Detection Of Acute Cellular Rejection Research Articles

Valor crítico da citrulina para as complicações do enxerto no transplante de intestino

A biochemical marker for detection of acute cellular rejection following small intestine transplantation has been sought. Citrulline, a non- protein amino acid synthesized mainly by functioning enterocytes, has been proposed. Trial sensitivity has been reportedly high but with low specificity. Thus, the goal was to determine, in a sufficiently large analysis, the significant value of citrulline level in the post-transplant setting, which would correlate with complications such as rejection and infection. Since March, 2004 2,135 dried blood spot (DBS) citrulline samples were obtained from 57 small intestine transplant recipients three months or more after post-transplant, i.e., once the expected period of recovery in the citrulline levels had occurred. Using a <13 vs. > 13 micromoles/L cut off point, sensitivity of DBS citrulline for the detection of moderate or severe ACR was extremely high (96.4%). Furthermore, specificity estimates (given the absence of ACR and these particular infections), while controlling for time-to-DBS sample were reasonably high (54%-74% in children and 83%-88% in adults), and the negative predictive value (NPV) was >99%. Citrulline is a non-invasive marker to evaluate problems of the intestinal graft after three months post-transplant. Due to the high NPV, a moderate or severe ACR can be ruled out, based exclusively on knowledge of a high value for DBS citrulline.

Over-Expression of AIF-1 in Liver Allografts and Peripheral Blood Correlates with Acute Rejection after Transplantation in Rats

Early and accurate detection of acute cellular rejection (ACR) is important in the management of liver allograft recipients. We hypothesized that expression of allograft inflammatory factor (AIF)-1 would be associated with liver allograft rejection as previous studies have shown that a relationship exists between kidney and heart transplantation. Indeed using rat orthotopic transplant models we found that the expression of allograft inflammatory factor-1 (AIF-1) can be detected in both allograft and peripheral blood leukocytes with peak levels detected 7 days following liver transplantation. Interestingly, AIF-1 expression increased 2-fold in acutely rejecting liver allografts compared to chronically accepted livers on days 5, 7 and 10 after transplantation. AIF-1 expression in peripheral blood leukocytes was also significantly greater in the rejection model than in the acceptance model. Flow cytometric analysis of peripheral blood leukocytes demonstrated that AIF-1 was expressed in ED2-positive cells, a marker for Kupffer cells. In vitro studies showed that AIF-1 expression in Kupffer cells was up-regulated by coculture with Th1 cytokines. However, neither LPS nor Escherichia coli (E. coli) administration had an affect on AIF-1 expression. These data indicate that high levels of AIF-1 expression reflect aggressive liver allograft rejection and suggest a role for monitoring AIF-1 in peripheral blood leukocytes as a monitor for increased immunosuppression.