Recapitulating the immune system of hemophilia A patients with inhibitors using immunodeficient mice.

BACKGROUND AND AIM: Treating hemophilia A patients who develop inhibitors remains a clinical challenge. A mouse model of hemophilia A can be used to test the efficacy of strategies for inhibitor suppression, but the differences in the immune systems of mice and humans limit its utility. To address this shortcoming, we established a humanized NOD/SCID-IL2rγnull hemophilia A (hu-NSG-HA) mouse model with a severely deficient mouse immune system presenting a patient's adapted immune cells. METHODS AND RESULTS: Through intrasplenic injection with patient inhibitor-positive peripheral blood mononuclear cells (PBMCs), utilizing an adeno-associated viral delivery system expressing human BLyS, and regular FVIII challenge, human C19+ B cells were expanded in vivo to secrete anti-FVIII antibodies. Both the inhibitor and the human anti-FVIII IgG, including the predominant subclasses (IgG1 and IgG4) present in the majority of inhibitor patients, were detected in the mouse model. We further segregated and expanded the different clones of human anti-FVIII-secreting cells through subsequent transplantation of splenocytes derived from hu-NSG-HA mice into another NSG-HA mouse. By transplanting a patient's PBMCs into the NSG-HA mouse model, we demonstrated the success of reintroducing a strong anti-FVIII immune response for a short period in mice with the immune systems of inhibitor-positive patients. CONCLUSION: Our results demonstrate a potential tool for directly obtaining functional human-derived antigen-specific antibodies and antibody-secreting cells, which may have therapeutic value for testing patient-specific immune responses to treatment options to assist in clinical decisions.

A microRNA signature for clinical outcomes of pediatric ALL patients treated with TPOG protocols.

MicroRNA (miRNA) expression is reportedly associated with clinical outcomes in childhood acute lymphoblastic leukemia (ALL). Here, we aimed at investigating whether miRNA expression is associated with clinical outcomes in pediatric ALL patients treated with the Taiwan Pediatric Oncology Group (TPOG) protocols. The expression of 397 miRNAs was measured using stem-loop quantitative real-time polymerase chain reaction miRNA arrays in 60 pediatric ALL patients treated with TPOG-ALL-93 or TPOG-ALL-97 VHR (very high-risk) protocols. In order to identify prognosis-related miRNAs, original cohort was randomly split into the training and testing cohort in a 2:1 ratio, and univariate Cox proportional hazards regression was applied to identify associations between event-free survival (EFS) and expressions of miRNAs. Four prognosis-related miRNAs were selected and validated in another independent cohort composed of 103 patients treated with the TPOG-ALL-2002 protocol. Risk score, including the impact of four prognosis-related miRNAs, was calculated for each patients, followed by grouping patients into the high or low risk-score groups. Irrespective of the training, testing, or validation cohort, risk-score group was significantly associated with EFS and overall survival (OS). Risk-score group combining with clinical characteristics including the age onset (≥10 years), white blood cell counts (≥100 × 109/L), cell type (T- or B-cell), sex, and risk groups of the treatment protocols were used as predictors of EFS using the multivariate Cox proportional hazards regression. Results showed that the risk-score group was the strongest predictor. In the validation cohort, hazard ratios (HRs) of the risk-score group were 7.06 (95% CI=1.93-25.84, p-value =0.003) and 14.03 (95% CI=3.34-59.04, p-value =0.003) for EFS and OS, respectively. High risk-score group had higher risk of having poor prognosis and risk of death than that in the low risk group. Accuracy of the prediction model for 5-year EFS could reach 0.76. For the prediction of 5-year OS, accuracy was 0.75. In conclusion, a miRNA signature was associated with clinical outcomes in childhood ALL patients treated with TPOG protocols and might be a suitable prognostic biomarker.

Acquired FXIII inhibitor: Patient characteristics and treatment outcome, a case series in Taiwan.

