A case of non-lupus full-house nephropathy diagnosed by kidney biopsy but observed IgA nephropathy on second biopsy.

We describe a case of full-house nephropathy without any underlying disease, including systemic lupus erythematosus. A 40-year-old woman was referred to our hospital with mild proteinuria and microscopic hematuria. The patient was diagnosed with immune complex-mediated glomerulonephritis with a predominant mesangioproliferative pattern based on renal histopathological results using full-house immunofluorescence staining. She showed no clinical criteria for the diagnosis of systemic lupus erythematosus, except for kidney disorders, and tested negative for antinuclear antibodies throughout her clinical course. However, in the second kidney biopsy, no C1q or C4 were detected in the immunofluorescence study, suggesting an immunoglobulin A nephropathy-like pattern. The patient responded favorably to corticosteroid treatment. We found a heterozygous CFHR3-CFHR1 deletion. The association between full-house nephropathy and CFHR3-CFHR1 deletion is unknown, but its influence on the histological pattern in our case is suspected. This indicates the diversity in the pathogenesis of non-lupus full-house nephropathy and warrants further investigation.

Fatal acute portal vein thrombosis associated with hepatic cysts in a patient with autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) often involves polycystic liver disease (PLD). In severe cases, PLD can develop various complications. However, fatal acute portal vein thrombosis (APVT) associated with PLD has not been reported. A 64-year-old male reported mild consciousness disorder. He had been under maintenance hemodialysis for end-stage renal disease due to ADPKD with PLD. Because of recurring hepatic cyst infections, he had sustained high levels of C-reactive protein. Regarding the mild consciousness disorder, a diagnosis of hepatic encephalopathy was made based on an elevation of serum ammonia without any other abnormal liver function tests. Several days after his admission, hepatobiliary enzymes elevated, and acute liver failure progressed. Enhanced abdominal computed tomography suggested the possibility of complete occlusion of the portal vein by a thrombus. Based on an absence of obvious portosystemic collaterals, a diagnosis of APVT was made. The patient died 19 days after admission. Patients with PLD with repeated cystic infections have been seen to develop liver failure, and APVT formation may be one cause of the rapid progression of fatal liver failure. In conclusion, this is the first paper to report on the involvement of APVT in patients with PLD.

A case of smoldering antineutrophil cytoplasmic antibody-associated vasculitis development during the course of primary Sjögren's syndrome.

Various forms of glomerular lesions have been described in primary Sjögren's syndrome (pSjS); however, myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is rarely reported, and the disease onset and clinical course of ANCA-associated vasculitis (AAV) complicated by pSjS are not well understood. A 51-year-old woman was referred to our hospital because of mild proteinuria and microscopic hematuria. She fulfilled the classification criteria for pSjS. We performed a kidney biopsy; however, it revealed no characteristic findings for pSjS, vasculitis, or other autoimmune diseases, including systemic lupus erythematosus. After 9 months, urinalysis abnormalities worsened and renal function was slowly declining, and ANCA was found to be positive. A second kidney biopsy was performed, revealing MPO-ANCA-associated pauci-immune segmental necrotizing glomerulonephritis with crescent formation. Even though immunofluorescence microscopy did not reveal any positive findings, additional electron microscopy demonstrated the presence of mesangial electron-dense deposits in both kidney biopsies. Based on kidney biopsy results and sequential serum ANCA measurements, we considered that smoldering ANCA-associated vasculitis had developed in this patient as this can develop during the clinical course of pSjS. She responded well to steroid therapy. Serum measurement, especially perinuclear, ANCA levels can be useful in patients with pSjS to detect the onset of ANCA-associated vasculitis, even in the absence of acute renal deterioration or severe urinary abnormalities.

Complement Factor H Gene Variant in a Patient with Thrombotic Microangiopathy on a Mixed Clinical Background.

