The anti-CD40L monoclonal antibody AT-1501 promotes islet and kidney allograft survival and function in nonhuman primates.

Prior studies of anti-CD40 ligand (CD40L)-based immunosuppression demonstrated effective prevention of islet and kidney allograft rejection in nonhuman primate models; however, clinical development was halted because of thromboembolic complications. An anti-CD40L-specific monoclonal antibody, AT-1501 (Tegoprubart), was engineered to minimize risk of thromboembolic complications by reducing binding to Fcγ receptors expressed on platelets while preserving binding to CD40L. AT-1501 was tested in both a cynomolgus macaque model of intrahepatic islet allotransplantation and a rhesus macaque model of kidney allotransplantation. AT-1501 monotherapy led to long-term graft survival in both islet and kidney transplant models, confirming its immunosuppressive potential. Furthermore, AT-1501-based regimens after islet transplant resulted in higher C-peptide, greater appetite leading to weight gain, and reduced occurrence of cytomegalovirus reactivation compared with conventional immunosuppression. These data support AT-1501 as a safe and effective agent to promote both islet and kidney allograft survival and function in nonhuman primate models, warranting further testing in clinical trials.

Differential effect of allogeneic versus syngeneic mesenchymal stem cell transplantation in MRL/lpr and (NZB/NZW)F1 mice.

MSC are being explored as a promising novel treatment for SLE. In this study, we: 1) assessed the differential effects of allogeneic versus syngeneic MSC transplantation on lupus-like disease, 2) explored the mechanisms by which MSC modulate disease, and 3) investigated whether lupus-derived-MSC have intrinsic immunomodulatory defects. We showed that in MRL/lpr mice and (NZB/NZW)F1 mice, both B6-MSC and lupus-MSC from young mice ameliorated SLE-like disease and reduced splenic CD3+CD4+ T lymphocytes and CD19+CD21+ B lymphocytes. However, lupus-MSC from older (NZB/NZW)F1 mice did not reduce spleen weights, glomerular IgG deposits, renal pathology, interstitial inflammation, CD3+CD4+ T lymphocytes or CD19+CD21+ B lymphocytes significantly. Thus MSC transplantation ameliorates SLE-like disease partly through decreasing CD4+ T cell and naïve mature B cell numbers. Allogeneic MSC may be preferred over syngeneic lupus-derived-MSC given the decreased overall effectiveness of post-lupus-derived-MSC, which appears partially due to disease and not exclusively intrinsic defects in the MSC themselves.

CTGF disrupts alveolarization and induces pulmonary hypertension in neonatal mice: implication in the pathogenesis of severe bronchopulmonary dysplasia.

The pathological hallmarks of bronchopulmonary dysplasia (BPD), one of the most common long-term pulmonary complications associated with preterm birth, include arrested alveolarization, abnormal vascular growth, and variable interstitial fibrosis. Severe BPD is often complicated by pulmonary hypertension characterized by excessive pulmonary vascular remodeling and right ventricular hypertrophy that significantly contributes to the mortality and morbidity of these infants. Connective tissue growth factor (CTGF) is a multifunctional protein that coordinates complex biological processes during tissue development and remodeling. We have previously shown that conditional overexpression of CTGF in airway epithelium under the control of the Clara cell secretory protein promoter results in BPD-like architecture in neonatal mice. In this study, we have generated a doxycycline-inducible double transgenic mouse model with overexpression of CTGF in alveolar type II epithelial (AT II) cells under the control of the surfactant protein C promoter. Overexpression of CTGF in neonatal mice caused dramatic macrophage and neutrophil infiltration in alveolar air spaces and perivascular regions. Overexpression of CTGF also significantly decreased alveolarization and vascular development. Furthermore, overexpression of CTGF induced pulmonary vascular remodeling and pulmonary hypertension. Most importantly, we have also demonstrated that these pathological changes are associated with activation of integrin-linked kinase (ILK)/glucose synthesis kinase-3ß (GSK-3ß)/ß-catenin signaling. These data indicate that overexpression of CTGF in AT II cells results in lung pathology similar to those observed in infants with severe BPD and that ILK/GSK-3ß/ß-catenin signaling may play an important role in the pathogenesis of severe BPD.

