[The value of urinary enzyme determinations in systemic lupus erythematosus (author's transl)]

During a period of 4 years urine samples from 54 patients with systemic lupus erythematosus (SLE) were repeatedly analysed for the activities of lactate dehydrogenase (LDH), leucine aminopeptidase (LAP) and alanine aminopeptidase (AAP). Increased urinary enzyme levels were consistently found in 8 patients with severe lupus nephritis and the nephrotic syndrome, as well as in 9 patients with chronic lupus nephritis resistant to therapy. A further group of 9 patients with lupus nephritis responded favourably to immunosuppressive therapy with arrest of kidney-damaging processes; a concomitant normalization of urinary enzyme levels was observed, giving an accurate reflection of the progression of the disease. Another 14 SLE patients showed raised enzyme levels preceding the development of clinical signs of nephropathy. The last 14 SLE patients displayed neither nephropathy nor altered enzyme activities. The determination of urinary enzyme activities is, therefore, considered to be a useful supplement to the routine biochemical analyses performed on the urine in cases of SLE.