Plasma A Proliferation-inducing Ligand Levels Research Articles

POS-109 INTERIM RESULTS OF PHASE 1 AND 2 TRIALS TO INVESTIGATE THE SAFETY, TOLERABILITY, PHARMACOKINETICS, PHARMACODYNAMICS, AND CLINICAL ACTIVITY OF BION-1301 IN PATIENTS WITH IgA NEPHROPATHY

IgA nephropathy (IgAN) is an autoimmune disease with no approved treatments. A critical step in IgAN pathogenesis is the production of galactose-deficient IgA1 (Gd-IgA1) leading to the generation of anti-Gd-IgA1 autoantibodies and the formation of immune complexes that result in kidney inflammation and damage. A Proliferation-Inducing Ligand (APRIL), a soluble factor that regulates B cell differentiation, proliferation and survival of plasma cells, and IgA class-switching is elevated in patients with IgAN. IgAN patients with high plasma APRIL levels are reported as having higher levels of Gd-IgA1 and proteinuria and lower estimated glomerular filtration rates compared to those with lower plasma APRIL levels. BION-1301 is a novel humanized blocking antibody targeting APRIL that has been evaluated in a Phase 1 study of healthy volunteers (HV). In that study, BION-1301 was well-tolerated with no serious adverse events (SAEs), a pharmacokinetic (PK) half life >30 days and demonstrated dose-dependent pharmacodynamic (PD) effects characterized by durable reductions in serum levels of free April (fAPRIL), IgA and Gd-IgA1, IgM, and to a lesser extent IgG. Here we present interim results from Part 3 of the Phase 1 and the Phase 2 Open-Label Extension (OLE) trials that characterize the safety, PK and PD profile, and preliminary efficacy of BION-1301 in patients with IgAN. The Phase 1 study (NCT03945318) comprises 3 parts. Parts 1 and 2 assessed single- and multiple ascending doses of BION-1301 in HV from 10mg to 1350mg and 50mg to 450mg once every 2 weeks for one month, respectively. Part 3 is an ongoing, open-label, two cohort design in approximately 20 IgAN patients with BION-1301 at 450mg once every 2 weeks for a total of 12 weeks. Key eligibility criteria for Part 3 include: (1) biopsy-verified diagnosis of IgAN within the past 10 years,(2) urine protein ≥0.5 g/24h or baseline UPCR ≥0.5 g/g, and (3) stable/optimized dose of ACE-I/ARB (or intolerant). Patients completing Part 3 are eligible to enroll in the Phase 2 OLE study (NCT04684745) to receive BION-1301 for an additional 2 years. To evaluate PK and PD effects of BION-1301, serum levels of BION-1301, fAPRIL, antidrug antibodies (ADA), neutralizing antibodies (NAbs), and Gd-IgA1 were quantitated using ELISA-based immunoassays. Serum levels of IgA, IgG, and IgM were measured by immunoturbidimetry. UPCR was assessed from 24-hour urine collections. BION-1301 has been well tolerated in IgAN patients receiving a 450mg IV dose every two weeks for 12+ weeks with no SAEs or treatment related AE’s. Consistent with PD responses reported in HVs, durable reductions in serum levels of fAPRIL and immunoglobulins were observed in IgAN patients. Clinically meaningful reductions in proteinuria were seen as early as 12 weeks and were associated with the reduction in Gd-IgA1 levels. Additional data from patients receiving long-term treatment will be updated. This abstract was also submitted for the 58thERA-EDTA Congress. BION-1301 offers disease modifying potential by directly targeting the underlying multi-hit immune pathogenesis of IgAN, which is not addressed with the current standard of care treatment. Promising early biomarker and clinical activity responses support the continued development of BION-1301 in IgAN.

Plasma levels of BAFF and APRIL are elevated in patients with asthma in Saudi Arabia

B-cell activation factor (BAFF) and a proliferation-inducing ligand (APRIL) are members of the tumor necrosis factor superfamily of cytokines and can induce B cell activation, differentiation, and antibody production via interaction with their receptors, including transmembrane activator, calcium modulator, and cyclophilin ligand interactor (TACI), B-cell maturation antigen (BCMA), and B-cell activating factor receptor (BAFF-R). Herein, we assessed the plasma protein levels of BAFF and APRIL in patients with asthma to determine whether their expression is correlated with total IgE production and examined the surface expression of BAFF/APRIL receptors on B cells. Blood samples were collected from 47 patients with controlled asthma symptoms and 20 healthy normal controls, and plasma levels of APRIL, BAFF, and total IgE protein were quantified by corresponding ELISA assays. Furthermore, lymphocytes were isolated and B cells were analyzed for the presence of BAFF-R, BCMA, and TACI receptors using flow cytometry. Our results showed that IgE, BAFF, and APRIL plasma levels were markedly increased in patients with asthma compared with healthy controls. Moreover, expression of BAFF-R and BCMA, but not that of TACI, was significantly increased in patients with asthma compared with healthy controls. Overall, the findings suggest BAFF and APRIL as key mediators of asthma, and determination of their plasma levels may be useful in monitoring asthma symptoms and treatment response.

