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

Abstract

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 vice versa 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.

A New Flow Cytometry-Based Single Platform for Universal and Differential Serodiagnosis of HTLV-1/2 Infection

“…In this scenario, the search for a single-step approach for differential laboratorial diagnosis of HTLV-1/2 is a challenge for the scientific community. Previous studies using conventional indirect immunofluorescence assay (IFA) over glass slides on light microscopy has already been proposed for differential diagnosis of HTLV-1/2 infections ( 35 , 36 ). These authors have shown that sensitivity of the IFA for HTLV-1/2 using glass slides by optical microscopy reached higher performance when the samples were tested simultaneously against both MT-2 and MoT antigens.…”

HIV-1 western blot assay: What determines an indeterminate status?

“…Besides this, HIV-2 cross reaction, contaminating cellular antigens on viral lysate based blot strips, infection with human T-cell lymphotrophic virus I/II (HTLV I/II), auto antibodies, pregnancy, abnormal bilirubin levels and in-vitro hemolysis have also been suggested as possible causes of indeterminate WB status. [6][7][8] Previous studies have indicated that approximately 20-30% of HIV-1 ELISA negative and 4-20% of HIV-1 ELISA positive specimens have indeterminate results by WB assay. [9][10][11][12] The problems with indeterminate results are myriad.…”

“…[16] Herein lies the importance in of the interpretation criteria for accurate diagnosis based on the WB band profiles. [15] It is accepted to confirm western blot indeterminate results with immunofluorescence and Polymerase chain reaction (PCR), [7,15] which cannot be used by all the laboratories in developing countries. Hence it is mandatory to convey about the best commercially available western blot kit to the scientific population and laboratories in this community, which gives good results.…”

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

“…Therefore, molecular assays are a useful means to differentiate between the two viruses. Furthermore, the retroviral infection can not be discarded nor confirmed in a high percentage of subjects showing reactive screening and indeterminate results by Wb (Lipka et al 1991, Zaaijer et al 1994, Gastaldello et al 2001, Thorstensson et al 2002. Molecular assays are then useful to the diagnosis of infection in these subjects with persistently indeterminate patterns.…”