We report the case of a patient with complement factor H gene variant, who developed thrombotic microangiopathy on a mixed clinical background. A 79-year-old woman was transferred to Sanjo General Hospital for maintenance hemodialysis. She suffered from gastric non-Hodgkin lymphoma about two years ago and received chemotherapy and radiation therapy, leading to complete remission. About 13 weeks prior to her transfer to our hospital, she was referred to another hospital due to acute kidney injury, hemolytic anemia, and thrombocytopenia. Hemodialysis was immediately initiated, after which intravenous methylprednisolone and oral prednisolone were started; however, she became anuric within approximately week. The possibility of thrombotic microangiopathy was examined. However, she was in poor general condition and did not get the consent of her family, so no invasive searches such as a kidney biopsy were performed. Despite the cause of acute kidney insufficiency being unclear, she was transferred to us for maintenance hemodialysis. Her general condition was stable, and her renal function improved; hence, two months after transfer, a kidney biopsy was performed. Her clinical and typical renal histological findings indicated a diagnosis of thrombotic microangiopathy. There was a possible CFH gene of a very rare variant "c.526 T > C (p.Phe176Leu)" in exon 5. She was able to withdraw from hemodialysis therapy two weeks after the initiation of an angiotensin-converting enzyme inhibitor. Based on her clinical course and kidney biopsy findings, she was diagnosed with thrombotic microangiopathy with a very rare CFH variant. To ensure proper treatment choices such as eculizumab, the presence of complement dysregulation should be considered in cases of secondary thrombotic microangiopathy.

Acute Kidney Injury Associated with Minimal Change Nephrotic Syndrome in an Elderly Patient Successfully Treated with both Fluid Management and Specific Therapy Based on Kidney Biopsy Findings.

Oliguric acute kidney injury (AKI) with minimal change nephrotic syndrome (MCNS) has long been recognized. Several mechanisms such as hypovolemia due to hypoalbuminemia and the nephrosarca hypothesis have been proposed. However, the precise mechanism by which MCNS causes AKI has not been fully elucidated. Herein, we describe an elderly patient with AKI caused by MCNS who fully recovered after aggressive volume withdrawal by hemodialysis and administration of a glucocorticoid. A 75-year-old woman presented with diarrhea and oliguria, and laboratory examination revealed nephrotic syndrome (NS) and severe azotemia. Fluid administration had no effect on renal dysfunction, and hemodialysis was initiated. Her renal function improved upon aggressive fluid removal through hemodialysis. Renal pathological findings revealed minimal change disease with faint mesangial deposits of IgA. After administration of methylprednisolone pulse therapy followed by oral prednisolone, she achieved complete remission from NS. The clinical course of this case supports the nephrosarca hypothesis regarding the mechanism of AKI caused by MCNS. Furthermore, appropriate fluid management and kidney biopsy are also important in elderly patients with AKI caused by NS.

Severe hypermagnesemia induced by magnesium oxide ingestion: a case series.

Hypermagnesemia is generally considered an exceptional iatrogenic condition usually caused by magnesium-containing cathartics. In particular, this condition often develops when magnesium-containing cathartics are administered to elderly patients with renal insufficiency or bowel movement dysfunction. Although magnesium oxide (MgO) is widely prescribed as a laxative, serum magnesium concentration has not been examined in most cases. In this report, we present the cases of four elderly patients with constipation and symptomatic hypermagnesemia caused by MgO ingestion, one of which had a lethal course. All of the patients were older than 65 years and with renal dysfunction. In addition, they had difficulties in expressing their symptoms because of cerebrovascular events or dementia. These cases suggest that hypermagnesemia caused by magnesium-containing cathartics is more likely to develop than previously recognized and that physicians should be aware that patients with chronic kidney disease and the elderly are at risk of hypermagnesemia on magnesium administration. We recommend serum magnesium monitoring for high-risk patients after initial prescription or dose increase.

Retinal Vasculopathy With Cerebral Leukodystrophy: Clinicopathologic Features of an Autopsied Patient With a Heterozygous TREX 1 Mutation.

Retinal vasculopathy with cerebral leukodystrophy (RVCL) is an autosomal-dominant disorder involving the cerebral, retinal, renal, and other systemic microvessels due to frameshift mutations in the TREX1 gene. Under physiological conditions, the TREX1 protein is localized in the cellular cytoplasm and perinuclear area, but translocates into the nucleus in response to oxidative DNA damage. It has been speculated that aberrant localization of the protein may be associated with systemic microangiopathy in patients with RVCL. However, cellular expression of TREX1 in the brain and visceral organs of patients with RVCL has been unclear. Here, we report the clinicopathologic features of an autopsied patient with a heterozygous T249fs mutation in TREX1. The patient showed the clinical phenotype of vasculopathy with retinopathy, nephropathy, and stroke. CT with contrast enhancement demonstrated a tumorous lesion in the subcortical white matter. Histologically, the lesion consisted of confluent foci of necrosis with calcification and fibrous thickening of small vessel walls. TREX1 immunohistochemistry demonstrated positivity in the nuclei of cells in the CNS and visceral organs, indicating aberrant localization of the truncated protein, and the expression was remarkable in oligodendrocytes within the lesion, suggesting possible involvement of the protein in the pathomechanism of vasculopathy leading to white matter degeneration.

