Immunofluorescence assay reactivity patterns of serum samples presenting indeterminate Western blot results for antibodies to HIV-1 and HTLV-I/II in Cordoba, 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

Efficiency of indirect immunofluorescence assay as a confirmatory test for the diagnosis of human retrovirus infection (HIV-1 and HTLV-I/II) in different at risk populations

Avaliou-se a eficiencia da tecnica de immunofluorescencia indireta (IFI) como metodo confirmatorio no diagnostico da infeccao por HIV-1 e HTLV-I/II. Para isto, processaram-se amostras com sorologia positiva ou negativa por Western blot (Wb) para ambos virus, pertencentes a populacoes em diferentes graus de risco de adquirir a infecao e determinaram-se os valores de sensibilidade, especificidade, valores preditivos positivo e negativo e o indice de concordancia Kappa da IFI para cada sistema viral em comparacao com o Wb. Como fontes de antigenos da IFI empregaram-se as linhas celulares H9 (HTLV-III b), MT-2 e MT-4 (persistentemente infectadas com HTLV-I), MO-T (persistentemente infectadas com HTLV-II). Os valores globais de sensibilidade e especificidade para o sistema HIV-1, foram 96,80 por cento e 98,60 por cento respectivamente, enquanto os valores preditivos positivo e negativo 99,50 por cento e 92,00 por cento respectivamente...