A How-to Guide to Building a Robust SARS-CoV-2 Testing Program at a University-Based Health System.

When South Florida became a hot spot for COVID-19 disease in March 2020, we faced an urgent need to develop test capability to detect SARS-CoV-2 infection. We assembled a transdisciplinary team of knowledgeable and dedicated physicians, scientists, technologists, and administrators who rapidly built a multiplatform, polymerase chain reaction- and serology-based detection program, established drive-through facilities, and drafted and implemented guidelines that enabled efficient testing of our patients and employees. This process was extremely complex, due to the limited availability of needed reagents, but outreach to our research scientists and multiple diagnostic laboratory companies, and government officials enabled us to implement both Food and Drug Administration authorized and laboratory-developed testing-based testing protocols. We analyzed our workforce needs and created teams of appropriately skilled and certified workers to safely process patient samples and conduct SARS-CoV-2 testing and contact tracing. We initiated smart test ordering, interfaced all testing platforms with our electronic medical record, and went from zero testing capacity to testing hundreds of health care workers and patients daily, within 3 weeks. We believe our experience can inform the efforts of others when faced with a crisis situation.

Identification of glomerular and podocyte-specific genes and pathways activated by sera of patients with focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) accounts for about 40% of all nephrotic syndrome cases in adults. The presence of several potential circulating factors has been suggested in patients with primary FSGS and particularly in patients with recurrent disease after transplant. Irrespectively of the nature of the circulating factors, this study was aimed at identifying early glomerular/podocyte-specific pathways that are activated by the sera of patients affected by FSGS. Kidney biopsies were obtained from patients undergoing kidney transplantation due to primary FSGS. Donor kidneys were biopsied pre-reperfusion (PreR) and a subset 1-2 hours after reperfusion of the kidney (PostR). Thirty-one post reperfusion (PostR) and 36 PreR biopsy samples were analyzed by microarray and gene enrichment KEGG pathway analysis. Data were compared to those obtained from patients with incident primary FSGS enrolled in other cohorts as well as with another cohort to correct for pathways activated by ischemia reperfusion. Using an ex-vivo cell-based assay in which human podocytes were cultured in the presence of sera from patients with recurrent and non recurrent FSGS, the molecular signature of podocytes exposed to sera from patients with REC was compared to the one established from patients with NON REC. We demonstrate that inflammatory pathways, including the TNF pathway, are primarily activated immediately after exposure to the sera of patients with primary FSGS, while phagocytotic pathways are activated when proteinuria becomes clinically evident. The TNF pathway activation by one or more circulating factors present in the sera of patients with FSGS supports prior experimental findings from our group demonstrating a causative role of local TNF in podocyte injury in FSGS. Correlation analysis with clinical and histological parameters of disease was performed and further supported a possible role for TNF pathway activation in FSGS. Additionally, we identified a unique set of genes that is specifically activated in podocytes when cultured in the presence of serum of patients with REC FSGS. This clinical translational study supports our prior experimental findings describing a potential role of the TNF pathway in the pathogenesis of FSGS. Validation of these findings in larger cohorts may lay the ground for the implementation of integrated system biology approaches to risk stratify patients affected by FSGS and to identify novel pathways relevant to podocyte injury.

Fecal calprotectin level measurements in small bowel allograft monitoring: a pilot study.