Atrial Fibrillation Had Less Impact on the Risk of Ischemic Stroke in Non-anticoagulated Patients Undergoing Hemodialysis: Insight from the RAKUEN study.

Objective The progress of non-anticoagulated patients with atrial fibrillation (AF) undergoing hemodialysis has not been determined. Using data from the RAKUEN (Registry of Atrial fibrillation in chronic Kidney disease Under hEmodialysis from Niigata) study, we examined the clinical characteristics and outcomes among hemodialysis patients with AF who were not receiving a vitamin K antagonist (VKA). Methods and Results Forty-three of 423 patients undergoing hemodialysis (-10%) were prescribed a VKA. The remaining 380 patients (age 64.8±12.8 years, male 70%) were enrolled in the present study. During a mean observation period of 36 months, AF (n=55) was independently associated with all-cause death (hazard ratio, 1.82; 95% confidence interval, 1.12-2.94; p=0.014), but was not associated with ischemic stroke (hazard ratio, 1.91; 95% confidence interval, 0.74-4.92; p=0.177) and major bleeding (hazard ratio, 1.80; 95% confidence interval, 0.80-4.08; p=0.150). The crude incidence rates of all-cause death and ischemic stroke in the AF patients were 15.75 (2.5-fold higher compared to the non-AF patients) and 3.63 (1.7-fold higher compared to the non-AF patients) per 100 person-years, respectively. Conclusion A great impact on death, but not ischemic stroke, was observed in non-anticoagulated hemodialysis patients with AF in comparison to those without AF from the analysis of the RAKUEN study.

Renal histopathological findings of retinal vasculopathy with cerebral leukodystrophy.

Retinal vasculopathy with cerebral leukodystrophy (RVCL) is a rare autosomal dominant systemic microvascular disease. Neurological disorders and visual disturbance are highlighted as manifestations of RVCL; however, there are few reports focused on nephropathy. Herein, we describe detailed renal histopathological findings in a daughter and father with RVCL, proven by TREX1 genetic analysis. A kidney biopsy of the daughter, 35-year-old with asymptomatic proteinuria, revealed unique and various glomerular changes. Atypical double contour (not tram track-like) of the capillary wall was widely found, an apparent characteristic finding. Glomerular findings were varied due to a combination of new and old segmental mesangial proliferative changes, mesangiolysis, and segmental glomerulosclerosis-like lesions; these changes may be related to endothelial cell damage. Collapsed tufts were also found and thought to be the result of ischemia due to arterial changes. Glomerular findings in a kidney biopsy of the father revealed similarity to the daughter's glomerulus at a relatively advanced stage, but the degree of variety in the glomerular findings was much less. Kidney biopsy findings suggesting endothelial cell damage of unknown etiology need to be considered for possible RVCL.

Enzyme replacement therapy in a patient of heterozygous Fabry disease: clinical and pathological evaluations by repeat kidney biopsy and a successful pregnancy.

Fabry disease is a rare X-linked lysosomal storage disorder of glycosphingolipid catabolism caused by deficient activity of the lysosomal hydrolase alpha-galactosidase A (ɑ-Gal A). A 20-year-old woman was referred to our hospital because of proteinuria and persistent macroscopic hematuria. Based on the typical renal pathological findings, deficient activity of the ɑ-Gal A, and heterozygous mutation in the ɑ-Gal A gene, she was diagnosed with Fabry disease. After 1 year of enzyme replacement therapy with agalsidase alfa at 0.2 mg/kg every other week, the patient's proteinuria and hematuria were disappeared. In our patient, enzyme replacement therapy with agalsidase alfa was observed to be safe and well-tolerated during her pregnancy, with no significant negative effects on her or her child. Here, we report clinical and pathological evaluations of a patient through repeat kidney biopsy after 6 years of enzyme replacement therapy. Furthermore, we discussed the appropriate enzyme replacement therapy and its safety in pregnant women with Fabry disease.

A Case of Transforming Growth Factor-ß-Induced Gene-Related Oculorenal Syndrome: Granular Corneal Dystrophy Type II with a Unique Nephropathy.

