Subclinical mastitis occurs frequently in association with dramatic changes in inflammatory/anti-inflammatory breast milk components.
BACKGROUND
Subclinical mastitis (SCM) is a frequent, but poorly characterized entity that may influence immune development of breastfed infants. Mechanisms driving the emergence of SCM and changes in immunological content of human milk during SCM remain to be explored. In this study, the breast milk environment was to describe during SCM.


METHODS
One hundred and ten samples of mature breast milk were collected from 44 healthy, HIV-negative mothers, included in a large infant feeding intervention cohort (ANRS 1271/Vertical Transmission Study). Immune markers related to inflammatory/anti-inflammatory balances and secreted in response to bacterial exposure were explored in SCM breast milk samples (Na/K ratio > 1) and compared to non-SCM controls.


RESULTS
SCM was observed in 23% of women (95% confidence interval (CI): 21-24) and associated with higher levels of inflammatory markers (β2 microgobulin, PS100A9, TNF-α, IL-6, IL-8, IL-17, and RANTES) and Th1-related cytokines (IL-2R, IL-12p40/70, IFN-α, IFN-γ, CXCL-9, andIP-10). High levels of factors secreted in response to bacteria and lipopolysaccharide (LPS) exposure were observed in SCM breast milk samples (MIP-1α, MIP-1β, LPS binding protein, α-defensins, and antileukoproteinase 1).


CONCLUSIONS
SCM is associated with important changes in breast milk microenvironment, with a proinflammatory/Th1-cytokine predominant profile. During SCM, cytokine imbalances in breast milk may have a notable influence on mucosal immune system of the infant early in life.
UMR Inserm U1058, EFS, Université Montpellier 1, Montpellier, France.|CHRU de Montpellier, Département de Bactériologie-Virologie, Montpellier, France.
Edouard
E
Tuaillon
UMR Inserm U1058, EFS, Université Montpellier 1, Montpellier, France.|Africa Centre for Health and Population Studies, University of KwaZulu-Natal, Durban, South Africa.|Department Virology, Faculty of Health Sciences, University of the Witwatersrand, Parktown, South Africa.
Johanes
J
Viljoen
UMR Inserm U1058, EFS, Université Montpellier 1, Montpellier, France.|CHRU de Montpellier, Département d'Information Médicale, Montpellier, France.
Pierre
P
Dujols
CHRU de Montpellier, Département de Néonatologie, Montpellier, France.
Gilles
G
Cambonie
UMR Inserm U1058, EFS, Université Montpellier 1, Montpellier, France.
Pierre-Alain
PA
Rubbo
UMR Inserm U1058, EFS, Université Montpellier 1, Montpellier, France.|CHRU de Montpellier, Département d'Information Médicale, Montpellier, France.
Nicolas
N
Nagot
Africa Centre for Health and Population Studies, University of KwaZulu-Natal, Durban, South Africa.|Royal Hospital for Sick Children, Glasgow, UK.
Ruth M
RM
Bland
Département de Biochimie, CHRU Montpellier, Université de Montpellier, Montpellier, France.
Stéphanie
S
Badiou
Faculty of Medicine, University of Southampton, Southampton, UK.
Marie-Louise
ML
Newell
UMR Inserm U1058, EFS, Université Montpellier 1, Montpellier, France.|CHRU de Montpellier, Département de Bactériologie-Virologie, Montpellier, France.
Philippe
P
Van de Perre
D000293:Adolescent; D000328:Adult; D001942:Breast Feeding; D015331:Cohort Studies; D016207:Cytokines / Q000737:chemistry; D005260:Female; D006801:Humans; D007249:Inflammation / Q000150:complications / Q000276:immunology*; D007774:Lactation; D008070:Lipopolysaccharides / Q000737:chemistry; D008413:Mastitis / Q000150:complications / Q000276:immunology*; D008895:Milk, Human / Q000737:chemistry*; D009092:Mucous Membrane / Q000276:immunology; D011188:Potassium / Q000737:chemistry; D012680:Sensitivity and Specificity; D012964:Sodium / Q000737:chemistry; D018417:Th1 Cells / Q000166:cytology; D018418:Th2 Cells / Q000166:cytology; D055815:Young Adult
D016207:Cytokines; D008070:Lipopolysaccharides; D012964:Sodium; D011188:Potassium