CX3CL1 (Fractalkine), is a unique chemokine that exists in both soluble and membrane-bound forms. It plays a key role in leukocyte trafficking and adhesion, particularly under inflammatory conditions. Its receptor, CX3CR1, is expressed on monocytes, NK cells, and cytotoxic T lymphocytes. By neutralizing CX3CL1, quetmolimab aims to reduce the recruitment and retention of these immune cells in inflamed tissues, thereby dampening chronic inflammation and potentially slowing disease progression.