Increased Number of Perivascular CD20-Positive B Lymphocytes in the Neuropathology of CLIPPERS: Findings of 6 Patients from Mainland China.

INTRODUCTION: Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) syndrome is a recently described chronic inflammatory disease of the central nervous system. There are few reports of CLIPPERS in the Chinese population to date. We summarized the clinical characteristics of 6 CLIPPERS patients to deepen the understanding of this disease. METHODS: The clinical manifestations and treatment of 6 CLIPPERS patients confirmed by pathology or clinical diagnosis in our hospital were retrospectively analyzed. RESULTS: The common clinical manifestations included ataxia, dysarthria, diplopia, dysphagia, dizziness, cognitive impairment, facial paresthesia, and paralysis. Most of the lesions showed typical symmetric "pepper powder"-like dot and nodular enhancement centered in the pontine and cerebellum except 1 patient with unilateral nodular enhancement. The brain histopathological examination of the 5 biopsied patients indicated that, with the exception of patient 4 with no lymphocyte infiltration, a large amount of perivascular lymphocytic infiltration was found in the other 4 patients, among whom only 1 patient was dominated by CD3+ T cell infiltration and the other 3 patients were dominated by CD20+ B cell infiltration. After treatment with intravenous methylprednisolone, all patients had significant clinical recovery associated with complete or significant MRI recovery, but they were prone to relapse after withdrawal or reduction of the corticosteroid. CONCLUSION: Our reports highlight the importance of neuropathological examinations when encountering atypical imaging manifestations, such as unilateral and large nodular Gd+ lesions, in order to establish a final diagnosis of CLIPPERS. In addition, the lymphocytic infiltration in the lesions of CLIPPERS may be dominated by CD20+ B cells instead of CD3+ T cells.