MO286DESIGN OF A PH1, MULTICENTER TRIAL TO INVESTIGATE THE SAFETY, TOLERABILITY, PK/PD OF BION-1301 IN HEALTHY VOLUNTEERS AND ADULTS WITH IGAN AND A MULTICENTER, OPEN-LABEL EXTENSION STUDY FOR IGAN PATIENTS WHO PARTICIPATED IN A PRIOR TRIAL OF BION-1301

Abstract Background and Aims IgA nephropathy (IgAN), the leading cause of primary glomerulonephritis, is an autoimmune disease with no approved treatments.1 Progression to end-stage-renal disease occurs in up to 45% of IgAN patients, requiring dialysis or kidney transplant to manage.2-4 A critical step in IgAN pathogenesis is the production of galactose-deficient IgA1 (Gd-IgA1) leading to the generation of anti-Gd-IgA autoantibodies and the formation of immune complexes that result in kidney inflammation and damage.5 A Proliferation-Inducing Ligand (APRIL), a soluble factor that regulates B cell differentiation, proliferation and survival of plasma cells, and IgA class-switching is elevated in patients with IgAN6, 7. IgAN patients with high plasma APRIL levels are reported as having higher levels of Gd-IgA1 and proteinuria and lower estimated glomerular filtration rates compared to those with lower plasma APRIL levels.7 BION-1301 is a novel humanized blocking antibody targeting APRIL. The primary objective of Study ADU-CL-19 is to assess the short-term safety and tolerability of BION-1301 in Healthy Volunteers (HV) and IgAN patients and to secondarily assess the short-term pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity, and preliminary clinical activity of BION-1301. The primary objective of Study ADU-CL-24 is to characterize the long-term safety of BION-1301 in IgAN patients who completed treatment in ADU-CL-19 while secondarily assessing the long-term PK, PD, immunogenicity, and preliminary clinical activity of BION-1301. Method The Phase 1 study (ADU-CL-19; NCT03945318) comprises 3 parts. Parts 1 and 2 are double-blind, randomized, placebo-controlled single and multiple ascending dose designs in HV; both parts have been completed. Part 3 is an ongoing multicenter (US and UK), multiple-dose, two cohort design in approximately 20 patients with IgAN (10/cohort). Key eligibility criteria for Part 3 includes: (1) urine protein ≥0.5 g/24h or baseline UPCR ≥0.5 g/g, (2) stable/optimized dose of ACE-I/ARB or intolerant to ACE-I/ARB, and (3) biopsy-verified diagnosis of IgAN within the past 10 years. In Part 3, patients in Cohort 1 are receiving BION-1301 at 450mg every 2 weeks for 3 months. The dose and schedule for Cohort 2 will be determined by the Safety Review Team (SRT) based on data from the first 5 patients. After 3 months of treatment, patients continue safety follow-up for approximately 6 months unless deciding to enroll in the open-label extension (OLE) study, withdraw from the study, or are lost to follow up. Study ADU-CL-24 (NCT04684745) is a Phase 2 Open-Label Extension (OLE) of Study ADU-CL-19. Eligibility for the OLE study is restricted to those patients who completed at least 75% of their intended doses as well as the End of Treatment (EOT) visit in Study ADU-CL-19. Patients who enroll directly from the ADU-CL-19 EOT visit are not required to attend an additional screening visit. This is encouraged to maintain un-interrupted dosing. Once enrolled in the OLE, patients receive BION-1301 at the same dose and regimen as assigned in the parent study for up to 2 years. The dose, route, and regimen of BION-1301 may change after review of emergent safety, PK, PD and efficacy data by the SRT. Results Parts 1 and 2 of the Phase 1 study in HV are complete and the data were presented at ASN in 20208 Part 3 of the Phase 1 and the Phase 2 OLE study are ongoing, and interim results from the first dose cohort in IgAN patients are being presented in a separate poster at this meeting. Conclusion The design of the Phase 1 and Phase 2 OLE studies described in HVs and IgAN patients have enabled the generation of short- and long-term safety, PK, PD, immunogenicity and preliminary efficacy data for BION-1301. The Phase 1 short-term data will guide the design of future later-stage trials of BION-1301, while the long-term data from OLE will enable a greater understanding of the potential long-term risk/benefit profile of BION-1301 in IgAN patients.