BACKGROUND: Protocol endoscopy with biopsy is currently the gold standard of small bowel transplantation (SBTx) monitoring, however it is invasive, costly, needs skilled operator, may require anesthesia and may cause complications. We investigated fecal calprotectin level (FCL) as a candidate noninvasive marker for monitoring patients after SBTx. METHODS: A pilot study was performed to test the use of FCL measurement in following up SBTx patients. Ileostomy effluents were collected at various postoperative days before endoscopy and biopsy. FCLs were measured by enzyme-linked immunosorbent assay and a cut-off level of 100 ng/mg was considered positive. The results were retrospectively evaluated in combination with clinical, endoscopic, and histopathological findings. FCLs are presented as median nanogram per milligram. RESULTS: FCLs were measured in 122 samples that were obtained from 29 patients after SBTx. Only 1 of 69 positive FCL did not accompany abnormal findings. Retrospective evaluation showed that 11 samples from six patients (FCL: 217) coincided with rejection episodes, six samples from three patients (FCL: 125) coincided with viral enteritis, 51 samples from 21 patients (FCL: 207) coincided with nonspecific inflammation, 11 samples from two patients (FCL: 998) coincided with chronic intestinal ulceration, and finally 50 samples from 19 patients (FCL: 43) coincided with normal findings. No significant FCL difference was found between rejection, infection, and inflammation. FCL evolution in individuals showed that FCL can predict rejection days before histopathological diagnosis. CONCLUSION: FCL is a sensitive test for ongoing organic intestinal allograft pathologies. It might be useful as prescreening marker to avoid unnecessary endoscopies.

Inducible nitric oxide synthase inhibitor SD-3651 reduces proteinuria in MRL/lpr mice deficient in the NOS2 gene.

Several studies have demonstrated the effectiveness of arginine analog nitric oxide synthase (NOS) inhibitor therapy in preventing and treating murine lupus nephritis. However, MRL/MpJ-FAS (MRL/lpr) mice lacking a functional NOS2 (inducible NOS [iNOS]) gene (NOS2) develop proliferative glomerulonephritis in a fashion similar to their wild-type (wt) littermates. This finding suggests that the effect of arginine analog NOS inhibitors is through a non-iNOS-mediated mechanism. This study was designed to address this hypothesis.NOS2 mice were given either vehicle or a NOS inhibitor (SD-3651) to determine if pharmacological NOS inhibition prevented glomerulonephritis, using wt mice as positive controls. Urine was collected fortnightly to measure albumin. At the time of full disease expression in wt mice, all mice were killed, and renal tissue was examined for light, immunofluorescence, and electron microscopic evidence of disease. Serum was analyzed for anti-double-stranded DNA antibody production.NOS2 mice had higher serum anti-double-stranded DNA antibody antibody levels than those of wt mice. SD-3651 therapy reduced proteinuria, glomerular immunoglobulin G deposition, and electron microscopic evidence of podocytopathy and endothelial cell swelling without affecting proliferative lesions by light microscopy.These studies confirm that genetic iNOS deficiency alone is insufficient to prevent proliferative glomerulonephritis and suggest that iNOS activity may inhibit autoantibody production. These results also suggest that SD-3651 therapy acts via a non-iNOS-mediated mechanism to prevent endothelial cell and podocyte pathology. Studies that elucidate this mechanism could provide a useful drug target for the treatment of nephritis.

Inducible nitric oxide synthase inhibitors reduce urinary markers of systemic oxidant stress in murine proliferative lupus nephritis.

BACKGROUND: Proliferative lupus nephritis (PLN) is characterized by increased expression of inducible nitric oxide (NO) synthase (iNOS). Inhibition of iNOS with NG-monomethyl L-arginine (L-NMMA) abrogates renal disease in two models of murine PLN, but the mechanism of this effect is unknown. Reactive oxygen species have both direct and indirect pathogenic effects in inflammatory lesions and are therefore potentially an important therapeutic target in PLN. We hypothesized that inhibition of iNOS activity would reduce ROS production in murine PLN. METHODS: A dose escalation of L-NMMA (0, 20, 100, and 500 mg/kg/day) was performed in New Zealand Black x New Zealand White F1 (NZB/W) mice with active renal disease. Twenty-four-hour urine nitrate + nitrite (NOX) was measured with a chemiluminescence NO analyzer. Twenty-four-hour urine 8-isoprostane F2alpha (8-iso-PGF2alpha) was measured by gas chromatography-negative ion chemical ionization mass spectrometry. MRL-MpJFASlpr (MRL/lpr) and NZB/W mice were divided into three groups and given either L-NMMA, L-N6-iminoethyl-lysine (L-NIL), or distilled water for 2 weeks. Urine NOX and 8-iso-PGF2alpha were determined after 2 weeks. RESULTS: L-NMMA reduced both urine NOX and 8-iso-PGF2alpha levels in a dose-dependent fashion in NZB/W and MRL/lpr mice. Urine NOX and 8-iso-PGF2alpha levels were highly correlated. Both specific (L-NIL) and nonspecific (L-NMMA) iNOS inhibition reduced urine NOX and 8-iso-PGF2alpha levels in both models of murine PLN. CONCLUSION: These findings suggest that iNOS activity is a major source of reactive oxidant stress in these models of murine PLN. Future studies will address the pathogenic role of reactive oxygen stress in PLN.

