent infection testing algorithm (RITA) to new HIV diagnoses, where a positive RITA result indicates likely acquisition of infection in the previous six months. Laboratories submit serum specimens to PHE for testing using the HIV 1/2gO AxSYM assay modified for the determination of HIV antibody avidity. Results are classified according to avidity index and data on CD4 count, antiretroviral treatment and the presence of an AIDS-defining illness. Between 2009 and 2011, 38.4% (6,966/18,134) of new HIV diagnoses in England, Wales and Northern Ireland were tested. Demographic characteristics of those tested were similar to all persons with diagnosed HIV. Overall, recent infection was 14.7% (1,022/6,966) and higher among men who have sex with men (MSM) (22.3%, 720/3,223) compared with heterosexual men and women (7.8%, 247/3,164). Higher proportions were among persons aged 15-24 years compared with those ≥50 years (MSM 31.2% (139/445) vs 13.6% (42/308); heterosexual men and women 17.3% (43/249) vs 6.2% (31/501)). Among heterosexual men and women, black Africans were least likely to have recent infection compared with whites (4.8%, 90/1,892 vs 13.3%, 97/728; adjusted odds ratio: 0.6; 95% CI: 0.4-0.9). Our results indicate evidence of ongoing HIV transmission during the study period, particularly among MSM.

The Recent Infection Testing Algorithm (RITA) in clinical practice: a survey of HIV clinicians in England and Northern Ireland.

OBJECTIVES: In order to estimate HIV incidence among high-risk groups, in January 2009 the Health Protection Agency introduced the Recent Infection Testing Algorithm (RITA) in England and Northern Ireland (E&NI), currently the only regions to inform patients of RITA results. This survey of HIV specialists aimed to investigate the role of RITA in patient management and explore clinicians' views on its role in clinical practice and during partner notification. METHODS: An online questionnaire was distributed to HIV specialists via the British HIV Association membership email list in February 2011. RESULTS: Forty-two HIV specialists from 32 HIV centres responded to the survey among 90 centres enrolled in the programme (response rate 36%). Testing for recent infection was considered standard of care by 83% of respondents, 80% felt confident in interpreting results and 92% discussed results with patients, particularly in the context of a possible HIV seroconversion illness (96%) or when deciding when to start antiretroviral therapy (70%). A third (36%) of specialists were initially concerned that RITA results may cause additional anxiety among patients; however, no adverse events were reported. The majority (90%) felt that results could assist with contact tracing by prioritizing patients with likely recent infection. However, only a few centres have currently incorporated RITA into their HIV partner notification protocols. CONCLUSIONS: RITA has been introduced into clinical practice with no reported patient adverse events. Access to results at centre level should be improved. National guidance regarding use of RITA as a tool for contact tracing is required.

HIV-1 seroconversion during pregnancy resulting in vertical transmission.

The uptake of antenatal HIV testing in England and Scotland improved from 33% in 1998 to 92% in 2004 after implementing an opt-out policy. However, there is the potential for missing HIV seroconversion during pregnancy unless a further test is carried out between antenatal booking, which mostly occurs between 12-14 weeks, and delivery. We report a 32-year old Caucasian woman who developed a primary symptomatic HIV infection late in pregnancy. Unfortunately, despite antiretroviral treatment, caesarean section and formula feeding to reduce the risk of mother to child transmission (MCT), the baby was found to be infected by 12 weeks of age. Despite a 95% uptake rate at King's College Hospital, another HIV seroconversion during late pregnancy was detected after the partner was admitted with AIDS defining diagnoses. In the absence of national data on HIV seroconversion rates in pregnancy, further maternal HIV testing later in pregnancy, especially for women at-risk in an ethnically diverse area such as London, should be considered.

New diagnoses of HTLV infection in England and Wales: 2002-2004.

