严重烧伤患者外周血树突细胞的变化及临床意义

目的 探讨严重烧伤患者外周血树突细胞(DC)的变化及与烧伤严重程度和脓毒症发生的关系.方法 22例严重烧伤患者根据脓毒症的诊断分为烧伤组(10例)和烧伤脓毒症组(12例);按烧伤总体表面积(TBSA)分为TBSA Ⅰ组(TBSA 30％～50％,14例)和TBSA Ⅱ组(TBSA 51％～80％,8例).采集患者伤后1、3、7、14和20 d外周静脉血,用流式细胞仪检测外周血中髓样树突细胞(mDC,Lineage1- HLA-DR+CD11e+)和浆样树突细胞(pDC,Lineage1-HLA-DR +CD123+)两种DC亚型的数量.以同期10例健康体检者作为对照.结果健康对照组外周血mDC为(0.450±0.150)％,pDC为(0.241±0.084)％.与健康对照组比较,烧伤组患者伤后1、3、7d外周血mDC(0.257±0.116)％、(0.274±0.086)％、(0.317±0.056)％]和pDC(0.122±0.058)％、(0.165±0.051)％、(0.177±0.024)％]均显著减少(均P＜0.05),14 d、20 d时mDC、pDC数量恢复至正常水平;烧伤脓毒症组患者伤后1d外周血mDC(0.230±0.090)％]和pDC(0.114±0.071)％]即较烧伤组进一步减少(均P＜0.05),至20 d时外周血mDC和pDC仍显著低于烧伤组mDC:(0.246±0.076)％比(0.412±0.097)％; pDC:(0.097±0.032)％比(0.203±0.039)％,均P＜0.05].与健康对照组比较,TBSA I组患者伤后1、3、7d外周血mDC(0.266±0.062)％、(0.289±0.071)％、(0.351±0.054)％]和pDC(0.131±0.025)％、(0.163±0.037)％、(0.178±0.038)％]均显著减少(均P＜0.05),14 d、20 d时mDC、pDC数量恢复至正常水平;TBSAⅡ组患者伤后1d外周血mDC(0.227±0.070)％]和pDC(o.112±0.047)％]即较TBSA Ⅰ组进一步减少(均P＜0.05),至20 d外周血mDC和pDC仍显著低于TBSA Ⅰ组mDC:(0.297±0.072)％比(0.423±0.046)％;pDC:(0.107±0.061)％比(0.197±0.042)％,均P＜0.05].结论严重烧伤患者早期外周血mDC和pDC数量均减少,烧伤程度越严重DC数量减少越明显;外周血DC数量减少导致烧伤后机体免疫功能低下,数量减少明显者易并发脓毒症;烧伤后定期检测外周血DC数量可以作为脓毒症的早期预警指标.

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

Objective To explore the changes in peripheral dendritic cells (DCs) in serious burn patients and its relationship with the burn severity and pathogenesis of sepsis.Methods 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.Results 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 l 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 Ⅰ 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.Conclusion 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.