Introduction

Immune-complex glomerulonephritis (ICGN) and non-ICGN are major forms of chronic kidney disease (CKD) in dogs. However, the difference between the progression of CKD in ICGN and non-ICGN is not fully understood.

Objectives

We aimed to clarify the association between pathological changes in the kidneys and clinicopathological changes in ICGN and non-ICGN, in dogs.

Methods

Renal biopsy specimens (n=24) were obtained from dogs with protein-losing nephropathies, and these were examined using light microscopy, electron microscopy, and immunofluorescence for the presence of immunoglobulins and complement 3. Severity of glomerular sclerosis (GS) and interstitial fibrosis (IF) were quantitatively evaluated, and correlations between these scores and clinicopathological parameters were statistically analyzed.

Results

Eighteen and six cases were diagnosed with ICGN and non-ICGN, respectively. The GS score in ICGN showed no significant correlation with any clinicopathological parameter, including plasma concentrations of urea, creatinine (pCre), total protein and albumin, and urinary protein/creatinine ratio; however, the IF score showed a significant correlation with pCre. The GS score in non- ICGN showed a significant correlation with pCre, but IF showed no correlation with any clinicopathological parameter.

Conclusions

Progression of CKD in ICGN was associated with IF severity, whereas in non-ICGN, it was associated with GS severity. This difference between ICGN and non-ICGN might be associated with the amount of proteinuria, which is severe in ICGN; the proteinuria is a major-inducing factor for IF, which is in turn associated with decreased renal function.