Upon admission and 7 days after the operation , fecal samples and fasting peripheral venous blood were collected from the patients to examine the intestinal flora and serum levels of interleukin-2 ( IL-2 ) , IgA , IgG , and IgM , NK cell activity , T lymphocytes subsets CD3 ( + ) , CD4 ( + ) , CD8 ( + ) and CD4 ( + ) / CD8 ( + ) ratio .
