Search

BACKGROUND The expression levels of several chemokine genes in heart allografts correlate with histologic rejection grade. Potential molecular differences between early and late rejection (grade > or =2) episodes were examined by testing chemokine and receptor-gene expression. METHODS Expression of inducible protein (IP)-10, monokine induced by IFN-gamma (Mig), interferon inducible-T cell alpha chemoattractant (I-TAC), regulated on activation normal T-cell expressed and secreted(RANTES), and their receptors CXCR3 and CCR5 was tested in 60 endomyocardial biopsies from 24 patients using quantitative (Taqman) real-time polymerase chain reaction (PCR). The biopsies were taken in the first 3 months or from the 9th to the 12th month following transplantation. RESULTS IP-10, Mig, RANTES, CXCR3, and CCR5 expression levels were increased in the later versus earlier biopsies (P< or =0.01) despite no change in histologic rejection-grade status. CONCLUSION These results demonstrate significantly increased expression of T-cell chemoattractants in heart allografts during later rejection when compared with episodes occurring shortly after transplantation. The findings suggest increased intensity of inflammation in rejection occurring at later times posttransplant that are revealed by molecular analyses of the graft.

Background. Factors directing T-cell infiltration into allografts during acute rejection remain poorly defined. Chemokines have been shown to mediate leukocyte recruitment into allografts in animal models of rejection. The goal of this study was to test the presence and levels of chemokine and receptor gene expression in serial endomyocardial biopsy specimens from heart transplant patients and to correlate the levels observed with histopathologic rejection grade. Methods. Three hundred sixteen serial endomyocardial biopsy specimens from 30 heart transplant patients were obtained during the clinically scheduled surveillance heart biopsy program. The follow-up period was 1 year. The expression of interferon (IFN)-γ inducible protein (IP)-10, monokine induced by IFN-γ (Mig), interferon-inducible T-cell alpha chemoattractant (I-TAC), regulated on activation normal T-cell expressed and secreted (RANTES), monocyte chemotactic protein (MCP)-1, interleukin (IL)-8, and the receptors CXCR3 and CCR5 were tested using quantitative, real-time polymerase chain reaction. Biopsy samples were examined histologically to assign rejection grade. Results. Expression of IP-10, Mig, I-TAC, RANTES, CXCR3, and CCR5, but not MCP-1 and IL-8, increased significantly in both grade 2 and grade 3 rejection (P ≤0.0096). These increases returned to normal after treatment with pulse steroid therapy to treat the rejection episode. Conclusion. The expression of IP-10, Mig, I-TAC, RANTES, CXCR3, and CCR5 in cardiac allografts significantly correlates with the presence and grade of acute rejection.

Chemokines have been shown to play a critical role in the recruitment of leukocytes to transplanted organs. Animal models and clinical studies have demonstrated predictable temporal and spatial correlations between chemokine production and leukocyte infiltration into allografts. Antagonism of chemokines or chemokine receptors has been shown to delay leukocyte infiltration and prolong graft function, demonstrating an important role for chemokines in allograft rejection.

Background Ischemia/reperfusion injury is an inherent consequence of solid organ transplantation that increases tissue inflammation and negatively impacts organ transplant function and survival. This study investigated the expression levels of chemokine and chemokine receptor genes in living versus cadaver donor renal allografts before and after reperfusion. Methods This study involved 39 renal transplant patients (19 cadaveric and 20 living donor). The ischemia biopsy was taken just before graft declamping and the reperfusion biopsy 30 min after declamping. Whole-cell RNA was isolated and chemokine (IL-8, CCL2/MCP-1, CXCL10/IP-10 and CCL5/RANTES) and chemokine receptor (CCR2 and CCR5) expression was tested by quantitative PCR. Results Just prior to declamping, ischemic cadaveric donor grafts had higher expression of CXCL10/IP-10 but not IL-8 or CCL2/MCP-1 than living donor grafts. IL-8 expression increased 50% from ischemia to reperfusion in living donor grafts but increased more than 13-fold during reperfusion of cadaver donor grafts. Increased total ischemia time induced greater IL-8 expression during reperfusion. MCP-1 expression also increased during reperfusion of living and cadaver donor grafts but differences were not observed between the two groups of grafts. RANTES, CCR2, and CCR5 expression did not change in ischemic vs. reperfusion biopsies. Conclusions The expression of chemokines directing neutrophil and macrophage recruitment increases during reperfusion of living and cadaveric donor renal allografts. Expression levels of IL-8 correlate with the ischemic time imposed on the renal graft. Early tissue injury may be attenuated by strategies antagonizing chemokines directing the recruitment of neutrophils and macrophages into kidney grafts.