Chronic Antibody Mediated Rejection of Renal Allografts: Pathological, Serological and Immunologic Features in Nonhuman Primates

The pathogenesis of late renal allograft loss is heterogeneous and difficult to diagnose. We have analyzed renal allografts in nonhuman primates to determine the relationship between alloantibodies and the graft pathology of late graft loss. Seventeen Cynomolgus monkeys were chosen from among those on several protocols for renal allotransplantation with mixed chimerism induction so that animals with and without alloantibodies were included. All animals received transient CD154 blockade and short-term cyclosporine treatment until day 28. Serial blood samples were tested for alloantibodies. Protocol biopsies and autopsy kidneys were scored for pathology and C4d deposition. Group 1, defined by complete lack of C4d deposition (24 tissue samples; 8 recipients), had no detectable alloantibodies (33 serum samples; 1-7 samples per recipient) and no evidence of chronic rejection. Three survived greater than 2 years with normal function and histology. Group 2, defined as having C4d deposition in peritubular capillaries, all made alloantibodies (100%), and most grafts later showed chronic allograft glomerulopathy (89%), and/or arteriopathy (89%). All grafts in Group 2 failed (3-27 months). Pathologic lesions of typical of chronic rejection in humans develop in monkeys, correlate with antecedent alloantibodies/C4d deposition and predict chronic rejection rather than durable accommodation.     

Stomatin‐like protein 2 overexpression in papillary thyroid carcinoma is significantly associated with high‐risk clinicopathological parameters and BRAFV600E mutation

Stomatin‐like protein 2 (SLP‐2), a member of the stomatin protein family, has emerged as a potential molecular hallmark of tumor progression in several human malignancies. The aim of this study was to analyze SLP‐2 expression pattern in benign and malignant thyroid tumors (n = 210) and to examine its relationship with clinicopathological parameters and BRAFV600E mutation in thyroid cancer. SLP‐2 immunohistochemical expression was not detected in benign adenomas and was absent/weak in follicular and anaplastic carcinomas. High expression levels of SLP‐2, found only in papillary thyroid carcinoma (PTC), particularly in the classical variant, were significantly associated with adverse clinicopathological parameters: lymph node metastasis (p = 0.002), extrathyroid invasion (p < 0.001), pT status (p < 0.001), and advanced tumor stage (p = 0.001). Additional genotyping of PTC cases for the BRAFV600E mutation revealed for the first time a close relation between SLP‐2 overexpression and the presence of BRAF mutation (p = 0.02) with high positive rates of lymph node metastasis (70%) and extrathyroid invasion (80%) in these cases. The significant association of SLP‐2 overexpression with unfavorable clinicopathological characteristics and BRAFV600E mutation indicates that SLP‐2 may have a role in aggressiveness of BRAF‐mutated PTC and that SLP‐2 evaluation could be clinically useful in identification of high‐risk PTC patients.     

Pilot Study Evaluating Regulatory T Cell–Promoting Immunosuppression and Nonimmunogenic Donor Antigen Delivery in a Nonhuman Primate Islet Allotransplantation Model

The full potential of islet transplantation will only be realized through the development of tolerogenic regimens that obviate the need for maintenance immunosuppression. Here, we report an immunotherapy regimen that combines 1‐ethyl‐3‐(3′‐dimethylaminopropyl)‐carbodiimide (ECDI)‐treated donor lymphoid cell infusion (ECDI‐DLI) with thymoglobulin, anti‐interleukin‐6 receptor antibody and rapamycin to achieve prolonged allogeneic islet graft survival in a nonhuman primate (NHP) model. Prolonged graft survival is associated with Treg expansion, donor‐specific T cell hyporesponsiveness and a transient absence of donor‐specific alloantibody production during the period of graft survival. This regimen shows promise for clinical translation.     

Survivin gene promoter polymorphism -31G/C as a risk factor for keratocystic odontogenic tumor development

Several single nucleotide polymorphisms in survivin gene promoters, notably -31G/C, have been shown to modulate the expression and activity of the survivin protein. Consequently, the -31G/C polymorphism has been identified as a risk factor for the development of several types of tumors. The aim of this study was to investigate a possible association between the -31G/C polymorphism and the risk for keratocystic odontogenic tumor (KCOT) development. DNA from 52 biopsy specimens of KCOTs and from 82 buccal swabs of healthy individuals was subjected to PCR restriction fragment length polymorphism analysis to identify individual genotypes. The distribution of genotypes in KCOT and control groups, respectively, was: GG: 30 (57.7%) vs. 26 (31.7%); CG: 17 (32.7%) vs. 45 (54.9%); and CC: 5 (9.6%) vs. 11 (13.4%), respectively. These differences were statistically significant. The G allele was more common in the KCOT group than in the control group: 76 (74%) vs. 96 (59%), respectively. Logistic regression analysis showed that GC heterozygotes had a considerably decreased susceptibility for KCOTs compared with GG homozygotes. The same was true for GC+CC vs. GG. The GG genotype of the -31G/C polymorphism might be a risk factor for KCOT development.     

