A renal biopsy study with light and immunofluorescent microscopy in rheumatoid arthritis

REnal biopsies were performed on 14 patients with active rheumatoid arthritis an proteinuria of whom 7 patients had reduced creatinine clearance. Glomerular hypercellularity was found in six and amyloid in seven biopsies. Immunofluorescence microscopy revealed glomerula deposits of immunoglobulins and complement in 10 of 12 biopsies, indicating an active immunologic process causing the impaired renal function.