FC 040INTERIM RESULTS OF PHASE 1 AND 2 TRIALS TO INVESTIGATE THE SAFETY, TOLERABILITY, PHARMACOKINETICS, PHARMACODYNAMICS, AND CLINICAL ACTIVITY OF BION-1301 IN PATIENTS WITH IGA NEPHROPATHY

Abstract Background and Aims IgA nephropathy (IgAN), the leading cause of primary glomerulonephritis, is an autoimmune disease with no approved treatments.1 Progression to end-stage-renal disease occurs in up to 45% of IgAN patients, requiring dialysis or kidney transplant to manage.2-4 A critical step in IgAN pathogenesis is the production of galactose-deficient IgA1 (Gd-IgA1) leading to the generation of anti-Gd-IgA1 autoantibodies and the formation of immune complexes that result in kidney inflammation and damage.5 A Proliferation-Inducing Ligand (APRIL), a soluble factor that regulates B cell differentiation, proliferation and survival of plasma cells, and IgA class-switching is elevated in patients with IgAN6, 7. IgAN patients with high plasma APRIL levels are reported as having higher levels of Gd-IgA1 and proteinuria and lower estimated glomerular filtration rates compared to those with lower plasma APRIL levels.7 BION-1301 is a novel humanized blocking antibody targeting APRIL that has been evaluated in a Phase 1 study of healthy volunteers (HV). In Parts 1 and 2 of the Phase 1 study in HV, we previously reported that BION-1301 was well-tolerated with no serious adverse events (SAEs), a pharmacokinetic (PK) half life >30 days and demonstrated dose-dependent pharmacodynamic (PD) effects characterized by durable reductions in serum levels of free April (fAPRIL), IgA and Gd-IgA1, IgM, and to a lesser extent IgG8. Here we present interim results from Part 3 of the Phase 1 and the Phase 2 Open-Label Extension (OLE) trials that characterize the safety, PK and PD profile, and preliminary efficacy of BION-1301 in patients with IgAN. Method The Phase 1 study (NCT03945318) comprises 3 parts. Parts 1 and 2 assessed single- and multiple ascending doses of BION-1301 in HV from 10mg to 1350mg and 50mg to 450mg once every 2 weeks for one month, respectively. Part 3 is an ongoing, open-label, two cohort design in approximately 20 IgAN patients with BION-1301 at a starting dose and regimen of 450mg once every 2 weeks for a total of 3 months. Key eligibility criteria for Part 3 include: (1) urine protein ≥0.5 g/24h or baseline UPCR ≥0.5 g/g, (2) stable/optimized dose of ACE-I/ARB or be intolerant to ACE-I/ARB, and (3) biopsy-verified diagnosis of IgAN within the past 10 years. Patients completing Part 3 are eligible to enroll in the Phase 2 OLE study (NCT04684745) to receive BION-1301 for up to an additional 2 years. To evaluate PK and PD effects of BION-1301, serum levels of BION-1301, free APRIL (fAPRIL), anti-drug antibodies (ADA), neutralizing antibodies (NAbs), and Gd-IgA1 were quantitated using ELISA-based immunoassays. Serum levels of IgA, IgG, and IgM were measured by immunoturbidimetry. UPCR was assessed from 24-hour urine collections. Results In Part 3 of Phase 1 and the Phase 2 OLE trial to date, BION-1301 has been well tolerated in IgAN patients receiving a 450mg dose every two weeks for 12+ weeks with no SAEs observed. Consistent with PD responses previously reported in HVs, durable reductions in serum levels of fAPRIL and immunoglobulins were also observed in IgAN patients. Clinically meaningful reductions in proteinuria were observed as early as 12 weeks and were associated with the reduction in IgA. Additional data from patients receiving long-term treatment will be updated. Conclusion BION-1301 is a novel humanized anti-APRIL monoclonal antibody being developed as a potential treatment for patients with IgAN. BION-1301 offers disease modifying potential by directly targeting the underlying multi-hit immune pathogenesis of IgAN, which is not addressed with the current standard of care treatment. Promising early biomarker and clinical activity responses support the continued development of BION-1301 in IgAN.

P0500RESULTS OF A PHASE 1 TRIAL TO INVESTIGATE THE SAFETY, TOLERABILITY, PHARMACOKINETICS, AND PHARMACODYNAMICS OF BION-1301 IN HEALTHY VOLUNTEERS

