Fukushima J. Med. Sci.,
Vol. 52, No. 2, 2006

[Original Article]

USEFULNESS OF COMPLEMENT SPLIT PRODUCT, Bb, AS A CLINICAL
MARKER FOR DISEASE ACTIVITY OF LUPUS NEPHRITIS

HIROSHI WATANABE, ETSUKO NOGUCHI, KIORI SHIO,
HARUYO IWADATE, HIROKO KOBAYASHI
and HIROMASA OHIRA

Department of Internal Medicine II, Fukushima Medical University School of Medicine,
Fukushima, 960-1295, Japan

(Received June 16, 2006, accepted August 31, 2006)

Abstract: To evaluate the usefulness of Bb, a split product of complement factor B, as a clinical marker for disease activity of lupus nephritis, we measured the Bb concentration of sera from 42 patients with lupus nephritis. Serum Bb levels were significantly higher in patients with active nephritis (active nephritis group, n=30) than in patients with nephritis in remission (remission group, n=12) (14.3±8.3 versus 7.4±5.9 μg/ml; p=0.012). In contrast, there was no significant difference in serum C3 levels between active nephritis group and remission group (42.5±20.9 versus 44.7±15.9 mg/dl; p=0.77). In the comparison of Bb levels between active nephritis group and remission group, the sensitivity was 66.6%, specificity was 83.3%, and the positive and negative likelihood ratios were 3.95% and 0.41%, respectively. The present results suggest that serum Bb level is a useful clinical marker for disease activity in lupus nephritis.

Key words: complement, systemic lupus erythematosus

渡辺浩志，深谷悦子，塩　季織，岩舘治代，小林浩子，大平弘正

Correspondence to: Hiroshi Watanabe, Department of Internal Medicine II, Fukushima Medical University School of Medicine, Fukushima City 960-1295, Japan.
E-mail: chiehiro@fmu.ac.jp