Detection of HIV type 1 env subtypes A, B, C, and E in Asia using dried blood spots: a new surveillance tool for molecular epidemiology.

ABSTRACT

PIP: The global surveillance of HIV-1 subtypes for genetic characterization is frustrated by the danger of processing and the difficulties of shipping whole blood or cells from many developing country regions. The authors therefore developed a technique for the direct automated sequencing of viral DNA from dried blood spot (DBS) specimens collected on absorbent paper. Such specimens can be mailed unrefrigerated in paper envelopes with low biohazard risk. 51 DBS specimens were collected nonrandomly from HIV-1-infected, mostly asymptomatic individuals in India, Myanmar, China, Indonesia, and Thailand in 1991, then shipped via airmail or hand carried without refrigeration to Bangkok from where they were forwarded to North America for processing. After more than 2 years in storage, including 6 months at ambient temperatures, proviral DNA in 42 of the DBS was successfully amplified by nested polymerase chain reaction, and a 389-nucleotide segment of the C2-V3 env gene region was sequenced, from which 287 base pairs were aligned and subtyped by phylogenetic analysis with neighbor-joining and other methods. From southern India, there were 25 infections with subtype C and two with subtype A; the first subtype E infection was identified from Myanmar, as well as six subtype B(B); one B(B) was identified from southwest China; subtype B was identified from Indonesia; and five DBS of ambiguous serotype classified as three B, one B(B), and one E were identified from Thailand. DBS can be used as a practical, cost-effective way of tracking the global distribution and spread of HIV-1 variants.