Retrospective study of HIV, hepatitis B, and HTLV-I infection at a London antenatal clinic

Soroprevalência de vírus linfotrópico de células T humanas, vírus da imunodeficiência humana, sífilis e toxoplasmose em gestantes de Botucatu - São Paulo - Brasil: fatores de risco para vírus linfotrópico de células T humanas

Com o objetivo de estudar a soroprevalência de vírus linfotrópico de células T humanas I/II (HTLV-I/II), vírus da imunodeficiência humana, sífilis e toxoplasmose, em gestantes atendidas em unidade básicas de saúde do município de Botucatu - São Paulo - Brasil, bem como os fatores de risco para a infecção pelo HTLV -I/II, foram realizados inquérito sorológico e avaliação dos resultados de exames solicitados na rotina do prénatal. Em 913 gestantes, a soroprevalência de HTLV- I e de HTLV- II foi de 0,1%. Sífilis, toxoplasmose e infecção pelo HIV foram encontradas. Nenhum dos fatores de risco pesquisados mostrou-se seguro para identificar gestantes com infecção pelo HTLV- I/II. A comparação da proporção de gestantes infectadas e de doadores de sangue da região sudeste do Brasil com testes reagentes para HTLV- I/II não mostrou diferença estatística.

Malignancy: Human T-Cell Lymphotropic Virus Type I and Adult T-Cell Leukaemia/Lymphoma

Adult T-cell leukaemia/lymphoma (ATLL) was first identified in Japan in 1977 [1,2]. The causative agent, the human T-lymphotropic virus type I (HTLV-I), was isolated 3 years later by Gallo's group from a patient initially diagnosed as having mycosis fungoides but subsequently reclassified as a case of ATLL [3]. Since this time, much has been discovered about the molecular pathogenesis of the disease. Despite this, treatment of ATLL remains disappointing and the prognosis of acute and lymphoma types poor. In the United Kingdom, cases of ATLL are mainly restricted to people of Afro-Caribbean descent but the disease is of general importance because ATLL has also been reported in non-endemic areas and may possibly spread into other populations via blood transfusion as blood donors in the UK are currently not screened for HTLV-I.

Overcoming barriers to hepatitis B immunisation by a dedicated hepatitis B immunisation service

AIMS

To determine the effectiveness of a selective hospital based hepatitis B immunisation programme and the barriers to be overcome in obtaining a successful outcome.

METHODS

Retrospective case note review of 265 infants born over a five year period to hepatitis B carrier mothers at a university affiliated hospital in Hackney, London.

RESULTS

A total of 242 infants (91%) were fully vaccinated; 217 (82%) had serology; 31 required booster doses. Percentages failing to reach second, third vaccinations, and serology on schedule rose exponentially (7%, 18%, 33% respectively). Mobility was high (25%) and significantly affected outcome. A total of 95% Hackney resident babies were fully vaccinated compared with 78% non-residents. Uptake of routine immunisations was higher in Hackney residents than non-residents and greater in those who were eligible for hepatitis B vaccine. Name changes occurred in 35%. Translation requirements were high (85% for Turkish, Vietnamese, and Asian families). Requirements for specific postnatal counselling of mothers and hepatology referral fell significantly during the course of the study. Only seven of 22 babies born in 1995 in Tower Hamlets compared with 53 of 58 Hackney babies received a full vaccination course in non-hospital based primary care.

CONCLUSION

In inner city areas with high prevalence of hepatitis B carriage, mobility, and diverse ethnicity, a dedicated centralised immunisation service can be highly effective, provided that adequate support services (translation, counselling, and parental referral) are available.

HTLV-I transmission from mother to child

Human T-lymphotropic virus type I (HTLV-I), a causative agent of adult T-cell leukemia, (ATL) is transmitted from mother to child. ATL cells originate from the CD4 subset of peripheral T cells. The main route of mother-to-child transmission is postnatal breast-feeding. Refraining from breast-feeding or limiting the duration of breast-feeding can reduce the risk of mother-to-child transmission. Other than postnatal breast-feeding, there seem to be two routes of HTLV-I transmission from mother to child. One is intrauterine transmission, and the other is via saliva. Intrauterine transmission is rare, although proviral DNA is detected in cord blood samples. HTLV-I proviruses in the cord blood may be defective. HTLV-I proviral DNA and antibodies against HTLV-I are also detected in saliva. However, no report has been published so far which showed direct evidence of HTLV-I transmission via saliva. The placenta can be infected by HTLV-I, but infection does not reach the fetus, possibly apoptosis of placental villous cells because it is induced by HTLV-I infection.

