ITGA4 and neoplasm: Regarding effects of BTK inhibition on the expression of CD49d or CD163, no information is available for healthy human immune cells, while it is known that CD49d is expressed in approximately 40% of chronic lymphocytic leukaemia, a B-cell malignancy, and contributes to resistance to BTKi treatment (20, 21) and that CD163 expression in tumour-infiltrating macrophages or circulating soluble CD163 is associated with poor prognosis in mantle cell lymphoma (22).