Reverse-Transcriptase Characteristics of Hepatitis B Virus Polymerase Gene in Treatment-Naïve Asymptomatic Chronic Hepatitis B Individuals

Nucleos(t)ide analogues (NUCs) remain the main treatment for chronic hepatitis B (CHB). Long-term use of NUCs significantly reduces disease progression; however, it might lead to resistance-associated mutations. We studied characteristics of polymerase gene related to NUCs resistance in naive hepatitis B surface antigen (HBsAg)-positive individuals. The research was done at Laboratory of Hepatitis, Eijkman Institute, Jakarta Thirty eight samples were obtained and submitted for HBV DNA detection. Identification of mutations was performed by PCR-sequencing, and analyzed to obtain NUCs resistance motifs. Genotype and subtype were determined based on HBsAg sequence. Mutation of rtQ238H/N was found in 37 (97.4%) samples. Of those, 23 (62.2%) showed rtQ238H mutation, 10 (27.0%) had rtQ238N mutation, and four (10.8%) with double mutations of rtA194T and rtQ238H. Genotype B was found in 26 (68.4%), C in 11 (28.9%), and D in one (2.6%) samples. Statistically, the mutation variant of rtQ238H was associated with genotype B (p<0.001), while rtQ238N with C (p<0.001). The ayw subtype was found in 25 (65.8%), adr in 11 (28.9%), and adw in two (5.3%) samples. No mutation associated with NUCs resistance was found in most samples. This emphasizes that NUCs are still a prospective treatment in naive CHB patients. Mutation of rtQ238H was a variant found to be significantly associated with HBV genotype B and rtQ238N with genotype C.