MS4A1 and lymphopenia: Its onset may occur early, at 6 months or up to 33 months after drug initiation, with a mean time of 7.6 months.After adjusting for the anti-CD20 drug, age, time of exposure, and EDSS, we observed that men have a significantly higher risk (OR 3.027, p < 0.05) of developing lymphopenia, without additional associations found (Table 7).