FCRL5

Class

Chimeric antigen receptor (CAR) T-cell therapy — anti-FCRL5 (Fc receptor-like protein 5)

Pathway

T-cell-mediated cytotoxicity against FCRL5-expressing myeloma plasma cells

FCRL5 (Fc receptor-like protein 5) is a surface protein found abundantly on mature B cells and, especially, on plasma cells — the antibody-producing cells that, when they turn malignant, cause multiple myeloma. Because FCRL5 is displayed densely and consistently on these cells, it serves as a recognition marker that can be exploited therapeutically. Chimeric antigen receptor (CAR) T-cell therapy re-engineers a patient's own T cells to carry an artificial receptor that binds FCRL5, redirecting the T cells' natural killing machinery toward any cell expressing it. This approach is part of a broader strategy in myeloma treatment of engineering immune cells to seek out and destroy plasma cells that have escaped normal growth control, complementing other plasma-cell-directed antibody and cellular therapies. The rationale for choosing FCRL5 specifically, rather than relying solely on other established plasma-cell markers, is that it offers an additional or alternative point of recognition, which may help address cases where a single target is insufficiently expressed or where resistance to one targeting strategy has emerged. Broadly, this mechanism matters wherever a malignant cell population can be distinguished from healthy tissue by a stable, tumor-associated surface marker, allowing engineered immune cells to be aimed precisely at diseased tissue.