Systemic Lupus Erythematosus CUMULATIVE INCIDENCE OF CLINICAL SYMPTOMS AND AUTOANTIBODY FORMATION IN SYSTEMIC LUPUS ERYTHEMATOSUS

Renal involvement in systemic lupus erythematosus (SLE), dysproteinemias, and certain rheumatic diseases, namely rheumatoid arthritis, Sjögren’s syndrome, and scleroderma (systemic sclerosis), is discussed. SLE is a systemic autoimmune disease that can lead to disease manifestations in almost every organ. SLE is characterized by the formation of a wide array of autoantibodies mainly directed against nuclear autoantigens, of which antibodies against double-stranded DNA (dsDNA) are the most prominent. Although the cause is still obscure, considerable progress has been made recently by identification of the nucleosome as the major driving autoantigen in SLE and the possible role of disturbances in apoptosis in disease development. The section on SLE reviews the major clinical and serologic features of the disease, the serologic analysis, new insights into the pathophysiology of lupus nephritis, and the histologic assessment of kidney biopsies. The therapeutic options for treatment of lupus nephritis are discussed as are the results of treatment of endstage renal disease in patients with SLE. The second part of this chapter deals with the renal involvement in dysproteinemias. The renal lesions of these diseases, characterized by an overproduction of abnormal immunoglobulins or their subunits, are quite heterogeneous. Because the kidney often is affected in these disorders, it is not unusual for examination of a kidney biopsy specimen to reveal clues for the diagnosis. On immunofluorescence, the distribution of the light or heavy chain isotype, or both, can be detected in the tissue deposits, whereas electron microscopy can define the ultrastructural organization. Incidence and types of renal involvement, the pathogenesis and risk factors for the various types of renal lesions, the histology of the different renal manifestations, and an Jo H.M. Berden Karel J.M. Assmann