[Changes in peripheral dendritic cells in serious burn patients and its clinical significance]

To explore the changes in peripheral dendritic cells (DCs) in serious burn patients and its relationship with the burn severity and pathogenesis of sepsis.

Twenty-two serious burn patients were divided into the burn group (n = 10) and the burn sepsis group (n = 12) according to diagnostic criteria of sepsis, they were stratified according to the total burn surface area (TBSA), into the TBSA I group (TBSA 30%-50%, n = 14) and the TBSA II group (TBSA 51%-80%, n = 8). Peripheral blood of all patients was collected on 1, 3, 7 ,14 ,20 day after burn. The number of two subtypes of peripheral DC i. e myeloid dendritic cells [mDC, Lineage1(-)HLA-DR(+)CD11c(+)] and plasmacytoid dendritic cells [pDC, Lineage1(-)HLA-DR(+)CD123(+)] were quantified by flow cytometer. Ten healthy volunteers served as normal controls at the same time.

In the healthy control group, mDC in the peripheral blood was (0.450 ± 0.150)% and pDC was (0.241 ± 0.084)%. Compared with the healthy control group, in the burn group both mDC [(0.257 ± 0.116)%, (0.274 ± 0.086)%, (0.317 ± 0.056)%] and pDC [(0.122 ± 0.058)%, (0.165 ± 0.051)%, (0.177 ± 0.024)%] decreased significantly on 1, 3, 7 day after burn (all P < 0.05), and the number returned to the normal level on 14 day and 20 day. Compared with the burn group, the number of mDC [(0.230 ± 0.090)%] and pDC [(0.114 ± 0.071)%] in patients of the burn sepsis group were significantly lower (both P < 0.05) on 1 day after burn. Both cells [mDC (0.246 ± 0.076)% vs. (0.412 ± 0.097)% and pDC (0.097 ± 0.032)% vs. (0.203 ± 0.039)%] were still significantly lower (both P < 0.05) on 20 day. Both mDC [(0.266 ± 0.062)%, (0.289 ± 0.071)%, (0.351 ± 0.054)%] and pDC [(0.131 ± 0.025)%, (0.163 ± 0.037)%, (0.178 ± 0.038)%] in the patients in the TBSA I group decreased significantly on 1, 3, 7 day after burn as compared with those of the healthy control group(all P < 0.05), and they returned to the normal level on 14 day and 20 day. Compared with the TBSA I group, mDC [(0.227 ± 0.070)%] and pDC [(0.112 ± 0.047)%] in patients of the TBSA II group decreased significantly(both P < 0.05)on 1 day after burn, and both cells [mDC (0.297 ± 0.072)% vs. (0.423 ± 0.046)% and pDC (0.107 ± 0.061)% vs.(0.197 ± 0.042)%] were still significantly lower (both P < 0.05) on 20 day.

Both the number of mDC and pDC decrease in peripheral blood in early stage in serious burn patients, and those who have more serious burn have lower number of mDC or pDC. Deficiency in mDCs and pDC subsets may contribute to immunosuppression in burn victims, and those who suffered obvious loss of mDC and pDC are susceptible to sepsis following severe burn. It indicates that the percentage of mDC and pDC can be a predictive index of sepsis after burn.