[A clinicopathological study of renal hemodynamics in patients with systemic lupus erythematosus]

We evaluated the clinical value of the glomerular filtration rate (GFR) and renal plasma flow (RPF) in patients with systemic lupus erythematosus (SLE). All of the patients fulfilled the criteria for SLE of the American Rheumatism Association and were divided into two groups by the criteria for disease activity. GFR and RPF were simultaneously measured by the standard clearance technique using sodium thiosulfate and sodium paraaminohippurate, respectively. Ninety-six clinically active patients and 60 inactive patients underwent one clearance study. In 36 other patients, repeated clearance studies were undertaken on two occasions during the period from the active to inactive phase. The mean RPF was 590.3 +/- 213.7 ml/min in 132 active patients and 485.7 +/- 184.0 ml/min in 96 patients without disease activity (p < 0.01), whereas the mean GFR was comparable between the two groups. In active SLE, the mean GFR in 76 patients with proteinuria was 76.0 +/- 38.2 ml/min as compared with 104.8 +/- 34.3 ml/min in 56 patients without proteinuria (p < 0.01); however, there was no significant difference in the mean RPF between the two groups. A fall in GFR was frequently observed in patients with class IV lupus nephritis. In contrast, there was no significant difference in the mean RPF between class IV patients and the patients in the other classes. As a result, a marked decrease in the filtration fraction (FF) was frequently observed in class IV lupus nephritis, irrespective of the use of diuretics or antihypertensive agents. Semiquantitative histological analyses revealed that mesangial proliferative changes were more responsible than glomerular sclerotic changes for these hemodynamic features.(ABSTRACT TRUNCATED AT 250 WORDS)