Hypertrophic pachymeningitis associated with antineutrophil cytoplasmic antibody-associated vasculitis: a case series of 15 patients.

OBJECTIVE: We aimed to describe the clinical characteristics and treatment course of hypertrophic pachymeningitis (HPM) in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). METHODS: We retrospectively analysed 15 patients (11 men and four women). HPM was diagnosed based on thickening and enhancing of the brain and/or spinal dura mater on gadolinium-enhanced magnetic resonance imaging (MRI) T1 sequence. RESULTS: The median age at HPM onset was 60 years. Headache and cranial nerve impairment were observed in 14 and 10 patients, respectively. Otitis media and/or mastoiditis were found as complications of AAV in 11 patients. Fourteen patients were classified as having granulomatosis with polyangiitis (GPA). Single-positive myeloperoxidase-ANCA, single-positive proteinase 3-ANCA, and double-positive ANCA were identified in seven patients, five patients, and one patient, respectively. With MRI, thickening of the dura mater in the cranial fossa and tentorium cerebelli was found in 10 and eight patients, respectively. For remission induction, all patients were treated with corticosteroids, and immunosuppressants were added in 10 patients. Dura mater thickening partially improved in all patients, and cranial neuropathy completely remitted in eight patients. In a median follow-up of 43 months, four patients had HPM relapse and underwent reinduction therapy. All six patients treated with cyclophosphamide at initial therapy did not relapse. CONCLUSIONS: HPM was mostly associated with patients with GPA with otitis media and/or mastoiditis having either type of ANCA serology. Treatment with corticosteroids with or without immunosuppressants was effective. However, HPM relapse occasionally occurred, especially when cyclophosphamide was not used in initial treatment.

The correlation of urinary podocytes and podocalyxin with histological features of lupus nephritis.

Objectives The objective of this study was to test the correlation of urinary podocyte number (U-Pod) and urinary podocalyxin levels (U-PCX) with histology of lupus nephritis. Methods This was an observational, cross-sectional study. Sixty-four patients were enrolled: 40 with lupus nephritis and 24 without lupus nephritis (12 lupus nephritis patients in complete remission and 12 systemic lupus erythematosus patients without lupus nephritis). Urine samples were collected before initiating treatment. U-Pod was determined by counting podocalyxin-positive cells, and U-PCX was measured by sandwich ELISA, normalized to urinary creatinine levels (U-Pod/Cr, U-PCX/Cr). Results Lupus nephritis patients showed significantly higher U-Pod/Cr and U-PCX/Cr compared with patients without lupus nephritis. U-Pod/Cr was high in proliferative lupus nephritis (class III±V/IV±V), especially in pure class IV (4.57 (2.02-16.75)), but low in pure class V (0.30 (0.00-0.71)). U-Pod/Cr showed a positive correlation with activity index ( r=0.50, P=0.0012) and was independently associated with cellular crescent formation. In contrast, U-PCX/Cr was high in both proliferative and membranous lupus nephritis. Receiver operating characteristic analysis revealed significant correlation of U-Pod/Cr with pure class IV, class IV±V and cellular crescent formation, and the combined values of U-Pod/Cr and U-PCX/Cr were shown to be associated with pure class V. Conclusions U-Pod/Cr and U-PCX/Cr correlate with histological features of lupus nephritis.

Analysis of cytochrome P450 gene polymorphism in a lupus nephritis patient in whom tacrolimus blood concentration was markedly elevated after administration of azole antifungal agents.

