Progression from minimal or focal to diffuse proliferative lupus nephritis.

Histologic classification of renal glomerular lesions in 46 patients with systemic lupus erythematosus revealed 17 as having either focal proliferative (10 patients) or minimal mesangial proliferative (7 patients) glomerulonephritis. Six of the 17 have progressed to a diffuse proliferative glomerular lesion on subsequent renal biopsies, 9 months to 5 years later. Five had clinical deterioration at the time of follow-up biopsies; currently one is undergoing hemodialysis and four others have decreased renal function. Although a comparison of those who progressed with those who are stable revealed greater proteinuria in some of those who progressed, no other clinical features of the initial illness were different in the two groups, nor were differences between the two groups noted on light microscopic examination of initial renal biopsies. However, ultrastructurally, electron-dense deposits, especially those subendothelial in location, were noted along glomerular capillary basement membranes more frequently and in greater number in those who progressed. These findings suggest that lupus patients with a mild proliferative glomerulonephritis may have clinical and histologic progression of the renal disease, and those who progress cannot be clearly defined by clinical or light microscopic features. Ultrastructural demonstration of subendotheial deposits suggests a greater likelihood of subsequent progressive disease.