Immunoadsorption in dilated cardiomyopathy

Introduction

Removal of cardiodepressant autoantibodies by immunoadsorption (IA) has been reported to induce early haemodynamic improvement in patients with dilated cardiomyopathy (DCM). The Immusorba TR-350 (Asahikasei-Kuraray Medical Co. Ltd, Japan) (TR) is an IA column currently used for Myasthenia gravis or Guillain-Barré syndrome. This column, in which tryptophan is immobilized as a ligand, has a property to have high affinity to IgG subclass 3. With this property, imunoglobulin substitution is not usually required after the IA treatment. Since cardiodepressant antibodies belong to IgG subclass 3, we investigated the effect of IA using this column on cardiac function in patients with DCM.

Methods

Seventeen DCM patients (left ventricular ejection fraction (LVEF) <30%) participated in the study. IA was conducted every other day three to five times. Blood was drawn at the rate of 80 to 100 ml/minute by direct venipuncture or from the blood access catheter and it was first passed through the plasma-separating column. The separated plasma was then passed through the TR at the rate of 20 ml/minute. A total of 1,500 to 2,000 ml plasma was processed per one session. Either heparin or nafamostat mesylate was used as an anticoagulant. The LVEF was measured by quantitative gated single photon emission computed tomography. The cardiodepressant antibodies were assayed ex vivo [1]. The β₁-adrenergic and muscarinic M₂-acetylcholine receptor antibodies were measured by ELISA.

Results

After the three to five sessions of IA treatment, cardiodepressant antibodies were almost completely cleared from the circulation. Three months after the IA sessions, the LVEF increased significantly from 18.7 ± 2.3 to 23.2 ± 2.6%, P < 0.05. The average increase rate was 33.1 ± 12.6% from the baseline. Limited to the 10 patients who initially revealed the high titer of cardiodepressant antibodies, the increase in LVEF was greater (54.5 ± 16.8% from the baseline). The cardiodepressant antibodies were not detected at this period except in one patient. All patients tolerated IA without any complication. Any cardiac event or mortality did not take place over the period of 3 months.

Conclusion

The IA treatment with TR may bring benefit in left ventricular function in patients with DCM, particularly in those with a high titer of cardiodepressant antibodies. Further long-term follow-up is, however, required before confirming its efficacy.