Standardisation of Western blotting to detect HTLV-1 antibodies synthesised in the central nervous system of HAM/TSP patients

Intrathecal synthesis of human T-lymphotropic virus type 1 (HTLV-1) antibodies (Abs) represents conclusive evidence of a specific immune response in the central nervous system of HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients. Western blotting (WB) for HTLV Abs in serum is a confirmatory test for HTLV-1 infection. The aim of this study was to standardise the Western blot to demonstrate the intrathecal pattern of Abs against HTLV-1 proteins in HAM/TSP patients. Paired cerebrospinal fluid (CSF) and serum samples were selected from 20 patients with definite HAM/TSP, 19 HTLV-1 seronegative patients and two HTLV-1 patients without definite HAM/TSP. The presence of reactive bands of greater intensity in the CSF compared to serum (or bands in only the CSF) indicated the intrathecal synthesis of anti-HTLV-1 Abs. All definite HAM/TSP patients presented with an intrathecal synthesis of anti-HTLV-1 Abs; these Abs were not detected in the control patients. The most frequent intrathecal targets of anti-HTLV-1 Abs were GD21, rgp46-I and p24 and, to a lesser extent, p19, p26, p28, p32, p36, p53 gp21 and gp46. The intrathecal immune response against env (GD21 and rgp46-I) and gag (p24) proteins represents the most important humoral pattern in HAM/TSP. This response may be used as a diagnostic marker, considering the frequent association of intrathecal anti-HTLV-1 Ab synthesis with HAM/TSP and the pathogenesis of this neurological disease.

Evaluation of two indigenous rapid and two ELISA assays for the diagnosis of HIV infection India.

Purpose: Human immunodeficiency virus (HIV) diagnostic tests are being used extensively in India. However, the evaluation data on these assays are very limited. The present study evaluates indigenous HIV test kits manufactured in India. Materials and Methods: A total of 200 characterised specimens were assayed with Comb AIDS - RS Advantage HIV 1+2 Immunodot Test, Enzaids HIV 1+2 ELISA test, Enzaids Duet HIV Antigen+antibody ELISA test and Signal HIV Flow Through HIV 1+2 test kits. Performance characteristics of these assays were calculated. Results: Sensitivity, specificity, positive predictive value, negative predictive value and efficiency of all the assays were 100% except for Signal HIV Flow Through HIV 1+2 test kit. The specificity, positive predictive value and efficiency of the Signal HIV Flow Through HIV 1+2 test kit were 98.9%, 98.9% and 99.4%, respectively. The Enzaids Duet HIV kit was found to be extremely sensitive in detecting p24 Ag with the sensitivity of 1.5 pg/mL. Conclusions: To conclude, selection of better diagnostic assay is very much important to resolve discrepancies in HIV diagnosis. All these assays under evaluation in this report have got excellent performance characteristics and much suitable to use in serial testing algorithms in use for resources limited settings.

Estandarización de la técnica de Western blot para el diagnóstico de la fasciolosis humana utilizando antígenos de excreción-secreción de Fasciola hepática / Western blot technique standardization of the diagnosis of human fasciolosis using Fasciola hepatica excreted-secreted antigens

Objetivos. Evaluar la eficacia de la técnica de electroinmunotransferencia (EITB) o Western blot utilizando antígenos de excreción-secreción de las formas adultas de Fasciola hepatica (Fh E/S Ag) para el diagnóstico de la fasciolosis humana. Materiales y métodos. Los antígenos fueron obtenidos a las 18 horas de incubación en medio Minimum Essential Eagle y preparados a la concentración proteica de 0,15 ug/uL; los cuales, al ser enfrentados con un pool de sueros de pacientes con fasciolosis confirmada por el hallazgo de huevos del parásito en las heces, se detectaron los antígenos de 10, 12, 17, 23, 27, 30, 36, 43, 66 y 136 KDa, con los cuales se desarrolló la técnica de Western blot. La sensibilidad se evaluó empleando sueros de 67 pacientes con fasciolosis, y la especificidad con sueros de 57 pacientes con otras parasitosis y diez sueros de personas no parasitadas. Resultados. De los 67 sueros, 64 reaccionaron con la banda de 23 KDa y 61 con la banda de 17KDa. Estas dos bandas no fueron detectadas por ninguno de los sueros de pacientes con otras parasitosis, ni de personas no parasitadas, siendo por ello consideradas como específicas y diagnósticas. Conclusiones. La sensibilidad de la prueba, utilizando las bandas de 17 y 23 KDa, fue de 95,5 por ciento cuando se presenta reacción positiva en una o en las dos bandas, siendo la especificidad para estos dos antígenos de 100 por ciento con un valor predictivo positivo de 100 por ciento y un valor predictivo negativo de 95,71 por ciento.

