A nephrotic case of vesicoureteral reflux representing focal segmental glomerulosclerosis associated with podocytic infolding lesions.

The case was a 54-year-old woman who had suffered from occasional incontinence of urine after a craniotomy for subarachnoid hemorrhage in 1991. In June 1998 she was admitted for nephrotic syndrome without hematuria. Intravenous pyelography and voiding cystourethrography revealed bilateral hydronephrosis, atonic bladder, and vesicoureteral reflux (VUR). Renal biopsy demonstrated the presence of focal segmental glomerulosclerosis with cellular lesions. However, periodic-acid methenamine silver (PAM) staining revealed bubbling and spike appearance in the diffuse peripheral loops, although immunofluorescence microscopy showed negative findings in the glomeruli. Electron microscopy revealed diffuse thickening of the glomerular basement membrane (GBM) accompanying diffuse podocytic infolding lesions into the GBM and numerous spherical microstructures in the GBM. No findings of dense deposits were observed in the GBM and mesangium. Her urinary protein excretion decreased and renal function improved after placement of an urethral catheter for one year. A second renal biopsy revealed a remarkable decrease in podocytic infolding lesions, although microstructures in the GBM remained. Although mechanisms of the occurrence of these peculiar podocytic infolding lesions are unclear, it is speculated that podocyte damage due to hydronephrosis may have caused the lesions.

[Case of immune complex crescentic glomerulonephritis with consistently high titers of MPO-ANCA for 6 years].

A male patient, now 65 years old, experienced fever, hemoptysis, and respiratory failure about six years ago. Soon thereafter, he developed rapid progressive renal dysfunction with pulmonary hemorrhage and positive findings for MPO-ANCA. We commenced methylprednisolone pulse (MP) therapy followed by oral prednisolone (PSL) and intravenous cyclophosphamide (CY) for the treatment of ANCA-associated microscopic polyangiitis (MPA). Therapeutic efficacy was obtained comparatively rapidly. Light microscopic findings of a percutaneous renal biopsy demonstrated focal necrotizing and crescentic glomerulonephritis. Immunofluorescent microscopy indicated diffuse deposition of IgG and C3 along the periphery of the tufts and in the mesangium. On the basis of these findings, the condition was diagnosed as immune complex crescentic glomerulonephritis associated with MPO-ANCA. MPO-ANCA titers were high (714 EU) at onset and remained high (250-450 EU) over the ensuing 6 years with oral administration of PSL 5 mg. Though his condition remitted completely, his MPO-ANCA titers recently increased to above 600 EU once more. We conducted a follow-up renal biopsy to ascertain if the fluctuation of MPO-ANCA titers reflected an early stage of relapse. Light microscopic findings of the biopsied tissue revealed no signs of necrosis or crescentic formation of the glomeruli. Immunofluorescent microscopic findings were negative. The elevated MPO-ANCA titers were not valuable for the early prediction of relapse in our case, and the immune complex may have played an important role. When judging relapse and remission in ANCA-associated glomerulonephritis, it is important to evaluate the overall clinical findings and histopathological findings in addition to the serial ANCA titers.

Gene cloning and deletion analysis of chitinase J from alkaliphilic Bacillus sp. strain J813.

Alkaliphilic Bacillus sp. strain J813 produces a novel chitinase (chitinase J). The gene encoding chitinase J (chij) was cloned and sequenced. Deduced amino acid sequence revealed that Chij contained a family 18 catalytic domain, a fibronectin type III-like domain and a chitin-binding domain. Analysis of deletion derivatives indicated that the chitin-binding domain was important for binding to chitin and it enhanced the hydrolysis of insoluble chitin. The subsites existing in the catalytic domain of Chij was thought to bind to insoluble chitosan, although Chij did not hydrolyze chitosan. Some amino acid-substituted mutants were prepared and characterized, suggesting that Glu198 should be the catalytic residue of Chij.

[Successful treatment of MRSA-associated glomerulonephritis with antibiotic therapy].

We report a case of methicillin-resistant Staphylococcus aureus (MRSA)-associated glomerulonephritis treated with antibiotic therapy. A 67-year-old man was admitted to our hospital because of proteinuria, hematuria, purpura, and high fever one month after a graft replacement of an abdominal aortic aneurysm. MRSA was detected in specimens of his blood, sputum, and joint fluid. Before his operation, he had shown no renal abnormalities. He presented with a rapid deterioration of renal function following MRSA infection. Maximum level of proteinuria was 1.5 g/day, serum creatinine (Cr) was 3.5 mg/dl, and blood urea nitrogen was 57 mg/dl. Renal biopsy revealed necrotizing crescentic glomerulonephritis. Immunofluorescence examination showed IgA and C3 deposits. Clinical and pathological examinations showed the typical features of MRSA-associated glomerulonephritis. Vancomycin and fosfomycin were administered intravenously. The serum level of C-reactive protein fell from 22.0 mg/dl to 0.1 mg/dl. Proteinuria also decreased and the patient's renal function improved in parallel with the decreased activity of MRSA infection. After three months of antibiotic treatment, proteinuria was negative and the level of serum Cr had dropped to 0.9 mg/dl. These findings suggest that antibiotic treatment can lead to complete remission of MRSA-associated glomerulonephritis.

Effective antibiotic treatment of methicillin-resistant Staphylococcus aureus-associated glomerulonephritis.

BACKGROUND: A new type of glomerulonephritis following a methicillin-resistant Staphylococcus aureus (MRSA) infection has been reported. The purpose of this study is to elucidate the clinicopathological features and the responsiveness to treatment of the disease. METHODS: We studied the treatment of 8 patients with glomerulonephritis related to MRSA infection. We observed the eight cases and analyzed clinical features, laboratory findings and histopathological data. RESULTS: On admission, all patients had no renal abnormalities. One to four months after suffering from MRSA infection, severe proteinuria and hematuria developed. Renal biopsy specimens revealed moderate to severe mesangial proliferative glomerulonephritis with various degrees of crescent formation. Immunofluorescence studies showed IgA and C3. Antibiotic therapy was performed in six cases, resulting in successfully reducing the proteinuria in parallel with the decreased activity of MRSA infection in five cases. The other 2 cases received corticosteroid treatment after complete cessation of MRSA infection, but they had a relapse of MRSA infection and later died from sepsis. CONCLUSIONS: These results suggested that MRSA-associated glomerulonephritis might respond to antibiotic treatment in most cases. This also indicated that special care must be taken in the application of steroid therapy for the glomerulonephritis with crescents, even though the MRSA infection has gone into an inactive state.

MPO-ANCA-positive slowly progressive glomerulonephritis with focal tuft necrosis and crescents.

A 37-year-old woman had been found to have proteinuria in October 1996. About 8 months later, the first renal biopsy was performed, revealing focal segmental necrotizing and crescentic glomerulonephritis. At that time, serum creatinine was 1.0 mg/dl and urinary protein 3+. In October 1999, laboratory tests revealed positivity for MPO-ANCA and a serum creatinine level of 1.42 mg/dl, anemia and proteinuria of 2+. A second renal biopsy showed almost the same histological findings. Accordingly, a diagnosis of MPO-ANCA positive glomerulonephritis was made. This patient was thought to be a rare case of MPO-ANCA-positive slowly progressive glomerulonephritis presenting focal segmental tuft necrosis and crescents.