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Abstract: SA-PO345

Hypocomplementemia and Membranous Nephropathy Among the Patients with Anti-U1 Ribonucleoprotein (RNP) Antibody

Session Information

Category: Glomerular Diseases

  • 1202 Glomerular Diseases: Immunology and Inflammation

Authors

  • Shima, Natsuki, Toranomon Hospital, Kawasaki, Japan
  • Sumida, Keiichi, Toranomon Hospital, Kawasaki, Japan
  • Yamanouchi, Masayuki, Toranomon Hospital, Kawasaki, Japan
  • Hoshino, Junichi, Toranomon Hospital, Kawasaki, Japan
  • Ubara, Yoshifumi, Toranomon Hospital, Kawasaki, Japan
Background

The significance of anti-ribonucleoprotein (RNP) antibody and anti-Sm antibody remains still unclear on patients with systemic lupus erythematosus (SLE) or mix connective tissue disease (MCTD).

Methods

Thirty patients showing the positivity for antinuclear antibodies (ANA) and anti-RNP antibody, who were diagnosed with SLE or MCTD and received renal biopsy in our hospital between January 1980 and December 2014, were retrospectively enrolled into this study. These 30 patients were classified into 4 groups based upon anti-dsDNA (+)/(-) and anti-Sm (+)/(-); group A (n = 10): anti-dsDNA(-) plus anti-Sm(-), group B (n = 7): anti-dsDNA(-) plus anti-Sm (+), group C (n = 6): anti-dsDNA(+) plus anti-Sm(-), and group D (n = 7): anti-dsDNA(+) plus anti-Sm(+). Among these 4 groups, clinical marker and renal histology were compared. Renal histology showed 3 types including pure subepithelial membranous nephropathy(MN), mesangial proliferative nephropathy(MES), and MN plus MES.

Results

Thirty patients with anti-RNP antibody included SLE (n = 25) and MCTD (n = 5). The mean age (SE) was 38.6 (2.5) years, and 26 out of 30 patients (87%) were women. Fourteen patients (47%) showed the positivity for anti-Sm antibody and thirteen patients (43%) showed the positivity for anti-dsDNA antibody. Anti-Sm (-) groups showed normocomplementemia, and anti-Sm (+) groups showed hypocomplementemia. Pure MN was noted in anti-dsDNA (-) group or anti-Sm (-) group. The comparison between group A and group B showed that anti-Sm (-) has a close relation with normo-complementemia and MN lesion, and anti-Sm (+) has close relation with hypo-complementemia and MES lesion on patients with RNP(+) and ds-DNA(-).The comparison between group C and group D showed that anti-Sm (+) has close relation with hypo-complementemia, but does not have any relation with renal histology on patients with RNP(+) and ds-DNA(+).

Conclusion

Our study indicates that the single positivity of anti-RNP antibody contributes to MN formation with normocomplementemia, while additional positivity of anti-Sm antibody results in hypocomplementemia-related MES formation.