The Specificity, Sensitivity and Clinical Correlation of CBA, RIPA and ELISA in Detecting AChR and MuSK IgG of Myasthenia Gravis
Condition: Detection Autoantibody of Myasthenia Gravis
MeSH terms: Myasthenia Gravis; Muscle Weakness
Study type: Observational

Summary: 
      Myasthenia gravis (MG) is a neuromuscular junction (NMJ) disorder mediated by autoantibodies
      against AChR, MuSK or other autoantigens located at the post synaptic membrane of the
      neuromuscular junction. Presence of autoantibodies specific for AChR or MuSK can establish
      diagnosis in conjunction with clinical presentations. In most established guidelines for the
      diagnosis and treatment of myasthenia gravis, determination of AChR and MuSK antibodies has
      been recommended. Radioimmunoprecipitation assay (RIPA), enzyme-linked immunosorbent assay
      (ELISA), and cell-based assay (CBA) are all commercially available and have been adopted for
      autoantibody detection by most referring neurologists. At present, specificity and
      sensitivity of these methods have not been compared in large cohorts within a context of
      stringent quality control. As a consequence, there are no national or international consensus
      regarding selection of methods and interpretation of results, resulting in challenges to
      neurologists managing these patients. To this end, the investigators proposed to conduct a
      multicenter, double-blind, prospective study to compare the sensitivity and specificity of
      CBA, RIPA and ELISA assays to detect AChR and MuSK antibodies.
    

Detailed description: 
      Participants: patients with suspected MG

      Aim: the specificity, sensitivity, and clinical correlation of AChR and MuSK IgG detection
      through the CBA, ELISA, and RIPA methods.

      Study design: A multicenter, double-blind, prospective study to compare the sensitivity and
      specificity of CBA, RIPA, and ELISA assays in detecting AChR and MuSK antibodies.

      Total enrollment: 3000 patients with suspected MG will be enrolled.

      Time frame: The enrollment time of this trial is 21 months, and the entire study period is
      about 24 months.

      Reagent resource: 1. Acetylcholine receptor autoantibody RIA kit: RSR limited, recommended
      cut-off value=0.5 nmol/L.

      2. Acetylcholine receptor autoantibody CBA kit: Tianjin New Terrain Biological Technology
      Co., Ltd; recommended cut-off value =1:10.

      3. Acetylcholine receptor autoantibody ELISA kit: RSR limited; recommended cut-off value=0.45
      nmol/L.

      4. Muscle-specific tyrosine kinase RIA kit: RSR limited, recommended cut-off value =0.05
      nmol/L.

      5. Muscle-specific tyrosine kinase CBA kit: Tianjin New Terrain Biological Technology Co.,
      Ltd; recommended cut-off value =1:10.

      6. Muscle-specific tyrosine kinase ELISA kit: IBL, recommended cut-off value=0.4 U/ml.

      Groups: The samples were divided into 3 groups according to the detected methods: CBA group,
      RIPA group and ELISA group.

      Study protocol: 1. When patients suspected of MG matched up with the inclusion and exclusion
      criteria, the serum sample of each patient would be divided into equal aliquots and randomly
      assigned to the CBA, ELISA, and RIPA testing laboratories for detection.

      2. All patient's information will be masked and monitored by members of ethics committees.
      Serum specimens from participants will be renumbered without any clinical information before
      doing the tests to be investigated. According to the standard procedure of kits, the operator
      in laboratories to perform the CBA, ELISA, or RIPA will complete the detection of AChR and
      MuSK antibodies of the enrolled participants' serum, and record the original value, control,
      or reference value.

      3. Each MG center will provide the clinical diagnosis results of the enrolled patients,
      treatment and follow up information of the participants. The diagnosis of MG and the tests to
      be investigated will be double blindly done.

      4. The data statistics, analysis, and summary of the project are operated by an independent
      third-party statistic team.

      Evaluation indicators: Evaluate the specificity, sensitivity, and clinical correlation of
      AChR and MuSK IgG detection through the CBA, ELISA, and RIPA methods.
    

Intervention name(s): CBA Assay
Intervention type(s): Diagnostic Test
Intervention description(s): Comparsion of specificity, sensitivity and clinical correlation of CBA, ELISA and RIPA assay in autoantibodies detection of myasthenia gravis
Other intervention name(s): ELISA Assay; RIPA Assay
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Patients with suspected MG, 1-90 years of age.
      
Biospecimen description: 
      sreum
    
Keywords: Cell-based assay; Radioimmunoprecipitation assay (RIPA); Enzyme-linked immunosorbent assay (ELISA); Autoantibody determination; Myasthenia gravis