Donor-specific pathological features associate with genetic background, lesion type distribution, and clinical...

Multiple sclerosis (MS) shows pronounced pathological and clinical variability between individuals, reflecting differences in genetic susceptibility, inflammatory activity, and tissue repair. This variability complicates efforts to relate lesion pathology to clinical trajectories. In previous work in the Netherlands Brain Bank MS autopsy cohort (NBB-MS), we showed that relative proportions of different lesion types, lesion load, and microglia/macrophage activity score, associate with clinical severity, while also revealing marked inter-individual variability. Here, we extend these observations by examining whether selected donor-specific pathological features relate to genetic background, quantitative lesion type distributions, and clinical disease course, and thereby help contextualize this heterogeneity.Brain tissue from 287 NBB-MS donors was assessed for the presence of the donor-specific pathological features, namely perivascular cuffs, microglial nodules, broad rim lesions (BRLs), and remyelination efficiency. Perivascular cuffs and microglial nodules were more prevalent among carriers of the MS susceptibility allele HLA-DRB1*15:01 (rs3135388). BRLs and perivascular cuffs were enriched in carriers of the MS severity-associated SNP in the DYSF-ZNF638 locus (rs10191329). Perivascular cuffs associated with increased microglia/macrophage activation score and decreased age at death. Microglial nodules in the normal appearing white matter associated with a higher proportion of active lesions. BRLs were linked to increased proportions of active and mixed active/inactive lesions, higher brainstem lesion rate, and a higher age related MS severity score. Poor remyelination efficiency associated with a higher proportion of mixed active/inactive and inactive lesions, and a shorter disease duration.Together, these findings show that specific pathological features of donors relate to genetic risk, lesion type distribution, and clinical outcome. Integrating these donor-specific pathological features alongside lesion classification will enable a more biologically refined interpretation of post-mortem MS tissue study results and will improve understanding of inter-individual heterogeneity in MS.