| Objective: 1.To observe the change in plasma level of the main pro-and anti-inflammation cytokines as well as the expression rate of monocyte HLA-DR in order to evaluate the immunity state in severe burn patients, and to explore the role of HLA-DR in the diagnosis of immuno suppression.2. To compare the ability of normal and immune-paralyzed monocyte to produce TNF-a when exposed to LPS, LPS+IFN-y or LPS+carbachol, and also their ability to produce IFN-y when exposed to LPS or LPS+carbachol. The effect of LPS, LPS+IFN-y or LPS+carbachol on the expression rate of monocyte HLA-DR was assayed at the same time, in order to the further function of monocytes in patients with severe burn injury.3. To investigate the effects of carbachol or IFN-y challenged by LPS in vitro on the transcription level of HLA-DR and its modulating gene CIITA of monocytes.Method: 1.Patients were divided into four groups according to total body surface area burned. Blood was drawn postburn 3,7,14 from patient with extremely severe burn , on postburn day 3,7,14,28,42 from patients with severe burn, on postburn day 3 from patients with moderate and mild burn, while blood was also drawn from healthy individuals as control. The plasma levels of IL-6, IL-10 and TNF-a were measured by means of ELISA. The extremely severe patient's plasma levels of IFN-y were also measured by means of ELISA.2. Monocytes were double stained with PE-CD14 andFITC-HLA-DR on postburn days 3,7,14 for severe burn group, on postburn days 3,7,14,28,42 for moderate burn group, and on postburn day 3 for both moderate and mild burn group, and the expression rate of HLA-DR was assessed by means of flow cytometry.3. According to the expression rate of HLA-DR, peripheral blood mononuclear cells were divided into normal group (HLA-DR>80%) and paralysis group (HLA-DR <30%). These cells were respectively co-culture with LPS, LPS+IFN-y or LPS+carbachol. TNF-a, the expression rate of monocyte HLA-DR and IFN-y were measured by means of ELISA and flow cytometry respectively. Total RNA was obtained from all the experimental groups and the control group, and the transcription levels of HLA-DR and CIITA were determined by means of RT-PCR.Results: 1. The plasma levels of IL-6, IL-10, TNF-a from severe and extremely burn patients were elevated compared with moderate, mild burned patient and healthy individuals, and they were positively related with severity of burn injury. The plasma levels of the cytokines declined with the recovery of the injury. The expression rate of monocyte HLA-DR declined dramatically after sever burn injury. The severer the burn was, the lower the rate was.2. The plasma level of IFN-y in patient with extremely severe and severe could not be detected when thymopeptide was not given and plasma level of IFN-y was found to be elevated in patients when thymopeptide was used, and the elevation persisted for after the drug was stopped.3. TNF-a level was elevated after the monocytes were exposed to LPS in vitro, but the elevation was suppressed when the monocytewere exposed to a combination of LPS with IFN-y or carbachol. Compared with normal group, monocytes from paralysis group generated less TNF- a, and even less when the monocytes were co-cultured with IFN-y or carbachol.4. Monocytes from the normal group could generate IFN-y when exposed to LPS, and carbachol enhanced the production. Monocytes from the paralysis group did not show such effects.5. The expression rate of monocyte HLA-DR from two groups declined when exposed to LPS, and when IFN-y or carbachol was added the declination was more prominent.6. The transcription levels of monocyte HLA-DR and CIITA of paralysis group were much lower than that of the normal group. And the transcription levels were decreased when monocytes were exposed to LPS. The addition of IFN-y or carbachol of monocyte culture increased the transcription levels of H...
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