Modified radioimmunoassay versus ELISA to quantify anti-acetylcholine receptor antibodies in a mouse model of myasthenia gravis.

In mouse models of myasthenia gravis (MG), anti-acetylcholine receptor (AChR) antibodies can be quantified to monitor disease progression and treatment response. In mice, enzyme-linked immunosorbent assay (ELISA) is the gold standard to quantify these antibodies. However, this method requires antigen purification, which is both time-consuming and expensive. In humans, radioimmunoassay (RIA)-which is more sensitive than ELISA-is commonly used to quantify AChR antibodies. At present, however, no commercial RIA kits are available to quantify these antibodies in mice. The aim of this study was to compare a modified commercial human RIA kit to two ELISA methods to detect AChR antibodies in an experimental autoimmune mouse model of MG (EAMG). C57BL/6 J mice were immunized with purified AChR from Tetronarce californica (T-AChR). Serum samples were analyzed by RIA and two ELISAs (T-AChR and purified mouse AChR peptide [m-AChR]). The modified RIA showed excellent sensitivity (84.1 %) and specificity (100 %) for the detection of AChR antibodies. RIA showed a good agreement with T-AChR ELISA (κ = 0.69) but only moderate agreement with m-AChR ELISA (κ = 0.49). These results demonstrate the feasibility of modifying a commercially-available RIA kit to quantify AChR antibodies in EAMG. The advantage of this technique is that it eliminates the need to develop the entire methodology in-house and reduces inter and intra-laboratory variability.

Mariscal A ，Martínez C ，Goethals L ，Cortés-Vicente E ，Moltó E ，Juárez C ，Barneda-Zahonero B ，Querol L ，Le Panse R ，Gallardo E ... -  《-》

Concordance between radioimmunoassay and fixed cell-based assay in subjects without myasthenia gravis: optimizing the diagnostic approach.

Acetylcholine receptor antibody (AChR-Ab) detection is crucial in myasthenia gravis (MG) diagnosis and, currently, the radioimmunoassay (RIA) is the gold standard. However, RIA may detect AChR-Ab against nonpathogenic intracellular epitopes. In this study, we performed fixed cell-based assay (F-CBA) in RIA-AChR-Ab positive subjects without MG symptoms, to assess whether F-CBA could show a higher specificity compared to RIA in detecting pathogenic Abs. We reviewed medical records of patients referred to our MG outpatient clinic because of RIA-AChR-Ab detection. MG diagnosis was based on clinical examination, electrophysiology and Ab detection. AChR-Abs were tested by RIA in the whole cohort. Serum samples from RIA-positive asymptomatic subjects were retested by F-CBA. Of 605 subjects who tested RIA-AChR-Ab positive, MG diagnosis was confirmed in 599. Six subjects were RIA-AChR-Ab positive although they had never had MG symptoms; in four of these subjects AChR-Abs were not detected by F-CBA, whereas the remaining two (both non-MG thymoma cases) were positive also by F-CBA. RIA false positivity for AChR-Ab is very rare. Previous literature has demonstrated that F-CBA has higher sensitivity than RIA for MG, especially in ocular cases. Our preliminary results show that, in rare instances, F-CBA may be more specific than RIA for MG diagnosis.

Falso S ，Marini S ，Carrozza C ，Sabatelli E ，Mascagna G ，Marini M ，Morroni J ，Evoli A ，Iorio R ... -  《-》

Detection of anti-acetylcholine receptor antibody by an ELISA using human receptor from a rhabdomyosarcoma cell line.

Martino G ，Twaddle G ，Brambilla E ，Grimaldi LM ... -  《ACTA NEUROLOGICA SCANDINAVICA》

Experimental autoimmune myasthenia gravis in the mouse.

Wu B ，Goluszko E ，Christadoss P 《-》

A Simple, Rapid and Non-Radiolabeled Immune Assay to Detect Anti-AChR Antibodies in Myasthenia Gravis.

To assess the practicality of dot-blot testing for rapid and sensitive detection of the antiacetylcholine receptor (anti-AChR) antibodies in myasthenia gravis (MG). In this case-control study, we tested serum specimens of 85 patients with MG, 85 healthy control individuals, and 85 patients without MG who have other autoimmune and neurological illnesses. All the serum specimens were tested for anti-AChR antibodies using 3 assays: in-house enzyme-linked immunosorbent assay (ELISA), the dot-blot assay, and commercial ELISA. In-house ELISA, commercial ELISA, and dot-blot test results were positive for anti-AChR antibodies in 65 (76.5%) patients with MG. The results of all 3 tests were negative for anti-AChR antibodies in healthy controls and patients without MG. We observed perfect concordance (K = 1, P <.001) between all 3 tests. In-house ELISA correlated significantly (r = 0.873, P <.001) with commercial ELISA. In-house ELISA and the dot-blot test demonstrated similar diagnostic performance in detecting anti-AChR antibodies. The dot-blot assay is a simple, nonradioactive immune assay for rapid detection of anti-AChR antibodies in MG.

Bokoliya S ，Patil S ，Nagappa M ，Taly A ... -  《-》