Outcome of pigs with short gut syndrome submitted to orthotopic intestinal transplantation.

PURPOSE: To evaluate the current model of small bowel resection and intestinal transplantation in pigs. METHODS: Forty two Large White pigs were distributed in five groups: G1(n=6), G2(n=6) and G3(n=6) were submitted to 80%,100% and 100% plus right colon resection respectively and G4(n=7) and G5(n=5) to 100% SBR plus IT without and with immunosuppression based on Tacrolimus and Mycophenolic acid. Evaluation included weight control, clinical status, biochemical analysis and endoscopies for graft biopsies. Follow-up in G1 and 2 was 84 days, while in G3, four and five was ± three weeks. RESULTS: G1 increased weight suggesting adaptation while G2 and 3 loused weight and inadequate adaptation. G4 and 5 died of acute cellular rejection (ACR) and sepses respectively. Overall survival in G1, 2, 3, 4 and 5 at 30 days was 100, 100, 0 and 20 %, respectively. Medium survival in G4 and 5 was 14 and 16 days. CONCLUSIONS: The resection of 80% of small intestine in pigs is not suitable for short bowel syndrome induction. Intestinal transplantation with the proposed immunosuppression protocol was effective in prevent the occurrence of severe acute rejection, but inappropriate to increase recipients survival.

Successful treatment of posttransplant lymphoproliferative disease with prolonged rituximab treatment in intestinal transplant recipients.

BACKGROUND: Posttransplant Epstein-Barr virus-associated B-cell lymphoproliferative disease (PTLD) has a higher incidence after intestinal transplantation than after transplantation of other solid organs and is associated with a high mortality. A new anti-CD20 monoclonal antibody, rituximab, has shown efficiency in the treatment of B-cell lymphoma, including PTLD, but its use has not yet been reported in intestinal transplant recipients. METHODS: We retrospectively reviewed five patients who were diagnosed with PTLD from March 1999 to August 2001, after intestinal transplantation. These patients were primarily managed with rituximab, associated with reduction or interruption of immunosuppression and antiviral therapy with ganciclovir and cytomegalovirus immune globulin. Rituximab was administered at weekly doses of 375 mg/m until full remission was ascertained, and the interval between doses was then increased. No patient received chemotherapy. RESULTS: One patient had nonmalignant lymphoproliferation, and four had malignant PTLD, as assessed by histopathology and monoclonality of the tumor. Two pediatric patients had severe generalized disease. All patients had received OKT3 as treatment of rejection before developing PTLD. All tumors showed proliferation of CD20 cells and were positive for Epstein-Barr virus by in situ hybridization. All patients responded to rituximab therapy and have achieved full remission with a follow-up of 3 to 30 (median, 8) months. CONCLUSION: Prolonged rituximab treatment, in association with reduction of immunosuppression and antiviral therapy, is highly efficient as part of the first-line treatment of CD20 B-cell PTLD after intestinal transplantation.

Portal versus systemic drainage of small bowel allografts: comparative assessment of survival, function, rejection, and bacterial translocation.

