We reviewed the initial serological data of 50 patients with biopsy-proven
lupus nephritis. As compared with a group of lupus patients without
nephritis, patients with
nephritis had lower serum
complement C3 (p less than 0.05) and C4 (p less than 0.005) levels and higher serum
DNA binding activity (p less than 0.001). The frequency of
rheumatoid factor, antiphospholipid, anti-ENA, and
fluorescent antinuclear antibodies was similar in both groups. We correlated the serological data of the patients with
nephritis with the clinical severity of their disease. Using a functional staging system based on the
serum albumin and
creatinine levels at the time of biopsy, we found that patients with functionally milder disease (
proteinuria without
nephrotic syndrome or
renal failure) had higher C3 (p less than 0.05) and lower
DNA binding (p less than 0.005) than patients in the more severe functional classes (
nephrotic syndrome with or without
renal failure). In contrast, C4 levels were always very low, irrespective of functional severity. We also correlated the serological data with the pathological findings. Patients suffering from diffuse proliferative
nephritis had higher
DNA binding values than patients with focal proliferative (p less than 0.01) or membranous (p less than 0.001)
nephritis. By contrast,
complement levels were not correlated with the severity of biopsy changes. Taken together, the data presented here suggest that C3 and
DNA binding, but not C4, correlate with the clinical severity of
lupus nephritis at presentation whereas
DNA binding, but not
complement levels, correlates with the severity of pathological changes.