To investigate the changes of serum immunoglobulin IgG in peripheral blood of infants aged 0-6 months, and to compare the effects of breast feeding and artificial feeding on the immune function of infants.

A total of 90 neonates born from January 2016 to December 2016 were divided into three groups: breast feeding group, mixed feeding group and artificial feeding group. There were 30 newborns in each group. Peripheral blood samples were collected at postnatal 1 d, 3 d, 7 d, 14 d, 42 d, 3 months and 6 months respectively. Serum levels of IgG were determined by radioimmunoassay, and the contents of each group were compared. T lymphocyte subsets(CD3⁺, CD4⁺, CD8⁺) in peripheral blood at postnatal 6 months were detected.

The content of IgG in serum of neonatal decreased gradually with the increase of postnatal days. The serum IgG content at postnatal 14 d in the breast feeding group, the mixed feeding group and the artificial feeding group was (95.14±4.55), (90.89±4.35), (91.74±4.19) mg/L respectively, and the breast feeding group was significantly higher than the other two groups, the difference among the groups was statistically significant (F=7.965, P<0.05).The CD8⁺ T lymphocyte cells in the breast feeding group, the mixed feeding group and the artificial feeding group was 0.389 4±0.060 1, 0.294 2±0.062 6, 0.308 4±0.071 6 respectively, and the breast feeding group was significantly higher than the mixed feeding group and the artificial feeding group, and the difference among the groups was statistically significant(F=4.941, P<0.05).

Breast feeding can reduce the serum IgG content of infant consumption, slowing the pace of decline, effectively improve the infant's own ability to synthesize IgG, so as to improve infant immunity, promote their healthy growth, it is worthy of clinical application.

Immunoglobulin G; Breast feeding; Artificial feeding; Mixed feeding; Immune function