Human T cell leukaemia/lymphoma virus infection in pregnant women in the United Kingdom: population study

OBJECTIVE

To assess the prevalence of human T cell leukaemia/lymphoma virus (HTLV) infection in pregnant women in the United Kingdom.

DESIGN

Population study.

SUBJECTS

Guthrie card samples from babies born in 1997-8. Samples were linked to data on mother's age and ethnic status and parents' country of birth and then anonymised.

SETTING

North Thames Regional Health Authority.

MAIN OUTCOME MEASURES

Presence of antibodies against HTLV in eluates tested by gelatin particle agglutination assay and results confirmed by immunoblot.

RESULTS

Of 126 010 samples tested, 67 had confirmed antibodies to HTLV (59 HTLV-I, 2 HTLV-II, 6 untyped) and six had indeterminate results. Seroprevalence was 17.0 per 1000 (95% confidence interval 9.2 to 28.3) in infants whose mothers were born in the Caribbean, 3.2/1000 (1.5 to 5.9) with mothers born in west and central Africa, and 6.8/1000 (3.1 to 12.9) in infants of black Caribbean mothers born in non-endemic regions. In infants with no known risk (both parents born in non-endemic regions and mother not black Caribbean) seroprevalence was 0.06-0.12 per 1000. Mother's country of birth, father's country of birth, and mother's ethnic status were all independently associated with neonatal seroprevalence. An estimated 223 (95% confidence interval 110 to 350) of the 720 000 pregnant women each year in the United Kingdom are infected with HTLV.

CONCLUSIONS

The prevalence of HTLV and HIV infections in pregnant women in the United Kingdom are comparable. The cost effectiveness of antenatal HTLV screening should be evaluated, and screening of blood donations should be considered.

Seroepidemiology of the human T-cell leukaemia/lymphoma viruses in Europe. The HTLV European Research Network

An extensive collaboration of laboratories and investigators has been developed to define the seroprevalence of human T-cell leukaemia/ lymphoma virus type I and II (HTLV-I and -II) infection in Europe. An algorithm for serological screening for HTLV-I and -II infection has been established by consensus. Data from screening almost 4 million subjects, including many unpublished studies, which conform to this algorithm are presented. In extensive studies the seroprevalence of HTL.V-I/II in blood donors is low, ranging from < 1 in 100,000 to 30 in 100,000 donors and is due predominantly to HTLV-I. In antenatal clinics in France and the United Kingdom the seroprevalence of HTLV-I is > 0.2%, but surveillance in this setting has been limited and extensive study of the seroprevalence of HTLV-I/II infection in pregnant women in Europe is urgently required to determine the need for HTLV-I/II antenatal screening. HTLV-I is present in populations who have immigrated to Europe from endemic areas and is spreading into indigenous European populations, particularly through sexual transmission to females. HTLV-II infection is present predominantly amongst IVDU and is usually a coinfection with HIV-I. There are considerable regional differences in HTLV-II seroprevalence.

The transmission dynamics of hepatitis B in the UK: a mathematical model for evaluating costs and effectiveness of immunization programmes

Complex hepatitis B (HBV) epidemiology makes it difficult to evaluate and compare effectiveness of different immunization policies. A method for doing so is presented using a mathematical model of HBV transmission dynamics which can represent universal infant and adolescent vaccination strategies and those targeted at genito-urinary (GU) clinic attenders and infants born to infectious mothers. Model structure, epidemiological underpinning, and parameterization, are described. Data from the UK National Survey of Sexual Attitudes and Lifestyles is used to define patterns of sexual activity and GU clinic attendance; data deficiencies are discussed, in particular that of UK seroprevalence of HBV markers stratified by age, sex, and risk factors. General model predictions of endemic HBV marker prevalence in homosexual and heterosexual populations seem consistent with published UK data. The simulations exhibit non-linearities in the impact of different vaccination strategies. Estimated number of carriers prevented per vaccine dose for each strategy provides a measure of costs and benefits, varying temporally over the course of a programme, and with level of vaccine coverage. Screening before vaccination markedly increases payback per dose in homosexuals but not in heterosexuals; mass infant vaccination gives the poorest effectiveness ratio and vaccination of infants after antenatal screening the best; in general, increasing vaccine coverage yields lower pay-back per dose. The model provides a useful framework for evaluating costs and benefits of immunization programmes, but for precise quantitative comparison more UK epidemiological data is urgently needed.

