THE TEMPORAL RELATIONSHIP BETWEEN URINARY C5B-9 AND C3DG AND CLINICAL-PARAMETERS IN HUMAN MEMBRANOUS NEPHROPATHY

We have previously reported that urinary excretion of the complement a ctivation products C3dg and C5b-9 in human membranous nephropathy (MN) correlated with clinical outcome in a cross-sectional analysis. We re port here the results of a retrospective longitudinal study of the tem poral relationship between urinary C3dg and C5b-9 excretion and clinic al parameters. A group of 23 adult patients with biopsy-proven MN were studied over a mean time period per patient of 3.5 years. Freshly voi ded urine samples were collected regularly; C3dg and C5b 9 were measur ed by ELISA (mean number of samples per patient = 13). During the peri od of the study, nine patients with declining renal function (group A) were treated with a standard steroid regimen. Serum creatinine had im proved or stabilized in seven of these patients at the end of treatmen t. All nine patients were excreting C3dg and C5b-9 before treatment. S ix other patients with declining renal function (group B) were not tre ated with steroids because of clinical contraindications. Serum creati nine continued to increase during the study in four of these six patie nts. C3dg and C5b-9 were present in the urine samples of these six pat ients on the majority of dates tested. Eight patients maintained stabl e renal function during the study (group C), either normal (6 patients ) or impaired (2 patients). Of these patients, six were consistently n egative for urinary C3dg and C5b-9 despite persistent proteinuria, and one patient who was initially positive became negative within 15 mont hs, and remained negative for the rest of the study period. One patien t was positive on one of 12 occasions tested. These results suggest th at urinary complement activation products indicate ongoing active glom erular damage and may prove to be important determinants for the intro duction and monitoring of therapy.