CD4 and myeloproliferative disorder: The MPN-Ruxo group had significantly fewer total lymphocytes, CD3+ cells, CD4+ cells, and CD56+ cells than the MPN-no Ruxo group (p = 0.003, 0.007, 0.007, and 0.002, respectively); however, CD19+ cells and IgG, which reflected humoral immunity, were maintained.