و مدت زمان دوام مصونيت B عوامل موثر بر پاسخ دهي به واكسن هپاتيت

The Factors Influencing the Immune Response to Hepatitis B Vaccine and Persistence of the Protection

Hepatitis B virus (HBV) infection and its sequelae which include cirrhosis and hepatocellular carcinoma is a major public health problem throughout the world. WHO strategy for effective control of HBV infection is vaccination with the surface antigen of virus(HBsAg).The results obtained from a large number of studies demonstrated that the vaccine induces a protective antibody response (anti-HBs>10 lU/L) in the majority of vaccines, but 1-10% of subjects fail to respond. This unresponsiveness to HBsAg has been attributed to a variety of mechanisms including expression of certain HLA antigens and haplotypes, defect in HBsAg-specific T-cell and B-cell reset-voice, defect in antigen presenting cell function, immunological tolerance and imbalance in T helper cell function. Furthermore immunization factors that influence immunogenicity include: hype of vaccine, dosage ,number and timing of injections, site and method of injections. Host characteristics, such as sex, age, weight, genetics, immunological competency of the host and smoking also may influence the immune response to HB vaccine. The level of anti-HBs dose wane after vaccination. This phenomenon may have fuctional significance for booster vaccination. In this review article the factors that affect the immunogenicity of HB - vaccine, immunological basis of unresponsiveness to vaccine and persistence of protection were evaluated.