This study was performed to investigate the cellular composition including lymphocyte subsets in preterm breast milk and to compare it with that in the full term breast milk.
The cellular composition of colostrum (within 72 hours ostpartum) and earlymature milk(5th-7th day postpartum) from 40 monthers delivering prematurely(mean gestational age: 33.9 weeks) and 40 monthers delivering at term(mean gestational age: 39.7
weeks)
was examined. Lymphocyte subsets including B cells, T cells, T cells, T4 and T8 cells were quantitated by alkaline phosphatase anti-alkaline phosphatase staining using specific monoclonal antibodies.
@ES The results were as follows ;
@EN 1) The mean total cell count in preterm colostrum(23.163±13334.0/μ1) and milk (18,900±8.259.9/μ1) was significantly higher than in full term colostrum(13.463±4,971.8/μ1) and milk(8,450±4,278.6/μ1), (p<0.05).
2) Counts for macrophages, neutrophils and lymphocytes were significantly higher in preterm colostrum (15,588±9,382.1/μ1, 4.484±2,453.9/μ1, 2,385±1,042.3/μ1) and milk(12,114±6.553.9/μ1, 4,479±1,489.9/μ1, 1,795±1,190.7/μ1) as compared
with
those of full term colostrum(8,697±3,319.0/μ1, 2,827±1,292.9/μ1, 1.682±1,077.0/μ1) and milk(5,264±2,717.5/μ1, 1,977±1,108.1/μ1, 988±523.9/μ1), (p<0.05).
3) Lymphocytes from preterm colostrum were 15.6±6.5% CD19 (B cell) and 80.2±6.9% CD3+(T cell) whereas lymphocytes from full term colostrum were 16.9±7.6% CD19+ and 79.7±5.6% CD3+, B and T cells in mature milk constituted 14.5±7.0% and
79.2±7.9%
of total lymphocytes in preterm group and 16.5±7.0% and 79.8±5.1% in full term group. The relative percentage distribution of T cell and B cell showed no significant difference between the two groups.
4) Lymphocyte subsets from preterm colostrum were 43.8±10.8% CD4+(T4 cell) and 26.0±6.8% CD8+(T8 cell) whereas lymphocyte subsets from full term colostrum were 46.2±5.6% CD4+ and 27.5±5.0% CD8+, T4 and T8 cells in mature milk constituted
38.4±9.1%
and 24±9.1% of total lymphocytes in preterm group and 40.1±9.7% and 25.7±7.1% in full term group. The T cell subset distribution showed no significant difference between the two groups.
5) The T4/T8 ratios in preterm colostrum and milk were 1.75±0.43 and 1.75±0.57 whereas those in full term group were 1.74±0.34 and 1.63±0.46.
In conclusion, the higher concentration of immunocompetent cells in preterm breast milk may be a natural protective mechanism to endow the immunocompromised preterm baby with extrinsic immunologic support.
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