Abstract Background and Aims IgA nephropathy (IgAN), the leading cause of primary glomerulonephritis, is an autoimmune disease with no approved treatments. Slow progression to end-stage-renal disease occurs in up to 50% of patients with IgAN over approximately 20-25 years, resulting in the need for dialysis or kidney transplant. A critical step in IgAN pathogenesis is the production of galactose-deficient IgA1 (Gd-IgA1) leading to the generation of anti-Gd-IgA autoantibodies and the formation of immune complexes that result in kidney inflammation and damage. Patients with IgAN have elevated levels of A proliferation-inducing ligand (APRIL), which may contribute to IgAN pathogenesis by regulating differentiation and proliferation of B cells. In a study of patients with IgAN, those with high plasma APRIL levels had higher levels of Gd-IgA1 and proteinuria and lower estimated glomerular filtration rates compared to those with lower plasma APRIL levels. BION-1301 is a first-in-class humanized antagonistic antibody targeting APRIL. BION-1301 reduced serum levels of IgA, IgM, and IgG with no drug-related toxicity in nonhuman primates and was well-tolerated with no dose-limiting toxicities in a Phase 1/2 first-in-human clinical study in patients with late-stage multiple myeloma. The Phase 1 trial described here will characterize the safety, pharmacokinetic (PK), and pharmacodynamic (PD) profiles of BION-1301 in healthy volunteers (HV) and patients with IgAN. Methods The protocol for this study (NCT03945318) is comprised of 3 parts, of which only Parts 1 and 2 are complete. Parts 1 and 2 assess BION-1301 in HV, and Part 3 will assess BION-1301 in patients with IgAN. Parts 1 and 2 are double-blind, randomized, placebo-controlled single and multiple ascending dose designs, respectively. Part 3 will assess a multiple dose regimen in IgAN patients. Part 1 enrolled 36 HV in 5 dose cohorts, randomized in a 3:1 ratio to receive a single dose of BION-1301 or placebo delivered by IV infusion. Part 2 enrolled 27 HV in 3 dose cohorts, randomized in a 2:1 ratio to receive 3 doses of BION-1301 or placebo delivered by IV infusion once every two weeks over a one month period. Dose escalation decisions were made by a Safety Review Team based on safety, tolerability, and PK-related stopping criteria. Results To-date, BION-1301 continues to be well tolerated. Its biological activity in the study is characterized by free APRIL, IgA, IgG, and IgM levels; unblinded safety, PK, and PD results for Parts 1 and 2 in Healthy Volunteers will be presented. Conclusion BION-1301, a humanized anti-APRIL antibody, may provide a novel avenue for the potential treatment of IgAN that offers potential advantages compared to currently used antihypertensive or immunosuppressive therapies.

The association between circulating APRIL levels and severity of obstructive sleep apnea in Chinese adults

BackgroundObstructive sleep apnea (OSA) is the most common type of sleep breathing disorder and is characterized by chronic intermittent hypoxia, which could cause inflammation and nuclear factor kappa B (NF-KB)-dependent inflammatory pathways activation. Circulating APRIL (a proliferation-inducing ligand) play an important role in promoting inflammation and NF-KB-dependent inflammatory pathways activation. We explored the role of APRIL as a potential mechanism of inflammation in OSA patients. MethodsAfter detailed sleep evaluated, venous blood and demographic data were collected from 155 subjects with varying severity of OSA and 52 control subjects. Plasma levels of APRIL were measured by human Magnetic Luminex assay. ResultsPlasma APRIL levels were significantly higher in OSA subjects compared with control subjects. Categorization of the OSA subjects into mild, moderate, and severe OSA subgroups found that plasma levels of APRIL increased with the severity of OSA. After adjusting confounding factors, found that increased plasma APRIL levels were conferred a higher odds ratio of OSA. Moreover, plasma APRIL levels were positively associated with the apnea-hypopnea index, which represents the severity of OSA. Furthermore, plasma APRIL showed higher discriminatory accuracy in predicting the presence of OSA. ConclusionsPlasma APRIL levels were significantly associated with the occurrence of OSA and its severity. APRIL could be a plasma biomarker with a positive diagnostic value for inflammation and NF-KB–dependent inflammatory pathways activation in subjects with OSA.Trial registration: The project was approved by the Chinese Clinical Trial Registry (No. ChiCTRROC-17011027).

Increased APRIL Expression Induces IgA1 Aberrant Glycosylation in IgA Nephropathy.

Aberrant glycosylated IgA1 molecules, mainly galactose-deficient IgA1 (Gd-IgA1), are important causal factors in IgA nephropathy; however, the underlying mechanism for the production of aberrantly glycosylated IgA1 is unknown. A recent genome-wide association study identified a novel IgAN susceptibility gene, TNFSF13, which encoded a proliferation-inducing ligand (APRIL) that promotes lymphocyte proliferation and IgA class switching. We aimed to explore the mechanism of APRIL's involvement in IgAN. We enrolled 166 patients with IgAN and 77 healthy controls and detected the plasma APRIL levels by the ELISA method, identified the mRNA expression of APRIL and its receptors by relative quantitative PCR, and confirmed by in vitro experiment. We identified increased plasma APRIL levels in IgAN, which was further proved by upregulated mRNA expression in B-lymphocytes from 27 IgAN patients. Analysis of the clinical characteristics of patients with IgAN showed that higher plasma APRIL level was associated with more severe clinical presentations (high proteinuria and low eGFR). The plasma APRIL level was positively correlated with Gd-IgA1 levels. Furthermore, exogenous APRIL could induce more production of Gd-IgA1 in cultured lymphocytes from patients with IgAN, compared with that from healthy controls. And, the relative higher expression of receptors of APRIL, that is, BCMA and TACI, in B-lymphocytes from IgAN patients were observed. Our findings implied that in patients with IgAN, increased APRIL is accompanied elevated expression of its receptors in B-lymphocytes, which induces overproduction of Gd-IgA1, ultimately contributing to the pathogenesis of IgAN.

