CD4 and systemic sclerosis: This receptor is also involved in the Sema4B-mediated inflammation in microglia/macrophages [11], the Sema4D-mediated cartilage destruction [7], the Sema4A-induced secretion of IL-17 by CD4+ T cells of systemic sclerosis patients [32] and the Sema4D-mediated inflammation in a mouse model of multiple sclerosis [33].