Changes of the CD4+ CD25+regulatory T cells in infant with sepsis

Abstract

Objective To study the change of CD4+ CD25+ Foxp3high regulatory T cells (Treg cells) and the molecules associated with Treg cells in different immune status in infant with sepsis, and to further clarity the pathogenesis of disturbed immune function in infant with sepsis. Method Totally 36 sepsis infants admitted in In-tensive Care Unit of Shenzhen Children' s Hospital from May 2007 to November 2007 and 16 age-matched healthy infants were collected for prospective study, after excluding autoimmune disease, immunodeficiency, inherited metabolic disorders, tumor, and drug-treatment that could affect immune function during lately 6 months. The study was approved by Ethics Committee of Shenzhen Children's Hospital. The 36 infants with sepsis were divided into two groups according to expression levels of HLA-DR in CD14-positive cells: DR-H group was defined as patients with HLA-DR > 30%, while DR-L group was defined as patients with HLA-DR < 30%. Expression levels of HLA-DR in CD14-positive cells and the proportion of Treg cells were analyzed by flow cytometry. Real-time PCR were used to evaluate the mRNA levels of Foxp3, CTLA-4,GITR, and IL-10 in CD4-posidve ceils. Statistical analysis was performed by one-way Anova. There was statistical difference with P < 0.05. Results The proportion of Treg cells in DR-L group was found to be significantly higher than that in healthy control or DR-H group (P <0.05).Compared with healthy control group or DR-H group, transcriptional levels of Foxp3, CTLA-4 and IL-10were significantly increased in DR-L group (P <0.05). The levels of GITR mRNA in DR-L group were detected to be higher than those in DR-H group (P < 0.05). Conclusions Aberrant increased proportion of Treg cells may be associated with suppressed immune status in infant with sepsis. Key words: Sepsis; HLA-DR; CD4+ CD25+ Foxp3high regulatory T cells; Infant; Immune suppression