Antibody Drug Treatment for Steroid-Resistant Rejection After Pediatric Living Donor Liver Transplantation: A Single-Center Experience

BACKGROUND

Antibody drugs have been used to treat steroid-resistant rejection (SRR) after liver transplantation. Although anti-thymocyte globulin has been used for SRR after liver transplantation in place of muromonab-CD3 since 2011 in Japan, the effectiveness of anti-thymocyte globulin after pediatric living-donor liver transplantation (LDLT) has not yet been reported. The aim of this study was to evaluate the effectiveness of antibody drug treatment for SRR after pediatric LDLT in our single center.

METHODS

Between May 2001 and December 2013, 220 pediatric LDLTs were performed. Initial immunosuppression after LDLT included tacrolimus and methylprednisolone therapy. Acute rejection was diagnosed by use of a liver biopsy and the administration of steroid pulse treatment, and SRR was defined as acute rejection refractory to the steroid pulse treatment.

RESULTS

Acute rejection and SRR occurred in 74 (33.6%) and 16 patients (7.3%), respectively. The graft survival rates of non-SRR and SRR were 92.4% and 87.5%, respectively (P = .464). The median concentration of alanine aminotransferase before and after the administration of antibody drug was 193.5 mU/mL (range, 8-508) and 78 mU/mL (range, 9-655), respectively (P = .012). The median rejection activity index before and after the administration of antibody drugs was 5 (range, 2-9) and 1 (range, 0-9), respectively (P = .004). After antibody drug treatment, 12 patients had cytomegalovirus infections, 2 patients had Epstein-Barr virus infections, 3 patients had respiratory infections, and 1 patient had encephalitis. The cause of death in 1 patient with SRR was recurrence of infant fulminant hepatic failure.

CONCLUSIONS

Antibody drug treatment for SRR after pediatric LDLT is safe and effective.

Increase of MZB1 in B cells in systemic lupus erythematosus: proteomic analysis of biopsied lymph nodes

Background

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease in which dysregulation of B cells has been recognized. Here, we searched for potential biomarkers of SLE using liquid chromatography-tandem mass spectrometry (LC-MS).

Methods

Lymph nodes from SLE patients and controls were analyzed by LC-MS. To validate the identified molecules, immunoblotting and immunohistochemistry were performed and B cells from SLE patients were analyzed by quantitative RT-PCR. B-cell subsets from NZB/W F1 mice, which exhibit autoimmune disease resembling human SLE, were analyzed by flow cytometry. Endoplasmic reticulum (ER) stress was induced by tunicamycin and the serum concentration of anti-dsDNA antibodies was determined by ELISA. TUNEL methods and immunoblotting were used to assess the effect of tunicamycin.

Results

MZB1, which comprises part of a B-cell-specific ER chaperone complex and is a key player in antibody secretion, was one of the differentially expressed proteins identified by LC-MS and confirmed by immunoblotting. Immunohistochemically, larger numbers of MZB1⁺ cells were located mainly in interfollicular areas and scattered in germinal centers in specimens from SLE patients compared with those from controls. MZB1 colocalized with CD138⁺ plasma cells and IRTA1⁺ marginal zone B cells. MZB1 mRNA was increased by 2.1-fold in B cells of SLE patients with active disease (SLE Disease Activity Index 2000 ≥ 6) compared with controls. In aged NZB/W F1 mice, splenic marginal zone B cells and plasma cells showed elevated MZB1 levels. Tunicamycin induced apoptosis of MZB1⁺ cells in target organs, resulting in decreased serum anti-dsDNA antibody levels. Additionally, MZB1⁺ cells were increased in synovial tissue specimens from patients with rheumatoid arthritis.

Conclusions

MZB1 may be a potential therapeutic target in excessive antibody-secreting cells in SLE.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1511-5) contains supplementary material, which is available to authorized users.

