Background and objectives: Membranoproliferative Glomerulonephritis (MPGN) and C3 Glomerulopathy are rare and overlapping disorders associated with dysregulation of the alternative complement pathway. Specific aetiological data for paediatric MPGN/C3 glomerulopathy are lacking, and outcome data are based upon retrospective studies without aetiological data. Design, setting, participants, and measurements: Eighty prevalent pediatric patients with MPGN/C3 glomerulopathy underwent detailed phenotyping and long-term follow-up within the National Registry of Rare Kidney Diseases (RaDaR). Risk factors for kidney survival were determined using COX proportional hazards model. Kidney and transplant graft survival was determined using Kaplan-Meier method. Results: Central histology review determined 39 C3 glomerulopathy, 31 immune-complex MPGN and 10 immune-complex glomerulonephritis (GN) cases. Patients were aged 2-15 (median 9 (IQR 7-11) years. Median complement C3 and C4 levels were 0.31g/L and 0.14g/L respectively; acquired (anti-complement autoantibodies) or genetic alternative pathway abnormalities were detected in 46% and 9% patients respectively, across all groups including immune-complex GN. Median follow-up was 5.18 (IQR 2.13-8.08) years. Eleven patients (14%) progressed to kidney failure with 9 transplants performed in 8 patients, 2 of which failed due to recurrent disease. Presence of >50% crescents on initial biopsy was the sole variable associated with kidney failure in multivariable analysis (Hazard Ratio 6.2, p = 0.045; 95% CI 1.05 to 36.6). Three distinct C3 glomerulopathy prognostic groups were identified according to presenting eGFR and >50% crescents on initial biopsy. Conclusions: Crescentic disease was a key risk factor associated with kidney failure in a national cohort of pediatric MPGN/C3 glomerulopathy and immune-complex GN. Presenting eGFR and crescentic disease help define prognostic groups in pediatric C3 glomerulopathy. Acquired abnormalities of the alternative pathway were commonly identified but not a risk factor for kidney failure.

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%'HE KGACTIOK BETWEEN 13I'HYL,ENB AND SULFUR CHLORIDE. 585 promote both activities, have not been made to lose entirely the reproductive element, thus indicating that the influence of the nutrients in affecting the ratio of vegetation to reproduction is quantitative and not qualitative.On the other hand, the hypothesis of the existence of but a single vitamine for ScZemfi.izia is more plausible, according to much of the experimental evidence. It i. very probable that reprodiiction in Sclerotinia is simply a different manifestation o€ the same activities as characterize vegetation. 'The single activity that is apparently most dependent on a vitamine supply is respiration. Respiration is common to all the materials which have yielded the vilamine; and the degree of metabolic, and hence respiratory, activity in these materials is proportional to the activity of the vitamine prepared from them. Thus the evidence is accumulating in favor of the view that there is a close connection between respiration in a cell and its vitamine content, and also its vitamine requirement. Just which cells in the plant world can synthesize this vitamine is still a n open question. The Sclerotinia vitamine is possibly identical with the water-soluble B of the higher animals; and since the latter cannot synthesize this vitamine, it becomes an important point to know which plant organs can, ?T PAUL, MIlWiESOTA.

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