Lower Frequency of Antibodies to MOG in Brazilian Patients with Demyelinating Diseases: an Ethnicity Influence?

OBJECTIVE:Antibodies against Myelin Oligodendrocyte glycoprotein (MOG-Ab) have been investigated as potential biological marker for neuromyelitis optica (NMO) and high-risk syndromes (HR) negative for AQP4-Ab in populations with different ethnic background. We tested AQP4 and MOG antibodies in a Brazilian population with high African ethnic background.METHOD:The study population was composed of adult patients from Rio de Janeiro with inflammatory demyelinating diseases (new and old cases). Blood samples were sent blindly to test the AQP4 and MOG antibodies by CBA. The frequency of positive MOG-Ab was estimated in the NMOHR and the NMO spectrum disorders (NMOSD). A systematic review with meta-analysis assessed the frequency of MOG-Ab in Caucasians and non-Caucasians.RESULTS:200 adult patients (52% Afro-Brazilian) 115 of them with NMOHR were tested. MOG antibodies were found in 5/68 negative cases of AQP4-Ab negative (7%). The criteria for NMOSD were fulfilled by 70 patients with NMOHR and none of them was positive for MOG-Ab. A low prevalence of MOG antibodies and a predominant phenotype of bilateral Optic Neuritis were found in most non-Caucasian patients.CONCLUSION:The low frequency of MOG Ab in patients from Rio de Janeiro and in other non-Caucasian populations suggests a racial/ancestral influence.