Urinary Podocytes for the Assessment of Disease Activity in Lupus Nephritis

Abstract

BackgroundDetection of podocytes in the urine indicates that severe injury of podocytes occurred in the glomerulus in children. MethodsThe pathological significance of podocytes in the urine was determined in patients with lupus nephritis. Podocytes were detected by immunofluorescence using a monoclonal antibody against podocalyxin present on the surface of podocytes. Subjects who participated in the present study were of the following types: patients with systemic lupus erythematosus with stable renal function (group A, n=8; WHO classes IIIa, b, IVb, and IVc at the time of biopsy); patients with clinically active lupus nephritis (group B, n=8; WHO classes IVb and IVc); and healthy control subjects (group C, n=10). ResultsPodocytes were absent in the urine of subjects in groups A and C. However, podocytes were present in the urine of group B subjects. Patients in group B were examined monthly for urinary podocytes and were treated with methylprednisolone followed by prednisolone. Urinary podocytes were absent in all patients in group B after treatment. ConclusionsThese data indicate that urinary podocytes may be markers of the severity of lupus nephritis and that steroid therapy may be effective for podocyte injury in lupus nephritis.