Many types of inherited renal diseases have ocular features that occasionally support a diagnosis. The following study describes an unusual example of a 40-year-old woman with granular corneal dystrophy type II complicated by renal involvement. These two conditions may coincidentally coexist; however, there are some reports that demonstrate an association between renal involvement and granular corneal dystrophy type II. Granular corneal dystrophy type II is caused by a mutation in the transforming growth factor-ß-induced (TGFBI) gene. The patient was referred to us because of the presence of mild proteinuria without hematuria that was subsequently suggested to be granular corneal dystrophy type II. A kidney biopsy revealed various glomerular and tubular basement membrane changes and widening of the subendothelial space of the glomerular basement membrane by electron microscopy. However, next-generation sequencing revealed that she had no mutation in a gene that is known to be associated with monogenic kidney diseases. Conversely, real-time polymerase chain reaction, using a simple buccal swab, revealed TGFBI heteromutation (R124H). The TGFBI protein plays an important role in cell-collagen signaling interactions, including extracellular matrix proteins which compose the renal basement membrane. This mutation can present not only as corneal dystrophy but also as renal disease. TGFBI-related oculorenal syndrome may have been unrecognized. It is difficult to diagnose this condition without renal electron microscopic studies. To the best of our knowledge, this is the first detailed report of nephropathy associated with a TGFBI mutation.

Diverse Renal Phenotypes Observed in a Single Family with a Genetic Mutation in Paired Box Protein 2.

A common renal phenotype of paired box protein 2 (PAX2) mutations is renal coloboma syndrome. We report a single family with diverse renal phenotypes associated with PAX2 mutation. The proband presented steroid-resistant focal segmental glomerulosclerosis with optic coloboma, whereas his two sons showed severe renal hypoplasia with end-stage renal disease, with or without optic coloboma. In all three cases, a heterozygous PAX2 genetic mutation was identified (exon 2; NM_003987.3:c.76dupG, p.Val26Glyfs*28). Based on histopathological findings of the proband, we hypothesized that autophagic dysfunction was associated with the pathophysiology of the focal segmental glomerulosclerosis with PAX2 mutation. Detailed funduscopic examination - including the optic disc - might be useful for the diagnosis of renal anomalies associated with PAX2 mutation.

Nephrotic Syndrome without Hematuria due to Infection-Related Glomerulonephritis Mimicking Minimal-Change Disease in a Child.

Nephrotic syndrome without hematuria due to infection-related glomerulonephritis is uncommon. The present report describes a case of nephrotic syndrome due to infection-related glomerulonephritis without hematuria and hypertension in an older child. A 14-year-old boy was referred to our hospital because of a 5-day history of fever, nausea, weight gain and recent leg edema without hypertension. Laboratory data showed nephrotic-range proteinuria, hypoalbuminemia, mild hypocomplementemia and acute renal injury without hematuria. Although, due to the clinical presentation, minimal-change nephrotic syndrome was mostly suspected, a renal biopsy showed endocapillary hypercellularity mainly of mononuclear cells with segmental mesangiolytic changes. Fine granular IgG and C3 deposits were noted by an immunofluorescent study; many relatively small electron-dense deposits were observed electron-microscopically. These findings led to the diagnosis of nephrotic syndrome due to infection-related endocapillary proliferative glomerulonephritis, although the causative organism of his nephritis was not detected. He recovered with rest and dietary cure. When we examine an acute nephrotic child, infection-related glomerulonephritis should be considered as the differential diagnosis to avoid unnecessary use of corticosteroids.

Glomerular expression of connexin 40 and connexin 43 in rat experimental glomerulonephritis.

BACKGROUND: Gap junctional intercellular communication is thought to play an important role in the maintenance of cell differentiation and homeostasis. Gap junctions connect glomerular mesangial cells to each other. In this study, we examined the glomerular expression of connexins (Cxs) 40 and 43 at both the protein and transcript levels in anti-Thy1.1 glomerulonephritis (GN). METHODS: Anti-Thy1.1 GN was induced by intravenous injection of anti-Thy1.1 monoclonal antibody 1-22-3. Cx protein expression was examined by immunofluorescence, immunoelectron microscopy, and Western blotting. Changes in mRNA levels were detected by real-time reverse transcriptase-polymerase chain reaction. RESULTS: Cx40 was detected in mesangial cells in normal rat glomeruli; its expression was reduced on days 3 and 7 and recovered to normal on day 14 following GN induction. Cx43 was detected in mesangial cells and podocytes in normal rat glomeruli, and its expression did not change during the disease course of GN. Expression of Cx40 and Cx43 was also detected in extraglomerular mesangial cells; this expression did not change during the disease course. Opposing patterns of expression between Cx40 and smooth muscle actin (SMA) were observed with double-immunofluorescence labeling. SMA is a differentiation marker of mesangial cells; it is often expressed during proliferation but not under physiological conditions. CONCLUSION: These results suggest that Cx40 expression in mesangial cells is related to mesangial cell regeneration. Thus, Cx expression regulation could be a therapeutic target for glomerular diseases.

