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

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).To investigate, in women, whether MFG and interleukin (IL)-6 differences are observed between mastitic milk (MM) and healthy milk (HM) of a mother.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).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.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.