Soko Kawashima

Immunopathologic co-localization of MPO, IgG, and C3 in glomeruli in human MPO-ANCA-associated glomerulonephritis.

Myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA)- associated glomerulonephritis (GN) is characterized by pauci-immune necrotizing glomerulonephritis(NGN). Although it has been thought that MPO-ANCA is involved in the pathogenesis of capillary injuries in NGN via activation of neutrophils, recent studies suggest a possible role of other factors such as immunoglobulins precipitated on the glomeruli. Here we performed a pathological study investigating a relationship of deposition of MPO, IgG, complements with regard to MPO-positive cells and glomerular capillaries in human MPO-ANCA-associated GN. Renal specimen including 317 glomeruli obtained from 20 patients with MPOANCA- associated GN were analyzed. All of the specimens showed significant focal segmental deposition of IgG. There was a significant glomerular infiltration of MPO-positive cells along with deposition of extracellular MPO in the active lesions of segmental and global NCG, with CD34 staining being decreased in the adjacent areas. IgG deposits were almost colocalized with C3 and partly with MPO, which are also associated with a decrease in CD34 staining, suggesting that immune complex formation and the resultant capillary injuries. Actually occurred, the colocalization of MPO, IgG and C3 was seen only in the glomerular lesions with low severity and activity. These results suggest that not only MPO itself released from the neutrophils but also immune complexes composed of MPO and anti-MPO antibody may play some pathogenetic roles for the glomerular injuries especially in the early phase of human MPO-ANCA-associated GN.

The effect of water loading on the urinary ratio of cortisone to cortisol in healthy subjects and a new approach to the evaluation of the ratio as an index for in vivo human 11β-hydroxysteroid dehydrogenase 2 activity

Factors that give rise to a large variation in the urinary ratio of free cortisone to cortisol (UFE/UFF) were investigated to accurately estimate 11β-hydroxysteroid dehydrogenase 2 (11β-HSD2) activity in humans in vivo. A water loading test was first carried out in two healthy subjects to examine the effect of water intake or urine volume on the urinary ratio of free cortisone to cortisol (UFE/UFF). The ratio was found to increase by water loading. We also examined urinary concentrations and amounts of cortisol, cortisone, creatinine, Na(+), K(+), and Cl(-), and urine volume, as possible factors affecting the urinary ratio (UFE/UFF), in 60 urine samples obtained from 15 healthy volunteers. Among these factors tested, the urinary concentration of cortisol was most highly correlated with the UFE/UFF ratio (r=-0.858), indicating that the in vivo activity of 11β-HSD2 (UFE/UFF) should fluctuate with the changes of the urinary concentration of cortisol. Based on the findings, we proposed a new estimation method of in vivo activity of 11β-HSD2 in humans, using the UFE/UFF ratio correlated with the urinary concentration of cortisol (UFE/UFF-cortisol concentration). Taking into consideration the intra-individual variabilities in the urinary concentration of cortisol, there were no significant within-day variations in 11β-HSD2 activity. The findings indicate that 11β-HSD2 activities can be accurately evaluated by simply measuring free cortisol and cortisone concentrations in spot urine samples. Furthermore, administrations of glycyrrhetinic acid in three healthy volunteers were performed to confirm the usefulness of the present assessment for the activity of 11β-HSD2.

The role of myeloperoxidase and myeloperoxidase–antineutrophil cytoplasmic antibodies (MPO-ANCAs) in the pathogenesis of human MPO-ANCA-associated glomerulonephritis

It is well known that antineutrophil cytoplasmic antibodies (ANCAs) are pathogenic and have a diagnostic value for ANCA-associated vasculitis. We demonstrated that a rise in myeloperoxidase (MPO)-ANCA titers during remission is often predictive of a future relapse in MPO-ANCA-associated vasculitis. Pathological examination of renal biopsies indicated that not only MPO-ANCAs, but also extracellular MPO, an in situ immune complex composed of MPO and MPO antibodies, may play important roles in the pathogenesis of glomerular capillary injury in MPO-ANCA-associated vasculitis.