Human T cell lymphotropic viruses (HTLV) are retroviruses transmitted through breastfeeding, sexual contact, blood transfusion and injecting drug use. HTLV is endemic in the Caribbean, and parts of Africa, Japan and South America, with isolated foci in other areas. Infection is life long. Fewer than 5% of those infected progress to one of the HTLV-related diseases, but these are debilitating and often fatal. In England and Wales, laboratory and clinical reports of new HTLV diagnoses are routinely collected, including infections identified by the blood service since the introduction of anti-HTLV testing in August 2002. Between 2002 and 2004, 273 individuals were diagnosed with HTLV: 102 (37%) were male and 169 female (sex was not reported for two). Median ages at diagnosis were 54 and 50 years respectively. Clinical reports were received for 78% (212/273) individuals. Where reported, 58% (116/199) of individuals were of black Caribbean ethnicity and 29% (57/199) white; 87% (128/147) were probably infected heterosexually or through mother-to-child transmission; 45% (66/146) were probably infected in the Caribbean and 40% (59/146) in the United Kingdom. An appreciable number of HTLV infections continue to be diagnosed within England and Wales, with increases in 2002-2003 because of anti-HTLV testing of blood donations. While most infections diagnosed are directly associated with the Caribbean, transmission of HTLV infection is occurring within England and Wales. Specialist care services for HTLV-infected individuals and their families have improved in recent years, but prevention remains limited.

Diagnoses of HIV-1 and HIV-2 in England, Wales, and Northern Ireland associated with west Africa.

OBJECTIVES: To describe HIV diagnoses, including those of HIV-2 infection, made in England, Wales, and Northern Ireland (E,W&NI) among those probably infected in west Africa, and to consider whether there is evidence for ongoing heterosexual transmission within the United Kingdom. METHODS: Reports of new HIV diagnoses received at the Communicable Disease Surveillance Centre were analysed. Individuals probably infected in west Africa and those infected through heterosexual intercourse within the United Kingdom by a heterosexual partner infected in west Africa were included. RESULTS: Between 1985 and 2003 inclusive, 1324 individuals diagnosed and reported with HIV had probably been infected in west Africa, with 222 diagnoses made in 2003. 917 (69%) were HIV-1 infected and 52 (6%) HIV-2 or HIV-1/HIV-2 co-infected. For 355 (27%) the HIV type was not reported. The proportion of HIV-2 and HIV-1/HIV-2 infections varied by country of infection (p<0.001): ranging from the Gambia (11.7%-15.2%) to Nigeria (0.7%-1.0%). A further 130 individuals were probably infected through heterosexual intercourse within the United Kingdom by a heterosexual partner infected in west Africa. 89 (68%) were HIV-1 infected and three (2%) HIV-2 infected or HIV-1/HIV-2 co-infected. For 38 (29%) HIV type was not reported. CONCLUSION: The number of people infected with HIV in west Africa and diagnosed in E,W&NI has increased in recent years, and there is evidence of heterosexual transmission within the United Kingdom from people infected in west Africa. While numbers of HIV-2 diagnoses remain relatively low, an appreciable proportion of people infected in some west African countries and diagnosed in the United Kingdom may be HIV-2 positive, with implications for prognosis and treatment.

New diagnoses of HTLV infection in England and Wales: 2002-2004.

Human T cell lymphotropic viruses (HTLV) are retroviruses transmitted through breastfeeding, sexual contact, blood transfusion and injecting drug use. HTLV is endemic in the Caribbean, and parts of Africa, Japan and South America, with isolated foci in other areas. Infection is life long. Fewer than 5% of those infected progress to one of the HTLV-related diseases, but these are debilitating and often fatal. In England and Wales, laboratory and clinical reports of new HTLV diagnoses are routinely collected, including infections identified by the blood service since the introduction of anti-HTLV testing in August 2002. Between 2002 and 2004, 273 individuals were diagnosed with HTLV: 102 (37%) were male and 169 female (sex was not reported for two). Median ages at diagnosis were 54 and 50 years respectively. Clinical reports were received for 78% (212/273) individuals. Where reported, 58% (116/199) of individuals were of black Caribbean ethnicity and 29% (57/199) white; 87% (128/147) were probably infected heterosexually or through mother-to-child transmission; 45% (66/146) were probably infected in the Caribbean and 40% (59/146) in the United Kingdom. An appreciable number of HTLV infections continue to be diagnosed within England and Wales, with increases in 2002-2003 because of anti-HTLV testing of blood donations. While most infections diagnosed are directly associated with the Caribbean, transmission of HTLV infection is occurring within England and Wales. Specialist care services for HTLV-infected individuals and their families have improved in recent years, but prevention remains limited.

In the shadow of HIV-HTLV infection in England and Wales, 1987-2001.

