Downregulation of the immune system in low-quality child care: the case of secretory immunoglobulin A (SIgA) in toddlers.

Does the experience of stress during child care lead to downregulation of the immune system, in particular in low-quality care? Saliva was collected from 68 toddlers attending center or family child care at home and at child care, and assayed for secretory IgA (SIgA). Caregiver sensitivity was used as an index of quality of care and was observed during three videotaped episodes of 10 min. Diurnal patterns of SIgA showed a steep fall in the morning followed by a flattening out. SIgA was not associated with type of care, but lower caregiver sensitivity was associated with lower SIgA levels in both types of care. Quality of child care is associated with a non-specific secretory component of children's mucosal immunity with well established protective effects against upper respiratory infections.