https://orcid.org/0000-0003-1814-4099
Abstract
Atypical B cells or age-associated B cells (ABCs) represent an alternative lineage of memory B cells. Emerging evidence suggests that context influences the apparent functional heterogeneity of ABCs. While data support a protective role for ABCs in the setting of infection, multiple other studies suggest that these cells play a pathogenic role in the setting of autoimmunity. After treatment with allogeneic stem cell transplantation (HCT), the memory B cell compartment is altered in patients who develop an autoimmune-like syndrome called chronic graft-versus-host disease (cGVHD). Chronic GVHD patients have significantly increased proportions of CD11c+ ABCs within the peripheral compartment that develop under constant exposure to host alloantigens and persist under conditions when B cell tolerance is not achieved. Herein, we review what is currently known about the molecular alterations in the heterogeneous memory B cell compartment of HCT patients, especially cGVHD patients who have developed autoimmune manifestations. In this mini-review, we summarize intrinsic factors in ABCs found in autoimmune states that likely influence their extrafollicular localization, differentiation potential into autoantibody secreting cells, and function. We highlight lessons from B cell studies in cGVHD to provide unique insights into the molecular underpinnings of the diverse functions of ABCs.
Accepted manuscripts
