14th International AIDS Conference Barcelona, Spain - July 7-12, 2002

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. TuOrC1191)

Xing H, Chen Z, Liang H, Feng Y, Chen JP, Zhao QB, Zhang YZ, Qin GM, Wei M, Shao YM
National Center for AIDS Prevention and Control, Beijing, China

BACKGROUND: The B'/C recombinant HIV-1 (CRF-CH1) found in China's first national molecular epidemic study (NMES1) in mid 90s has been carefully studied in the NMES2 in 2001-2. The two sets of data are compared and will help to explain its epidemic and prepare for future vaccine trials.

METHODS: Epidemiology data, CD4, CD8 counts, viral load and genetic sequencing from HIV infected people were conducted randomly from all provinces in China. Virus isolation was performed to all available fresh samples (20 % of the total).

RESULTS: Preliminary data collected in NMES2 showed that the same CRF-CH1 has been spread to 12 provinces compared with 7 provinces in NMES1. The proportion of IDUs with CRF-CH1 has increased from 16% to 50% in mid-west and provinces with predominant CRF-CH1 (>80%) infection has increased from 1 to 4 in northwest. The significantly low viral load found in CRF-CH1 infected people has been confirmed again in NMES2. The patterns in three tat mutants which correlates further with low, lower and lowest viral load in CRF-CH1 infected people found in NMES1 remained the same in NMES2. A specific mutation was found in the NFkB binding region from all CRF-CH1 LTRs, which has been reported having a negative impact on HIV replication. The third NFkB binding region found in CRF-CH1 LTRs appears not functioning because of its very low binding capability in the specific sequence bearing the specific mutation.

CONCLUSIONS: The CRF-CH1 has spread rapidly in mid-west and northwest China. The low viral load induced by the CRF-CH1 may be explained by the specific mutation found in its Tat and LTR, and suggest a host-adapted feature might exists in this strain. In order to explain its contradictory phenomena of low viral load in individuals and rapid spreading in populations, three cohorts have been building up in two study and testing both host and viral factors focusing on viral load in the major ethic groups in the epidemic region.

020707
TuOrC1191

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