Dyspepsia in Montenegrin chronic kidney disease patients undergoing hemodialysis: endoscopic and histopathological features

Purpose

The main purpose of this study was to analyze the characteristics of dyspepsia and contributing factors in Montenegrin maintenance hemodialysis patients.

Methods

The study included 43 patients undergoing hemodialysis with symptoms of dyspepsia and 40 control dyspeptic subjects with preserved kidney function. All subjects underwent an interview about dyspeptic symptoms, physical and biochemical examination, and upper gastrointestinal endoscopy with pathohistological analysis of biopsy specimens.

Results

Early satiety, bloating and heartburn were the most common symptoms in hemodialysis patients but without significant difference in frequency in relation to controls. Chronic kidney disease patients had statistically lower concentration of total proteins and albumin (p?<?0.001), as well lower BMI values (p?=?0.002). Despite this, no significant correlation of laboratory parameters with dyspeptic symptoms was found. Pathohistological examination indicated that the most common finding in hemodialysis patients was chronic active gastritis (58%), while chronic atrophic gastritis was significantly more common in dialytic patients (p?=?0.032). Patients on hemodialysis had more frequently atrophy of corpus mucosa, which was positively related to dialysis duration (p?=?0.001) and negatively related to pH values (p?=?0.004) and bicarbonate concentration (p?=?0.049). Helicobacter pylori was considerably more common in patients who underwent shorter time on hemodialysis (p?<?0.001) and had higher values of bicarbonate (p?=?0.037).

Conclusion

Maintenance hemodialysis patients are at risk for chronic gastric diseases that correlated with both dialysis vintage and duration.

     

Effect of mixed hematopoietic chimerism on cardiac allograft survival in cynomolgus monkeys

BACKGROUND: We have previously reported the successful induction of mixed chimerism and long-term acceptance of renal allografts in MHC-mismatched nonhuman primates after nonmyeloablative conditioning and donor bone marrow transplantation. In this study, we extended our regimen to cardiac allotransplantation and compared the immunological responses of heart and kidney allograft recipients. METHODS: Five cynomolgus monkeys were conditioned with low-dose total body irradiation (1.5 Gy on days -6 and -5), supplemental thymic irradiation (7 Gy on day -1), antithymocyte globulin (50 mg/kg on days -2, -1, and 0), splenectomy (day 0), donor bone marrow transplantation (day 0), and a 4-week posttransplant course of cyclosporine. Heart allografts from MHC-mismatched donors were transplanted heterotopically on day 0. RESULTS: Two monkeys failed to develop multilineage chimerism and rejected their allografts soon after cyclosporine was stopped (postoperative days [PODs] 43 and 56). Three monkeys developed multilineage chimerism, which persisted 20 to 43 days posttransplant by flow cytometric analysis and to POD 124 by polymerase chain reaction analysis. Allograft survival in these recipients was prolonged to 138, 428, and 509 days, and in vitro mixed leukocyte reaction and cell-mediated lympholysis (CML) assays demonstrated donor-specific hyporesponsiveness. However, in contrast to kidney allograft recipients, long-term heart allograft recipients eventually developed humoral and cellular immunity against the donor and rejected the grafts. At the time of rejection, 1.3% to 9.5% of donor coronary arteries exhibited intimal proliferation. CONCLUSIONS: The induction of transient mixed hematopoietic chimerism leads to long-term heart allograft survival in MHC disparate monkeys without chronic immunosuppression. However, unlike kidney allografts, full tolerance to cardiac allografts was not achieved. Organ-specific modifications of the preparative regimen may be necessary to prevent the chronic cellular and humoral immune responses elicited by cardiac allografts.     

Four Stages and Lack of Stable Accommodation in Chronic Alloantibody-Mediated Renal Allograft Rejection in Cynomolgus Monkeys

The etiology of immunologically mediated chronic renal allograft failure is unclear. One cause is thought to be alloantibodies. Previously in Cynomolgus monkeys, we observed a relationship among donor-specific alloantibodies (DSA), C4d staining, allograft glomerulopathy, allograft arteriopathy and progressive renal failure. To define the natural history of chronic antibody-mediated rejection and its effect on renal allograft survival, we now extend this report to include 417 specimens from 143 Cynomolgus monkeys with renal allografts. A subset of animals with long-term renal allografts made DSA (48%), were C4d positive (29%), developed transplant glomerulopathy (TG) (22%) and chronic allograft arteriopathy (CAA) (19%). These four features were highly correlated and associated with statistically significant shortened allograft survival. Acute cellular rejection, either Banff type 1 or 2, did not correlate with alloantibodies, C4d deposition or TG. However, endarteritis (Banff type 2) correlated with later CAA. Sequential analysis identified four progressive stages of chronic antibody-mediated rejection: (1) DSA, (2) deposition of C4d, (3) TG and (4) rising creatinine/renal failure. These new findings provide strong evidence that chronic antibody-mediated rejection develops without enduring stable accommodation, progresses through four defined clinical pathological stages and shortens renal allograft survival.