CD4 and type 1 diabetes mellitus: The chemokine receptor XCR1 gene also contacted by regulatory regions harbouring T1D associated variants rs11718385, rs2856758 and rs1799988 has also been implicated in Treg defects in human allergic asthma, with reduced XCR1 expression on CD4 + CD25highCD127low/ − regulatory T cell (Treg) shown to be associated with impaired regulatory function [50].