BACKGROUND: Portal venous drainage of small bowel grafts is theoretically more physiologic than systemic drainage, but is technically more demanding. Comparisons in animal models have not demonstrated a clear advantage of one technique over the other, but clinical data are lacking. STUDY DESIGN: Clinical records of 36 patients who underwent 37 small bowel transplantation procedures from January 1995 to August 2001 were reviewed. Portal drainage was performed in 19 patients (PD group). Systemic drainage was performed in 18 patients (SD group). Median followup was 531 days. RESULTS: PD and SD patients had similar ICU stays (median 7 versus 9 days) and endotracheal intubation durations (median 3 versus 5 days). All current survivors, with the exception of one patient in each group, are independent from parenteral nutrition. Liver function tests were similar in both groups. There was a twofold increase in tacrolimus dosage in the PD group to achieve similar trough levels indicating a "first-pass" hepatic clearance effect. Cumulative incidence of acute rejection episodes and OKT3-requiring rejection episodes were similar in both groups. To the contrary, a lower incidence of gram-negative rods of Enterococcus sp. in blood or bronchoalveolar lavage suggested that the clearance of translocated intestinal bacteria was more efficient in the PD group. Graft and patient survival rates were similar in both groups. CONCLUSIONS: Systemic venous drainage of small bowel transplants is a dependable technique, associated with similar results as portal venous drainage, in terms of overall mortality, morbidity, rejection, function, and patient and graft survival. But attention should be paid to an impaired clearance of intestinal bacterial translocation after systemic drainage.

Evaluation of the reactive T-cell infiltrate in uveitis and intraocular lymphoma with flow cytometry of vitreous fluid (an American Ophthalmological Society thesis).

PURPOSE: To describe the reactive T-cell infiltrate in uveitis and intraocular lymphoma using flow cytometry of clinical intraocular specimens acquired during diagnostic pars plana vitrectomy. METHODS: This was a retrospective review of diagnostic vitreous specimens (1992-2011) obtained at a university-based, tertiary care center. Seventy-eight patients with uveitis or lymphoma undergoing pars plana vitrectomy were selected for intraocular testing based on clinical diagnostic uncertainty. Pars plana vitrectomy with flow cytometry, gene rearrangement studies, and cytology was performed. RESULTS: T-cell infiltrates were found in all diagnostic categories with limited power to discriminate between uveitis and T-lymphocyte reactive infiltrates in response to intraocular lymphoma. Statistically significant differences by two-sample test of means between group means were found between 35 uveitis and 35 B-cell lymphoma cases for T-cell markers CD2, 3, 4, 5, and 7, but not for CD8. The CD4:CD8 ratio had a higher mean value in the uveitis group (P=.0113), and 8 T-cell lymphomas had a statistically greater number of CD3+ lymphocytes compared to uveitis (P=.0199) by two-sample test of means. Likelihood ratios were highest for CD2, CD5, CD7, CD4:CD8 ratio, CD20, and CD22. CONCLUSIONS: Discrimination between uveitis and lymphoma based on cell identification by flow cytometry was limited because of the prevalence of T lymphocytes in all diagnostic categories, emphasizing the importance of a reactive T-cell infiltrate in B-cell lymphomas, which may impede diagnosis. Flow cytometry may allow identification of more cases of T-cell lymphoma than reported when it is combined with gene rearrangement and cytology.

Selective cyclooxygenase-2 inhibitor suppresses renal thromboxane production but not proliferative lesions in the MRL/lpr murine model of lupus nephritis.