WHAT IS KNOWN AND OBJECTIVE: Both itraconazole (ITCZ) and voriconazole (VCZ) are potent inhibitors of cytochrome P450 (CYP) 3A, and their effects have been reported to be equal. However, ITCZ is metabolized by CYP3A, whereas VCZ is mainly metabolized by CYP2C9 and CYP2C19 and only partially by CYP3A. We experienced the case of a patient who showed a 5-fold increase in trough levels of tacrolimus (FK) level after switching from ITCZ to VCZ. Our objective is to discuss the mechanism of the increase drug-drug interaction in terms of serum concentration of the azole drugs and patient pharmacogenomics. CASE SUMMARY: A 53-year-old woman was treated with FK (1 mg/day) for lupus nephritis. Because fungal infection was suspected, she received ITCZ (100 mg/day). When ITCZ was replaced with VCZ (400 mg/day), the blood concentration of FK increased markedly from 6·1 to 34·2 ng/mL. During coadministration with FK, the levels of ITCZ and VCZ were 135·5 ng/mL and 5·5 µg/mL, respectively, with the VCZ level around 3-fold higher than the previously reported level (1·4-1·8 µg/mL). Her CYP genotypes were CYP2C19*1/*2, CYP3A4*1/*1 and CYP3A5*3/*3. WHAT IS NEW AND CONCLUSION: The patient was a CYP2C19 intermediate metabolizer (IM) and deficient in CYP3A5. The increase in plasma VCZ level appears to have been at least in part, associated with the CYP2C19 IM phenotype. One possible explanation for the marked increase in blood FK concentration was increased inhibition of CYP3A because of the impaired metabolism and subsequent increased plasma concentration of VCZ. This case shows that the severity of drug interactions may be influenced by metabolic gene polymorphism.

Pro32Thr polymorphism of inosine triphosphate pyrophosphatase gene predicts efficacy of low-dose azathioprine for patients with systemic lupus erythematosus.

We evaluated the relationship between the efficacy of low-dose azathioprine (AZA) therapy and the inosine triphosphate pyrophosphatase (ITPA) 94C>A (Pro32Thr) polymorphism in patients with systemic lupus erythematosus (SLE). We performed a multiple regression analysis to assess the influence of various factors on the reduction in SLE disease activity index (SLEDAI) scores. The ITPA 94C>A polymorphism had the highest correlation with the change in SLEDAI score (r = 0.354, P = 0.006).

Revised classification of lupus nephritis is valuable in predicting renal outcome with an indication of the proportion of glomeruli affected by chronic lesions.

OBJECTIVES: To determine if the International Society of Nephrology/Renal Pathology Society (ISN/RPS) 2003 classification of lupus nephritis (LN) is helpful in predicting renal outcome. METHODS: A total of 92 patients with LN who underwent renal biopsy in our hospital were re-classified according to the ISN/RPS 2003 criteria. RESULTS: The mean patient age was 36.8 yrs and the median observation period was 65 months. The relative frequency for each class was as follows: Class I (minimal mesangial LN) 0%, Class II (mesangial proliferative LN) 13%, Class III (focal LN) 17%, Class IV (diffuse LN) 60% and Class V (membranous LN) 10%. Within Class IV, diffuse segmental (Class IV-S) was 25% and diffuse global (Class IV-G) 75%. During the observation period, renal function was more likely to deteriorate in Class IV-G cases than in Class IV-S cases. Importantly, when Class IV-G was subdivided into cases involving active lesion alone [IV-G (A)] or chronic lesion [IV-G (A/C)], the majority of cases in IV-G (A) was nephrotic, but responded well to therapy. In contrast, renal function declined only in IV-G (A/C) cases. Patients with Class IV-G (A/C) had persistent proteinuria in spite of intensified therapies. Moreover, the higher proportion of chronic lesions was related with the deterioration of renal function. CONCLUSIONS: This study showed that in Class IV-G cases, renal outcome differed in the presence of chronicity. Chronicity could be a critical factor in predicting outcome. Thus, the revised classification of LN is clinically valuable in identifying different renal outcomes among patients with diffuse LN.

Expression of IL-19 and its receptors in RA: potential role for synovial hyperplasia formation.

