C5 Measurement in Membranoproliferative Glomerulonephritis Patients with C3 Nephritic Factor

Hiroyuki Ohi, Shizuhiko Watanabe, Masato Seki, Takayuki Fujita, Fumihiko Ohmori, Michinobu Hatano
1987 Nephron  
% normal Dear Sir, We confirmed the presence of a C3 nephritic factor (C3NeF), which is an auto-antibody to C3bBb, in sera from 14 patients with membranoproliferative glomerulonephritis (MPGN) who had a persistently low level of C3. The serum complement components in these patients were as shown, in figure 1, Cl being 98 ± 22% and C4 being 88 ± 37% normal (mean ± SD). It should be noted that C5 varied widely in the range of 55 ± 35% normal, in spite of the low value of C3. C3NeF activates C3 in
more » ... the fluid phase, but neither forms C5 convertase nor activates C5; it forms C3 and C5 convertases and activates C3 and C5 from the terminal component in the solid phase1. On this basis, we considered that, in such patients, the C5 level might reflect activation by C3NeF itself or a C3NeF-related factor in the kidney, and we examined the relationship between the changes in C5 level and responses to treatment of prognosis in C3NeF patients in whom long-term observations were possible. It was found that patients whose C3 and C5 levels were persistently low tended to be refractory to treatment, and that in some of these patients the condition leaned towards renal insufficiency. Those whose C5 level did not decrease, although with a persistently low C3 level, and those whose C5 level was low initially and increased after treatment did respond to the treatment, and such patients showed no tendency to renal insufficiency. Similar results were obtained in persistently low C3 patients in whom C3NeF was not detected.
doi:10.1159/000184349 pmid:3600936 fatcat:dckrp74zkzhtzj5a52yhmggx24