FAILURE OF EARLY DETECTION OF PERINATAL TRANSMISSION OF A NON-B CLADE HIV-1 STRAIN WITH THE ROCHE (VERSION 1.5) DNA-BASED POLYMERASE CHAIN REACTION (PCR)

A Bitnun¹, S King¹, C Major², S Li¹, S Read^1
1Division of Infectious Diseases, The Hospital for Sick Children, University of Toronto, Toronto, Ontario; ²Laboratories Branch, Ministry of Health and Long Term Care, Toronto, Ontario

Objectives: To describe a failure of early detection of perinatal HIV-1 infection with a non-B clade HIV-1 strain using the Roche version 1.5 HIV DNA PCR assay.
Methods: HIV DNA PCR was performed using the Roche version 1.5 assay. A positive PCR was defined by duplicate optical density (OD) readings of 0.35 or higher in accordance with the manufacturers instructions. Virus isolation was performed by co-culture with cord blood mononuclear cells and the presence of virus determined by p24 antigen detection.
Case report: The child’s mother immigrated to Canada from Nigeria late in pregnancy. She had received no prior prenatal care and was unaware of being infected with the HIV. HIV-1 infection was identified serologically. Zidovudine, lamivudine and nevirapine were initiated 2 weeks prior to delivery at which time her viral load was 17,000 copies/mL and her CD4 count 160 cells/mL. Intravenous zidovudine was administered during labour. A healthy appearing baby girl, born by C-section, was discharged home on prophylactic zidovudine monotherapy. HIV DNA PCR (OD 0.051 and 0.154) and HIV culture taken at 1 day of age were negative. At 1 month of age the HIV DNA PCR was indeterminate (OD 0.336 and 0.798) and a repeat specimen was requested. The HIV culture at that time was positive. At 2 months of age the HIV DNA PCR was positive (OD 0.992 and 0.944). The viral isolate was identified as a probable clade A strain based on sequence analysis of the polymerase region generated for resistance testing at the BC Center for Excellence.
Conclusions: The reliability of the Roche version 1.5 HIV DNA PCR assay in the early detection of perinatally transmitted non-B clade HIV-1 strains requires ongoing attention. Viral culture can be helpful in detecting perinatal HIV infections that are missed by the HIV DNA PCR assay.