Enhancing the sensitivity of HIV DNA detection: a magnetic bead-based method / 中国输血杂志

【Objective】 To establish a magnetic bead enrichment strategy for the detection of human immunodeficiency virus deoxyribonucleic acid (HIV DNA) in peripheral blood, and to verify the improvement of the sensitivity of this method for the detection of HIV DNA in HIV infected patients after early antiretrovital treatment (ART). 【Methods】 Peripheral whole blood was collected at 4 timepoints in one ART HIV window period (WP) patient. Peripheral blood mononuclear cells (PBMCs) were isolated on a Ficoll gradient. CD4+ T lymphocytes were enriched from total PBMCs by negative sorting. HIV DNA concentration in magnetic beads enriched group and whole blood group was detected by HIV DNA detection kit. 【Results】 CD4+ T cells were isolated by magnetic beads and identified by FCM for purity at (96.4 ± 2.6)%. The viability was (95.9 ± 2.9)%, as demonstrated by trypan blue staining. The person on continued ART treatment in this study had significantly greater reduction in HIV viral load and undetectable HIV plasma RNA at follow up timepoint 4. No HIV DNA was detected in the whole blood group at all 4 timepoints. The quantitative results of HIV DNA in the CD4+ T lymphocyte group of the magnetic bead enrichment group were 73.4, 429.3, 137.1, 449.9 copies/106 CD4+ T cell′s respectively. 【Conclusion】 The magnetic bead enrichment method can be more sensitive in detecting the limit low copy HIV DNA in blood samples, and provide early confirmatory data for HIV WP infection and breakthrough infection after ART treatment.

Diagnosis of Perinatal Transmission of HIV-1 Infection by HIV DNA PCR

To determine the sensitivity and specificity of HIV DNA PCR (Qualitative) at various age groups to detect or rule out HIV infection in infants born to HIV infected mothers. Pediatric and perinatal HIV clinic in a tertiary pediatric hospital.Sixteen infants born to HIV positive mother enrolled in the prevention of mother to child transmission of HIV at our center were tested for HIV infection by HIV DNA PCR at 1.5 months, 3 months, 5.5 months and/or 7 months of age. Their HIV status was confirmed by an HIV ELISA test at 18 months of age by 2 different ELISA kits. Eight patients (50%) had a negative HIV DNA PCR whereas 8 patients (50%) had a positive DNA PCR of which 6 patients (75%) had a false positive HIV DNA PCR and no false negative DNA PCR. Thus, the sensitivity of HIV DNA PCR was 100% and specificity was 57.1% with a total efficiency of the test being 62.5%. The efficiency of HIV DNA PCR at 1.5 months of age was 50%, at 3 months of age 42.9%, at 5.5 months of age 60% and at 7 months of age was 100%. HIV DNA PCR has a high sensitivity but low specificity to diagnose HIV infection in infants less than 7 months of age. Hence, the results of the test have to be interpreted with caution in infants born to HIV positive mothers.