Mastitis Is Associated with IL-6 Levels and Milk Fat Globule Size in Breast Milk

Abstract

BACKGROUND: From animal studies, it is known that mastitic inflammation of the mammary lobes can produce proinflammatory cytokines and can damage the milk fat globule (MFG). OBJECTIVE: To investigate, in women, whether MFG and interleukin (IL)-6 differences are observed between mastitic milk (MM) and healthy milk (HM) of a mother. METHODS: MM was obtained from the specific nipple pore leading to the mastitic lobe of 17 women; HM was obtained from the other breast. Milk sampling occurred at days 0 (pre-treatment), 1, and 2 (post-treatment). MFG size and IL-6 were measured by laser light scattering and enzyme-linked immunosorbent assay, respectively. We analyzed MFG and IL-6 differences between HM and MM, whether any differences occurred over time with treatment, and whether differences were observed between mothers with systemic symptoms (fever/malaise, Group A) or without systemic symptoms (Group B). RESULTS: On day 0, MM had higher MFG size (P < .01) and IL-6 levels (P < .001) than HM. This difference significantly decreased over time with treatment for both MFG size (P < .01) and IL-6 (P < .05). On day 0, Group A mothers had significantly larger MFG size (P < .01) and IL-6 (P < .001) than Group B. CONCLUSIONS: MM contains larger MFG and higher IL-6 levels than milk from the healthy breast. This difference is larger if accompanied by systemic symptoms of mastitis (fever/malaise). These changes decreased over time with treatment. Therefore, early initiation of appropriate treatment may be useful in limiting the processes that contribute to alterations in MFG size and IL-6.