Mastitis and immunological factors in breast milk of lactating women in Malawi

Although an elevated sodium concentration in human milk is suggested to be an indicator of mastitis, it is unclear whether elevated sodium concentrati ons are associated with immunological and inflammatory mediators in human m ilk We conducted a cross-sectional study to evaluate the relationships betw een elevated breast milk sodium concentrations and levels of lactoferrin, l ysozyme, secretory leukocyte protease inhibitor (SLPI), interleukin-1 (IL-8 ), and RANTES (regulated on activation normal T cell expressed and secreted ) in human milk at 6 weeks postpartum in 96 lactating women in Blantyre, Ma lawi. Mastitis, as indicated by an elevated breast milk sodium concentratio n, was present in 15.6% of the women. Women with and without mastitis had r espective median levels of other factors as follows: lactoferrin, 1,230 ver sus 565 mg/liter (P < 0.0007); lysozyme, 266 versus 274 mg/liter (P = 0.55) ; SLPI, 76 versus 15 mu g/liter, (P < 0.0002); IL-8, 339 versus 25 ng/liter (P < 0.0001); and RANTES, 82 versus 3 ng/liter (P < 0.0001). Elevated sodi um concentrations in breast milk are associated with an increase in levels of some immunological and inflammatory factors in breast milk.