Analysis of CD4+CD25+Foxp3+ regulatory T cells in patients of haemorrhagic fever with renal syndrome

Abstract

To investigate the percentage and significance of CD4(+)CD25(+)Foxp3(+) regulatory T cells in the patients with haemorrhagic fever with renal syndrome (HFRS). Peripheral blood samples were collected from 27 HFRS patients, and 19 healthy controls to examine the proportion of the CD4(+)CD25(+)Foxp3(+) cells. RT-PCR was used to detect the Foxp3 mRNA expression in the mononuclear cells in peripheral blood. Biopsy was conducted on the HFRS patients during oliguria stage. Peripheral blood samples and morning urine samples were collected in the stages and in the very day of renal biopsy to examine the urine protein, urine creatinine (Cr), blood Cr, and creatinine clearance rate (Ccr). The percentages of CD4(+)CD25(+)Foxp3(+) in the HFRS patients in the hypotension, oliguria, polyuria, and convalescent stages were 5.0% +/- 1.2%, 3.1% +/- 0.8%, 4.2% +/- 0.9%, and 5.0% +/- 1.1% respectively, all significantly lower than that of the normal control group (6.5% +/- 2.1%, all P < 0.01). The proportion of CD4(+)CD25(+)Foxp3(+)T cells in the CD4(+)T cells in the oliguria stage was significantly lower than those in other stages and that of the normal controls (P < 0.01). The percentage of CD4(+)CD25(+)Foxp3(+) in the patients with HFRS was significantly correlated with the renal injury index (r = 0.51, P < 0.01), but not significantly correlated with urine protein and renal function changes (r = 0.11 and 0.18, both P > 0.05). The expression level of Foxp3 mRNA in peripheral mononuclear cells of the HEFS patients in the oliguria stage was (503 +/- 64), significantly lower than that of the normal controls (3102 +/- 409, P < 0.01) and those of the HFRS patients in the hypotension, polyuria, and convalescent stages (1805 +/- 291, 1869 +/- 320, and 2697 +/- 420, all P < 0.01). The proportion of CD4(+)CD25(+)Foxp3(+) regulatory T cells decreases in patients with HFRS, which may contribute to the pathological process in such disease.