12th Annual Conference of the British HIV Association 29 March–1 April 2006, Brighton, UK

THE DEMOGRAPHIC, CLINICAL AND VIROLOGICAL CHARACTERISTICS OF PATIENTS NEWLY DIAGNOSED WITH NON-B HIV-1 SUBTYPES IN LONDON

HIV Med 2006; 7(Suppl. 1):1 (abstract no. O2)

Ana Garcia, Clare Booth, Gaia Nebbia, Anurhada Chawla and Anna Maria Geretti
Royal Free Hospital, London, UK

OBJECTIVES: To characterise newly diagnosed persons infected with HIV-1 subtypes other than B.

METHODS: HIV-1 subtype was determined by phylogenetic analysis of protease and RT. Drug resistance was assigned according to the IAS-USA list (2005) and Stanford interpretation algorithm when intermediate or high- level resistance. Serum samples were tested by a guanidine-based antibody avidity test to identify seroconversion within the previous 4–6 months (avidity index <0.60).

RESULTS: From April 2004–November 2005, among 200 newly diagnosed persons, 112 (56%) were subtype B, including 106 (95%) males, 91 (81%) whites, 100 (89%) MSM; and 22 (25%) recent seroconverters. The median age was 34.5 years (19–57), CD4 395 cells/µl (4–1.184), viral load 5.0 log₁₀ copies/ml (4.3–6.9). Non-B subtypes comprised 36 C (41%), 14 A (16%), 10 CRF02 (11%), 7 D (8%), 5 G (6%), 4 CRF01 (5%), 4 CRF06 (5%), 1 CRF13 (1%), 1 CRF16 (1%), and five complex mosaic sequences (6%). Phylogenetic analysis identified seven clusters, each including two MSM. The non-B population comprised 34 males (39%), 61 (69%) black Africans, 72 (82%) heterosexuals, 5 (5%) MSM, and 9 (10%) recent seroconverters. The median age was 36, CD4 387 cells/µl (46–803), viral load 4.7 log₁₀ copies/ml (2.5–5.8). Among the non-B subtypes there were eight (9%) white European, four were from UK, one from Portugal, two from Poland, six were male and two female, and five were heterosexuals and three homosexuals: infected with subtype C (3), CRF06 (2), and one each with D, CRF01, and CRF02. Only one patient in this group was a recent seroconverter. Three MSM with CRF06 formed one phylogenetic cluster. Primary drug resistance was found in 14/200 (7%) by IAS and 9/200 (4.5%) by Stanford, including 12/112 (11%) MSM with subtype B, 1/12 heterosexual with subtype B and 1/12 heterosexual with complex mosaic sequence.

CONCLUSIONS: The genetic diversity of HIV-1 continues to increase in London. Although non-B subtypes are commonly associated with immigration from Africa or Asia, they are no longer restricted to non-indigenous populations. Transmitted drug resistance is nearly entirely confined to MSM with subtype B at the present time.

2006-03-29
O2

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