INTRODUCTION: Acquired factor XIII (FXIII) inhibitor is a rare but possibly underdiagnosed bleeding disorder. To date, less than one hundred cases have been reported, but the number has increased rapidly in recent years, especially in Japan. Because of the rarity of this disorder, no treatment guidelines are available. In some reports, physicians treated the bleeding with cryoprecipitate or factor XIII concentrate and eradicated the inhibitor with various immune suppressants. METHODS: From January 2015 to December 2018, we collected consecutive patients diagnosed as having acquired FXIII inhibitor. FXIII activity and inhibitor were measured by a fluorescent factor XIII assay using isopeptidase reaction catalyzed by activated factor XIII and the Bethesda method, respectively. Factor XIII antigen was measured by latex-enhanced immunoassay. RESULTS: We found five adult patients with detectable FXIII inhibitor. Four of them were older than 70. Two had systemic lupus erythematosus. All the patients presented with ecchymosis and intramuscular hematoma. No life-threatening bleeding was observed. Delayed diagnosis was common with varied time periods needed to achieve a correct diagnosis. All bleedings were treated and improved by cryoprecipitate. Steroids were given to all patients and cyclophosphamide, rituximab, and other immune suppressants were also used. FXIII inhibitor was totally resolved in three, partially resolved in one, and persisted in one patient. CONCLUSION: We documented five patients with acquired FXIII inhibitor, found over 4 years. The most common presentations were ecchymosis and intramuscular hematomas. Cryoprecipitate was effective in controlling most bleeds. Steroid, cyclophosphamide and rituximab were effective in eradicating inhibitor in some patients.

Targeting fibroblast CD248 attenuates CCL17-expressing macrophages and tissue fibrosis.

The role of fibroblasts in tissue fibrosis has been extensively studied. Activated fibroblasts, namely myofibroblasts, produce pathological extracellular matrix. CD248, a type I transmembrane glycoprotein, is expressed in fibroblasts after birth. In human chronic kidney disease, upregulated CD248 in myofibroblasts is linked to poor renal survival. In this study, we demonstrated a novel interaction between CD248 and macrophages to be a key step in mediating tissue fibrosis. CD248 was upregulated in myofibroblasts in murine models of renal and peritoneal fibrosis. Cd248 knockout (Cd248-/-) could attenuate both renal and peritoneal fibrosis. By parabiosis of GFP reporter mice and Cd248-/- mice, we showed that attenuation of renal fibrosis was associated with a decrease of macrophage infiltration in Cd248-/- mice. Moreover, decrease of chemokine (C-C motif) ligand 17 and Ccl22 was found in macrophages isolated from the fibrotic kidneys of Cd248-/- mice. Because galectin-3-deficient macrophages showed decreased Ccl17 and Ccl22 in fibrotic kidneys, we further demonstrated that CD248 interacted specifically with galectin-3 of macrophages who then expressed CCL17 to activate collagen production in myofibroblasts. Mice with DNA vaccination targeting CD248 showed decreased fibrosis. We thus propose that CD248 targeting should be studied in the clinical tissue fibrosis setting.

Current animal models of hemophilia: the state of the art.

Hemophilia is the most well-known hereditary bleeding disorder, with an incidence of one in every 5000 to 30,000 males worldwide. The disease is treated by infusion of protein products on demand and as prophylaxis. Although these therapies have been very successful, some challenging and unresolved tasks remain, such as reducing bleeding rates, presence of target joints and/or established joint damage, eliminating the development of inhibitors, and increasing the success rate of immune-tolerance induction (ITI). Many preclinical trials are carried out on animal models for hemophilia generated by the hemophilia research community, which in turn enable prospective clinical trials aiming to tackle these challenges. Suitable animal models are needed for greater advances in treating hemophilia, such as the development of better models for evaluation of the efficacy and safety of long-acting products, more powerful gene therapy vectors than are currently available, and successful ITI strategies. Mice, dogs, and pigs are the most commonly used animal models for hemophilia. With the advent of the nuclease method for genome editing, namely the CRISPR/Cas9 system, it is now possible to create animal models for hemophilia other than mice in a short period of time. This review presents currently available animal models for hemophilia, and discusses the importance of animal models for the development of better treatment options for hemophilia.

Lack of Thromboxane Synthase Prevents Hypertension and Fetal Growth Restriction after High Salt Treatment during Pregnancy.

Preeclampsia (PE) is a potentially fatal pregnancy-related hypertensive disorder characterized by poor placenta development that can cause fetal growth restriction. PE-associated pathologies, including thrombosis, hypertension, and impaired placental development, may result from imbalances between thromboxane A2 (TXA2) and prostacyclin. Low-dose aspirin, which selectively inhibits TXA2 production, is used to prevent high-risk PE. However, the role of TXA2 in aspirin-mediated protective effects in women with PE is not understood fully. In this study, we examined the role of prostanoids in PE using human samples and an induced PE mouse model. We demonstrated that the administration of salted drinking water (2.7% NaCl) to wild-type mice resulted in elevated placental TXA2 synthase (TXAS) and plasma TXA2, but not prostacyclin, levels, which was also found in our clinical PE placenta samples. The high salt-treated wild-type pregnant mice had shown unchanged maternal body weight, hypertension (MAP increase 15 mmHg), and decreased pup weight (~50%) and size (~24%), but these adverse effects were ameliorated in TXAS knockout (KO) mice. Moreover, increased expression of interleukin-1ß and downstream phosphorylated-p38-mitogen-activated protein kinase were concordant with apoptosis induction in the placentas of salt water-treated wild-type mice. These alterations were not observed in TXAS KO mice. Together, our data suggest that TXA2 depletion has anti-PE effects due to the prevention of hypertension and placental damage through downregulation of the interleukin-1ß pathway.