Use of dried blood spots for the detection and confirmation of HTLV-I specific antibodies for epidemiological purposes

AIMS--To modify and evaluate a gelatin particle agglutination test that could provide a sensitive, specific and inexpensive method for the detection of HTLV-I antibody in dried blood spot samples (DBS) collected on filter paper. METHODS--A set of 26 reference samples confirmed as HTLV-I antibody positive were assembled from patients with tropical spastic paraparesis or adult T cell leukaemia and blood donors. Serum samples and simulated antibody positive dried blood spot eluates were tested using the Serodia assay together with two confirmatory tests: HTLV BLOT 2.3, a western blot, and Select-HTLV, an enzyme immunoassay (EIA). Both confirmatory tests use synthetic peptides to differentiate between antibodies to HTLV-I and -II. The modified Serodia assay was then used to test anonymously 10,135 DBS collected from neonates from London. Samples reactive in the modified Serodia test producing a positive result were titrated to an end point and confirmed as before. RESULTS--All 26 eluates made from simulated DBS derived from positive reference samples were identified as positive by the modified Serodia HTLV-I test and were confirmed as anti-HTLV-I positive by EIA. Two eluates derived from relatively low titre reference samples gave indeterminate results on western blotting. Screening of the 10,135 neonatal DBS resulted in six repeat reactives, five of which were confirmed. The remaining reactive sample gave an indeterminate result on western blotting and there was insufficient eluate for testing by EIA. The overall seroprevalence of HTLV-I in this population was 0.05% (five of 10,135). CONCLUSION--The modified Serodia HTLV-I assay provides a sensitive, specific and inexpensive (10 pence/test) method for screening large numbers of DBS. The format of the assay makes it ideally suited for simultaneous screening of antibodies to HIV-1, HIV-2 and HTLV-I using semi-automated equipment.

[Clinical evaluation of various preventive methods for non-hemolytic transfusion reactions]

A study has been carried out on the incidence of non-hemolytic transfusion reaction on a group of patients suffering from thalassemia. Of this group, the rate of reactions per patient, based on the relationship between the number of patients with non-hemolytic transfusion reactions and the total number had risen to 31.8%. 83.7% of the patients with non-hemolytic transfusion reactions did not give a positive reaction to lymphocytotoxicity. 654 patients having, or not having shown a non-hemolytic transfusion reaction received washed red cell concentrates prepared extemporaneously. This process allowed the rate of reaction per patient to drop to 3.9%. The transfusion of deleucocytated red cell concentrates by filtration, carried out on a group of 188 patients, made the rate of reaction per patient drop to 2.8%. As regards to rate reaction per patient, there is no significant difference statistically between these two groups, however, it must be pointed out that the administration of filtered red cell concentrates, by deleucocytation, notably improves the incidence of a feverish reaction, while the administration of washed red cell concentrates has an important impact on allergic reactions. Interestingly, in solution, the washed red cell concentrates have the added advantage of having only very small quantities of free iron or vasoactive proteic derivatives. The new four bag system, now allows us to collect, separate and wash in a closed circuit. Compared to the traditional method this system has the advantage of assuring greater efficiency and security. In conclusion, for the first time, the administration of washed red cell concentrates on patients who receive regular transfusions, may represent a good procedure, combined or not with deleucocytation by filtration, as to prevent the occurrence of non-hemolytic reactions.