OBJECTIVE: IL-19 is a novel cytokine of the IL-10 family. In this study, we sought to examine whether IL-19 plays a role in the pathogenesis of RA. METHODS: Expression of IL-19, IL-20 receptor 1 (IL-20R1) and IL-20R2 was examined by RT-PCR and immunohistochemical analysis in rheumatoid synovium. The effects of IL-19 on synovial cells established from rheumatoid synovium (RASCs), with regard to IL-6 production and signal transducers and activators of transcription3 (STAT3) activation, were examined by ELISA and western blot analysis, respectively. The effect of IL-19 on RASC apoptosis was examined by Hoechst staining, flow cytometry analysis of annexin V binding and caspase-3 activity. RESULTS: IL-19, IL-20R1 and IL-20R2 mRNA were detected by RT-PCR in synovial tissues from RA patients. Immunohistochemical analysis showed IL-19 was predominantly expressed in the hyperplastic lining layers of RA synovial tissues. The majority of IL-19-positive cells were vimentin-positive and CD68-positive synovial cells, serving as markers of fibroblasts and macrophages, respectively. IL-20R1 and IL-20R2 (IL-20Rs) were expressed in both the lining and sublining layers of RA synovium. In RASC, IL-19 was induced by lipopolysaccharide stimulation and constitutive expression of IL-20Rs was observed, suggesting IL-19 has an autocrine action. In terms of this function, IL-19 induced STAT3 activation and increased IL-6 production by RASC above the medium control. Moreover, IL-19 significantly reduced RASC apoptosis induced by serum starvation. CONCLUSIONS: These data suggest that IL-19, produced by synovial cells, promotes joint inflammation in RA by inducing IL-6 production and decreasing synovial cell apoptosis.

Nestin expression in the kidney with an obstructed ureter.

Nestin is an intermediate filament protein originally identified in neuroepithelial stem cells. This cytoskeletal-associated protein is also expressed in some non-neuronal organs including renal tubular cells and glomerular endothelial cells during kidney development. Little is known, however, about nestin expression in the kidney during injury. In this study, we find nestin expression induced in renal tubular and interstitial myofibroblasts in the adult rat kidney following unilateral ureteral obstruction. The degree of nestin expression was well correlated with the degree of tubulointerstitial fibrosis. Immunohistochemical identification of specific nephron segments showed that nestin was primarily expressed by proximal tubules, partially by distal tubules and thick ascending limbs of Henle but not by collecting ducts. The nestin-positive tubular cells also expressed vimentin and heat-shock protein 47 (HSP47) suggesting these cells reverted to a mesenchymal phenotype. Not all vimentin- or HSP-expressing cells expressed nestin; however, suggesting that nestin is distinct from these conventional mesenchymal markers. Nestin expression was also found associated with phenotypical changes in cultured renal cells induced by hypoxia or transforming growth factor-beta. Nestin expression was located in hypoxic regions of the kidney with an obstructed ureter. Our results indicate that nestin could be a novel marker for tubulointerstitial injury.

Widespread crystalline inclusions affecting podocytes, tubular cells and interstitial histiocytes in the myeloma kidney.

Numerous crystalline inclusions were observed in glomerular and tubular epithelial cells in a 46-year-old female patient with multiple myeloma and renal dysfunction. On light microscopy, epithelial cells were filled with homogenous materials and were remarkably swollen. Infiltrations of histiocytes with expanded cytoplasm were also seen in the interstitium of the kidney and bone marrow. On electron microscopy, cytoplasmic inclusions had crystalline structure showing rhomboid and oval shapes. Immunofluorescence study revealed that these cells were positive for IgG-kappa. The combination chemotherapy followed by autologous stem cell transplantation led to a partial resolution of her renal dysfunction, continued by a slight reduction in the number of crystalline-containing podocytes at the second renal biopsy. Crystal inclusions in the kidney are rarely found and cause renal impairment in multiple myeloma.

The subcellular localization of cyclin dependent kinase 2 determines the fate of mesangial cells: role in apoptosis and proliferation.

