Increased expression of peripheral blood leukocyte genes implicate CD14+ tissue macrophages in cellular intestine allograft rejection

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 CCL5 was 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 CCL5 gene and intragraft CD14(+) monocyte-derived macrophages at graft reperfusion and early post-ITx. CCL5 gene up-regulation and CD14(+) macrophages likely prime cellular ITx rejection. Infiltration of reperfused intestine allografts with CD14(+) macrophages may predict rejection events.     

Purification and characterization of approximately 35 kDa antioxidant protein from curry leaves (Murraya koenigii L.).

Curry leaves (Murraya koenigii L. Spreng, Rutaceae) is an herbal species used in traditional medicine in eastern Asia. In this study, the antioxidant protein was purified by homogenization of curry leaves powder in Tris buffer, 65% ammonium sulphate precipitation and gel filtration on Sephadex G-75 column which resulted in three peaks (PI, PII and PIII). PII protein inhibited lipid peroxidation in human RBC ghost at 100 microg by 80%, whereas PI and PIII at 600 microg showed moderate antioxidant activity (40-50%). Homogeneity of PII was confirmed by rechromatographing on Sephadex G-75 and reverse phase HPLC. The antioxidant protein (PII) from curry leaves (APC) showed apparent molecular weight of 35 kDa by SDS-PAGE and MALDI/MS analysis. The protein nature of APC was established by the presence of amino acids and loss of antioxidant activity on heat and protease treatment. The APC at 0.8 microM inhibited lipoxygenase activity by 71%, effectively prevented diene, triene and tetraene lipids formation at 3 microM, and scavenged about 85% hydroxyl and DPPH radicals at 150-fold lesser concentration compared to BHA and alpha-tocopherol (400 microM). In addition, APC reduced cytochrome c and ferric ion, chelated ferrous ion, and inhibited ferrous sulfate: ascorbate-induced fragmentation and sugar oxidation to 80-90%. Thus, the present study demonstrates the in vitro characterization of antioxidant protein from the curry leaves (M. koenigii L.).     

CD154‐expressing CMV‐specific T cells associate with freedom from DNAemia and may be protective in seronegative recipients after liver or intestine transplantation

Cell‐mediated immunity to CMV, if known, could improve antiviral drug therapy in at‐risk children and young adults with LT and IT. Host immunity has been measured with CMV‐specific T cells, which express IFNγ, but not those which express CD154, a possible substitute for IFNγ. CMV‐specific CD154+ T cells and their subsets were measured with flow cytometry after stimulating PBL from recipient blood samples with an overlapping peptide mix of CMV‐pp65 antigen for up to 6 hours. CMV‐specific CD154+ T cells co‐expressed IFNγ in PBL from three healthy adults and averaged 3.8% (95% CI 3.2%‐4.4%) in 40 healthy adults. CMV‐specific T cells were significantly lower in 19 CMV DNAemic LT or IT recipients, compared with 126 non‐DNAemic recipients, 1.3% (95% CI 0.8‐1.7) vs 4.1 (95% CI 3.6‐4.6, P < .001). All T‐cell subsets demonstrated similar between‐group differences. In logistic regression analysis of 46 training set samples, 12 with DNAemia, all obtained between days 0 and 60 from transplant, CMV‐specific T‐cell frequencies ≥1.7% predicted freedom from DNAemia with NPV of 93%. Sensitivity, specificity, and PPV were 83%, 74%, and 53%, respectively. Test performance was replicated in 99 validation samples. In 32 of 46 training set samples, all from seronegative recipients, one of 19 recipients with CMV‐specific T‐cell frequencies ≥1.7% experienced DNAemia, compared with 8 of 13 recipients with frequencies <1.7% (P = .001). CMV‐specific CD154+ T cells are associated with freedom from DNAemia after LT and IT. Among seronegative recipients, CMV‐specific T cells may protect against the development of CMV DNAemia.     

Allospecific CD154 + T-cytotoxic memory cells as potential surrogate for rejection risk in pediatric intestine transplantation

Sindhi R, Ashokkumar C, Higgs BW, Gilbert PB, Sun Q, Ranganathan S, Jaffe R, Snyder S, Ningappa M, Soltys KA, Bond GJ, Mazariegos GV, Abu‐Elmagd K, Zeevi A. Allospecific CD154 + T‐cytotoxic memory cells as potential surrogate for rejection risk in pediatric intestine transplantation.
Pediatr Transplantation 2012: 16: 83–91. © 2011 John Wiley & Sons A/S. Abstract: Clinical end‐points dictate large trial enrollments and exclude children with the rare intestine transplant procedure (ITx), who experience higher drug‐related morbidity. We evaluate the novel rejection‐risk parameter, allo‐(antigen)‐specific CD154 + TcMs (i) as surrogates for ACR using Prentice’s criteria, (ii) for association with immunosuppression targets to determine Fleming’s surrogate end‐point designation, and (iii) as time‐to‐event end‐point in a simulated comparison of alemtuzumab (NCT#01208337, n = 14) and rabbit anti‐human thymocyte globulin (rATG, n = 16) among 30 children with ITx. CD154 + TcM were measured in MLR before, and at 1–60 and 61–200 days after ITx (NCT#01163578). CD154 + TcM correlate significantly with rejection severity (Spearman r = 0.685, p = 2.03E?5) and associate with biopsy‐proven ITx rejection with sensitivity/specificity of 90%/84% independent of immunosuppressant. The rejection‐risk threshold of CD154 + TcM resolves rapidly in 200‐day follow‐up (46 ± 20 vs. 158 ± 59 days, p = 0.009, K–M) with alemtuzumab, which demonstrates lower 90‐day ACR incidence (50% vs. 69%, p=NS, Fisher’s exact), and is associated with accelerated prednisone minimization to ≤2.5 mg/day, compared with rATG (120 ± 28 vs. 180 ± 30 days, p = 0.027, K–M). As a surrogate end‐point, time‐to‐rejection‐risk resolution measured with CD154 + TcM portends 50% reduction in sample sizes in a simulated trial of alemtuzumab vs. rATG. Rejection‐risk assessment with CD154 + TcM may enable informed immunosuppression minimization, and preliminary efficacy comparisons in pediatric ITx.