Four-color FISH/immunohistochemistry analyses for codetection of donor-derived nuclei, T cells, and dystrophin-positive myofibers in DMD-BMT1 muscle. T cells are stained in green (FITC), dystrophin-positive myofibers are stained in magenta (Cy5), nuclei are stained in blue (DAPI), and donor nuclei have a red hybridization signal (rhodamine). (a and b) T cells are not fused to dystrophin-positive myofibers, but appear to reside between myofibers. (c) T cells are of donor origin, as shown by the red dystrophin exon 45 hybridization signal after FISH analysis (white arrow) (d–f) Donor nuclei fused to dystrophin-positive myofibers are not T cells (white arrowheads).