BCGワクチンとアレルギー:系統的レビューとメタ解析/BCG vaccination and allergy: a systematic review and meta-analysis.


Author:Arnoldussen DL, Linehan M, Sheikh A.
Title:BCG vaccination and allergy: a systematic review and meta-analysis.
Citation:Journal of Allergy Clinical Immunology. 2011 Jan;127(1):246-53, 253.e1-21. doi: 10.1016/j.jaci.2010.07.039. Epub 2010 Oct 8.
Abstract:BACKGROUND:There is conflicting evidence on whether BCG vaccination might represent an effective primary preventative strategy against the development of allergic sensitization and disease.
OBJECTIVES:We sought to systematically review the relationship between BCG vaccination and the risk of sensitization, eczema/atopic dermatitis, allergic rhinoconjunctivitis, asthma, and other allergic conditions, such as food allergy and anaphylaxis.
METHODS:Four international databases were searched for published epidemiologic or interventional studies. Additional online study databases were searched and vaccine manufacturers and a panel of international experts were contacted in an attempt to locate unpublished or ongoing studies. Quality assessment was undertaken by using internationally established criteria. Meta-analyses were undertaken by using fixed- or random-effects modeling. Funnel plots were used to assess for the risk of publication bias.
RESULTS:We identified 767 articles, of which 17 satisfied our inclusion criteria; there was only 1 randomized controlled trial, with the remaining studies being epidemiologic investigations. Meta-analyses did not show any protective effect of vaccination against the risk of sensitization, as judged by specific IgE tests (odds ratio [OR], 1.31; 95% CI, 1.07-1.60) or skin prick testing (OR, 0.87; 95% CI, 0.67-1.13); the risk of atopic eczema/dermatitis (OR, 0.84; 95% CI, 0.64-1.09); or the risk of allergic rhinoconjunctivitis (OR, 1.07; 95% CI, 0.89-1.28). BCG vaccination was associated with a protective effect against the risk of asthma (OR, 0.73; 95% CI, 0.56-0.95), although this might be explained by publication bias.
CONCLUSIONS:BCG vaccination is unlikely to be associated with protection against the risk of allergic sensitization and disease. The observed possible benefit in relation to the development of asthma is unlikely to be due to allergic sensitization.
専門医コメント 本来BCGは結核やハンセン病の予防に投与されるワクチンですが、リンパ球のTh1系を刺激する効果があり、Th2系を抑制するためアトピー性疾患の発症を予防する効果があるのではないかと言われています。このように理論上はアレルギーが予防されると考えらるものでも、実際に患者さんで起こっていることは異なっているようです。