Objectives. To evaluate the performance of the enzyme-linked immunoelectrotransfer blot assay (EITB, Western blot) using excretory/secretory antigens from adult forms of Fasciola hepatica (Fh E/S Ag) for the diagnosis of human fasciolosis. Materials and methods. Antigens were obtained after 18 hours of incubation in culture medium Minimum Essential Eagle, prepared at a protein concentration of 0.15 ug/uL and run against a pool of sera of patients with proven fasciolosis (confirmed by the finding of parasite eggs in the stool microscopy). Antigens of 10, 12, 17, 23, 27, 30, 36, 43, 66 and 136 kDa were detected and used to develop the Western blot technique. The sensitivity was evaluated using sera from 67 fasciolosis patients, and the specificity using sera from 57 patients with other parasitic diseases, and 10 from healthy individuals. Results. Out of the 67 sera, 64 reacted with the 23 kDa band and 61 with the one of 17 kDa. These two bands were not detected in sera from patients with other parasitic diseases or in those from healthy volunteers and thus could be considered specific and diagnostic. Conclusions. The sensitivity of the test, using the bands of 17 and 23 kDa, was 95.5 percent for positive reactions to at least one of these two bands, being its specificity 100 percent with a positive predictive value of 100 percent and negative predictive value of 95.71 percent.

Evolución inmunológica de madres HIV reactivas y sus hijos / Immunology evolution of mother reactive HIV and sons

De 23 partos de madres HIV reactivas, ingresaron en el estudio 17 de ellas y 22 niños, confirmados por 2 ELISA, IFI (inmunofluorescencia indirecta) y Western blot. El propósito fue controlar cada tres meses su inmunidad celular (IMC) y humoral por medio de test de rosetas, subpoblaciones linfocitarias CD3, CD4, CD8, relación CD4/CD8 para linfocitos T, DR para linfocitos B, CMI multitest para linfocitos T con memoria. Proteinograma electroforético, inmunoglobulinas séricas (IgG, IgM e IgA), C3 y C4 por inmunodifusión radial. Del total de madres, 10 (58,8 por ciento) presentaron una relación CD4/CD8<1, la mitad de ellas un recuento CD4<400/mm3 (252, 252, 359, 279, 194/mm3). Valores tan bajos como este último se detectaron en forma previa a la muerte de una de ellas. De este grupo, cuatro presentaron hipergammaglobulinemia y elevación de IgG con sintomatología clínica, a diferencia del resto de madres con déficit de IMC pero con valores de CD4 por encima de 400/mm3; durante los controles seriados, en tres de ellas se produjo un segundo embarazo en cuyo curso se observó una disminución de la IMC. En cuanto a los niños, nueve se tornaron negativos después de los seis meses de vida; de los trece que continúan siendo seropositivos, dos presentaron un déficit de IMC, con disminución progresiva de CD4 (4 085; 3 401; 2 008; 1 445/mm3), (662; 491; 1 519/mm3) y de relación CD4/CD8 (1,88; 0,99; 0,58; 0,82), (0,69; 0,31; 0,30). No se observaron valores tan bajos de CD4 como en los adultos, pero sí un descenso del 50 por ciento del valor inicial en un niño durante su primer año de vida. Estos niños corresponden al grupo de madres con CD4<400/mm3. Los resultados sugieren que la negativización se produce después de los seis meses de vida. El déficit de IMC, sobre todo una relación CD4/CD8<1, CD4<400mm3, hipergammaglobulinemia y elevación de IgG son de mal pronóstico. Las madres con severo compromiso inmunitario presentan mayor riesgo de infectar intraútero. Durante el curso de su embarazo presentaron una disminución de IMC. El chequeo seriado de inmunidad permite detectar actividad del virus en infectados y su evolución a enfermedad antes de que se presente sintomatología clínica

HTLV-I antibody study in normal individuals and unselected hospital patients in Malaysia.

A serological investigation for human T cell leukemia virus I (HTLV-I) infection was carried out at the University Hospital, Kuala Lumpur. A total of 626 sera from a non-patient population and 1,038 sera from unselected in-patients were screened for HTLV-I antibodies using an enzyme-linked immunosorbent assay (ELISA). 27/1664 (1.6%) were found to be reactive. However, on Western blotting, only 2 sera were confirmed positive, both showing reactions for the major core (p19 and p24) and the envelope (gp46) proteins. Both of the serum samples were from unselected hospital patients. Most of the remaining sera which were reactive on screening showed indeterminate results on Western blotting. These were further tested by radioimmunoprecipitation assay (RIPA) and none of these sera gave a positive reaction. Therefore, only 2/1038 (0.19%) unselected patients could be confirmed to have antibodies to HTLV-I. None of the normal individuals screened showed a positive Western blot result. Our data indicate that HTLV-I infection is present in our population, but at a low prevalence rate.