Correlation between the duration of life support and the emergence of a diffuse inflammatory infiltrate in human donor pancreas

Purpose:This study assesses the correlation between the duration of life support and the presence of an inflammatory infiltrate in human donor pancreas. It extends our previous observations (In’t Veld et al., 2010) and studies the phenotype of the infiltrating cells using markers for the different leukocyte subtypes, the time course and the quantity of the infiltrating cells using an automated image analysis approach. Methods:Pancreas biopsy specimens from non-diabetic organ donors with different durations of life support (0, 3, 6, 9 and ≥12 days) were used (n=10 per time point). Sections were stained for CD45, CD8 and CD68 and digitally imaged using a Pathway 435 inverted fluorescence microscope. AttoVision™ imaging software was used for segmentation of individual nuclei on basis of DAPI positivity and nuclear size. Cytoplasm of CD45+, CD8+ and CD68+ cells was defined as a ROI of 3 pixels around the nucleus. With this method, an estimated average of 200,000 cells per patient was counted. Summary of Results:Donor pancreas from patients with a short duration of life support (0-3 days) showed low levels of infiltrating CD45+, CD8+ and CD68+ cells. Infiltration levels strongly increased from 6 - ≥12 days of life support onwards: CD68+ cells were found to increase 10-fold between day 0 and day 6 (p<0.01), remaining at this level at day 9 and ≥12, with up to 9% of total cells found to be CD68+ in some donors. CD8+ and CD45+ cells were less markedly increased, with a significant (p<0.05) 2-fold increase for CD8+ and a significant (p<0.01) 5-fold change for CD45+ between day 0 and day 9.Conclusions:These results show that increased duration of life support is associated with increased leukocytic infiltration in the human donor pancreas. Clinical conditions surrounding organ retrieval are therefore an important parameter that may determine the immunological characteristics of the donor material. They should be taken into account when assessing pancreatic inflammatory lesions including insulitis.