Apoptosis is closely linked to proliferation. In this study we showed that inducing apoptosis in mouse mesangial cells with ultraviolet (UV) irradiation was associated with increased cyclin A-cyclin dependent kinase (CDK) 2 activity. Inhibiting CDK2 activity with Roscovitine or dominant negative mutant reduced apoptosis. Because apoptosis typically begins in the cytoplasm, we tested the hypothesis that the subcellular localization of CDK2 determines the proliferative or apoptotic fate of the cell. Our results showed that cyclin A-CDK2 was nuclear in proliferating cells. However, inducing apoptosis in proliferating cells with UV irradiation was associated with a decrease in nuclear cyclin A and CDK2 protein levels. This coincided with an increase in protein and kinase activity for cyclin A-CDK2 in the cytoplasm. Translocation of cyclin A-CDK2 also occurred in p53-/- mesangial cells. Finally, we showed that caspase-3 activity was significantly reduced by inhibiting CDK2 activity with Roscovitine. In summary, our results show that apoptosis is associated with an increase in cytoplasmic cyclin A-CDK2 activity, which is p53 independent and upstream of caspase-3. We propose that the subcellular localization of CDK2 determines the proliferative or apoptotic fate of the cell.

Podocyte expression of the CDK-inhibitor p57 during development and disease.

BACKGROUND: The mature podocyte is a terminally differentiated cell with a limited proliferative capacity. The precise cell cycle proteins necessary for establishing podocyte quiescence during development or permitting podocyte cell cycle re-entry in disease states have not been fully defined. Accordingly, we studied the role of the cyclin dependent kinase (CDK)-inhibitor p57Kip2 (p57) in modulating these processes. METHODS: The expression of p57 protein in relation to markers of DNA synthesis was examined in developing mouse kidneys, and in the passive Heymann nephritis (PHN) and anti-glomerular antibody models of glomerular disease by immunohistochemistry. The role of p57 in glomerulogenesis was explored by examining renal tissue from embryonic p57-/- mice, and the expression of p21, p27 and p57 protein and mRNA was examined in podocytes in vitro. RESULTS: The de novo expression of p57 during glomerulogenesis coincides with the cessation of podocyte proliferation, and the establishment of a mature phenotype, and p57 is expressed exclusively in podocytes in mature glomeruli. However, p57 knockout mice have normal glomerular podocyte development. In addition, mRNA but not protein levels of p57 increased upon differentiation of podocytes in vitro. There was a marked decrease in p57 expression in both animal models of podocyte injury. This was diffuse in PHN, whereas in the murine model, loss of expression of p57 occurred predominantly in proliferating podocytes, expressing proliferating cell nuclear antigen (PCNA). CONCLUSION: Despite the de novo expression of p57 protein coinciding with the cessation of primitive podocyte proliferation during glomerulogenesis, embryonic p57-/- mice glomeruli were histologically normal. Cultured podocytes did not require changes in p57 protein levels to undergo differentiation. These data suggest that p57 alone is not required for podocyte differentiation, and that other cell cycle regulators may play a role. Furthermore, although injury to mature podocytes in experimental glomerular disease is associated with a decrease in p57, the levels of all three members of the Cip/Kip family of CDK inhibitors appear to determine the capability of podocytes to proliferate.

Platelet-activating factor antagonist, SM-12502, attenuates experimental glomerular thrombosis in rats.

Platelet-activating factor (PAF) is involved in many pathologic conditions through its potent proinflammatory and vasoactive effects. Using a specific PAF antagonist, SM-12502, we investigated the role of PAF in rat experimental glomerular thrombosis. In this model, sequential injections of nephrotoxic serum (NTS) and lipopolysaccharide (LPS) selectively induce glomerular fibrin deposition accompanied by neutrophil accumulation. SM-12502, when injected simultaneously with either NTS or LPS, strongly inhibited glomerular fibrin deposition in a dose-dependent manner. In contrast, neutrophil invasion was similar in both SM-12502-injected and uninjected rats, suggesting that the antithrombotic effect was not mediated by inhibition of neutrophil migration. However, serum myeloperoxidase activity, a marker of neutrophil activation, was significantly suppressed by treatment with SM-12502. From a previous finding supporting the indispensable role of neutrophils in this model and the current observations, SM-12502 is suggested to attenuate glomerular thrombosis by inhibiting neutrophil activation. Thus, the present findings suggest an involvement of PAF in this glomerular thrombosis model.

