CSF2 and myeloid sarcoma: F. Facciotti identified a previously uncharacterized population of extrafollicular B helper T cells, which produced IL-10 and could play a prominent pathogenic role in SLE.35 Li reported that the abnormal increases in GM-CSF+B-cell frequencies and responses in patients with MS, their enhanced capacity to activate proinflammatory myeloid cells, and the observations from B-cell depletion therapy in patients all point to a pathogenic role for the effector B-cell subset in MS.36 However, the relationship between B cells and psoriasis is still unclear.