Contributions
Abstract: EP1288
Type: ePoster
Abstract Category: Clinical aspects of MS - 1 Diagnosis and differential diagnosis
MOG is a CNS-specific antigen expressed on the surface of myelin sheaths. Anti MOG antibodies (Abs) have been recently described as diagnostic marker of acquired demyelinating CNS diseases different from Multiple Sclerosis (MS), as seronegative Aquaporin-4 Neuromyelitis Optica spectrum disorders, pediatric ADEM or very early onset pediatric MS. To date there is not a standardized protocol to detect anti-MOG Abs although the most specific methods are cell based assays (CBA). Here we present our work to set up the FACS procedure for routine detection.
Glial LN18 cell line untransfected or stably transfected with full-length MOG were provided by Hemmer lab (Monaco). They were incubated with patients' sera, marked with anti-human IgG secondary antibody and analyzed by FACS. In each assay we tested 4 internal controls: 1 healthy commercial serum (NC), 1 purified anti-MOG Ab, 1 human IgG anti-MOG+ patient serum and 1 human IgG1 anti-MOG+ patient serum. We expressed the Ab titers as the difference in median fluorescence intensity (ΔMFI) between the MOG-transfected and untransfected LN18. The ΔMFI threshold was 23, i.e. the average ΔMFI plus 6 SD of healthy control (HC). Values higher than 23 were tested again to evaluate the IgG subclasses.
Medium values of positive controls were 1982 for purified anti-MOG Ab and 357 for IgG anti-MOG+ human sample. The low and high CBA detection limits were assessed using serial dilution of both positive controls (R2= 0.99). All 61 HC and 13 MS tested sera were negative for anti-MOG (mean ΔMFI 2.5, SD 3 and mean 1.5, SD 2, respectively). No differences were found between HC and MS, while the difference between HC and both positive controls was significant (p< 0.0001). From June 2015 to April 2017 we performed 570 anti-MOG Ab detections on 488 patients from different Italian neurology department. Cross reactivity to AQP4 and MOG was never detected at the same time. We identified 21 IgG anti-MOG+ patients (4.3%), mostly IgG1, except for one IgG3. We identified also 4 BORDERLINE PATIENTS with Ab titre around the threshold. In this case we suggested a retest after 3 months. In fact, 1 of these patients became IgG1 anti-MOG+ 3 months later.
Our CBA test is reliable and reproducible and do not provide false positive results. We are the only one Italian laboratory offering a CBA test for diagnostic routine. The anti MOG detection represents a new diagnostic tool to discriminate from different inflammatory CNS diseases.
Disclosure: Marco Capobianco received speaking honoraria from Almirall, Biogen, Merck-Serono, Novartis, Sanofi-Genzyme, TEVA and served in advisory board for Biogen, Novartis, Merck-Serono, Bayer, Roche
Antonio Bertolotto received honoraria for serving in the scientific advisory boards of Biogen, Merck, Mylan, Sanofi-Genzyme, and received speaker honoraria from Biogen, Genzyme, Novartis, TEVA; his institution has received grant support from Almirall, Bayer, Biogen, Genzyme, Merck, Novartis, TEVA, from the Italian Multiple Sclerosis Society, Fondazione Associazione Ricerca Biomedica ONLUS and San Luigi ONLUS.
Arianna Sala received honoraria from Biogen.
Michela Spadaro received honoraria from Biogen.
Abstract: EP1288
Type: ePoster
Abstract Category: Clinical aspects of MS - 1 Diagnosis and differential diagnosis
MOG is a CNS-specific antigen expressed on the surface of myelin sheaths. Anti MOG antibodies (Abs) have been recently described as diagnostic marker of acquired demyelinating CNS diseases different from Multiple Sclerosis (MS), as seronegative Aquaporin-4 Neuromyelitis Optica spectrum disorders, pediatric ADEM or very early onset pediatric MS. To date there is not a standardized protocol to detect anti-MOG Abs although the most specific methods are cell based assays (CBA). Here we present our work to set up the FACS procedure for routine detection.
Glial LN18 cell line untransfected or stably transfected with full-length MOG were provided by Hemmer lab (Monaco). They were incubated with patients' sera, marked with anti-human IgG secondary antibody and analyzed by FACS. In each assay we tested 4 internal controls: 1 healthy commercial serum (NC), 1 purified anti-MOG Ab, 1 human IgG anti-MOG+ patient serum and 1 human IgG1 anti-MOG+ patient serum. We expressed the Ab titers as the difference in median fluorescence intensity (ΔMFI) between the MOG-transfected and untransfected LN18. The ΔMFI threshold was 23, i.e. the average ΔMFI plus 6 SD of healthy control (HC). Values higher than 23 were tested again to evaluate the IgG subclasses.
Medium values of positive controls were 1982 for purified anti-MOG Ab and 357 for IgG anti-MOG+ human sample. The low and high CBA detection limits were assessed using serial dilution of both positive controls (R2= 0.99). All 61 HC and 13 MS tested sera were negative for anti-MOG (mean ΔMFI 2.5, SD 3 and mean 1.5, SD 2, respectively). No differences were found between HC and MS, while the difference between HC and both positive controls was significant (p< 0.0001). From June 2015 to April 2017 we performed 570 anti-MOG Ab detections on 488 patients from different Italian neurology department. Cross reactivity to AQP4 and MOG was never detected at the same time. We identified 21 IgG anti-MOG+ patients (4.3%), mostly IgG1, except for one IgG3. We identified also 4 BORDERLINE PATIENTS with Ab titre around the threshold. In this case we suggested a retest after 3 months. In fact, 1 of these patients became IgG1 anti-MOG+ 3 months later.
Our CBA test is reliable and reproducible and do not provide false positive results. We are the only one Italian laboratory offering a CBA test for diagnostic routine. The anti MOG detection represents a new diagnostic tool to discriminate from different inflammatory CNS diseases.
Disclosure: Marco Capobianco received speaking honoraria from Almirall, Biogen, Merck-Serono, Novartis, Sanofi-Genzyme, TEVA and served in advisory board for Biogen, Novartis, Merck-Serono, Bayer, Roche
Antonio Bertolotto received honoraria for serving in the scientific advisory boards of Biogen, Merck, Mylan, Sanofi-Genzyme, and received speaker honoraria from Biogen, Genzyme, Novartis, TEVA; his institution has received grant support from Almirall, Bayer, Biogen, Genzyme, Merck, Novartis, TEVA, from the Italian Multiple Sclerosis Society, Fondazione Associazione Ricerca Biomedica ONLUS and San Luigi ONLUS.
Arianna Sala received honoraria from Biogen.
Michela Spadaro received honoraria from Biogen.