RESUMO
Brazil is home to the highest absolute number of human T-cell lymphotropic virus type-1 (HTLV-1)-infected individuals worldwide; the city of Salvador, Bahia, has the highest prevalence of HTLV-1 infection in Brazil. Due to the complex nature of several diseases associated with this retrovirus, a multidisciplinary health care approach is necessary to care for people living with HTLV-1. The Bahia School of Medicine and Public Health's Integrative Multidisciplinary HTLV Center (CHTLV) has been providing support to people living with HTLV and their families since 2002, striving to ensure physical and mental well-being by addressing biopsychosocial aspects, providing clinical care and follow-up, including to pregnant/postpartum women, as well as comprehensive laboratory diagnostics, psychological therapy, and counseling to family members. To date, CHTLV has served a total of 2,169 HTLV-infected patients. The average patient age is 49.8 (SD 15.9) years, 70.3% are female, most are considered low-income and have low levels of education. The majority (98.9%) are HTLV-1 cases, and approximately 10% have been diagnosed with tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM), while 2.2% have infective dermatitis and 1.1% have adult T-cell lymphoma. In all, 178 pregnant/postpartum women [mean age: 32.7 (±6.5) years] have received care at CHTLV. Regarding vertical transmission, 53% of breastfed infants screened for HTLV tested positive in their second year of life, nearly 18 times the rate found in non-breastfed infants. This article documents 20 years of experience in implementing an integrative and multidisciplinary care center for people living with HTLV in Bahia, Brazil. Still, significant challenges remain regarding infection control, and HTLV-infected individuals continue to struggle with the obtainment of equitable and efficient healthcare.
RESUMO
Serological screening for human T-cell lymphotropic virus type 1 (HTLV-1) is usually performed using enzyme-linked immunosorbent assay (ELISA), particle agglutination, or chemiluminescence assay kits. Due to an antigen matrix improvement entailing the use of new HTLV antigens and changes in the format of HTLV screening tests, as well as newly introduced chemiluminescence assays (CLIAs), a systematic evaluation of the accuracy of currently available commercial tests is warranted. We aimed to assess the performance of commercially available screening tests for HTLV infection diagnosis. A diagnostic accuracy study was conducted on a panel of 397 plasma samples: 200 HTLV-negative plasma samples, 170 HTLV-positive plasma samples, and 27 plasma samples indeterminate by Western blotting (WB). WB-indeterminate samples (i.e., those yielding no specific bands for HTLV-1 and/or HTLV-2) were assessed by PCR, and the results were used to compare agreement among the commercially available ELISA screening tests. For performance analysis, WB-indeterminate samples were excluded, resulting in a final study panel of 370 samples. Three ELISA kits (Murex HTLV-1/2 [Murex], anti-HTLV-1/2 SYM Solution [SYM Solution], and Gold ELISA HTLV-1/2 [Gold ELISA]) and one CLIA kit (Architect rHTLV-1/2) were evaluated. All screening tests demonstrated 100% sensitivity. Concerning the HTLV-negative samples, the SYM Solution and Gold ELISA kits had specificity values of >99.5%, while the Architect rHTLV-1/2 test presented 98.1% specificity, followed by Murex, which had a specificity of 92.0%. Regarding the 27 samples with WB-indeterminate results, after PCR confirmation, all ELISA kits showed 100% sensitivity but low specificity. Accuracy findings were corroborated by the use of Cohen's kappa value, which evidenced slight and fair agreement between PCR analysis and ELISAs for HTLV infection diagnosis. Based on the data, we believe that all evaluated tests can be safely used for HTLV infection screening.