Sukriti Sukriti1, Nirupma Trehanpati1, Manoj Kumar2, Chandana Pande1, Syed S Hissar1, Shiv Kumar Sarin3,4. 1. Department of Molecular and Cellular Medicine, Institute of Liver and Biliary Sciences, Delhi, India. 2. Department of Hepatology, Institute of Liver and Biliary Sciences, Delhi, India. 3. Department of Molecular and Cellular Medicine, Institute of Liver and Biliary Sciences, Delhi, India. sksarin@ilbs.in. 4. Department of Hepatology, Institute of Liver and Biliary Sciences, Delhi, India. sksarin@ilbs.in.
Abstract
BACKGROUND: Dendritic cells (DCs) promote pathogen recognition, uptake and presentation of antigen through DC-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) and toll-like receptors (TLRs). AIMS AND OBJECTIVES: We aimed to study temporal changes in DCs, TLRs and DC-SIGN during acute viral hepatitis B (AVHB) infection and compare them to chronic (CHB) and to investigate the earliest time point of activated pathogen recognition receptors in hepatitis B viral infection. METHODS: We measured the frequencies of circulating myeloid (mDC) and plasmacytoid (pDC) dendritic cells and IFN-α production along with the expression of DC-SIGN and Toll Like Receptors (TLR's) in HBV patients at different time points. Also investigated in healthy volunteers, the dynamic changes in TLRs expression after receiving hepatitis B vaccine. RESULTS: On follow-up of AVHB patients, we found the mDC population was significantly higher at week 4 and 6 (p < 0.02, 0.01), whereas the pDC population was unchanged at week 6 compared with week 0. Whereas frequencies of mDCs and pDCs were found to be elevated in AVHB and CHB patients than HC (p < 0.00 and 0.01, respectively) but was comparable among AVHB vs CHB. The DCs in CHB patients were functionally impaired with significantly low IFN-α production and low DCSIGN expression (p < 0.04 and 0.00, respectively). Even after stimulation by TLR agonists, no change was found in IFN-α production in CHB patients. MyD88 and IL-6, IFN-α mRNA levels were also found down-regulated. Interestingly, on follow-up after HBV vaccine, TLRs expression was found high at day 3 after vaccination. DISCUSSION: The initial events of immune activation might be responsible for modulating immune response. These novel observations would pave the way for the development of antiviral strategies for chronic HBV infection.
BACKGROUND: Dendritic cells (DCs) promote pathogen recognition, uptake and presentation of antigen through DC-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) and toll-like receptors (TLRs). AIMS AND OBJECTIVES: We aimed to study temporal changes in DCs, TLRs and DC-SIGN during acute viral hepatitis B (AVHB) infection and compare them to chronic (CHB) and to investigate the earliest time point of activated pathogen recognition receptors in hepatitis B viral infection. METHODS: We measured the frequencies of circulating myeloid (mDC) and plasmacytoid (pDC) dendritic cells and IFN-α production along with the expression of DC-SIGN and Toll Like Receptors (TLR's) in HBV patients at different time points. Also investigated in healthy volunteers, the dynamic changes in TLRs expression after receiving hepatitis B vaccine. RESULTS: On follow-up of AVHB patients, we found the mDC population was significantly higher at week 4 and 6 (p < 0.02, 0.01), whereas the pDC population was unchanged at week 6 compared with week 0. Whereas frequencies of mDCs and pDCs were found to be elevated in AVHB and CHB patients than HC (p < 0.00 and 0.01, respectively) but was comparable among AVHB vs CHB. The DCs in CHB patients were functionally impaired with significantly low IFN-α production and low DCSIGN expression (p < 0.04 and 0.00, respectively). Even after stimulation by TLR agonists, no change was found in IFN-α production in CHB patients. MyD88 and IL-6, IFN-α mRNA levels were also found down-regulated. Interestingly, on follow-up after HBV vaccine, TLRs expression was found high at day 3 after vaccination. DISCUSSION: The initial events of immune activation might be responsible for modulating immune response. These novel observations would pave the way for the development of antiviral strategies for chronic HBV infection.
Authors: G J Webster; S Reignat; M K Maini; S A Whalley; G S Ogg; A King; D Brown; P L Amlot; R Williams; D Vergani; G M Dusheiko; A Bertoletti Journal: Hepatology Date: 2000-11 Impact factor: 17.425
Authors: Renate G van der Molen; Dave Sprengers; Rekha S Binda; Esther C de Jong; Hubert G M Niesters; Johannes G Kusters; Jaap Kwekkeboom; Harry L A Janssen Journal: Hepatology Date: 2004-09 Impact factor: 17.425