Local delivery of a direct renin inhibitor into the kidney ameliorates progression of experimental glomerulonephritis.

BACKGROUND: Increasing evidence indicates that locally blocking renin-angiotensin system activity exerts a beneficial effect on glomerulonephritis (GN) progression leading to irreversible glomerulosclerosis. This is the first study on the pharmacological effect of the renal delivery of aliskiren, a direct renin inhibitor, in a progressive model of anti-Thy-1 GN. METHODS: Local blockade of renin activity was accomplished by subrenal capsular implantation of a collagen sponge with aliskiren. The pharmacological effect was evaluated by semiquantitative and quantitative analysis of immunohistological findings and by analysis of glomerular microcirculation using an intravital microscope system. RESULTS: Quantitative mesangial matrix analysis showed that local treatment with aliskiren significantly suppressed mesangial matrix expansion and ameliorated the glomerular sclerotic index in the progressive model of ATS GN. Immunofluorescent studies revealed that renin expression at the juxtaglomerular region was enhanced in the ATS + aliskiren group, and pathological expressions of α-smooth muscle cell actin and type I collagen in ATS GN were remarkably decreased by local treatment with aliskiren. Furthermore, local delivery of aliskiren significantly improved glomerular blood flow levels. CONCLUSION: This study revealed that renally delivered aliskiren has a renoprotective effect on potentially progressive glomerulosclerosis.

The effect of renal administration of a selective cyclooxygenase-2 inhibitor or stable prostaglandin I2 analog on the progression of sclerotic glomerulonephritis in rats.

BACKGROUND AND METHODS: There is increasing evidence that a change in glomerular hemodynamics may promote the development of glomerulosclerosis. In this study, we focused on the pharmacological effects of 2 contrasting agents, etodolac, a preferential cyclooxygenase-2 inhibitor, and beraprost sodium (BPS), a prostaglandin I(2) analog, delivered renally, on the disease course of progressive anti-Thy-1 (ATS) glomerulonephritis. RESULTS: Intravital microscopic analysis showed that the diameters of glomerular capillaries and glomerular blood flow in unilaterally nephrectomized (Nx) rats treated locally with BPS were significantly increased, as compared to those of Nx rats treated locally with normal saline (NS) or etodolac. We then examined the effects of BPS and etodolac on the course of progressive glomerulosclerosis. Mesangial cell proliferation, adhesion of glomerular capillary tufts and crescent formation in the BPS-treated group appeared to be more severe compared to the ATS + NS and the ATS + etodolac groups. Scoring of mesangial proliferation and glomerulosclerosis revealed that local BPS treatment significantly worsened glomerular pathology. At day 28, there were significant differences in blood flow between the ATS + etodolac group and both the ATS + NS and ATS + BPS groups, indicating that local treatment with etodolac enhanced the recovery of glomerular circulation. CONCLUSION: This study provides hemodynamic-based evidence showing that disturbance of intraglomerular microcirculation is a critical marker for progressive glomerulonephritis.

Effects of connexin-mimetic peptides on perfusion pressure in response to phenylephrine in isolated, perfused rat kidneys.

