Cimetidine effects on the immunosuppression induced by burn injury

• Lymphocyte proliferation is significantly suppressed in burn patients.
• The significant reduction in the lymphocyte count and frequency of CD3 and CD4 was observed.
• The frequency of CD19 + and HLA DR + cells was increased compare to normal donors.
• Cimetidine increased the frequency of CD8 + T cells as well as the proliferation rate of PBMC.
• Cimetidine may have beneficial effects on cell mediated immunity following burn injury.

Although many studies on the immune response following burn injuries have been reported, more attention has been given to the immunosuppression mechanism and mediators that shape the process of immune suppression. Specifically, information is not available concerning the immunomodulatory effects of the drugs which are involved in the immune response restoration. In this study, we investigated the effects of Cimetidine on the modulation of immune response in patients with burn injury of 20–60%. Two groups of patients were involved in this study; the patients in one group were treated with 15 mg/kg per day of Cimetidine while the patients in the other group were treated with placebo. Peripheral blood mononuclear cell (PBMC) expressing CD3, CD4, CD8, CD19 and CD3/HLA-DR was analyzed by flow cytometry. Cell proliferation assay using H3 thymidine was performed on PBMC samples. The proliferation assay showed a significant suppression of cell proliferation rate in post-burn patients (p = 0.001). We observed a significant reduction in the lymphocyte count (p = 0.001) and frequency of CD3 (p = 0.007) and CD4 (p = 0.001) T cells in post-burn patients. Also, the frequency of CD 19 + and HLA DR + cells was increased compare to normal donors following burn injury. Treatment with Cimetidine increased the frequency of CD8 + T cells in the patient's peripheral blood. The PBMC proliferation rate was restored following the treatment with Cimetidine (p = 0.02). Our data indicates that Cimetidine may have beneficial effects on cell mediated immunity following burn injury.