| AIDS is a kind of severe disease caused by human immunodeficiency virus(HIV). It has the characteristic of high death rate, high spreading speed and causing grave damage. HIV is divided into two types, HIV-1 and HIV-2, and AIDS is mainly caused by HIV-1. The mutation rate of HIV-1 is high and kinds of subtypes with different gene sequence occur during spreading. The study of molecular epidemiology of HIV-1, especially the subtype detection, plays important role in tracing infection origin, controlling epidemic situation and setting up as well as carrying on therapy plan.Recently, some HIV infection cases were reported in Shannxi province. HIV-1 env gene were amplified by PCR from peripheral blood mononuclear cells (PBMCs) obtained from 15 HIV-1 sero-positive injecting drug users(IDUs) , promiscuity crowd and professional blood-providers from Shannxi. The C2-V3 region (about 450 bp) of them were sepuenced. Sequence analysis showed that there were three HIV-1 subtypes-B,E and C, with 3.0% ,1.7% and 2.3% gene divergence inside each subtype, in Shannxi. The 10 subtype B strains, after compared with sequences of several reference HIV-1 strains, were closely related to those found in Thailand and Yunnan, Xinjiang, Henan, Sichuan province of China. And the nucleotide sequence between them ranged from 3.1% to 3.8%. Meanwhile, the 3 subtype E and 2 subtypeC strains were most close to those found in Henan as well as Xinjiang, and their nucleotide sequence divergence were 3.3% and 4.7% respectively. The low level of sequence divergence among HIV-1 subtype E and C strains suggested recent epidemic of each virus, and about 1 years delaying of introduction of subtype B.We set up a new method-genechip to determine the subtype of HIV-1 and putted it into practical use to investigate its value of diagnosis. The character sequences of HIV were used as probe .The non-homology sequences of vegetative genes were used as control. The viral nucleotides were reversely transcribed and enlarged by polymerase chain reaction (PCR). Then it was labeled with fluorescence, and hybridized with the diagnosis genechip. The genechips were scanned using scanner. All kinds of serum (normal, HIV-1 B subtype, HIV-1 E subtype, HIV-1 C subtype, HIV-2) could be detected. Diagnosis genechip for HIV can be used for clinicdiagnosis as a new HIV-1 subtype detecting method.To evaluate the sensitivity and specificity of four HIV molecular-epidemiological analysis methods, the subtypes of 15 HIV - 1 serum-positive specimens and 5 HIV serum-negtive specimens were analyzed, using Peptide-binding enzyme immunoassay (PEIA) Heteroduplex mobility assay (HMA) ,gene sequences analysis and gene chip made by ourselves . We found that these four laboratory methods were sensitive and specific in the determination of HIV subtypes, while results of gene chip are more close to those of genetic sequences analysis. Since gene sequences analysis was certificated as standard method in detecting HIV types and subtypes by most researchers, and genechip was cheap and had the potential to detect more kinds of diseases at a time, we could conclude that genechip made by ourselves was a new and good method to detect HIV infection and determine the subtypes.During the study of HIV molecular epidemiology ,we foundd the first case in China that a man(Zhang) who had sexal relation with his HIV infected wife (Wang) during a long period of time was not infected by HIV. The serum specimen collected from Zhang and Wang were detected by serological assay ELISA and PA, and the confirmatory test was performed by Western Blot specific to HIV. Results showed that the serum sample from Wang was found to be HIV-1 antibody positive and HIV-2 antibody negtive. Western Blot was further used as confirmatory test, among which, reactive bands of HIV-1 gp 160 > gp!2(K p66> p55^ gp41> p3K p24> p!7 were showed on the serum sample from Wang. The sample from Zhang was found to be HIV-112 antibody negtive by ELISA and PA ,and repeated testsafter three , six monthes and one year show...
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