C3 nephritic factor and SLE: report of four cases and review of the literature.

We present four patients with C3 nephritic factor associated with partial lipodystrophy and/or mesangiocapillary glomerulonephritis type II. Each of these patients subsequently developed features of SLE, with an onset between 2 and 24 years after the development of the lipodystrophy or glomerulonephritis. All four patients had antinuclear antibodies and three of the four had anti-Ro antibodies. These patients bring to six the number of reported cases of this association. Possible explanations for the link between these two conditions are discussed.