Parâmetros de reatividade de amostras de soro com resultados indeterminados por Western blot para anticorpos contra HIV-1 e HTLV I/II em Córdoba, Argentina

Serum samples (n: 110) from blood donors and high risk individuals from Cordoba, Argentina with indeterminate HIV-1 and HTLV-I/II Wb profiles were studied for specific antibodies to HTLV-I/II and HIV-1 by indirect immunofluorescence assay (IFA) and for the presence or absence of HIV-1 and HTLV-I/II specific bands by Wb. This study was carried out in order to characterize their putative reactions with HIV-1 and HTLV-I/II proteins and to resolve the retrovirus infection status of these individuals. Results indicated that blood donors sera displaying indeterminate HIV-1 or HTLV-I/II Wb patterns were not immunoreactive to HTLV-I/II and HIV-1 on IFA. However, a high rate of indeterminate HIV-1 and HTLV-I/II Wb samples from high risk individuals had positive HTLV-I/II and HIV-1 IFA results respectively. Our study supports the growing evidence that HTLV-HIV indeterminate seroreactivity in low risk population is due to a cross reaction against nonviral antigens, and in high risk populations the indeterminate samples show serological cross-recognition between HIV-1 proteins and HTLV-I/II proteins on Wb. These results point out the necessity to investigate the HTLV-I/II reactivity in indeterminate HIV-1 samples and viceversa in order to confirm the diagnosis. Finally, this study shows the potential usefulness of IFA in elucidating the status of HIV-1 and HTLV-I/II infection of individuals with indeterminate Wb profiles, thus enabling resolution of retrovirus infection status.Amostras de soro sangüíneo (n: 110) de indivíduos de comportamento de risco e doadores de sangue da cidade de Córdoba, na Argentina, com perfis de reactividade para HIV-1 e HTLV-I/II indeterminada por Western blot (Wb), foram estudadas para anticorpos específicos contra HTLV-I/II e HIV-1 por meio do Ensaio de Imunofluorescência Indireta (IFI). Este estudo foi realizado para caracterizar as reações putativas com proteínas HIV-1 e HTLV-I/II e resolver o estado da infecção por retrovírus destes indivíduos. Os resultados mostram que os soros dos doadores sangüíneos que apresentam padrões indeterminados para HTLV-I/II e HIV-1 no Wb não são reagentes contra HTLV-I/II e HIV-1 por IFI. Mas, um alto índice de amostras de individuos com alto risco com resultado indeterminado no Wb para HIV-1 e HTLV-I/II apresentaram resultados positivos para HTLV-I/II e HIV-1 por IFI, respectivamente. Nosso estudo sugere que a reatividade indeterminada para HTLV-HIV na população de baixo risco deve-se a uma reação cruzada contra antígenos não virais; e que na população de alto risco as amostras indeterminadas apresentam reação cruzada entre as proteínas HIV-1 e HTLV-I/II no Wb. Estes resultados indicam que se faz preciso pesquisar a reatividade de HTLV-I/II nas amostras indeterminadas de HIV-1 e vice-versa, para confirmar o diagnóstico. Por último, este trabalho mostra a utilidade potencial da IFI para determinar o estado de infecção HIV-1 e HTLV-I/II dos indivíduos com perfis indeterminados por Wb, permitindo assim, a resolução do estado real de infecção por retrovírus

Usefulness of a Nested-polymerase chain reaction for molecular diagnosis of human T-cell lymphotropic virus type I/II

This study aimed at implementing a Nested-polymerase chain reaction (Nested-PCR) for the molecular diagnosis of human T-cell lymphotropic virus type I/II (HTLV-I and HTLV-II) infections in peripheral blood mononuclear cells of infected subjects in Argentina. The sensitivity and specificity of the assay for the detection of regional strains were assessed by comparing them with the molecular assay of reference PCR-hybridization. The Nested-PCR detected 1 MT-2 cell (³ 8 proviral copies)/1x106 non-infected cells showing high sensitivity for provirus detection. While both molecular assays showed high specificity (100%) for HTLV-I and HTLV-II detection, the sensitivity values differed: 100% for Nested-PCR and 67% for PCR-hybridization assay. Moreover, this technique showed less sensitivity for the detection of DNA sequences of HTLV-II (33%) than for the detection of DNA sequences of HTLV-I (75%). The high sensitivity and specificity of the Nested-PCR for regional strains and its low costs indicate that this assay could replace the PCR-hybridization assay for the molecular diagnosis of HTLV-I/II infections. It will be interesting to assess the usefulness of this assay as a tool for the molecular diagnosis of HTLV-I/II infections in other developing countries. Other studies that include a greater number of samples should be conducted

Loss of maternally derived human herpesvirus-6 immunity and natural infection in argentinian infants

AbstractBackground: Human herpesvirus-6 (HHV-6) infection is widespread throughout the world. No data are available in Argentina about the loss of maternally derived HHV-6 immunity and natural infection in infants.Methods: A population of 100 pregnant women and 407 children between 1 and 15 months of age were assayed by indirect immunofluorescence to detect and quantify specific IgG anti-human herpesvirus-6 (anti-HHV-6) antibodies in Córdoba City, Argentina.Results: There was no significant difference in the positive rate between infants aged 1 to 9 months (range, 43.6–35.5%) and pregnant women (37%). Seropositive ratio dropped in the 10-month group (23.33% seropositive) and rose sharply in the 11-month group (38.89%), 12-month (60.61 %), and 13- to 15-month group (63.46%). The geometric mean titer (GMT) for infants in the 12 to 15 months age group (23.4–41.64) was significantly higher than the GMT for infants 10 months of age (11.04) (P < 0.05 with the Tukey-HSD test).Conclusions: This study shows a significant association between loss of passive HHV-6 antibody and age among infants. The results support evidence that HHV-6 enters the susceptible population at 11 months, leading to a high prevalence of antibodies in children between 13 and 15 months of age