Four cases of anti-myeloperoxidase antibody-related rapidly progressive glomerulonephritis during the course of idiopathic pulmonary fibrosis.

We report here 4 cases of rapidly progressive glomerulonephritis (RPGN) which developed during the management of idiopathic pulmonary fibrosis. In each patient, pulmonary disease preceded the onset of nephritis by 1 to 6 years. All patients had a high titer of serum autoantibodies against myeloperoxidase (MPO-ANCA) when the diagnosis of RPGN was made. Although the association of pulmonary fibrosis with ANCA-related glomerulonephritis has been occasionally described in the past literature, the sequence of pulmonary and renal injury has not been well defined. The present report demonstrates that idiopathic pulmonary fibrosis exists as a preceding condition in some patients with MPO-ANCA-related nephritis.

Modulation of apoptosis by the cyclin-dependent kinase inhibitor p27(Kip1).

Proliferation and apoptosis are increased in many types of inflammatory diseases. A role for the cyclin kinase inhibitor p27(Kip1) (p27) in limiting proliferation has been shown. In this study, we show that p27(-/-) mesangial cells and fibroblasts have strikingly elevated rates of apoptosis, not proliferation, when deprived of growth factors. Apoptosis was rescued by restoration of p27 expression. Cyclin A-cyclin-dependent kinase 2 (CDK2) activity, but not cyclin E-CDK2 activity, was increased in serum-starved p27(-/-) cells, and decreasing CDK2 activity, either pharmacologically (Roscovitine) or by a dominant-negative mutant, inhibited apoptosis. Our results show that a new biological function for the CDK inhibitor p27 is protection of cells from apoptosis by constraining CDK2 activity. These results suggest that CDK inhibitors are necessary for coordinating the cell cycle and cell-death programs so that cell viability is maintained during exit from the cell cycle.

A case of cimetidine-induced acute tubulointerstitial nephritis associated with antineutrophil cytoplasmic antibody.

We present a case of acute tubulointerstitial nephritis (ATIN) that developed in a 63-year-old man who had been taking cimetidine for treatment of a gastric ulcer. The constellation of clinical, laboratory, and histopathologic findings suggested drug-induced ATIN. Of interest, the patient had antineutrophil cytoplasmic antibody (ANCA) in his sera, reactive with myeloperoxidase, elastase, and lactoferrin. Prominent renal histological features included marked plasmacyte infiltration into the renal interstitium. Withdrawal of cimetidine resulted in complete resolution of renal findings, and the titers of ANCA concomitantly declined. Thus, cimetidine may have played a causative role in the development of ANCA-associated ATIN.

Tubulointerstitial mast cell infiltration in glomerulonephritis.