Features of Microparticle-Associated Procoagulant Activity in Patients with Thrombocytopenias of Immune and Central Origin

Introduction: The risk of bleeding in patients with thrombocytopenia is increased with platelet counts less than 20 or 30 x 109/L. Nevertheless, some patients with thrombocytopenia of peripheral and central origin (immune thrombocytopenia [ITP] and myelodysplastic syndromes [MDS] respectively) have fewer bleeding symptoms than expected. This fact suggests there may be compensatory mechanisms for the thrombocytopenia, such as the presence of microparticles (MPs).Objective: The aim of this study was to evaluate and characterize the microparticle-associated procoagulant activity in ITP and MDS patients with thrombocytopenia.Methods: Thirty-five patients with chronic ITP and twenty-six patients with MDS with a platelet count less than 50 x109/L and twenty-five healthy controls were included. Blood cell counts were determined with a Coulter Ac. T Diff cell counter (Beckman Coulter, Madrid, Spain). Citrated blood was centrifuged at 1,500 g for 15 min at 23°C. Platelet-poor plasma obtained was additionally centrifuged twice at 23°C (15 min at 1,500 g, and 2 min at 13,000 g, [PFP]) and aliquots were stored at -70ºC until analysis.Phosphatidylserine-MP (Ph-MP) and tissue factor-MP (TF-MP)-dependent procoagulant activities were determined with the ZYMUPHEN kits (Hyphen BioMed, Neuville sur Oise, France) following the manufacturer’s instructions.The identification of MP’s cell origin was determined by flow cytometry labeling MPs with Annexin-V-fluorescein and the following specific monoclonal antibodies (mAb) conjugated with phycoerythrin: anti CD41 mAb for platelets, anti CD14 mAb for monocytes, anti CD144 mAb for endothelial cells, anti CD235 mAb for red cells and anti CD45 mAb for leukocytes.APRIL plasma levels were determined by ELISA (DuoSet ELISA, R&D Systems, Minneapolis,MN, USA).Results: Ph-MP associated procoagulant capacity in MDS and ITP patients was higher than in controls (p<0.01) whereas MP-TF associated procoagulant activity was only increased in MDS patients and practically negligible in ITP and control groups (p<0.01).MPs analysis by flow cytometry of seventeen controls, twenty ITP and six MDS patients showed that ITP patients had an increased percentage of MPs from platelets and red cells, whereas MDS had an increased percentage of monocytes derived MPs. Proportion of MPs derived from other cell types were similar to the control group.Increased percentage of monocyte-derived MPs in MDS patients is in accordance with the higher MP-TF-associated capacity observed in this group since monocytes are tissue factor rich cells. Nevertheless, no differences were found in monocyte count with control and ITP groups and monocyte count did not correlate with MPs associated procoagulant activity and the percentage of monocyte-derived MPs.In the ITP group neither MP-Ph-associated procoagulant activity nor the percentage of red cell-derived MPs correlated with red cell count. On the contrary, MP-Ph-associated procoagulant activity and the percentage of platelet-derived MPs inversely correlated with platelet count.ITP is an antibody-mediated autoimmune disease characterized by accelerated platelet destruction. A proliferation-inducing ligand (APRIL) is a factor that promotes B-cell maturation and survival. All patients with ITP and thrombocytopaenia showed higher APRIL plasma levels than MDS and control groups (p<.01), which inversely correlated with platelet count and correlated to MP-Ph-associated procoagulant activity. These observations support the proposed pathogenic role of APRIL in the development of this disease and that the increase in platelet-derived MPs was due to peripheral platelet destruction.Conclusion: Peripheral and central thrombocytopenias might present a MP-associated procoagulant activity to compensate bleeding risk present in these patients. Cellular origin of these MPs differed according to thrombocytopaenia etiology. DisclosuresNo relevant conflicts of interest to declare.

