Clinical features of chronic hepatitis B patients with YMDD mutation after lamivudine therapy

Objective: To study the clinical features of chronic hepatitis B (CHB) patients with tyrosine-methionine-aspartateaspartate (YMDD) mutation after lamivudine therapy. Methods: This investigation was a retrospective study of 63 CHB patients with YMDD mutation during lamivudine therapy. Clinical data, including period and types of YMDD mutation; hepatitis B virus (HBV) DNA levels and alanine aminotransferase (ALT) levels before and after YMDD mutation were measured. YMDD mutation in the HBV DNA polymerase gene was determined using polymerase chain reaction (PCR) and direct sequencing. HBV DNA quantification was determined using real-time PCR. Relevant serum markers of HBV were measured. The follow-up period was 12 months after YMDD mutation. Results: YMDD mutation occurred 7～44 months (median, 21.5 months) after the start of lamivudine therapy. The majority of the cases (42/63, 66.6%) had YMDD mutants detected between 12 and 24 months. Four types of YMDD mutation were observed in this study, rtL180M/M204V mutation was the predominant type (26/63, 41.3%). A proportion of patients (16/63, 25.4%; 12/63, 19.1%) had higher HBV DNA levels and ALT levels (after mutation vs before mutation),respectively. Conclusion: The majority of patients with YMDD mutants had similar or lower HBV DNA levels and ALT levels compared with baseline values. This subset of patients might have benefited from the continued lamivudine therapy. The patients with increased ALT and HBV DNA levels (breakthrough hepatitis) should benefit from the addition of a newer nucleotide analogue (e.g. adefovir).

Phenotypic and functional characteristics of dendritic cells derived from human peripheral blood monocytes

Objective: This study is aimed at developing a simple and easy way to generate dendritic cells (DCs) from human peripheral blood monocytes (PBMCs) in vitro. Methods: PBMCs were isolated directly from white blood cell rather than whole blood and purified by patching methods (collecting the attached cell and removing the suspension cell). DCs were then generated by culturing PBMCs for six days with 30 ng/ml recombinant human granulocyte-macrophage stimulating factor (rhGM-CSF) and 20 ng/ml recombinant human interleukin-4 (rhIL-4) in vitro. On the sixth day, TNF-alpha (TNFα) 30 ng/ml was added into some DC cultures, which were then incubated for two additional days. The morphology was monitored by light microscopy and transmission electronic microscopy, and the phenotypes were determined by flow cytometry. Autologous mixed leukocyte reac-tions (MLR) were used to characterize DC function after TNFα or lipopolysaccharide (LPS) stimulations for 24 h. Results: After six days of culture, the monocytes developed significant dendritic morphology and a portion of cells expressed CD1a, CD80 and CD86, features of DCs. TNFα treatment induced DCs maturation and up-regulation of CD80, CD86 and CD83. Autologous MLR demonstrated that these DCs possess potent T-cell stimulatory capacity. Conclusion: This study developed a simple and easy way to generate DCs from PBMCs exposed to rhGM-CSF and rhIL-4. The DCs produced by this method acquired morphologic and antigenic characteristics of DCs.