Xist RNA repeat E is essential for ASH2L recruitment to the inactive X and regulates histone modifications and escape gene expression

Long non-coding RNA Xist plays a crucial role in establishing and maintaining X-chromosome inactivation (XCI) which is a paradigm of long non-coding RNA-mediated gene regulation. Xist has Xist-specific repeat elements A-F which are conserved among eutherian mammals, underscoring their functional importance. Here we report that Xist RNA repeat E, a conserved Xist repeat element in the Xist exon 7, interacts with ASH2L and contributes to maintenance of escape gene expression level on the inactive X-chromosome (Xi) during XCI. The Xist repeat E-deletion mutant female ES cells show the depletion of ASH2L from the Xi upon differentiation. Furthermore, a subset of escape genes exhibits unexpectedly higher expression in the repeat E mutant cells than the cells expressing wildtype Xist during X-inactivation, whereas the silencing of X-linked non-escape genes is not affected. We discuss the implications of these results to understand the role of ASH2L and Xist repeat E for histone modifications and escape gene regulation during random X-chromosome inactivation.

Identification of ecdysteroidogenic enzyme genes and their expression during pupal diapause in the cabbage armyworm, Mamestra brassicae

In this study, we identified ecdysteroidogenic enzymes in the cabbage armyworm, Mamestra brassicae, and demonstrated reduced expression of these genes during diapause. Some insects employ a temporary developmental arrest, diapause, to survive in severe environments. The titres of the moulting hormone ecdysteroid were reduced in diapause pupae of M. brassicae; therefore, ecdysteroidogenesis might be suppressed by a diapause-specific mechanism. To clarify expression changes of ecdysteroidogenic enzyme genes during diapause in M. brassicae, we first identified the genes for seven ecdysteroidogenic enzymes: Neverland, Non-molting glossy (Nm-g), CYP307A1 (Spook), CYP306A1 (Phantom), CYP302A1 (Disembodied), CYP315A1 (Shadow) and CYP314A1 (Shade). Enzymatic assays using heterologous expression in Drosophila Schneider 2 (S2) cells and analysis of mRNA distribution indicated that the identified genes were ecdysteroidogenic enzymes of M. brassicae. Expression levels of these ecdysteroidogenic enzyme genes were compared between prothoracic glands in different pupal stages throughout diapause. Immediately after pupation, diapause-destined pupae showed similar expression levels of ecdysteroidogenic enzyme genes to those of nondiapause pupae. All of these genes showed reduced gene expression after diapause initiation. Expression was immediately increased in diapause-destined pupae at the postdiapause quiescence phase. These results indicate that reduced expression of ecdysteroidogenic enzyme genes suppresses ecdysteroidogenesis and maintains developmental arrest during diapause.

Evaluation of purine utilization by Lactobacillus gasseri strains with potential to decrease the absorption of food-derived purines in the human intestine

It is well accepted that frequent and heavy intake of purine-rich foods causes elevation of serum uric acid levels, which is a risk factor of hyperuricemia. Reducing intestinal absorption of dietary purines may attenuate the elevation of serum uric acid levels and exacerbation of hyperuricemia. This reduction may be achieved by the ingestion of lactic acid bacteria that take up purines in the intestine. In this study, we investigated the degree of uptake and utilization of purines of three lactobacilli strains. Among them, Lactobacillus gasseri PA-3 (PA-3) showed the greatest incorporation of ¹⁴C-adenine. PA-3 also incorporated ¹⁴C-adenosine and ¹⁴C-AMP. Additionally, using defined growth medium, PA-3 demonstrated greater proliferation in the presence of these purines than in their absence. Although further investigation is required, ingestion of PA-3 may lower serum uric acid levels by reducing intestinal absorption of purines in humans.

Relationship Between Graft Liver Function and the Change of Graft Liver and Spleen Volumes After Technical Variant Liver Transplantation

BACKGROUND

Although there have been a few reports describing the changes of graft liver and spleen volumes after liver transplantation (LT), little is known about the relationship between graft liver function and the changes of these volumes after technical variant liver transplantation (TVLT). We therefore performed a retrospective study to investigate the relationship between graft liver function and these volumes after TVLT.

