出産ストレスと初乳中S-IgA濃度に関する精神神経免疫学的研究

Childbirth Stress and Psychoneuroimmunologic Implications of Secretory Immunoglobulin-A in Breast Milk

要旨

　本研究の目的は，出産ストレスが初乳中S-IgA濃度の個人差に及ぼす影響について，精神神経免疫学の知見を基盤とし，Lazarusらのストレスシステム理論・認知評価理論から関連検証することである．また，生体内ストレス反応経路の知見からストレス関連ホルモンを測定し，初乳中S-IgA濃度が出産ストレスを反映する物質であるかを客観的に評価した．対象は，初産・経産婦を含めた62名の母親である．パス解析から，Lazarusらの理論に基づく心理社会的要因では，..対処行動」が初乳免疫に与える影響要因であること，身体的ストレッサーである分娩所要時間が，副腎系cortisolを介する初乳中S-IgA濃度への間接的効果であること，分娩後60分cortisol濃度・CgA濃度が初乳中S-IgA濃度と強い因果関係があることが示された．したがって，初乳中S-IgA濃度は，出産ストレスを反映する免疫物質であることが明らかとなり，この知見は，科学的根拠に基づく免疫学的視点から，助産師の早期授乳計画への新しいアプローチとなることが示された．

Abstract

　The purpose of this study was to examine the influence of the stress of childbearing on individual differences in the level of S-IgA in the colostrum, in relation to the stress system theory and the cognitive evaluation theory established by Lazarus et al. based on psychoneurological-immunological knowledge. The levels of stress-related hormones in the colostrum were also determined based on a knowledge of the in-vivo stress reaction pathways,for the purpose of objectively evaluating whether the level of S-IgA in the colostrum would be reflective of the stress of childbearing.The subjects were62mothers,consisting of both primiparous women and multiparous women. The analysis indicated that “behavior to cope with something”, one of the psychosocial factors assessed based on the theories propounded by Lazarus et al., was the most important factor that influenced the local colostrum immunity. The time to delivery, a physical stressor,indirectly influenced the colostrum S-IgA level mediated by adrenal cortisol secretion. Furthermore, the serum cortisol and CgA levels showed a strong correlation with the colostrum S-IgA level measured 60 minutes after delivery. Thus, it is clear that the colostrum level of S-IgA is an immune substance reflective of the stress of childbearing stress. The knowledge gained from such a study could pave the way for a new approach to early lactation plans by midwives, from an immunological standpoint, based on scientific evidence.