Objective: To compare clinical characteristics across immunopathological subtypes of patients with multiple sclerosis.

Methods: Immunopathological subtyping was performed on specimens from 547 patients with biopsy and/or autopsy confirmed CNS demyelination.

Results: The frequency of immunopathological subtypes were pattern I (23%), II (56%), and III (22%). Immunopatterns were similar in terms of age at autopsy/biopsy (median age 41 years, range 4-83 years, p=0.16) and proportion female (54%, p=0.71). Median follow-up after symptom onset was 2.3 years (range 0-38y). In addition to being overrepresented among autopsy cases (45% vs. 19% in biopsy cohort, p<0.001), index attack-related disability was higher in pattern III vs. pattern II (median EDSS 4 vs. 3, p=0.02). Monophasic clinical course was more common in patients with pattern III than pattern I or II (59% vs. 33% vs. 32%, p<0.001). Similarly, patients with pattern III pathology were likely to have progressive disease compared to patients with patterns I or II, when followed for ≥5 years (24% overall, p=0.49), with no differences in long-term survival, despite a more fulminant attack presentation.

Conclusion: All three immunopatterns can be detected in active lesions, although they are found less frequently later into the disease due to the lower number of active lesions. Pattern III is associated with a more fulminant initial attack than either pattern I or II. Biopsied patients appear to have similar long-term outcomes irrespective of their immunopatterns. Progressive disease is less associated with the initial immunopattern and suggests convergence into a final common pathway related to the chronically denuded axon.