C3 and arthritic joint disease: SRI-4 response rates: 55.17%/65.52% in IL-2-group vs 30.00%/36.67% in placebo group at week 12 (p=0.052) and week 24 (p=0.027): primary endpoint at week 12 not met;no sign. difference between IL-2 and placebo group in change of SLEDAI, BILAG, PGA, and prednisone dose; higher improvement rate for rash and arthritis in IL-2 group, complete remission in pat. with lupus nephritis in 53.85% in IL-2 group vs 8.33% at week 12 (p=0.013) and 16.67% at week 24 (p=0.036) in placebo group; 24-h UPE ↓, (s)albumin ↑, complement C3/C4 ↑ (ns), anti-dsDNA-abs ↓ in IL-2 group compared to baseline