METHODS

We retrospectively investigated the cases of 140 TVLT procedures that were performed in our department between July 1987 and October 2012 and in which follow-up was conducted at our department. We calculated the graft liver volume to standard liver volume (GV/SLV) ratio, the spleen volume to standard spleen volume (SV/SSV) ratio, and the spleen volume to graft liver volume (S/L) ratio by CT volumetry. We clarified the relationship between graft liver function (according to the pathological findings) and the graft liver and spleen volumes at 2, 5, and 10 years after TVLT.

RESULTS

In the normal liver function group, the GV/SLV, SV/SSV, and S/L ratios decreased until 6 months after TVLT and then converged at 10 years after TVLT to 0.95, 1.27, and 0.27, respectively. In the graft liver failure group, the GV/SLV, SV/SSV, and S/L ratios at 10 years after TVLT were 0.67, 5.01, and 1.55, respectively. A significant correlation was observed between the GV/SLV ratio and the presence of mild liver fibrosis at 2 and 5 years after TVLT (P = .03 and P = .04, respectively).

CONCLUSIONS

Post-transplant CT-volumetry is a noninvasive and effective means of evaluating graft liver status.

Complementary Indicators for Diagnosis of Hepatic Vein Stenosis After Pediatric Living-donor Liver Transplantation

INTRODUCTION

Although hepatic vein stenosis after liver transplantation is a rare complication, the complication rate of 1% to 6% is higher in pediatric living-donor liver transplantation than that in other liver transplantation cases. Diagnosis is very important because this complication can cause hepatic congestion that develops to liver cirrhosis, graft loss, and patient loss. However, this is unlikely in cases where there are no ascites or hypoalbuminemia.

OBJECTIVES

Eleven of 167 patients who had undergone pediatric living-donor liver transplantation were identified in the outpatient clinic at Jichi Medical University as having suffered from hepatic vein stenosis, and were enrolled in the study.

METHODS

We conducted a retrospective study in which we reviewed historical patient records to investigate the parameters for diagnosis and examine treatment methods and outcomes.

RESULTS

The 11 patients were treated with 16 episodes of balloon dilatation. Three among these received retransplantation and another 2 cases required the placement of a metallic stent at the stenosis. Histological examination revealed severe fibrosis in four of nine patients who had a liver biopsy, with mild fibrosis revealed in the other five grafts. Furthermore, hepatomegaly and splenomegaly diagnosed by computed tomography, elevated levels of hyarulonic acid, and/or a decrease in calcineurin inhibitor clearance were found to be pathognomonic at diagnosis, and tended to improve after treatment.

CONCLUSIONS

Diagnosis of hepatic vein stenosis after liver transplantation can be difficult, so careful observation is crucial to avoid the risk of acute liver dysfunction. Comprehensive assessment using volumetry of the liver and spleen and monitoring of hyarulonic acid levels and/or calcineurin inhibitor clearance, in addition to some form of imaging examination, is important for diagnosis and evaluation of the effectiveness of therapy.

Initial Atomic Motion Immediately Following Femtosecond-Laser Excitation in Phase-Change Materials

Despite the fact that phase-change materials are widely used for data storage, no consensus exists on the unique mechanism of their ultrafast phase change and its accompanied large and rapid optical change. By using the pump-probe observation method combining a femtosecond optical laser and an x-ray free-electron laser, we substantiate experimentally that, in both GeTe and Ge_{2}Sb_{2}Te_{5} crystals, rattling motion of mainly Ge atoms takes place with keeping the off-center position just after femtosecond-optical-laser irradiation, which eventually leads to a higher symmetry or disordered state. This very initial rattling motion in the undistorted lattice can be related to instantaneous optical change due to the loss of resonant bonding that characterizes GeTe-based phase change materials. Based on the amorphous structure derived by first-principles molecular dynamics simulation, we infer a plausible ultrafast amorphization mechanism via nonmelting.

High Prevalence of Pollinosis Symptoms among the Farmers Cultivating Japanese Pears

In a district of Japanese pear cultivators, a questionnaire survey and an IgE antibody survey were conducted on the pollinosis. A high prevalence of 36.3 % of the farmers complained of pollinosis symptoms. By the IgE antibody survey, the symptoms were found to be related to the airborne pollens in the orchard.

