Sustained ITP increases the frequency of functional LT-HSCs in vivo. (A) Experimental outline for B-D. (Bi, Ci, Di) Peripheral blood from primary recipients 4 to 20 weeks after transplantation. (Bii, Cii, Dii) Analysis of BM from primary recipients 20 weeks after transplantation. (Biii, Ciii, Diii) Analysis of peripheral blood from secondary recipients 4 to 20 weeks after transplantation. (Biv, Civ, Div) Analysis of BM from secondary recipients 20 weeks after transplantation. The horizontal dotted line shows the expected ratio if ITP had no effect on chimerism; for primary recipients, this was calculated on the basis of the transplanted ratio of donor cells, and for secondary recipients, this was calculated on the basis of the end point of the primary recipients (n = 5 mice per recipient group). (E) Experimental outline for panel F. (F) After 11 weeks, 2 of 9 recipients receiving 3 control LT-HSCs and 2 of 5 recipients receiving 10 LT-HSCs experienced chimerism, whereas 0 recipients receiving ITP LT-HSCs experienced chimerism (P = .013). P value was calculated with a χ² test. A successful transplantation was defined as >1% CD45.2 chimerism. After 11 weeks, 1 mouse transplanted with 10 control LT-HSCs showed >1% CD45.2 chimerism, and 1 mouse showed trace amounts of chimerism (<1%) as marked by an asterisk (*). All data are shown as mean ± SD.