Objectives: We investigated the prevalence of hepatitis B virus (HBV) markers and occult HBV infection in a general adult population in Korea. Methods: HBsAg, anti-HBs and anti-HBc were analyzed on 1,091 samples of routine medical check-up examinees by chemiluminescence immunoassay. Nucleic acid amplification test (NAT) was performed on 1,047 HBsAg-negative samples by multiplex real-time polymerase chain reaction (PCR) kit for simultaneous detection of HBV, hepatitis C virus, and human immunodeficiency virus (Cobas Taqscreen MPX) in pools of six and reactive pools were resolved to individual samples, and further discriminated by PCR-based assay for HBV (Cobas Ampliscreen HBV). Results: The prevalences of HBsAg, anti-HBc, and anti-HBs were 4.0, 39.3, and 75.4%, respectively. The prevalence of anti-HBc significantly decreased with decreasing age (p< 0.001). Occult HBV infection was found in 7 (0.7%) of 1,047 HBsAg-negative subjects, and 5 of them were anti-HBc-negative. Sequencing of HBV S gene in 3 cases revealed one wild-type and two mutant strains (W74S, F85Y; T63I, W74S, T131N substitutions). Conclusions: This study helps to understand the current status of hepatitis B infection and the prevalence of occult HBV infection in a general adult population in Korea.

Diffuse panbronchiolitis (DPB) is a chronic obstructive pulmonary disease of unknown etiology. Observations of significantly increased frequency of human leukocyte antigen (HLA)-B54 in Japanese patients and occurrence of familial cases suggest possible genetic predisposition to the disease susceptibility. To evaluate the possible association of HLA with the disease in Koreans, we have analyzed 30 patients for HLA class I (A, B, C) and class II (DR) antigens by the serologic and DNA typing methods, respectively. The most significant change in the patients compared to the control subjects was increased frequency of HLA-A11 (53.3% versus 17.5%, corrected p [pc] = 1.2 x 10(-)4, odds ratio [OR] = 5.4). In addition, B55 showed significant positive association (16.7% versus 3.5%, pc = 0.05, OR = 5.5), and B62 and Cw4 showed rather weak association with the disease. Certain A11-associated haplotypes showed much stronger positive association with the disease, compared to A11 antigen itself. Observations of a strong association of HLA-A11 in Koreans and B54 in Japanese with DPB suggest that the candidate gene(s) responsible for the disease susceptibility is located within the HLA class I region, most probably between HLA-A and HLA-B loci.