TAFAZZIN deficiency leads to a mild peripheral leukopenia in adult mice. (A) Schematic outlining the approach of transplanting fetal liver cells from WT or TAFAZZIN-KO donors (CD45.2) into WT recipient mice (CD45.1). CD45.1 and CD45.2 staining of leukocytes in the peripheral blood quantifies the degree and contribution of engraftment. (B) The frequency of CD45.2 donor cells, both WT and TAFAZZIN-KO, in the peripheral blood remains stable following transplantation. (C) Complete blood counts of the peripheral blood demonstrate a mild leukopenia in mice transplanted with TAFAZZIN-KO fetal liver cells. (D) Flow cytometry was used to enumerate specific populations within the peripheral blood, with a focus on the transplanted CD45.2 cells. The lack of TAFAZZIN results in significantly fewer B cells, T cells, myeloid cells, and neutrophils. (E) Flow cytometric analysis of mature and progenitor populations within the bone marrow did not reveal any differences between mice reconstituted with WT or TAFAZZIN-KO fetal liver cells. Error bars indicate the mean ± SD. t tests were performed. **P < .01; ***P < .001; ****P < .0001. NS, not statistically significant.