Objective To study changes of humoral immunity of the premature infants in different pathological conditions and detect the reason of the deficiency of humoral immunity in premature infants .Methods Two hundred and forty-six prematur were enrolled and 30 healthy neonates were selected as control group .The percentages of IgG ,IgA ,IgM and comp lement C3 ,C4 were detected by full automatic biochemical analyzer .Results The results showed that IgG ,IgM ,IgA ,C3 and C4 in the premature in-fants were lower than those in the normal term infants and there was a highly significant difference with the decrease of fetal age . IgG ,IgM ,IgA ,C3 and C4 of the group of the premature infants ranging from 32 to 36 weeks had reduced in different degree ,rela-tive to the groups of BW <2 000 g ,hypertension during pregnancy ,cesarean section(P<0 .05) .Conclusion The results showed that function of humoral immunity in the premature infants was depressed and low gestational age ,low birth weight ,cesarean sec-tion and hypertension during pregnancy may be the leading cause of the deficiency of humoral immunity .

Objective To assess the value of flow cytometry in the diagnosis of postoperative infection following renal transplantation. Methods According to postoperative imaging findings and laboratory examination outcomes, 51 recipients undergoing the first renal transplantation were divided into the bacteria (n=33), fungus (n=9) and BK virus (n=9) groups. Twenty-eight recipients with stable conditions after renal transplantation were assigned into the stable group. Flow cytometry was adopted to detect the percentage and absolute counting of lymphocyte subpopulation in the peripheral blood of recipients in each group. Renal function, percentage and absolute counting of lymphocyte subpopulation in the peripheral blood were statistically compared among different groups. Receiver operating characteristic (ROC) curve was drawn to evaluate the diagnostic value of the percentage and absolute counting of lymphocyte subpopulation in infectious diseases after renal transplantation. Results Compared with the stable group, the serum creatinine (Scr) and blood urea nitrogen (BUN) levels in the bacteria, fungus and BK virus groups were significantly up-regulated, respectively (P=0.035, 0.007, 0.024; 0.037, 0.006, 0.032). Compared with the stable group, the percentage of CD16+CD56+natural killer (NK) cells was significantly declined in the bacterial (P=0.036) and fungus groups (P=0.015), and the proportion of CD4+/CD8+T cells was dramatically decreased in the fungus group (P=0.004). Compared with the bacterial group, the percentage of CD3+CD8+T cells was significantly elevated (P=0.013 and 0.008), the proportion of CD3+CD4+T cells was considerably declined (P=0.003 and 0.010), and the percentage of CD4+/CD8+T cells was significantly declined (P=0.003 and 0.005) in the fungus and BK virus groups. Compared with the stable group, the quantity of CD3+T cells, CD3+CD8+T cells and CD16+CD56+NK cells was significantly declined in the bacterial, fungus and BK virus groups, respectively (P=0.025, 0.002, 0.003; 0.015, 0.005, 0.006; 0.001, 0.001, 0.031). In addition, the quantity of CD3+CD4+T cells was considerably decreased in the fungus and BK virus groups (P=0.001, 0.003). The quantity of CD19+B cells was significantly reduced in the BK virus group (P=0.019). Compared with the bacterial group, the quantity of CD3+CD4+T cells was considerably lower in the fungus group (P=0.023). ROC curve analysis revealed that the quantity of CD3+CD4+T cells [area under curve(AUC)=0.8492] and CD16+CD56+NK cells (AUC=0.8889) yielded relatively high accuracy in the diagnosis of fungal infection. The quantity of CD3+T cells (AUC=0.8472), CD3+CD4+T cells (AUC=0.8452) and CD19+B cells (AUC=0.8115) yielded relatively high accuracy in the diagnosis of BK virus infection. Conclusions Flow cytometry detection of the lymphocyte subpopulation in peripheral blood can evaluate the immune function of patients. Absolute counting of lymphocyte subpopulation can directly assess the degree of immunity. These two combined parameters provide guiding significance for the diagnosis and differential diagnosis of infectious diseases in recipients after renal transplantation.