Antenatal survey for the seroprevalence of HTLV-1 infections in the West Midlands, England

The sera of 3522 women who attended an antenatal clinic in Birmingham, England were tested anonymously for antibodies against HTLV-1. Samples from 5 women (0.14%) were positive, one serum showed indeterminate reactivity. Two of the women (0.06%) were born in the West Indies (of Afro-Caribbean ethnic origin), one (0.03%) in Africa (of African ethnic origin), and three (0.09%) were white Caucasian women born in the UK. Thus, HTLV-1 infection in pregnant women in the UK, though comparatively rare, is not negligible. As transmission of HTLV-1 to the newborn via breast milk has been observed and as seropositive mothers can be advised to refrain from breastfeeding or to treat their milk, the question of routine screening for HTLV-1 infection during antenatal care is discussed.

The prevalence of human retroviral infections in female patients attending a central London sexually transmitted disease clinic: 1985-1990

OBJECTIVES

To determine the prevalence of infection with HIV-1, HIV2, HTLV-1 and HTLV-2 in female attenders at a central London sexually transmitted disease clinic in an 8 week period in 1989-1990, and compare it with similar samples studied between 1985 and 1987.

DESIGN

Anonymous testing of serum samples from consecutive female patients having routine serological investigation for syphilis. Testing was for clinically important retroviruses, Hepatitis B core antibodies (anti-HBc), and p24 and reverse transcriptase (RT) antigens. Age (in 5 year bands), nationality (in broad geographical zones), diagnosis on the day of presentation, and history of intravenous drug usage were recorded for each patient. Annual gonorrhoea rates were analysed from 1981 to 1990.

SETTING

Outpatients of the department of genitourinary medicine.

PATIENTS

A total of 850 females attending consecutively and having routine syphilis serology.

MAIN RESULTS

The prevalence of anti-HIV-1 in female attenders in 1989-1990 was 0.35% (3/850). Prevalence in the same clinic has remained statistically unchanged since the first female cases were identified in 1986. No cases of HIV-2, HTLV-1 or HTLV-2 were identified, and no early HIV-1 infection evidenced by the presence of p24 or RT antigenaemia was found. Female gonorrhoea rates continued to decline but other STD monthly/annual rates have remained unchanged.

CONCLUSIONS

Over the last 5 years prevalence of HIV-1 infection in females in our clinic has remained unchanged and other retroviral infections have remained absent. However, the unaltered rates of other genital infections, their potential role in the heterosexual spread of HIV-1 infection, and the lack of evidence for any major changes in female sexual behaviour suggests there is a need to remain vigilant. This work complements the MRC multicentre, unlinked, genitourinary medicine clinic, anonymous testing programme, and our group will continue to apply this simple methodology to specimens from female attenders to contribute to the surveillance of the evolving HIV-1 epidemic.

Application of screening and confirmatory assays for anti-HTLV-I/II in U.K. populations

During an epidemiological study of a low risk U.K. population diverse screening and confirmatory assays for the detection of anti-HTLV-I/II were assessed. Sera from 2,900 antenatal patients were tested for anti-HTLV-I/II by gelatin particle agglutination assay (GPA). All reactive sera, and 133 randomly selected unreactive sera, were further tested by Abbott and DuPont ELISAs, "in house" competitive and IgG capture radioimmunoassays (RIAs), and Western blot (WB). Sera which reacted with any HTLV-I proteins by WB were tested by radio immunoprecipitation assays (RIPA). The two ELISAs detected all the GPA reactive specimens that were subsequently confirmed as anti-HTLV-I/II positive. Confirmation of positive screening results required the use of both WB and RIPA. Serological diagnosis of HTLV infection involves access to specialised assays that are not commercially available.

[Investigation of a transfusion contaminated by HTLV-I virus]

In front of the successive development of an HTLV-I seroconversion and a neuromyelopathy in a French Caucasian following a cardiac transplantation, an ascendant epidemiologic investigation must be manage to search a risk factor or a possible blood donor contaminated with HTLV-I virus. We selected an HTLV-I seropositive donor whose RBC participated to the patient's transfusion. This woman from Martinique island was a regular donor in our blood center and a second investigation was initiated to examine the patients transfused with the blood products issued from her previous donation. Nine were identified and controlled among them a patient who has received a RBC was found HTLV-I seropositive. An evaluation of the infectivity of the different blood products according to their type and specificity has been done. These data confirm that transmission of the HTLV-I is possible through donation of healthy seropositive donor and can induce the development of associated pathology, and prove the importance of screening blood donors for HTLV-I antibodies.