Abstract A54: Regulating MUC16 expression to decrease ovarian tumor proliferation and increase efficacy of therapeutic antibodies

The membrane-spanning mucin MUC16 promotes proliferation and metastasis of and protects ovarian cancer cells from innate immune responses and antibody-mediated cytotoxicity. We are hypothesizing that studying the regulation of MUC16 as well as developing techniques to prevent production of this mucin by ovarian tumor cells will be important in curtailing the growth of these tumors as well as increasing the efficacy of antibody-based therapeutics. We first investigated the downregulation of MUC16 by siRNA. Four different siRNA constructs were used to downregulate expression of this mucin. When the VK8 antibody was used in flow cytometry experiments to monitor knockdown, a complete loss of the mucin was observed between 48-72 h after transfection of the siRNA. MUC16 was recovery was observed by 96 h post-transfection. While the results with VK8 showed conclusive loss of the mucin, when flow cytometry was conducted with OC125 as the detecting antibody, the maximum inhibition was between 40-60%. The disparity in the data could not be attributed to the differences in the antigen affinities or the concentrations of the two detecting antibodies. The data with siRNA is in stark contrast with cell lines transfected with intracytoplasmic scFv of a MUC16-capturing antibody. In this case complete loss of MUC16 is observed irrespective of the detecting antibody used in the flow cytometry experiments. Even though the knockdown of MUC16 was not complete when analysis was conducted with OC125 antibody, the resulting cells showed a significant decrease in cell proliferation. A trend towards decreased immunoprotection of the cancer cells in the MUC16 siRNA knockdown cells was also observed when the cancer cells were subjected to lysis by natural killer cells isolated from healthy volunteers. To maximize downregulation of MUC16 and to develop a strategy that may potentially be used to decrease expression of this mucin in vivo, we developed a triblock copolymer poly(ethylene glycol)-b-poly{N-[N-(2-aminoethyl)-2-aminoethyl] aspartamide}-b-poly(ε-caprolactone) (PEG-b-PAsp(DET)-b-PCL) capable of self-assembling into micelles that were loaded with MUC16 siRNA. In vitro experiments showed efficient knockdown of the mucin that was dependent on concentration of siRNA used. Even when the siRNA was delivered via the PEG-PAsp-PCL nanoparticles and VK8 antibody showed complete knockdown, only approximately 60-70% knockdown was observed using OC125. Using a different approach, we also investigated if the expression of MUC16 by ovarian, breast and pancreatic cancer cells can be regulated by small molecule inhibitors of DNA methylation and histone deacetylation. The DNA methyltransferase inhibitor, 5-aza-2'deoxycytidine (5-azadC) was found to increase by 2-3-fold the expression of MUC16 in all of the approximately fifteen cell lines tested in our studies. Treatment of most cell lines with the histone deacetylase inhibitor (HDAC), trichostatin also resulted in increase in MUC16 expression, although the increase was not as robust and consistent between the cell lines tested. However, MassARRAY and CHIP analysis of the MUC16 5'-flanking region showed no epigenetic modifications of the promoter of this mucin. Overall our results indicate that while siRNA can be used to inhibit MUC16 expression the data should be interpreted with caution as differences in the activities of the antibodies used in the assays have different specificities for this mucin. These conclusions also suggest the presence of different isoforms and splice variants of the mucins that are likely to be detected with distinct affinities and specificities by the MUC16 antibodies. Our experiments with 5-azadC and trichostatin indicate MUC16 expression is not regulated via direct epigenetic regulation of its gene. Instead, transcription factors and signaling events required to control MUC16 expression are likely regulated via epigenetic mechanisms.

Citation Format: Mildred Felder, Arvinder Kapur, Ryan Serbin, San Zheng, May Xiong, Norishige Yamada, Manish Patankar. Regulating MUC16 expression to decrease ovarian tumor proliferation and increase efficacy of therapeutic antibodies. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr A54.