The Clinical Features of LRP4/Agrin Antibody Positive Myasthenia Gravis: A Multi-center Study.

The Clinical Features of LRP4/Agrin Antibody-Positive Myasthenia Gravis: A Multi-center Study OBJECTIVE: To study prevalence and clinical characteristics of LRP4/Agrin antibody-positive double seronegative MG (DNMG). METHODS DNMG patients at 16 US sites were tested for LRP4 and Agrin antibodies and clinical data was collected. RESULTS Of 181 DNMG patients, 14.9% (27) were positive for either LRP4 or Agrin antibodies. Twenty-three DNMG patients (12.7%) were positive for both antibodies. More antibody-positive patients presented with generalized symptoms (69%) compared to antibody-negative patients (43%) (p<=0.02). Antibody-positive patients' maximum MGFA classification was significantly higher than antibody-negative patients (p<=0.005). 70% of antibody-positive patients were MGFA Class III-V compared to 39% of antibody-negative patients. Most LRP4 and Agrin antibody-positive patients (89%, 24/27) developed generalized MG but with standard MG treatment 81.5% (22/27) improved to MGFA Class I-II during a mean follow-up of 11 years. DISCUSSION Antibody-positive patients had more severe clinical disease than antibody-negative ones. Most DNMG patients responded to standard therapy regardless of antibody status. This article is protected by copyright. All rights reserved.