[Clinical and pathological study of lupus nephritis without clinical renal involvement]

To analyze the clinical and pathological changes in systemic lupus erythematosus (SLE) patients without clinical renal abnormalities, I performed histopathological examinations of renal biopsy specimens from 40 SLE patients, who were divided into two groups. Group A consisting of 16 patients had almost no clinical evidence of renal involvement. Group B consisting of 24 patients had clinical renal manifestations, proteinuria, hematuria or both due to lupus nephritis. Light microscopy showed minor to moderate proliferative changes in the patients of Group A, and severer changes in the patients of Group B. Immunofluorescent study revealed depositions of immunoglobulins and complement in varying degrees in all the patients of Groups A and B. By electron microscopic study, electron-dense deposits and mesangial deposits were found in all patients of Group A. However, subendothelial, subepithelial and intramembranous deposits were seen in less than one-half of the patients of Group A. The amounts of the deposits were small. By contrast, a large amount of electron-dense deposits existed in the patients of Group B. The prognosis was better for patients of Group A than those of Group B. I concluded that various abnormalities of the renal glomeruli exist in SLE patients even without urinary abnormalities.