Periodontitis is a highly complex and multifactorial disease. In recent years, researchers began to focus on bacterial-host interactions. It had been recognized that though the bacteria present in plaque initiates the periodontal inflammation, the host response to these pathogens equally matters in the progression of the disease. Therefore, the severity of this disease is due to a variety of factors, including the presence of periodontopathic bacteria, high levels of proinflammatory mediators and low levels of antiinflammatory mediators. However, the immune response initiated by periodontal disease seems to be much broader. This review attempts to enlighten the various immune mechanisms involved in periodontal disease initiation and progression.

AIM:The study was initiated to evaluate the reactogenicity and immunogenicity of a recombinant hepatitis B vaccine in age group >40 years and to study the response of a single booster dose in primary non-responders to the hepatitis B vaccination. METHODS:A total of 102 volunteers without markers of hepatitis B infection (negative for HBsAg, anti-HBc antibody, HBeAg and anti-HBs antibody) received 20 µg of recombinant HB vaccine intramuscularly at 0, 1, and 6 months. Anti HBs titers were evaluated by a quantitative Elisa kit at 90 and 210 days. A booster dose of 20 µg HB vaccine was given after 6 months of the 3 rd vaccine dose to the 15 nonresponders and anti-HBs titers were measured after 1 month. RESULTS:Seroprotection (anti-HBs GMT³ 10 IU/L) was achieved in 85.3 % (87/102) volunteers. The mean GMT titers of the vaccine responders was 136.1 IU/L. Of the seroprotected individuals, there were 32.4 % (33/102) hyporesponders (antiHBs titers <10-99 mlU/ml) and 52.9 % (54/102) were responders (anti-HBs titers >100 IU/L). All the non-responders (15/15) responded to a single dose of the booster dose of recombinant HB vaccine and their mean anti-HBs antibody titers were more than 100.5 mIU/ml after the booster dose. CONCLUSION:Recombinant hepatitis B vaccine offers good seroprotection in the age group >40 years and has a good safety profile. A single booster dose after 6 months in primary non-responders leads to good seroprotective anti-HBs antibody titers. However, larger population based studies are needed to evaluate the role of a booster dose in selected group of non-responders and whether such an approach will be cost effective.Das K, Gupta RK, Kumar V, Kar P. Immunogenicity and reactogenicity of a recombinant hepatitis B vaccine in subjects over age of forty years and response of a booster dose among nonresponders.

Background: Children with cancer have a greatly enhanced risk of contracting hepatitis B infection due to immunosuppression secondary to chemotherapy and radiotherapy, frequent blood transfusions, bone and peripheral vein punctures, tissue damage and mucositis. During the past 3 decades, multimodality therapy for childhood leukemia has resulted in markedly improved survival. Inspite of screening and immuno prophylaxis, hepatitis B infection rates in children with leukemia are high. In view of this, we decided to study the prevalence of hepatitis B among children with leukemia in our institution, and the possible risk factors.Methods: This was a cross sectional study carried out at a tertiary pediatric care center in North Kerala among 104 children between 1 and 12 years of age on treatment for leukemia.Results: Among the 104 children, only 17 (16.3%) had received primary immunization against hepatitis B. Of the 87 children who had not received primary immunization, 44.8% (n=39) developed hepatitis B, compared to 11.8% (n=2) in the vaccinated group (p=0.01).Conclusions: This study highlights the importance of primary immunization against hepatitis B in children with leukemia, and the need for universal coverage.