Systematic review and meta-analysis for 2017 clinical practice guidelines of the Japan research committee of the ministry of health, labour, and welfare for intractable vasculitis for the management of ANCA-associated vasculitis

Abstract Objectives: To provide evidence for the revision of clinical practice guideline (CPG) for the management of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) by the Japan Research Committee for Intractable Vasculitis. Methods: PubMed, CENTRAL, and the Japan Medical Abstracts Society were searched for articles published between January 1994 and January 2015 to conduct systematic review (SR), and the quality of evidence was assessed with GRADE approach. Results: Nine randomized controlled trials (RCTs) and two non-RCTs were adopted for remission induction therapy, three RCTs and two non-RCTs for plasma exchange, and five RCTs and one non-RCT for remission maintenance therapy. A significant difference was found in efficacy and safety for the following comparisons. In the non-RCT adopted for remission induction therapy, glucocorticoid (GC) + cyclophosphamide (CY) was significantly superior to GC monotherapy regarding remission. GC + intravenous CY for remission induction therapy was superior to GC + oral CY regarding death at one year, serious adverse events, and serious infection. Concomitant use of plasma exchange for remission induction therapy of AAV with severe renal dysfunction reduced risk of end-stage renal disease versus non-users at month 3. Conclusion: This SR provided necessary evidence for developing CPG for the management of ANCA-associated vasculitis.

A Dialysis Patient With Hyperphosphatemia, Hyperkalemia, and Azotemia Without an Excessive Intake

INTRODUCTION I t is well known that the strict control of serum inorganic phosphorus (IP) and potassium (K) concentrations is important for the prevention of various complications and improving the prognosis of patients with chronic kidney disease (CKD). Hyperkalemia is associated with sudden cardiac death in hemodialysis (HD) patients and hyperphosphatemia is associated with an increase in cardiovascular events and mortality in CKD patients. It is a common practice to restrict IP and K intake when HD patients present with these electrolyte abnormalities. However, these abnormalities are not always caused by an excessive intake. We evaluated and treated a CKD case with hyperphosphatemia, hyperkalemia, and azotemia, likely caused by poor carbohydrate intake.

SAT0183 Autoantibodies for Several Antigens in Neutrophil Cytoplasm other than PR3 and MPO Promote Release of Nets from Neutrophils

Background Neutrophil extracellular traps (NETs) were first described as web-like structures that trap and neutralize microbes at sites of infection. NETs are comprised of chromatin components and neutrophil cytoplasmic proteins. Because these components of NETs might provide an immunogenic substrate for autoimmune responses during regular encounters with commensal and pathogenic microbes, it has been reported that NETs are involved in autoimmunity such as SLE or ANCA associated vasculitis (AAV). It has also been reported that autoantibodies themselves for important cytoplasmic auto-antigens of neutrophils such as MPO or PR3 induce NETs production. However, the role of other neutrophil cytoplasmic antigens for the production of NETs is unclear. Objectives Thus, we investigated how auto-antibodies for these antigens other than PR3 and MPO are involved in NETs productions by neutrophils. Methods Human peripheral blood neutrophils were obtained from healthy donors. Neutrophils were seed onto Polystyrene chamber slide system and incubated with PMA (control) or PMA plus several kinds of anti-neutrophil cytoplasmic antigens for 3 hours. Cells were fixed and stained with Hoechst 33342 and Sytox Green for DNA and anti-MPO antibody. The percentage NETs producing cells and the quantitation of nuclear decondensation were analyzed using Image J software. We distinguished cells that released NETs fiber from cells that just died of NETosis. Results Anti-MPO antibody strongly promoted both NETosis induction and release of NETs fiber. Although anti-PR3 antibody promoted NETosis induction, it did not increase the release of NETs fiber. Antibody for cathepsin G, found in the azunophil granule, also promoted NETosis induction only. There were some other antibodies, such as anti-lactoferrin and anti-neutrophil elastase, that promoted both NETosis and release of NETs fiber. Conclusions It has been thought that ANCAs directed against granule proteins of neutrophils are implicated in the pathogenesis of AAV, partly because ANCAs promote NETs production by neutrophils. We showed that not only anti-MPO and anti-PR3 but also antibodies for other neutrophil cytoplasmic antigens promote NETs production. The mechanism these antibodies for cytoplasmic protein induce NETosis and how important they are for the pathogenesis of AAV are to be elucidated. Disclosure of Interest None Declared