Blood plasma specimens are the clinical standard for HIV-1 pol gene genotyping from viral populations; however, it is not always successful, often from low viral loads or the presence of polymerase chain reaction (PCR) inhibitors. Objective To describe the successful of HIV-1 genotyping in two samples of cerebrospinal fluid (CSF), after genotype procedures failed from blood. Method Two HIV-infected patients enrolled in a neurocognitive research study were evaluated when standard HIV-1 genotyping failed from blood plasma samples. Genotyping was performed using the commercial system TRUGENE HIV-1 Genotyping Kit and the OpenGene DNA Sequencing System (Siemens Healthcare Diagnostics, Tarrytown, NY, USA). Results CSF genotyping was performed via the same commercial platform and was successful in both cases. Conclusion This report demonstrates that CSF could be used as an alternate clinical specimen for HIV-1 genotyping when it fails from blood.

The aims of this study were to investigate the frequency of HIV-1 RNA level discordance between the cerebrospinal fluid (CSF) and plasma and of CSF viral escape (CVE) in patients with HIV-1 subtype C on antiretroviral therapy, and evaluate the CSF white blood cell (WBC) performance characteristics in predicting CSF discordance in HIV+ group and the frequency of cognitive impairment in individuals with CSF HIV discordance or escape. HIV-1 RNA levels were assessed in plasma and CSF samples from 68 HIV+ participants without opportunistic infection. CSF discordance was found in 7.4% and CVE in 10%, with comparable frequencies between HIV-1B and C. Twenty samples (29%) showed increased CSF WBC counts. This group had higher CSF and plasma HIV-1 RNA levels than the group with normal WBC counts (p < 0.0001 and 0.006, respectively). The odds of CSF discordance were 18 times higher for a person with CSF WBC count of > 5 cells/mm³ than the group with normal CSF WBC count. CSF WBC counts (cut-off of 15 cells/mm³) showed high-performance characteristics as a predictive biomarker of CSF discordance (AUC the ROC curve 0.98). The frequency of cognitive impairment for CSF escape or discordance was 83% and 80%. The odds of cognitive impairment in these groups were 19 and 15 times higher than those for an HIV(-) person. Viral discordance or escape in the CNS occurs at a comparable frequency for HIV-1C and HIV-1B. The CSF WBC count was effective as a predictive biomarker of CSF and plasma discordance.