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The transcription factor, t-bet, promotes inflammatory polarization and intestinal homing of many inflammatory cells. In previous studies, the t-bet and granulysin genes were upregulated in peripheral blood before and after intestine transplantation (ITx) rejection, but not during rejection, possibly because of sequestration in allograft mucosa. Mucosal sequestration of t-bet and granulysin may also explain the presence of inflammatory CD14 monocyte-derived macrophages (MDM) and immunoglobulin G B-cell lineage cells, and loss of mature non-inflammatory CD138 plasma cells in allograft mucosa during ITx rejection in these previous studies.

Nevocytes (NC) and mastocytes (MC) have different progenitors but share stem cell factor as regulator/activator of NC and for differentiation/proliferation of MC. Both cell types express stem cell factor receptor CD117. We hypothesize that large/giant congenital melanocytic nevi (L/GCMN) may associate with MC hyperplasia. Forty-nine L/GCMN were examined, 12 samples from uninvolved skin of L/GCMN patients and 6 control skin samples studied with Giemsa and immunohistochemistry for CD117 and MC-tryptase. Picrosirius red (PR) was used to assess fibrosis. Digital images were used to count MC/mm2using ImageJ software. Western blot (WB) for MC-tryptase in 12 GCMN and 12 non-nevus samples was performed. Analysis of variance (Tukey) and Pearson statistical tests were applied. Increased MCs were observed in nevus tissue (75.1 ± 35.3 MCs/mm2) and in uninvolved skin (53.74 ± 27.7 MC/ mm2). P= 0.109 from patients with L/GCMN, compared with controls from individuals without L/GCMN (28.74 ± 8.4 MC/mm2); P= 0.001 supported by results of WB analysis for tryptase. A positive trend toward correlation of MC numbers with fibrosis, assessed by PR staining fell short of statistical significance (r= 0.245; P= 0.086); no difference in fibrosis was found between nevus and non-nevus skin from patients with L/GCMN (P= 0.136). We found a higher density of MC, both in normal-appearing skin and nevus areas of L/GCMN patients, compared with control skin samples from individuals without nevi. Given the abnormal wound healing and allergic reactions described in L/GCMN patients, these findings suggest a potential role for MC in the biology of L/GCMN, making them a potential target for therapeutic intervention.

Tufting enteropathy (TE) is an uncommon disease causing intractable diarrheas starting in early childhood and resulting in failure to thrive, dependence on total parenteral nutrition, and eventually requiring transplantation for treatment. The diagnosis has been based on histology showing the presence of epithelial “tufts” in the small bowel and colonic mucosa and variable villus alterations with mild to no inflammatory changes and preserved brush border. The gene for TE has been identified to be the EpCAMgene on chromosome 2p21. With Institutional Review Board approval, all cases of intractable diarrhea in children in whom TE was suspected or diagnosed were retrieved from the pathology files (17 patients). Other cases of infantile, neonatal, and childhood diarrhea were also retrieved to serve as controls for the staining studies (total 37 patients). EpCAMMOC31 antibody staining was performed on all cases. The study cohort comprised 17 patients (13 boys, 4 girls) with a diagnosis of TE ranging in age at diagnosis from 3 months to 9 years, all presenting with protracted diarrhea andor failure to thrive, usually since birth. Staining with MOC31 was carried out in all but 2 patients (both consults) and was completely negative in the epithelium irrespective of the site of biopsy or resection. In contrast, MOC31 was positive in all other cases tested, giving a sensitivity and specificity of 100 for loss of staining. MOC31 is a diagnostic stain for TE and should be included in the panel in any case of prolonged diarrhea in children to exclude this possibility.

Intestinal allograft mucosa undergoes repopulation with host immunocytes. However, critical changes within key immunocyte subsets are not known.

Recurrent rejection shortens graft survival after intestinal transplantation (ITx) in children, most of whom also experience early acute cellular rejection (rejectors). To elucidate mechanisms common to early and recurrent rejection, we used a test cohort of 20 recipients to test the hypothesis that candidate peripheral blood leukocyte genes that trigger rejection episodes would be evident late after ITx during quiescent periods in genome-wide gene expression analysis and would achieve quantitative real-time PCR replication pre-ITx (another quiescent period) and in the early post-ITx period during first rejection episodes. Eight genes were significantly up-regulated among rejectors in the late post-ITx and pre-ITx periods, compared with nonrejectors: TBX21, CCL5, GNLY, SLAMF7, TGFBR3, NKG7, SYNE1, and GK5. Only CCL5was also up-regulated in the early post-ITx period. Among resting peripheral blood leukocyte subsets in randomly sampled nonrejectors, CD14+monocytes expressed the CCL5 protein maximally. Compared with nonrejectors, rejectors demonstrated higher counts of both circulating CCL5+CD14+monocytes and intragraft CD14+monocyte-derived macrophages in immunohistochemistry of postperfusion and early post-ITx biopsies from the test and an independent replication cohort. Donor-specific alloreactivity measured with CD154+T-cytotoxic memory cells correlated with the CCL5gene and intragraft CD14+monocyte-derived macrophages at graft reperfusion and early post-ITx. CCL5gene up-regulation and CD14+macrophages likely prime cellular ITx rejection. Infiltration of reperfused intestine allografts with CD14+macrophages may predict rejection events.