Rheumatoid arthritis is an autoimmune disease that affects smaller joints, resulting in bone erosion, joint inflammation, and significant disability. Current rheumatoid arthritis treatments are associated with the risk of relapse and side effects, the latter including immunosuppression.Therefore, developing more efficient therapies is of interest. Memory B cells have been implicated in the disease, given the presence of autoantibodies and discrepancies in memory B cell numbers when comparing patients with healthy individuals. Hence, this study aimed to characterize the memory B cell subsets present in patients with untreated, early rheumatoid arthritis, where no treatment would act as a confounding factor. To elucidate the immune cell heterogeneity, singlecell RNA sequencing was used. Data from three patients was integrated and compared to a public dataset from a healthy donor. Two memory B cell subsets were linked to the production of interleukin-6, with one of them also expressing tumor necrosis factor-α. These cytokines are known to be highly expressed in patients with rheumatoid arthritis. Furthermore, a third memory B cell subset expressed high levels of B cell activating factor receptor, associated with pro-survival signals and likely autoimmunity. In the equivalent subset of the healthy donor this receptor was not upregulated. Targeting these subsets specifically with treatments could improve patient prognosis and reduce side effects. However, further research is needed to evaluate the contribution of these memory B cells in the context of rheumatoid arthritis.