Rather they showed slightly increased white blood cell counts and splenomegaly.21, 22 Even though MIM deficiency has a number of CXCR4‐independent effects, these data show that enhanced CXCR4 activity does not have to lead to leukopenia in the peripheral tissues, nor to major alterations in leucocyte subset numbers and frequencies in the bone marrow. This evidence concerns the gene MTSS1 and Splenomegaly.