Investigate an association with BMI and early B cell repopulation in a large cohort of multiple sclerosis (MS) patients treated with CD20-depleting therapy

Findings from a prior retrospective cohort of 45 patients indicated larger body surface area (BSA) was associated with faster repopulation of B cells after CD20 depletion, attributed to underestimation of CD20-depleting therapy dosing for patients with high BSA. Body mass index (BMI) is also associated with increased MS risk and radiographic markers of disease in relapsing-remitting disease. We aimed to confirm an association with BMI and early B cell repopulation after CD20 depletion therapy in an approximately 4-fold larger sample of patients than prior data.

This is a retrospective cohort study at a single academic referral center. Patients were identified through chart review using ICD billing codes. Normal BMI was defined 18.5-25. Overweight/obese BMI was defined as 25 or greater. The outcome of interest was early B cell repopulation defined as presence of greater than or equal to 1% CD19 cells on serum lymphocyte subset profile. Logistic regression was used to compare the categorical outcome on the normal vs overweight/obese BMI groups.

An initial 405 patients were identified. After excluding patients with missing ocrelizumab infusion and lymphocyte subset data, a total sample size of 157 patients were analyzed. The mean age and female sex of the cohort were 51.8 years (SD 12.9) and 99 (63.1%), respectively. 67 (42.7%) patients were categorized having normal BMI (18.5-25) and 90 (57.3%) patients as overweight/obese BMI (>25). The model revealed an effect of BMI: patients who were overweight/obese showed an increase in repopulation [Coef=0.49, SE=0.22, p=0.03]. There was no effect of sex or age.

Our study provides supportive evidence that greater BMI is associated with B cell repopulation after CD20-depleting therapy.