Laboratory Diagnosis Of Dual Hiv-1/Hiv-2 Infection In Ghanaian Patients

Abstract

Objective: To determine the true prevalence of HIV dual infections in a previously
characterised HIV seropositive patient group due to inconsistencies between different
diagnostic methods.
Design: A cross-sectional study of an HIV seropositive group with different diagnostic
methods.
Setting: Three hospitals in the Northern, Ashanti and Greater Accra Regions of Ghana.
Subjects: One hundred and forty five HIV infected patients/individuals sampled from
June to September 2002.
Main outcome measures: Using serological and molecular methods, the seropositive
status of HIV-infected patients, previously determined by a preliminary screening
process, was confirmed and discrepancies noted. The data was used to propose a more
accurate laboratory diagnosis of HIV dual infections involving HIV-1 and HIV-2.
Results: HIV-1 infections were mostly accurately detected, but difficulties were
encountered in diagnosing HIV-2 infections. To achieve a positive detection on
confirmatory immunoblots, antibody concentration in some samples tested was
enhanced by using larger volumes. In other cases, diagnosis of HIV infections by
PCR, especially HIV-2, was possible only after increasing the DNA template or MgCl2
concentrations. Such samples would otherwise have been inaccurately scored for HIV
infections.
Conclusion: Based on the results of this study, we propose that the accurate diagnosis
of HIV dual infections, especially HIV-2 component, must use an algorithm that
involves PCR. Our results however underscore conclusions of a previous study that
most dually seroreactive samples are predominantly HIV-1 infections with crossreactivity
to HIV-2 antigens.

East African Medical Journal Vol. 85 (11) 2008: pp. 534-543