BACKGROUND: Gap junction intercellular communication plays a fundamental role in various tissues and organs. Gap junctions transfer ions and molecules between adjacent cells and are formed by connexins (Cx). It is supposed that vascular conducted responses, which most likely spread through gap junctions in vascular beds, regulate microcirculatory blood flow and maintain vascular resistance. This study provides functional evidence supporting the critical role of gap junctions in a physiological setting and in phenylephrine (PE)-induced vasoconstriction using an ex vivo kidney perfusion technique. METHODS: Using the isolated, perfused kidney model, infusion of gap junction inhibitors and PE, we examined the local effect of gap junction communication. Additionally, gap junction proteins Cx37, Cx40 and Cx43 were detected by immunofluorescence. RESULTS: First, changes in the perfusion pressure were analyzed by infusing the nonselective gap junction uncoupler, 18α-glycyrrhetinic acid (18α-GA), and specific connexin-mimetic peptide inhibitors, (37,43)Gap27, (40)Gap27 and (43)Gap26. Administration of 18α-GA and (43)Gap26 significantly elevated perfusion pressure while infusion of (40)Gap27 and (37,43)Gap27 had no effect. Second, we examined the effect of infusing gap junction inhibitors on PE-induced vasoconstriction. Infusion of 18α-GA and (40)Gap27 significantly suppressed the increase in perfusion pressure induced by PE, while (43)Gap26 and (37,43)Gap27 had no effect. Third, we confirmed by immunofluorescence that Cx37, Cx40 and Cx43 were found in the endothelial cells of interstitial microvessels and that Cx40 was localized in glomerular mesangial cells as well as in smooth muscle cells of the juxtaglomerular area. CONCLUSIONS: This study showed that Cx43 plays a pivotal role in regulating renal vascular resistance and that Cx40 attenuates PE-induced vasoconstriction. These results provide new evidence that gap junctions may control renal circulation and vascular responses.

Local delivery of angiotensin II receptor blockers into the kidney passively attenuates inflammatory reactions during the early phases of streptozotocin-induced diabetic nephropathy through inhibition of calpain activity.

BACKGROUND/AIMS: Inhibition of the renin-angiotensin-aldosterone system plays a pivotal role in the prevention and treatment of diabetic nephropathy. Angiotensin II receptor blockers (ARB) exert a renoprotective effect and attenuate the progression of diabetic nephropathy. However, the underlying cellular and molecular mechanisms in the kidney remain to be elucidated. The present study was undertaken to focus on the effect of local angiotensin II type 1 receptor blockade on the inflammatory reaction during the early stages of diabetic nephropathy. METHODS AND RESULTS: Local ARB treatment significantly reduced urinary protein excretion and serum blood urea nitrogen levels in streptozotocin-induced diabetic nephropathy. In addition, this treatment attenuated monocyte/macrophage infiltration into the glomeruli and the enhanced glomerular expression of endothelial nitric oxide synthase at both the mRNA and protein levels. Immunohistochemical study revealed activation of nuclear factor (NF)-kappaB, as shown by an increase in the expression of the p65 subunit of NF-kappaB and its translocation from the cytoplasm to the nucleus in both tubular epithelial and glomerular cells of the diabetic kidney. Local ARB treatment induced an apparent reduction in p65 nuclear localization and intensity of staining. To search for a common and fundamental candidate that influences endothelial cell function and vascular inflammation, we examined glomerular calpain activity in diabetic rats with or without ARB treatment. Glomerular expression of 145/150-kDa spectrin breakdown products, a specific product of calpain activation, was dramatically increased in diabetic animals while the protein expression reverted to a normal level after ARB treatment. CONCLUSION: Our findings provide a conceptual basis for the development of therapeutic strategies aiming at local inhibition of the renin-angiotensin system to prevent the progression of diabetic nephropathy.

Human voltage-dependent anion selective channel 1 is a target antigen for antiglomerular endothelial cell antibody in mixed connective tissue disease.

The purpose of this study was to identify the endothelial cell antigens that react with circulating antiendothelial antibody (AECA) in mixed connective tissue disease (MCTD). We screened serum AECA reactivity in 23 patients with MCTD using a human glomerular endothelial cell (HGEC) cellular ELISA. Proteomics, two-dimensional gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry were used to identify the endothelial cell antigens of HGECs that reacted with serum antibodies from MCTD patients. Sera from 12 patients (52.0%) were positive for anti-HGEC antibody based on cellular ELISA. MALDI-TOF mass spectrometry used in combination with immunoblotting using serum antibody revealed one protein spot that represented a 36-kDa cell component of HGECs, with an isoelectric point (IP) of about 9, which had a high homology with the voltage-dependent anion-selective channel 1 (VDAC-1). This protein spot was confirmed to react with the antibody specific to VDAC-1. This is the first report of the presence of antibody to VDAC-1 from HGECs in the sera from MCTD patients. Although future studies will be needed to clarify the disease specificity of the a-VDAC-1 antibody in MCTD, the results show that modern proteomics technology is useful for identifying antigens that react with AECA in autoimmune diseases such as MCTD.