Mast cells are involved in chronic inflammation and tissue fibrosis. To determine whether these cells are also involved in tubulointerstitial injury in glomerulonephritis, we assayed mast cell infiltration in the kidneys of 107 patients with primary or secondary glomerulonephritis. Using a monoclonal antihuman tryptase antibody, we detected mast cells in the renal cortical tubulointerstitium, the periglomerular areas, and the medullary interstitium, but not in glomeruli. Renal cortical tubulointerstitial mast cells, including periglomerular area, were estimated as 0.8+/-1.6 cells/mm2 in minimal change nephrotic syndrome (n=7), 1.5+/-0.7 cells/mm2 in minor glomerular abnormalities without nephrotic syndrome (n=7), 6.5+/-7.7 cells/mm2 in membranous nephropathy(n=10), 12.9+/-15.5 cells/mm2 in lupus nephritis (n=15), 13.4+/-8.3 cells/mm2 in focal segmental glomerular sclerosis (n=6), 18.5+/-21.1 cells/mm2 in ANCA-related nephropathy (n=5), 19.8+/-14.2 cells/mm2 in membranoproliferative glomerulonephritis (n=5), 21.3+/-17.7 cells/mm2 in immunoglobulin A (IgA) nephropathy (n=42), and 33.0+/-33.8 cells/mm2 in diabetic nephropathy (n=10). Except for patients with the rapidly progressive glomerulonephritic syndrome (RPGN), the number of infiltrating mast cells significantly correlated with the serum concentration of creatinine at the time of renal biopsy (r=0.59; P < 0.0001) and with the intensity of tubulointerstitial injury as measured by leukocyte infiltration (r=0.72; P < 0.0001) and fibrosis (r=0.75; P < 0.0001). In contrast, mast cell infiltration did not correlate with urinary protein excretion. In relation to serum creatinine concentration, the number of mast cells was fewer in patients with RPGN than in those with chronic glomerulonephritis. These data suggest that mast cells may contribute to the renal deterioration in glomerulonephritis by inducing chronic tubulointerstitial injury.

Case of propylthiouracil-induced vasculitis associated with anti-neutrophil cytoplasmic antibody (ANCA); review of literature.

A 39-year-old Japanese woman had been receiving propylthiouracil for 5 years for hyperthyroidism when she developed myalgia, scleritis, proteinuria, fever, and inflammation of the nose. Examination of a renal biopsy specimen showed focal segmental necrotizing glomerulonephritis. Indirect immunofluorescent staining showed a highly positive perinuclear pattern of anti-neutrophil cytoplasmic antibody (ANCA) in her serum. Enzyme-linked immunosorbent assay (ELISA) of the ANCA showed positivity for anti-proteinase 3, anti-myeloperoxidase, anti-leukocyte elastase, and anti-lactoferrin, but anti-cathepsin G and anti-lysozyme were negative. Because ELISA showed the titer of anti-leukocyte elastase antibody to be markedly elevated, we challenged this data by performing dot blot analysis. The patient's serum reacted with the native form, but not with denatured leukocyte elastase. Propylthiouracil-induced vasculitis was suspected. Symptoms abated within 2 weeks and all values of ANCA were reduced after the drug was withdrawn. Vasculitis is a rare side-effect of propylthiouracil therapy. Recently it was reported in association with ANCA. We present the findings of this patient and compare them with those described in 19 published cases of propylthiouracil-induced vasculitis associated with ANCA.

Role of serotonin in nephrotoxic serum nephritis in WKY rats.

Our objective was to determine whether serotonin is involved in inducing nephrotoxic serum nephritis in WKY rats. After injection of antiglomerular basement membrane antiserum, urinary protein excretion was significantly decreased in rats treated with the serotonin receptor antagonist, MCI-9042, and in rats treated with p-chlorophenylalanine. Similarly, severe necrotizing lesions and crescent formation were inhibited in a dose-dependent manner by treatment with MCI-9042 and p-chlorophenylalanine. The number of intraglomerular ED-1-positive cells was increased on day 3 and thereafter in the placebo group. A significant increase in the number of crescent lesions was observed in the placebo group on day 7 and thereafter. Neither adenosine diphosphate- nor collagen-induced platelet aggregations were inhibited in platelet-rich plasma from rats treated with MCI-9042. No significant differences were observed in the production of circulating antibody and antibody deposition in rat glomeruli among the study groups. These results indicate that pathologic changes and urinary protein excretion are closely related to the presence of serotonin in nephrotoxic serum nephritis of WKY rats. Thus serotonin may play a key role in the glomerular injury in this model. Studies on the mode of action of MCI-9042 on platelet aggregation in vivo indicate that the antiplatelet effect of this drug did not contribute to the inhibition of renal injury in this experimental model. This study suggests that serotonin participates in macrophage-mediated immune injury in nephrotoxic serum nephritis of WKY rats.