Text Box: THE ROLE OF BREAST MILK SOLUBLE FAS AND SOLUBLE FAS-LIGANED PROTEIN IN THE DEVELOPMENT OF IMMUNOLOGICAL TOLERANCE
Kamel MM.*, Abd Allah ST.*, Soliman GT.* and sharkawy E** 
* Departments of Pediatric and clinical pathology **, El- Minia Faculty of Medicine, El-Minia, Egypt

Objectives: Breast milk contains a complex immune system that augments host defense, helps prevent autoimmune diseases and fosters the development of the digestive tract. In addition to immunoglobulin, maternal immune cells, immunoreactive peptides and cytokines, soluble Fas and soluble Fas ligand have been demonstrated. The aim of this study is to determine whether soluble Fas (sFas) and soluble Fas ligand (sFasL) are present in human milk, their relative amounts and to detect any differences as lactation progressed or between fullterm and premature milk. Also, the possible significance of Fas/Fas ligand system in the development of immune tolerance and apoptosis. 
Methods: We report the results of an ELISA-based quantitation of soluble Fas and soluble Fas ligand in human milk. Forty-four breast milk samples of milk / colostrum were utilized from healthy woman delivering premature (< 37 weeks) (n =12) or full term (37-42 weeks) infants (n = 32). 
Results: Our results establish the presence of significant amount of soluble Fas and soluble Fas ligand in premature and full term milk in the different lactational stages. A large amount of soluble fas is detected in colostrum (3777.5 - 4126 pg/ ml), transitional milk (2553.1 - 3224.1 pg/ml), and mature milk (1757.5 ¨C 2113.3 pg/ml) of mothers delivering prematurely or at full term, whereas Fas ligand is present only in the range of 175.7 - 353.2 pg/ ml. In fullterm, we found a statistically significant increase in the levels of soluble Fas and soluble Fas ligand in colostrum when compared with transitional and mature milk, while in premature milk the differences were not significant. Soluble Fas and soluble Fas ligand throughout the three lactational stages of breast milk show no significance difference in full-term milk versus premature milk. 
Conclusion: We can conclude that breast milk, particularly colostrum, contains considerable amounts of soluble Fas and soluble Fas ligand. The excess of soluble Fas in human milk may bind to Fas ligand preventing apoptosis and preserving epithelial barriers, and may represent an additional new mechanism whereby human milk favours immune tolerance and normal gastrointestinal development.
1984