INTRODUCTION: Proliferative lupus nephritis (LN) is marked by increased renal thromboxane (TX) A2 production. Targeting the TXA2 receptor or TXA2 synthase effectively improves renal function in humans with LN and improves glomerular pathology in murine LN. This study was designed to address the following hypotheses: (1) TXA2 production in the MRL/MpJ-Tnfrsf6(lpr)/J (MRL/lpr) model of proliferative LN is cyclooxygenase (COX)-2 dependent and (2) COX2 inhibitor therapy improves glomerular filtration rate (GFR), proteinuria, markers of innate immune response and glomerular pathology. METHODS: Twenty female MRL/lpr and 20 BALB/cJ mice were divided into 2 equal treatment groups: (1) SC-236, a moderately selective COX2 inhibitor or (2) vehicle. After treatment from the age of 10 to 20 weeks, the effectiveness of inhibition of TXA2 was determined by measuring urine TXB2. Response endpoints measured at the age of 20 weeks were renal function (GFR), proteinuria, urine nitrate + nitrite (NO(x)) and glomerular histopathology. RESULTS: SC-236 therapy reduced surrogate markers of renal TXA2 production during early, active glomerulonephritis. When this pharmacodynamic endpoint was reached, therapy improved GFR. Parallel reductions in markers of the innate immune response (urine NO(x)) during therapy were observed. However, the beneficial effect of SC-236 therapy on GFR was only transient, and renal histopathology was not improved in late disease. CONCLUSIONS: These data demonstrate that renal TXA2 production is COX2 dependent in murine LN and suggest that NO production is directly or indirectly COX2 dependent. However, COX2 inhibitor therapy in this model failed to improve renal pathology, making COX2 inhibition a less attractive approach for treating LN.

Outcome of pigs with short gut syndrome submitted to orthotopic intestinal transplantation

PURPOSE: To evaluate the current model of small bowel resection and intestinal transplantation in pigs. METHODS: Forty two Large White pigs were distributed in five groups: G1(n=6), G2(n=6) and G3(n=6) were submitted to 80%,100% and 100% plus right colon resection respectively and G4(n=7) and G5(n=5) to 100% SBR plus IT without and with immunosuppression based on Tacrolimus and Mycophenolic acid. Evaluation included weight control, clinical status, biochemical analysis and endoscopies for graft biopsies. Follow-up in G1 and 2 was 84 days, while in G3, four and five was ± three weeks. RESULTS: G1 increased weight suggesting adaptation while G2 and 3 loused weight and inadequate adaptation. G4 and 5 died of acute cellular rejection (ACR) and sepses respectively. Overall survival in G1, 2, 3, 4 and 5 at 30 days was 100, 100, 0 and 20 %, respectively. Medium survival in G4 and 5 was 14 and 16 days. CONCLUSIONS: The resection of 80% of small intestine in pigs is not suitable for short bowel syndrome induction. Intestinal transplantation with the proposed immunosuppression protocol was effective in prevent the occurrence of severe acute rejection, but inappropriate to increase recipients survival. .

Liver retransplantation of more than two grafts for recurrent failure.

BACKGROUND: Transplantation of more than two livers for recurring graft failure has not been specifically addressed in the literature. METHODS: A retrospective analysis was conducted from a total of 2527 overall liver transplants at our institution. Main indications for multiple retransplant included primary nonfunction, chronic rejection, hepatic artery thrombosis, and recurrent disease. RESULTS: We identified 39 patients who received more than two grafts (32 received 3 grafts, 5 received 4 grafts, and 2 received 5 grafts). All patients required interposition arterial grafts from the aorta and hepatojejunostomy for the biliary reconstruction. Seventeen patients are still alive at last follow-up. Perioperative mortality rates after 3rd, 4th, and 5th liver graft were 25%, 14%, and 50%, respectively. Patient and graft survival rates were 72% and 56% at 1 year, respectively. Median length of stay was 27 days and median graft survival was 2.9 years. CONCLUSIONS: Selection of patients and a significant use of available resources are some of the important factors that clinicians need to take into account when dealing with multiple retransplantations. With such conditions, however, liver retransplantation of more than two grafts can be a life-saving procedure.

A role for the thromboxane receptor in L-NAME hypertension.

