Rituximab reduces anti-cardiolipin levels in patients with systemic lupus erythematosus

Introduction

Patients with systemic lupus erythematosus (SLE), can produce antibodies directed against the complex phospholipds-β-glycoprotein 1. Rituximab is an antibody directed to most B-cells, except precursors and mature plasma cells. It can produce reductions in antibody titers.

We have treated SLE patients refractory to conventional immunosuppressive therapy, with Rituximab and we searched for a reduction in anticardiolipin autoantibodies.

Material and methods

We have performed an observational, retrospective and multicentric study from 3 Spanish hospitals. We analysed 46 patients with complex clinical index (SLEDAI, physician global assessment scale) and laboratory determinations, included anticardiolipin levels, at start, week 24 and final visit.

Results

We have treated 46 patients, 3 men and 43 women, 91.3% Caucasians. Antiphospholipid syndrome was present in 14 patients (30.4%). A Lupus Anticoagulant (LA) was detected in 42.9%.

40 patients received the dose for arthritis (2x1g) and 4x375mg/m2 in the others. The mean of cycles used was 2 (1-3).

After the Rituximab therapy the LA was positive in only 10% (p<0.05). Anticardiolipin levels were reduced too, IgG aCL showed a significant reduction from 8.57 UI (3.44, 53.20) to 5.93 UI (1.70, 40.50), p<0.002. A non significant reduction in IgM aCL was detected 4.61 UI (2, 19.6) to 2.75 (1.02, 6.3). We have not detected new thrombotic events after Rituximab therapy.

Discussion

We have observed a reduction in the anticardiolipin antibody titers and LA among SLE patients treated with Rituximab. No new thrombotic episodes were observed after treatment with a mean follow-up of 21.1 months. We think may be necessary a longer follow-up to decide a possible efficacy for Rituximab in the management or antiophospholipid syndrome.

In spite of the absence of significant improvement of patient in the EXPLORE study, an analysis by Tew, shows a reduction of anticardiolipin antibodies levels to near normal. A bibliographic search for similar studies has not yield other results.