A Double Negative Loop Comprising ETV6/RUNX1 and MIR181A1 Contributes to Differentiation Block in t(12;21)-Positive Acute Lymphoblastic Leukemia.

Childhood acute lymphoblastic leukemia (ALL) with t(12;21), which results in expression of the ETV6/RUNX1 fusion gene, is the most common chromosomal lesion in precursor-B (pre-B) ALL. We identified 17 microRNAs that were downregulated in ETV6/RUNX1+ compared with ETV6/RUNX1- clinical samples. Among these microRNAs, miR-181a-1 was the most significantly reduced (by ~75%; P < 0.001). Using chromatin immunoprecipitation, we demonstrated that ETV6/RUNX1 directly binds the regulatory region of MIR181A1, and knockdown of ETV6/RUNX1 increased miR-181a-1 level. We further showed that miR-181a (functional counterpart of miR-181a-1) could target ETV6/RUNX1 and cause a reduction in the level of the oncoprotein ETV6/RUNX1, cell growth arrest, an increase in apoptosis, and induction of cell differentiation in ETV6/RUNX1+ cell line. Moreover, ectopic expression of miR-181a also resulted in decreased CD10 hyperexpression in ETV6/RUNX1+ primary patient samples. Taken together, our results demonstrate that MIR181A1 and ETV6/RUNX1 regulate each other, and we propose that a double negative loop involving MIR181A1 and ETV6/RUNX1 may contribute to ETV6/RUNX1-driven arrest of differentiation in pre-B ALL.

Functional importance of apolipoprotein A5 185G in the activation of lipoprotein lipase.

BACKGROUND: Apolipoprotein A5 (APOA5) over-expression enhances lipolysis of triglyceride (TG) through stimulation of lipoprotein lipase (LPL) activity; however, an APOA5 G185C variant was found associated with hypertriglyceridemia. The aim of this study was, therefore, to explore the importance of APOA5 185GG in the activation of LPL. METHODS: A fragment containing mature human APOA5 cDNA was obtained by RT-PCR and subcloned into pET-15b vector. Site-directed mutagenesis was performed to generate 19 variants. Recombinant human APOA5 wild type and variants were produced in Escherichia coli, and then activation of LPL was measured. RESULTS: Activity of APOA5 variants on LPL-mediated 1,2-dimyristoyl-sn-glycero-3-phosphocholine hydrolysis was reduced by 17 to 74% in comparison to wild type APOA5 (P<0.0001). All variants also showed reduced activation (P<0.0001) of LPL-mediated hydrolysis of very low-density lipoprotein (VLDL); activation abilities of APOA5 variants ranged from 31 to 81% of wild-type APOA5. CONCLUSIONS: APOA5 residue 185G is very important in LPL-mediated VLDL hydrolysis, and any mutation at this residue will decrease LPL activation and concomitant TG modulation.

Multiplex reverse transcription-polymerase chain reaction as diagnostic molecular screening of 4 common fusion chimeric genes in Taiwanese children with acute lymphoblastic leukemia.

BACKGROUND: The classification of B-lineage acute lymphoblastic leukemia (ALL) by specific chromosomal translocations has prognostic implications for risk-directed therapy. Reverse transcription-polymerase chain reaction (RT-PCR) assay is a useful tool for detecting fusion transcripts from common chromosomal translocations of ALL cells. METHODS: Multiplex RT-PCR and nested-PCR assays were used to detect ALL-type BCR-ABL1 transcripts of the t(9;22), TCF-PBX1 transcripts of t(1;19), the MLL-AF4 transcripts of t(4;11), and 2 variants of ETV6-RUNX1 of the cryptic t(12;21) in 148 leukemic samples upon diagnosis. The patients received risk-directed protocols of the Taiwan Pediatric Oncology Group-ALL-2002 that consisted of multiple chemotherapeutic agents of different intensities. Event-free survival (EFS) and overall survival (OS) rates were analyzed for genetic abnormalities detected by multiplex PCR and conventional cytogenetic analysis by the Kaplan-Meier method, and compared with the Mantel-Haenszel test. The Cox proportional hazards model was implemented to identify independent prognostic factors for EFS and OS. RESULTS: In this cohort of Taiwanese children, the relative frequencies of the 4 translocations of B-lineage ALL were 8% with ALL-type t(9;22)/BCR-ABL1, 4% with (1;19)/TCF-PBX1, 2% with t(4;11)/MLL-AF4, and 17.6% with t(12;21)/ETV6-RUNX1. Patients with t(12;21)/ETV6-RUNX1 fusion, hyperdiploidy, and t(1;19)/TCF-PBX1 fusion had the most favorable outcomes, whereas those with the t(9;22)/BCR-ABL1 fusion or t(4;11) and other MLL gene rearrangement had poor prognosis (P<0.001 for EFS and OS). BCR-ABL1, MLL gene rearrangement, and very high-risk group were independent prognostic factors after Cox regression analysis. CONCLUSIONS: The biological factors of leukemia cells are associated with treatment outcomes in childhood ALL. Multiplex RT-PCR assay is an efficient and sensitive diagnostic tool that may improve the ability to accurately and rapidly risk-stratify children with ALL.