Actions of the lipid mediator thromboxane (Tx) A2 acting through the TP receptor contribute to the pathogenesis of cardiovascular disease. To further explore the role of TxA2 in hypertension, we examined the consequences of deficiency of the TP receptor on the course of hypertension associated with endothelial dysfunction and salt sensitivity. To this end, the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) was administered to TP-deficient (Tp-/-) and wild-type (Tp+/+) control mice in drinking water for 21 wk along with a high-salt (HS; 6% NaCl) diet. Administration of L-NAME increased urinary excretion of TxB2 to a similar extent in both Tp+/+ and Tp-/- animals. L-NAME also caused significant and sustained elevations in blood pressure that reached a maximum between weeks 3 and 6. However, the severity of hypertension was attenuated in the Tp-/- mice throughout the study period (P<0.001). At the end of the study, the wild-type mice developed significant cardiac hypertrophy (23.6+/-2% increase in heart-to-body weight ratio). The severity of cardiac hypertrophy was attenuated in the TP-deficient group (11.1+/-2.6%; P<0.05). In contrast, kidney hypertrophy was exaggerated in the Tp-/- mice compared with controls (37.1+/-5.4 vs. 12.3+/-2.3%; P<0.01). Moreover, the severity of glomerulosclerosis, tubule vacuolization, and interstitial chronic inflammation was also enhanced in the Tp-/- group (P<0.01). Thus, in L-NAME hypertension, TP receptors contribute to elevated blood pressure and cardiac hypertrophy. In this model, TP receptors also provided unexpected protection against kidney injury.

The effect of immunosuppression on peritoneal adhesions formation after small bowel transplantation in rats.

BACKGROUND: The reported incidence of adhesion related small bowel obstruction after abdominal organ transplantation is considerably lower than other abdominal procedures. The purpose of the study was to investigate the influence of immunosuppression on peritoneal adhesion formation after intestinal transplantation in rats. METHODS: Four groups of rats (n = 6) underwent small bowel intestinal transplantation in syngeneic (Groups A, B) and allogeneic (Groups C, D) combinations. Groups B and D received tacrolimus immunosuppression 1 mg/kg/d. Animals were euthanized on postoperative day 7, and the total adhesion score (TAS), tissue hydroxyproline content (HPC), TGF-beta mRNA expression levels and histology were examined. RESULTS: All of the animals in Group C showed severe histological (Grade III) acute cellular rejection. There were no histological signs of rejection in Group D. A significant reduction in TAS was observed in tacrolimus treated animals in both syngeneic and allogeneic combinations (Groups B and D), compared with controls (Groups A and C) (P < 0.001 and P < 0.01, respectively). TAS results correlated with the differences in TGF-beta levels that showed significant reduction when each immunosuppressed group was compared with its nontreated counterpart, i.e., (Groups B versus A, P < 0.05, and Groups D versus C, P < 0.01). TGF-beta levels were significantly high in the rejection group (C) and correlated with the intense adhesion formation that was demonstrated in that group. Group C was also the only group in which a significant elevation in HPC was demonstrated (P < 0.001). CONCLUSION: Intense adhesion formation occurs during early posttransplant acute rejection. Postsurgical adhesion formation is significantly reduced in immunosuppressed rats after intestinal transplantation.

Role of MHC-linked genes in autoantigen selection and renal disease in a murine model of systemic lupus erythematosus.

We previously described a renal protective effect of factor B deficiency in MRL/lpr mice. Factor B is in the MHC cluster; thus, the deficient mice were H2b, the haplotype on which the knockout was derived, whereas the wild-type littermates were H2k, the H2 of MRL/lpr mice. To determine which protective effects were due to H2 vs factor B deficiency, we derived H2b congenic MRL/lpr mice from the 129/Sv (H2b) strain. Autoantibody profiling using autoantigen microarrays revealed that serum anti-Smith and anti-small nuclear ribonucleoprotein complex autoantibodies, while present in the majority of H2k/k MRL/lpr mice, were absent in the H2b/b MRL/lpr mice. Surprisingly, 70% of MRL/lpr H2b/b mice were found to be serum IgG3 deficient (with few to no IgG3-producing B cells). In addition, H2b/b IgG3-deficient MRL/lpr mice had significantly less proteinuria, decreased glomerular immune complex deposition, and absence of glomerular subepithelial deposits compared with MRL/lpr mice of any H2 type with detectable serum IgG3. Despite these differences, total histopathologic renal scores and survival were similar among the groups. These results indicate that genes encoded within or closely linked to the MHC region regulate autoantigen selection and isotype switching to IgG3 but have minimal effect on end-organ damage or survival in MRL/lpr mice.