Human Immunodeficiency Virus (HIV), the aeti%gic agent of AcquiredrnInullllllodeficiency Syndrome (AIDS) is known to manifest high degree of genetic variability.rnBased on the genomic structure two types of HIV, HIV-l and HIV-2 are known to date. Thernpresence of a distinct strain of HIV-l in Ethiopia has been reported. Differences in the patternrnof viraemia and immunologic reactions from the one documented in European and NorthrnAmerican patients has been observed in Ethiopians infected with this virus. Treatment withrnazidothymidine (AIT) has been shown to result in decreased serum levels of P2-microglobulinrn(PrM), tumour necrosis factor alpha (TNF-a) and neopterin in the European and NorthrnAmerican HIV-l patients. Whether there are differences in sensitivity to antiviral compounds,rnsuch as AZf, dideoxyinosine (ddl) or interferon alpha (IFN-(J.) in Ethiopian HIV-l strains andrnthe effect of treatment on the immunological reactions were not known. The in vitro sensitivityrnof 8 Ethiopian strains to antiviral compounds was investigated in parallel with 8 Swedishrnstrains all from untreated AIDS patients. The antiviral effects were measured by p24 antigenrncapture EUSA and Reverse transcriptase activity assay. A pilot controlled study of 200mg andrn600mg oral AZT was conducted in 53 HIV-l infected Ethiopians. The treatment effects werernevaluated by assessment of the clinical status of the patients and the measurement of serumrnlevels of PrM, TNF-(J. and neopterin. No statistically significant difference in drug sensitivityrnwas found between the Ethiopian and The Swedish strains to All, ddl and IEN-(J. in vitro. Inrnthe majority of the treated patients improvement in their clinical conditions was reported andrna gain in body weight was observed. A statistically significant decrease in the levels of PrM,rnTNF-(J. and neopterin were found in the treated patients in contrast to the control patients.