Quantitation of Viral Load in Patients Infected with HIV-1 Subtype E or A

Abstract

Quantitation of viral load in a HIV infected person gives important information for monitoring of the clinical status of the patients and evaluation of and viral effects of admininstred drugs. Although conventional Amplicor HIV-1 monitor system (Roche's conventional method) is used widely, the sensitivity of this system is not enough for measurement of subtype E and A giving lower titer of these subtype viruses than the actual quantity
In Japan, HIV-1 subytpe B cases used to be predominant but recently subtype E cases are increasing especially among heterosexuals thus it becomes required to increase the sensitivity of measurement of HIV-1 RNA of subtype E or A. Therefore we establised the Kanagawa primer method using newly developed subtype E and A primers added to the primers of Roche's conventional method. The results were compared with the conventional Amplicor and also with Roche's new version method which contained new primers.
Kanagawa primer method gave 4 to 16 times more sensitive results as compared with Roche's conventional method for subtype E measurement. As for subtype A case, Kanagawa primer method gave a value 1.2×104 copies/ml while it was undetectable by Roche's conventional method. Roche's new version method showed equal sensitivity to Kanagawa primer method. As for subtype B, the results of these three methods showed no difference
Addition of our newly developed subtype E and A primers to the Roche's conventional method enabled to measure subtype E and A with high sensitivity. For quantitative measurement of HIV-1 RNA, it is important to consider the subtype of the virus in test samples.