MATERNAL BLOOD B-CELL (CD19-FEEDING BEHAVIOR AND SERUM PROLACTIN CONCENTRATION() PERCENTAGES AND SERUM IMMUNOGLOBULIN CONCENTRATIONS CORRELATE WITH BREAST)

PROBLEM: Lactating women recover from pregnancy-induced immunosuppress ion while actively secreting immunologically active agents into milk. Few clinical studies have examined changes in postpartum maternal immu ne status or explored mechanisms. METHOD OF STUDY: We measured blood B -cell (CD19+) percentages and serum concentrations of immunoglobulin ( Ig) G, IgM, and IgA at 1 to 2 weeks, 1 month, and 2 months postpartum in a longitudinal study of seven healthy, lactating women.RESULTS: Mor e frequent or extended breast-feeding sessions were correlated with lo wer CD19+ percentages, reduced serum IgG, and higher serum IgA and IgM concentrations. CD19+ percentages were correlated negatively with ser um prolactin concentrations. Blood samples drawn before and 30 min aft er breast-feeding did not differ in CD19+ percentages or serum Ig conc entrations. CONCLUSIONS: These findings confirm our previous cross-sec tional study showing a negative correlation between CD19+ percentages and serum prolactin. Because lactation practices are modifiable, these findings suggest that women can influence the course of lactation-ass ociated immunologic changes.