Effect of thrombopoietin‐receptor agonists on a proliferation‐inducing ligand (APRIL) plasma levels in patients with immune thrombocytopaenia

Immune thrombocytopaenia (ITP) is an antibody-mediated autoimmune disease characterized by accelerated platelet destruction and suboptimal platelet production. Patients with ITP have increased plasma levels of a proliferation-inducing ligand (APRIL), a factor that can promote B-cell maturation and survival 1. Two thrombopoietin-receptor agonists [TPO-RA; romiplostim (Nplate®; Amgen, Thousand Oaks, CA, USA) and eltrombopag (Promacta®, Revolade®; GlaxoSmithKline, London, UK)] have recently been approved for the treatment of chronic ITP. They both bind to the thrombopoietin receptor (TPO-R) and activate megakaryopoiesis. We aimed to investigate whether TPO-RA treatment of patients with ITP had any effect on APRIL plasma levels and to compare these results with those observed in ITP patients treated with intravenous immunoglobulins (IVIg). Two groups of chronic ITP patients were included; one group (n = 13) was treated with a TPO-RA (two with romiplostin and 11 with eltrombopag, 46% female; mean age, 63 years) and the other group (n = 17) was treated with IVIg (82% female; mean age, 70 years). The ITP patients were studied before and after responding to therapy, defined as a platelet count ≥30 × 109 l−1 and at least twofold increase over the baseline count. Fiveteen patients with myelodysplastic syndromes who presented thrombocytopaenia (40% female; mean age, 75 years) and 35 healthy control subjects (56% female; mean age, 51 years) were also included for comparison. This study was performed in accordance with the policy of the local Ethics Committee. Blood samples were collected in EDTA. The APRIL concentration was measured by an enzyme-linked immunosorbent assay (R&D Systems, Minneapolis, MN, USA) in platelet-poor plasma. The platelet count of patients with ITP before treatment and of patients with myelodysplastic syndromes were lower than those in the control group (P < 0.001). After responding to the treatments, ITP patients had increased platelet counts (Figure ​(Figure1A1A). Figure 1 (A) Platelet count. (B) Plasma APRIL levels (C) Correlation between a proliferation inducing ligand (APRIL) plasma levels and platelet count. The Wilcoxon matched-pairs signed-ranks test was performed to compare data of patients with immune thrombocytopaenia ... All patients with ITP and thrombocytopaenia showed higher APRIL plasma levels than the control group (P < 0.01, Figure ​Figure1B),1B), which was inversely correlated with platelet count (Figure ​(Figure1C). This1C). This observation supports the proposed pathogenic role of APRIL in the development of this disease 2. Moreover, plasma APRIL levels in ITP patients were also higher than in the myelodysplastic syndrome patients (P < 0.01, Figure ​Figure1B),1B), which suggested that increased APRIL levels were not due to thrombocytopaenia but rather to the mechanism that caused the disease. Plasma levels of APRIL were reduced to control values in patients with ITP who responded to TPO-RA treatment, whereas they remained high after response to IVIg (Figure ​(Figure1B1B). Gu et al. 3 reported normal APRIL plasma levels in patients with ITP with normal platelet counts who had undergone splenectomy or been treated with corticosteroids. In our TPO-RA-treated group, only two of the patients were splenectomized and one was receiving concomitant corticosteroid treatment, so the reduced APRIL levels might be due to another cause. A beneficial effect of TPO-RA treatment on the immune system has been reported 4. Transforming growth factor-β1, an anti-inflammatory cytokine that inhibits B-cell proliferation and antibody production 5, was increased in patients with ITP who responded to TPO-RA treatment. It is therefore tempting to speculate that TPO-RAs possess immunomodulatory activity in addition to their profound effect on megakaryopoiesis. This possibility gives value to this study, despite the small size of the groups included, and gives support to the necessity of performing a study with more patients to elucidate the mechanism involved in the reduction of APRIL levels caused by TPO-RAs.

Raised Expression of APRIL in Chinese Children With Acute Lymphoblastic Leukemia and its Clinical Implications

This study was to determine the expression of a proliferation-inducing ligand (APRIL) and its receptors, B-cell maturation antigen (BCMA) and transmembrane activator and calcium-modulating cyclophilin ligand interactor in childhood acute lymphoblastic leukemia (ALL). The correlation between the plasma APRIL levels and clinical status was also evaluated. Plasma samples from 20 untreated children with ALL, 23 children with ALL in remission, and 15 normal controls were assayed for APRIL plasma concentration by enzyme-linked immunosorbent assay. Real-time quantitative polymerase chain reaction was performed to determine the mRNA expression of APRIL and its receptors in blood mononuclear cells in 20 untreated ALL children and 15 normal controls. The untreated ALL patients had higher plasma APRIL levels than the remission group and the normal controls (P<0.001, respectively). No significant difference was found between the remission group and the normal controls in the plasma APRIL levels (P=0.339). The plasma APRIL levels in the untreated patients correlated with white blood cell count at diagnosis (P=0.002) and risk category (P=0.013). The mRNA expression of both APRIL and BCMA in blood mononuclear cells of the ALL patients were higher than those of the normal controls (both P<0.001). No significant difference was found between the patients and the normal controls in the transmembrane activator and calcium-modulating cyclophilin ligand interactor expression (P>0.05). These findings indicate that APRIL and BCMA are over expressed in untreated ALL children. The levels of APRIL correlate with the progression of childhood ALL, which may provide certain clues for monitoring ALL clinically.

