Immunoadsorption plasmapheresis (IAPP) is effective for eliminating pathogenic molecules such as anti-DNA antibody (anti-DNA Ab) and immune complexes from the serum of patients with systemic autoimmune diseases. The purpose of this study was to assess patients with lupus nephritis (LN) treated by IAPP using a phenylalanine column and determine its efficacy with respect to conventional therapies. Six patients (M = 1, F = 5) with histologically proven LN associated with proteinuria and abnormal sedimentation on urinalysis were the subjects for this study. All were treated with oral corticosteroid (prednisolone 1 mg/kg/day) and IAPP (Immusorba PH - 350; 2 L of plasma twice weekly for 2 weeks). Serum anti-DNA Ab and complement, urinary protein, and creatinine clearance were measured over 6 weeks (pretreatment, before and after each of 2 IAPP sessions, and 1 and 4 weeks after the second IAPP session). Clinical efficacy of IAPP was compared with conventional pharmacotherapy regimes by conducting a retrospective review of 23 LN patients treated at our hospital using corticosteroid pulse therapy (CSPT, N = 7, intravenous methylprednisolone 500 mg/day for 3 days), intravenous cyclophosphamide pulse therapy (IVCY, N = 7), or corticosteroid monotherapy (CSMT, N = 9, oral prednisone 1 mg/kg body weight daily, for 4 weeks). Immunosuppressants and anticoagulants were not used. With IAPP, mean urinary protein excretion decreased from 2.2 +/- 1.7 g/day pretreatment to 0.4 +/- 0.6 g/day post-treatment (P < 0.001). Mean serum anti-DNA Ab also decreased from 84.0 +/- 88.1 U/mL pretreatment to 5.8 +/- 5.5 U/mL post-treatment (P < 0.05). In combination with corticosteroid therapy, IAPP would appear to be an effective and safe treatment for LN.