Hepatitis B virus genotypes and HBsAg subtypes in refugees and injection drug users in the United States determined by LiPA and monoclonal EIA

Hepatitis B virus (HBV) genotyping and hepatitis B surface antigen (HBsAg) subtyping were carried out on sera from 196 HBsAg-positive patients, including 151 refugees entering the United States and 45 injection drug users in Seattle. HBsAg subtyping was performed by enzyme immunoassay (EIA) using a panel of monoclonal antibodies and the HBV genotype was determined by polymerase chain reaction (PCR) followed by detection of amplified HBV DNA by a reverse-phase hybridization line probe assay (LiPA) using genotype-specific probes. HBV DNA was detected by PCR in 155 (79%) of the 196 sera and all 155 were genotyped by LiPA. Samples from Southeast Asia were predominantly genotype B/subtype ayw1 and genotype C/adr; samples from the former Soviet Union and eastern Europe were mostly genotype D/ayw2 and genotype D/ayw3; samples from east Africa were mainly genotype A/adw2 and genotype D/ayw2; and samples from injection drug users were mostly genotype D/ayw3 and genotype A/adw2. Some strains of ayw3 gave atypical monoclonal antibody reactivity patterns in the subtyping assay due to a Val/Ala instead of a Thr at amino acid residue 118 and a Thr instead of a Met at residue 125. A strain of ayw2 also gave an atypical monoclonal antibody reactivity pattern due to an Ala instead of a Thr at amino acid residue 123. LiPA genotyping and monoclonal EIA subtyping can provide useful information for epidemiological studies.