Effects Of Thrombopoietin Receptor Agonists On APRIL Plasma Levels In Patients With Immune Thrombocytopenia

IntroductionImmune thrombocytopenia (ITP) is an example of an autoimmune disease in which B-lymphocytes produce autoantibodies against platelets. Antibody-mediated platelet destruction and suboptimal platelet production leads to a decrease in platelet count. ITP patients with thrombocytopaenia have increased plasma levels of a proliferation-inducing ligand (APRIL), a factor that can promote B-cell maturation and survival.Two new compounds that bind to the thrombopoietin receptor (TPO-R) and activate the megakaryopoiesis have been recently approved for the treatment of chronic ITP as second-line treatment. ObjectiveIt has been recently reported an improved regulatory T-cell activity in patients with chronic ITP treated with TPO-R agonists (TPO-RA) (Bao et al, 2010). So we aimed to evaluate the effect of TPO-RA treatment on APRIL plasma levels in ITP patients before (ITP-1) and after responding (ITP-2) to the treatment. MethodsThis was an observational and prospective study. Thirteen patients with chronic ITP in whom treatment with a TPO-RA was indicated, and thirty-three healthy controls were included. ITP patients were studied at two times: at inclusion (ITP-1), when platelet count was less than 30x109/L for patients without concomitant medication or less than 65x109/L for patients receiving corticosteroids or intravenous immunoglobulin; and after a response to TPO-RA therapy was elicited (ITP-2). The response to TPO-RA was defined as a platelet count >30x109/L in patients without additional treatment or >65x109/L for those with concomitant treatments.EDTA-anticoagulated whole blood was centrifuged at 1,500 g for 15 min at 23°C to obtain platelet poor plasma which was then centrifuged at 10,000 g for 15 min at room temperature. Supernatant plasma was stored at –70°C until analysis. Plasma TPO and APRIL concentrations were determined using a commercially available enzyme-linked immunosorbent assay (ELISA, Duoset-R&D, Minneapolis, Mn, USA). Platelet counts were determined with a Coulter Ac. T Diff cell counter (Beckman Coulter, Madrid, Spain).Comparisons of quantitative variables were made with ANOVA and Dunn test. Results were expressed as mean±SD. Correlations were calculated with Spearman test. Values of p≤0.05 were considered statistically significant. ResultsPlatelet count in the ITP-1 group ((23±17)x109/L) increased after responding to TPO-RA to values similar to controls (controls: (233±77)x109/L and ITP-2: (140±36)x109/L).TPO plasma level was higher in ITP-1 patients (30.05±26.81 pg/ml, p<0.005) than in healthy controls (7.36±11.74 pg/ml) but not significantly different when compared with the values of the ITP-2 group (26.81±17.62 pg/ml).ITP-1 patients showed significantly higher APRIL plasma levels (37.60+28.73 ng/ml, p<0.0001) than controls (2.20±3.11 ng/ml) and ITP-2 patients (4.92+4.68 ng/ml), indicating that TPO-RA treatment caused a diminution in APRIL plasma levels.When looking into the relationship between APRIL plasma levels and platelet count, a significant correlation was only found in the ITP-1 group (r=-0.5919, p<0.05). This supports the potential role of APRIL in the reduction of platelet counts in ITP patients. ConclusionITP patients with thrombocytopaenia that responded to TPO-RA treatment increased their platelet count reducing plasma APRIL levels and without changing the moderately high levels of plasma TPO. Reductions in APRIL levels caused by TPO-RA treatment could be an additional mechanism that contributes to an increased platelet count in ITP patients treated with these agents.Bao W, Bussel JB, Heck S, et al. Improved regulatory T-cell activity in patients with chronic immune thrombocytopenia treated with thrombopoietic agents. Blood. 2010 Nov 25;116(22):4639-4645 Disclosures:No relevant conflicts of interest to declare.

