Trend in XY chimerism of peripheral blood relative to bone marrow function. Peripheral blood FISH analysis demonstrating XY chimerism (number of XY nuclei/total nuclei counted) with corresponding absolute neutrophil count (ANC) representing bone marrow function. Recovery of ANC occurred with XY chimerism suggesting either transient engraftment of son's cells or immunomodulatory effect of CD34⁺ infusion facilitating resolution of GVHD with subsequent stable marrow function and near complete restoration of patient XX chimerism on POD 113. Time of ANC recovery and platelet recovery are noted as defined by CIBMTR reporting standards. Timing of immunosuppression relative to clinical course is also noted.