OBJECTIVEAn approach for analysis of HIV quasispecies using Miseq high-throughput sequencing platform (hereinafter referred to as Miseq platform) was established and applied to contact tracing for a possible case of HIV sexual transmission.

METHODSFour plasma specimens were collected from 2 HIV infections (P1 and P2) suspected to be involved in the sexual transmission and 2 local HIV infections as controls (P3 and P4). The RNAs were extracted from the specimens and then reverse-transcribed into cDNA. After HIV subtyping, Miseq platform was performed to detect and sequence the HIV quasispecies (352 bp) in each specimen. The frequency of quasispecies was counted and ranked. Intrapersonal and interpersonal genetic distance and phylogenetic tree were calculated by using the top 5, 20, 100, 500, and all quasispecies, respectively.

RESULTSThe subtypes of HIV from all 4 specimens were CRF01_AE. 23 788 to 37 397 cleaned sequences representing 1 229 to 1 412 unique HIV quasispecies were obtained from these specimens by using Miseq platform. The average genetic distance (3.5%-4.5%) between quasispecies from specimens P2 and P1 was significantly lower than that (10.3%-19.6%) between quasispecies from P2 and the controls (P3 or P4). Phylogenetic tree analysis indicated that sequences from specimens P1 and P2 clustered together while sequences from P3 and P4 exhibited completely independent clusters. When the top 20 or more quasispecies from each specimen were analyzed, sequences from P1 showed a paraphyletic relationship with those from P2, which may indicated that the direction of HIV transmission was from P1 to P2.

CONCLUSIONWith the feature of convenient and economic operation, Miseq platform has high practical value in contact tracing of possible HIV transmission.