Expression and prognostic significance of the apoptotic genes BCL2L13, Livin, and CASP8AP2 in childhood acute lymphoblastic leukemia.

Improved treatment of childhood acute lymphoblastic leukemia (ALL) depends on the identification of new molecular markers that are able to predict treatment response and clinical outcome. The development of impaired apoptosis in leukemic cells is one factor that may influence their response to treatment. We investigated the expression of three apoptosis related genes, BCL2L13, CASP8AP2, and Livin, as well as their prognostic significance, in a retrospective study of 90 pediatric ALL patients diagnosed between 1996 and 2007 in Taiwan. Univariant analysis revealed that high expression of BCL2L13 was associated with inferior event-free survival and overall survival (p<0.001 and 0.005, respectively). Multivariate analysis for EFS and OS demonstrated that high expression of BCL2L13 was an independent prognostic factor for childhood ALL in this ethnic group.

Pharmacogenomic variations in treatment protocols for childhood acute lymphoblastic leukemia.

OBJECTIVES: This retrospective study evaluates the role of pharmacogenomic determinants in the treatment of childhood acute lymphoblastic leukemia (ALL) in the Taiwanese population. METHODS: A total of 105 childhood ALL patients received combined chemotherapy of different intensities based on risk-directed Taiwan Pediatric Oncology Group (TPOG)-ALL-93 protocols. Seventeen genetic polymorphisms in 13 pharmacogenomic targets were analyzed by PCR-based restriction fragment length polymorphism (RFLP) and sequence-specific oligonucleotide (SSO) probe hybridization. Pharmacogenomic polymorphisms were correlated with event-free survival (EFS) of patients, with confounding effects adjusted by multivariate regression. RESULTS: Three polymorphic alleles in the multi-drug resistance 1 (MDR1) ABCB1 gene, and homozygotic MDR1 2677GG, 3435CC, and 2677G-3435C genotypes were highly associated with a significant reduction in EFS in those patients treated by the standard risk (SR) protocol (TPOG-ALL-93-SR). The hazard ratios were 6.8 (p = 0.01), 21.7 (p = 0.009), and 6.8 (p = 0.01), respectively. CONCLUSIONS: Independent pharmacogenomic determinants associated with treatment outcome were identified in subsets of Taiwanese ALL patients.

Common sequence variant in lipoprotein lipase gene conferring triglyceride response to fibrate treatment.

AIMS: Little is known about whether the variations in the lipoprotein lipase (LPL) and apolipoprotein gene cluster (APOA1/C3/A5) confer appreciable triglyceride lowering after fibrate treatment among patients with hypertriglyceridemia. MATERIALS & METHODS: We investigated whether variations in these genes confer a triglyceride lowering response after fibrate treatment among 145 patients with hypertriglyceridemia receiving 6 months of fibrate treatment. RESULTS: Overall triglycerides decreased from 746.2 mg/dl to 465.9 mg/dl and the mean percentage of triglyceride lowering was 50.7 +/- 38.6%. A total of two polymorphisms, LPL IVS8 +483T>G and APOA1 +2169G>C, were associated with a significant percentage of triglyceride lowering. Common haplotype effects of LPL on the triglyceride lowering percentage were significant (p = 0.002) and the percentage of variance explained by the LPL haplotype was 7.5%. One common LPL haplotype encompassing three polymorphisms was associated with a -45.40% change (p < 0.001) and risk of a 5.9-fold risk for developing a poor response (95% confidence interval: 1.11-31, p = 0.037), compared with the most frequent LPL haplotype. CONCLUSION: Our results indicate that the LPL gene variant may cause triglyceride lowering after fibrate treatment among patients with hypertriglyceridemia.