Performances of HTLV serological tests in diagnosing HTLV infection in high-risk population of São Paulo, Brazil

Abstract

SUMMARYTesting problems in diagnosing human T-lymphotropic virus (HTLV) infection, mostly HTLV-II, have been documented in HIV/AIDS patients. Since December 1998, the Immunology Department of Instituto Adolfo Lutz (IAL) offers HTLV-I/II serology to Public Health Units that attend HTLV high-risk individuals. Two thousand, three hundred and twelve serum samples: 1,393 from AIDS Reference Centers (Group I), and 919 from HTLV out-patient clinics (Group II) were sent to IAL for HTLV-I/II antibodies detection. The majority of them were screened by two enzyme immunoassays (EIAs), and confirmed by Western Blot (WB 2.4, Genelabs). Seven different EIA kits were employed during the period, and according to WB results, the best performance was obtained by EIAs that contain HTLV-I and HTLV-II viral lysates and rgp21 as antigens. Neither 1 st and 2 nd , nor 3 rd generation EIA kits were 100% sensitive in detecting truly HTLV-I/II reactive samples. HTLV-I and HTLV-II prevalence rates of 3.3% and 2.5% were detected in Group I, and of 9.6% and 3.6% in Group II, respectively. High percentages of HTLV-seroindeterminate WB sera were detected in both Groups. The algorithm testing to be employed in HTLV high-risk population from São Paulo, Brazil, needs the use of two EIA kits of different formats and compounds as screening, and because of high seroindeterminate WB, may be another confirmatory assay.

A New and Frequent Human T-Cell Leukemia Virus Indeterminate Western Blot Pattern: Epidemiological Determinants and PCR Results in Central African Inhabitants

“…Such HTLV indeterminate WB patterns have been reported, for the last 20 years, by several authors and are found mainly, and their signification studied, in tropical areas, such as Central Africa and Southeast Asia (24,28,31,41,47,54). However, they have also been reported in other areas, such as European countries (68), the United States (11,51,73), the Caribbean area (17,57), Central and South America (Brazil, Argentina) (6,35,44,50,61), and more recently the Middle East (74). Most of the studies concern blood donors (10,11,16,63) or epidemiological work in the general population (43) but also organ donors for transplantation (22,36), lactariums (19,58,70), and neurological patients (1,73).…”

“…Screening tests are usually enzyme-linked immunoassorbent assays (ELISAs) (3,5,18,43,66) or particle agglutination (PA) (33). Confirmatory tests are immunofluorescence (IF) (23) but mostly Western blot (WB) analyses (30,35,38,39,64,71). Moreover, research of integrated provirus, in the DNA from peripheral blood cells, could be done by qualitative and/or quantitative PCR (2,4,8,68).…”

Confirming the presence of HTLV-1 infection and the absence of HTLV-2 in blood donors from Arequipa, Peru

“…Brazil 5,6,14,15 , and suggested the use of two ELISAs of different compounds and formats for screening in this country (contrary to the recommendation of the Ministry of Health of Brazil) 16 . The same strategy has been conducted in Argentina, where the combination of two HTLV screening assays was shown to be useful for blood banks 3 .…”

Long‐term serological follow‐up of blood donors with an HTLV‐Indeterminate Western Blot: Antibody Profile of Seroconverters and Individuals With False Reactions

“…The result is more frequent in low-risk blood donors, causing the loss of haemocomponents in blood centres and affecting the counseling of the donors [Lal et al, 1992a;Mauclère et al, 1997;Césaire et al, 1999;Lu and Chen, 2003;Berini et al, 2007;Jacob et al, 2007]. Certain indeterminate WB patterns, like HTLV-1 Gag indeterminate profile (HGIP), have been interpreted as seronegative [Césaire et al, 1999], but the possibility of true HTLV-1 infection should be take into consideration, especially in blood donors living in endemic areas, in intravenous drug users and in patients with neurological diseases.…”