Serological, molecular characteristics and cytokines profile of HBsAg negative/HBV DNA positive patients in clinic

Abstract Background In this study, the serological characteristics, sequencing analysis and cytokine levels of HBsAg negative and HBV DNA positive patients were analyzed to preliminarily determine whether being HBsAg clearance was related to immune function. Methods Evaluate the basic medical records and laboratory data of 279 HBsAg negative and HBV DNA positive patients. Serum samples from 30 HBsAg negative and HBV DNA positive patients, 20 matched HBsAg persistently positive patients and 16 healthy people were tested for 48 cytokines, chemokines and growth factors. Sanger sequencing was used to analyze the HBV S region sequences of HBsAg negative and HBV DNA positive patients samples. Results Of the 76428 HBV-infected patients enrolled, 358 (0.47%) were defined as HBsAg negative and HBV DNA positive patients. The main serological patterns of HBsAg negative and HBV DNA positive patients were anti-HBe and anti-HBc positive, accounting for 47.67%. HBV DNA load<200IU/ml was found in 94.98%. Serum sCD40L, G-CSF, IFN-γ, MIP-1α, RANTES and Eotaxin levels were significantly higher in the HBsAg negative group than in the HBsAg positive group(P＜0.05), but IL-4, IL-6, IL-8, IL-13, IL-17A, PDGF-AA, TGF-α and TNF-β levels were lower in the HBsAg negative group(P<0.05). Between the HBsAg negative group and the healthy control group, there were also differences in the levels of several serum cytokines, chemokines, and growth factors. The levels of AST/ALT were positively correlated with IL-15(P=0.040/0.009) and IL-18(P=0.031/P=0.003). Nine HBsAg negative samples were sequenced, revealing amino acid substitutions in the HBV S protein, including immune escape mutations(Y100C, S114T, C124Y, P127L, G130R, T131N, M133T) and affecting HBsAg secretion mutations(E2R/K/D). Conclusions The levels of HBV DNA replication and transcription are low in most HBsAg negative and HBV DNA positive patients. Since there were fewer HBsAg negative and HBV DNA positive patients in this study with significant and meaningful HBV mutations, viral factors might not be the primary causes. Therefore, it is more valuable to proceed from the host factor. By inducing a slightly stronger host immune response and controlling liver inflammation, several cytokines and chemokines, including G-CSF, IFN-γ, MIP-1α, RANTES and Eotaxin, may promote in the clearance of HBsAg.