BACKGROUND: Cortical lesions (CLs) frequently observed in Caucasian patients with multiple sclerosis (MS) contribute to disability. However, it remains unclear whether CLs are associated with clinical features and genetic risk factors, such as HLA-DRB1*15:01 and -DRB1*04:05 in Asian MS patients.
OBJECTIVE: To elucidate the frequency of CLs and their association with HLA-DRB1 and DPB1 alleles in Japanese MS patients.
METHODS: Three-dimensional double inversion recovery imaging and clinical information were retrospectively obtained from 92 Japanese MS patients.
RESULTS: CLs of any type, intracortical lesions (ICLs), and leukocortical lesions (LCLs) were detected in 39.1%, 26.1%, and 28.3% of patients, respectively. MS patients with ICLs had a significantly higher frequency of secondary progression and greater Expanded Disability Status Scale (EDSS) scores than those without ICLs. Similar trends were observed with CLs and LCLs. The number of all three lesion types positively correlated with EDSS scores. The frequency and number of ICLs were significantly higher in HLA-DRB1*15:01 carriers than in HLA-DRB1*15:01 non-carriers, but significantly lower in HLA-DRB1*04:05 carriers than in HLA-DRB1*04:05 non-carriers. Multivariate logistic regression analysis revealed a negative association of HLA-DRB1*04:05 with ICLs.
CONCLUSION: ICLs are associated with greater disease severity in Japanese MS patients and are partly suppressed by the HLA-DRB1*04:05 allele.