Like human immunodeficiency virus (HIV), human T-cell leukaemia/ lymphoma viruses (HTLV) I and II are persistent retroviral infections. Once infected, the lifetime risk of developing the HTLV-associated diseases, malignant or inflammatory, is low (approximately 5%). For those affected, however, these diseases are debilitating, with few treatment options and a poor prognosis. Surveillance of HTLV infections by the Communicable Disease Surveillance Centre (CDSC) has been ongoing since serological testing became available in 1986. Testing of blood donations in England and Wales commenced during August 2002 and awareness of HTLV infection is likely to increase. Therefore, a baseline retrospective review of cases prior to 2002 was conducted. The age and sex distribution of identified HTLV cases has differed little over time. Eighty-five per cent of individuals were linked to the Caribbean by birthplace or ethnicity. Though HTLV infection is chronic and incurable, preventive measures are possible. Improved surveillance is needed to support effective prevention activities.

HTLV infection in England and Wales in 2002--results from an enhanced national surveillance system.

Human T-cell lymphotropic virus (HTLV) is a retrovirus transmitted through breastfeeding, sexual contact, blood transfusion and injecting drug use. HTLV is endemic in the Caribbean and parts of Africa, Japan and South America, with isolated foci in other areas. Infection is life-long. Less than 5% of those infected progress to one of the HTLV-related diseases, but these are debilitating and often fatal. Laboratory reports of new HTLV diagnoses are followed up through clinicians to establish information such as probable country of infection, country of birth, clinical details and reason for test. Clinician reports are also received for HTLV-infected blood donors identified by the National Blood Service. Seventy-seven individuals newly diagnosed with HTLV infection in 2002 were reported to the Communicable Disease Surveillance Centre (CDSC) by June 2003. Thirty-three (43%) were male, and 44 (57%) female, with median ages at diagnosis of 58.5 and 50.1 years respectively. Seventy-three (95%) individuals were HTLV-I positive and three HTLV-II positive, with one remaining untyped. For 52 of the 77 infections, clinician reports were received. Where ethnicity was reported (48), 30 (63%) were Black Caribbean, 12 (25%) White, and the remainder (6) of other ethnicities. Probable route of infection was reported for 31 individuals: nine (29%) were probably infected heterosexually, seven (23%) through mother-to-child transmission, 12 (40%) through either route, two through blood transfusion, and one through injecting drug use (HTLV-II positive). Where probable country of infection was reported (31), 14 (45%) were probably infected in the UK, 13 (42%) in the Caribbean, and four elsewhere. Where reported (50), reason for test was: symptoms for 19 (38%) individuals, blood donation for 21 (42%), and the remainder for other reasons. Numbers of new HTLV diagnoses were relatively high in 2002, and the characteristics of patients and clinical presentations differed from previous years, mainly due to the introduction of blood donor testing for anti-HTLV. Beyond 2004, the number of HTLV-infected individuals detected through blood donation is expected to decline. While numbers of individuals affected are small compared to many other diseases, the infection is chronic and untreatable, and it is important that adequate standards of diagnosis, prevention, care and support are provided, and surveillance maintained.

Prospective study of HTLV-I infection in an initially asymptomatic cohort.

A prospective clinical study of 20 initially asymptomatic HTLV-I-seropositive carriers was commenced in 1991 to determine the natural history of the infection in relation to HTLV-I proviral load, immune responses, and lymphocyte phenotype. Proviral load varied widely between carriers but was relatively constant within an individual over time. The lymphocyte phenotype and prevalence of activated lymphocytes were not predictive of disease and the magnitude of the cytotoxic T-lymphocyte response to HTLV-I was independent of proviral load. Incident conditions, some related to HTLV-I infection, including a case of HTLV-I-associated myelopathy (HAM), were documented in 9 carriers. Development of myelopathy and uveitis was associated with high peripheral blood HTLV-I proviral load that predated symptoms. Persistently high proviral load appears to predate the development of HTLV-I-associated inflammation in neuro-ophthalmic tissue.

Quantification of proviral DNA load in human T-cell leukaemia virus type I infections.

