Longitudinal assessment of CD19 B-cell counts after depleting therapy in relapsing-remitting multiple sclerosis: an Egyptian cohort study

Abstract Background Multiple sclerosis is a chronic neurological disorder affecting the central nervous system. It is classified as the foremost neurological contributor to disability among young adults. In 2017, Ocrelizumab, a humanized IgG1 monoclonal anti-CD20 antibody, received approval for the treatment of relapsing and progressive forms of MS. Results This prospective cohort investigation sought to track total CD19 B-cell counts throughout the course of B-cell depletion therapy in MS patients, correlating these counts with disease activity. A total of 30 Egyptian patients diagnosed with Relapsing-Remitting Multiple Sclerosis, according to the 2017 McDonald criteria, were enrolled in the study. All participants underwent comprehensive assessments at baseline, 6 months, and 12 months post-therapy. Clinical, radiological, and laboratory assessment involved cerebral and spinal MRI, and CD19 B-cell counts were determined through flow cytometry for immunophenotyping. Our patients were predominantly female (73.3%). We observed a significant drop in CD19 B-cell counts from a median of 30.65 cells/µL pre-treatment to 2.76, 4.43, and 4.74 cells/µL at 1, 6, and 12 months, respectively. This B-cell depletion was strongly linked to a substantial reduction in the median Annualized Relapse Rate, which decreased from 2.0 before treatment to 0 after 12 months of Ocrelizumab therapy. Clinical outcomes showed a drop in the EDSS median score from 4.5 pre-treatment to 3.5 at 6 months and 2.5 at 12 months. Radiologically, most patients maintained a stable lesion burden in their brain and spinal cord in both number and size. A statistically significant reduction ( p < 0.05) in gadolinium-enhancing lesions was noted after 12 months. Conclusion Ocrelizumab proved highly effective in reducing relapses, preventing disability progression, and decreasing disease activity (both clinical and radiological) in our group of Egyptian MS patients over 12 months using a fixed dose schedule.