Collagenofibrotic Glomerulonephropathy Associated with Immune Complex Deposits

Abstract

A 66-year-old Japanese male, who suffered from persistent proteinuria and leg edema, underwent renal biopsy. Light microscopy revealed marked narrowing of the glomerular capillary lumen with a diffuse accumulation of weakly PAS-positive material. By electron microscopy, abundant abnormal collagen fibers were observed predominantly in the subendothelial space and occasionally in the mesangial matrix. The fibers had a periodicity of about 60 nm and were immunoreactive for anti-type III collagen. Subendothelial electron-dense deposits were also found in some of the capillary walls. The serum level of procollagen III peptides was elevated and changed in parallel with the amount of proteinuria during the patient’s clinical course. On the basis of these findings, a diagnosis of the collagenofibrotic glomerulonephropathy was made. A review of the literature, including 29 similar or identical cases, failed to reveal the etiology and pathogenesis of this disease. We suggest that this disease may be divided into two different clinical subtypes, an adult-onset type and a pediatric type.

A canine autosomal recessive model of collagen type III glomerulopathy

“…Glomerular C3 deposits were not detected in another described canine case where C3 was investigated, while glomerular IgM and IgG deposits were occasionally seen. 6 In humans, immunofluorescence for IgG is mainly negative, and staining for C3 and IgM is negative or shows focal and segmental staining, often along the capillary walls, 10,[15][16][17]20,31 coinciding with our findings. The deposits are described as non-specific 2 and not indicative of an immune-mediated process, 1 as also confirmed by lack of immune complexes by EM.…”

“…These observations suggest that the abnormal glomerular collagen differs structurally from normal collagen. Except from a human case report describing fibrils with deviant vague periodicity, 16 faint periodicity has not been a feature in previous reports of Col3GP. Diverging or absent cross-striation can result from packing defects of the collagen molecules forming the fibrils, due to altered ionic strength, pH, temperature, phosphate concentration and collagen concentration.…”

“…'Primary glomerular fibrosis' was used by Ikeda et al 15 in 1990 after identifying the fibrils as collagen type III. Since then 'collagenofibrotic glomerulonephropathy' , 'collagenofibrotic glomerulopathy' 16,17 and 'Col3GP' 2,18 have been in use. We have chosen to apply the term Col3GP because it describes the anatomical location of the primary pathology and precisely accounts for the characteristics of the glomerulopathy.…”

Banded Collagen in the Kidney with Special Reference to Collagenofibrotic Glomerulopathy

“…The presence of the different type of collagen fibers can be identified with immunogold staining. Rarely, electron-dense deposits are also observed [29]. Unlike nail-patella syndrome, the basement membrane is of normal thickness and is devoid of lucency, fibrils, or moth-eaten appearance.…”

Quiz Page

“…Supportive therapy to control edema and hypertension may be useful. There are few reports of improved GFR, proteinuria, and anemia with prednisolone (40 mg/d), 6 but this response seems time limited. After kidney failure, a few patients have received kidney transplants with no reports of disease recurrence.…”