Immunoglobulin localization in the normal human mammary gland: Variation with the menstrual cycle

Differences in immunoglobulin localization (IgG, IgM, IgA) in benign versus malignant lesions of the human mammary gland have been previously demonstrated. The present investigation was undertaken to evaluate the influence of menstrual cycling on these immunoglobulins in the breast. Tissues were studied from 53 normal breasts. The patients were 16 to 51 years old, with a mean age of 35 ± 9 years, and were documented as having regular menstrual cycling, lack of debilitating disease, and abstinence from use of hormones or from medications that might influence the pituitary-ovarian axis. Immunoglobulin localization in the tissue section was determined by direct immunofluorescence with antibodies specific for IgG, IgA, IgM, and IgA secretory component. The breast tissues were categorized into 5 histologically distinct menstrual cycle phases. No significant IgG localization was noted. IgA concentration was noted principally in the preovulatory phase of the cycle (P < 0.03). IgM showed a similar variance, and IgA secretory component paralleled IgA localization. No correlation between IgA and IgM localization and plasma cell infiltration nor between plasma cell infiltration and menstrual cycle phase could be documented. These data suggest that menstrual cycling influences the human beast as part of the secretory immune system.