A nested PCR was designed using primers from the pol and tax genes of human T-cell leukaemia virus type I (HTLV-I). The assay reliably detected a single copy of HTLV-I proviral genome in DNA from 1 x 10(5) Peripheral blood mononuclear cells (PBMCs). Using serial dilutions of sample DNA, the assay was applied prospectively to study proviral load in patients with HTLV-associated disease and carriers. The median proviral load expressed as number of copies/100 PBMCs was found to be 14.0 copies in patients with HAM and 1.55 copies in initially asymptomatic carriers. The assay was used to test for low proviral load in subjects who may have HTLV-I infection, and to monitor response to therapy.

Performance of the Amplicor human immunodeficiency virus type 1 PCR and analysis of specimens with false-negative results.

Over a 4-year period, the Roche Amplicor kit was used in a United Kingdom reference laboratory for the detection or confirmation of human immunodeficiency virus (HIV) type 1 infection, particularly in infants born to HIV-infected mothers. Of 408 specimens from adults and older children tested, the 122 seronegative specimens were all Amplicor negative. Of the 286 seropositive specimens, 268 were Amplicor positive. On the basis of these results, the Amplicor assay has a specificity of 100% and a sensitivity of 93.7%. In addition, for 247 specimens from infants and young children, serological results may not have been diagnostic because of placental transfer of maternal antibodies. Forty-eight were Amplicor positive, and of the 199 Amplicor-negative specimens, 19 were assumed to be false negative on the basis of clinical data, serological markers (including p24 antigen), and/or results for previous or follow-up specimens. This represents a sensitivity of 75% for the Amplicor test for specimens from patients under 2 years of age. Of these 37 false-negative specimens plus 2 specimens from other laboratories, 31 could be characterized by amplifying extracted material from them by an in-house nested gag PCR spanning the Amplicor target region. The amplicons were sequenced and found to represent subtypes A (35.5%), B (22.6%), C (22.6%), D (16.1%), and G (3.2%). False-negative results by the Amplicor assay may be ascribed to low-target copy number, the physical behavior of one primer (SK462), and sequence variation in the target region of the other primer (SK431).

Successful treatment of HTLV-1-associated acute adult T-cell leukaemia lymphoma by allogeneic bone marrow transplantation.

HTLV-1-associated acute adult T-cell leukaemia-lymphoma (ATL) is a highly aggressive malignant disorder with a median survival of 6 months or less. We describe an Afro-Caribbean female with very poor prognosis ATL who underwent chemotherapy with a 4 d infusion schedule of cyclophosphamide, doxorubicin and etoposide, followed by successful allogeneic bone marrow transplantation (BMT) from her HTLV-1-negative histocompatible sister. The patient remains in complete remission 23 months after BMT and has 100% donor haemopoiesis with no evidence of HTLV-1 infection on PCR testing. We suggest that allo-BMT can prolong disease free survival or may even be curative in HTLV patients.

Management of blood donors whose donations are repeatedly falsely positive by the HIV antibody screening test.

Since 1985, over 1,800,000 donations have been screened by the West Midlands Regional Blood Transfusion Service for antibody to HIV. Twelve regular donors gave three or more donations that were alternatingly positive and negative in the screening test, but not confirmed to be HIV positive by supplementary testing. Extensive investigation of six of these donors, including the polymerase chain reaction (PCR), failed to confirm HIV infection. The donors were reassured but, nevertheless, retired to comply with the guidelines of the National Blood Transfusion Service. These findings indicate that, for UK donors, ambiguous serological findings are unlikely to reflect HIV infection. On the rare occasions where serological results are particularly ambiguous, PCR testing of donors' blood may be helpful.

Analysis and genotyping of PCR products of the Amplicor HIV-1 kit.

The Roche Amplicor PCR kit was used to detect HIV-1 DNA in UK patients of known serostatus. Four false-negative and/or equivocal results were obtained from patients who were known to be anti HIV seropositive (Tosswill et al., 1994). Cells from the blood of these patients were shown to contain HIV DNA after extraction, concentration and amplification by nested PCR using primers flanking those in the kit. To determine whether DNA sequence divergence was the cause of these discrepancies, the gag region targeted by the primers in the kit was sequenced for specimens giving positive, equivocal and false-negative results. No greater degree of sequence divergence was found within the primer and probe target regions among the equivocals and false-negatives than among the positive control specimens. The few misleading results were probably attributable to low copy numbers of proviral DNA in these specimens. Sequences obtained from the target and flanking regions of the kit were sufficient to allow the genotype of the virus to be determined.