Raised expression of APRIL in Chinese patients with immune thrombocytopenia and its clinical implications

Background: Immune thrombocytopenia (ITP) is an immune-mediated disorder in which destruction of platelets is accelerated by anti-platelet autoimmune antibodies. B-cell-activating factor (BAFF) and a proliferation-inducing ligand (APRIL), essential factors for B cell survival are elevated in systemic autoimmune diseases and correlated with clinical findings. High expression of BAFF has been shown in patients with ITP, but the status of APRIL in ITP is still unknown.Objective: To determine the expression of APRIL and it receptors, B-cell maturation antigen (BCMA) and trans-membrane activator and calcium modulator and cyclophilin ligand interactor (TACI), in patients with ITP, and evaluate the correlation between plasma APRIL levels and platelet accounts or other clinical parameters.Methods: Plasma samples from 57 patients with ITP, and 30 normal healthy subjects were assayed for APRIL plasma concentration by enzyme linked immunosorbent assay. Real-time quantitative polymerase chain reaction was performed to determine the mRNA expression of APRIL and its receptors (BCMA and TACI) in peripheral blood mononuclear cells (PBMNCs) in 25 normal controls and 34 untreated ITP patients with active disease.Results: The APRIL levels in the plasma samples from patients with ITP were significantly higher than those from healthy controls (p = 0.000). PBMNCs may be a source of the excess APRIL. Treated patients with normal platelet count have relatively normal plasma APRIL (p = 0.599). Plasma APRIL levels in active patients were significantly correlated with platelet counts (r = − 0.387 and p = 0.024).Conclusion: APRIL is over expressed in untreated active ITP patients and might be a pathogenic factor of this disorder.

BAFF and APRIL expression in B-cell chronic lymphocytic leukemia: Correlation with biological and clinical features

B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are involved in normal B cell survival and differentiation. We analyzed BAFF and APRIL plasma levels in patients with B-cell chronic lymphocytic leukemia (B-CLL). We also tested intracellular BAFF and APRIL expression in B-CLL and evaluated their prognostic relevance. The percentage of leukemic B cells with intracellular APRIL or BAFF expression correlated significantly with adverse prognostic factors such as ZAP-70 and CD38. Moreover, we found a close relationship between LPL protein expression or LPL/ADAM29 MFI ratio and proportion of B-CLL cells with intracellular BAFF or APRIL expression. Furthermore, patients with a low percentage of leukemic cells with intracellular BAFF or APRIL expression had a significantly longer overall survival than those with a high proportion of APRIL or BAFF positive leukemic cells.

High circulating immunoglobulin A levels in infants are associated with intestinal toxigenic Staphylococcus aureus and a lower frequency of eczema

Intestinal bacteria trigger IgA production and delayed maturation of mucosal IgA response is linked to allergy development. Our aim was to investigate if plasma levels of IgA or APRIL (a proliferation inducing ligand), an important factor for IgA class switch recombination, in infancy correlates with intestinal colonization by any specific bacteria or yeast. We also examined if plasma IgA or APRIL levels are related to sensitization and the development of eczema. IgA was quantified in plasma obtained from infants at birth and at 4 and 18 months of age and APRIL was measured at 4 months of age. Colonization by major bacterial groups and yeast was followed in the first 8 weeks of life by quantitative culture of stool samples. A clinical evaluation regarding the presence of allergen-specific IgE or eczema and eosinophil counts in blood was performed at 18 months of age. In multiple linear regression analysis, only colonization by Staphylococcus aureus strains producing toxins with superantigen function (SEA-D or TSST-1) made an independent contribution to plasma IgA levels at 4 months of age. Further, increased levels of APRIL in plasma at 4 months were negatively associated with sensitization while IgA plasma levels were inversely correlated to eczema development and blood eosinophil counts at 18 months of age. Early intestinal colonization by toxigenic S. aureus strains seems to promote systemic IgA responses. Furthermore, high levels of APRIL and IgA in the circulation at 4 months of age seem to correlate negatively with allergy development.

Age-related changes in BAFF and APRIL profiles and upregulation of BAFF and APRIL expression in patients with primary antibody deficiency

In some patients with common variable immunodeficiency (CVID) and immunoglobulin (Ig) A deficiency (IgAD), tumor necrosis factor (TNF) family receptor transmembrane activator and calcium-modulator and cyclophilin ligand interactor (TACI) gene mutations have been reported. B cells from individuals with TACI mutations do not produce IgG and IgA in response to the TACI ligand a proliferation-inducing ligand (APRIL) which probably suggests impaired isotype switching. To clarify the pathogenesis of CVID and IgAD of Japanese patients, we investigated the mutations of TNF family members TACI, APRIL, B-cell activating factor (BAFF), B-cell maturation antigen (BCMA) and BAFF receptor (BAFF-R) genes and the expression levels of BAFF and APRIL in patients with CVID, IgAD and X-linked agammaglobulinaemia (XLA). We also investigated the relationship between age and the blood plasma levels of BAFF and APRIL. The causative gene mutations of TNF family members in our patients were not detected. In healthy subjects, the BAFF and APRIL plasma levels correlated inversely with age. The BAFF and APRIL plasma levels of patients with CVID, IgAD and XLA were significantly higher than those of healthy children. Elevated BAFF and APRIL expression levels might partially reflect the common immunological feature of primary antibody deficiency.