Expansion of myeloid and erythroid cells but not lymphocytes occurs in the spleens of TSLP transgenic mice. TG mice did not have significantly more B lymphocytes (A, IgD⁺; B, IgM⁺) or T lymphocytes (C, CD4⁺; D, CD8⁺) than their littermates (LM). However, TG mice had significantly more myeloid (E, Gr-1⁺) and erythroid (F, Ter-119⁺) cells. (NS indicates not significant; *P ≤ .004). The results are presented as the average number of cells ± SEM (n = 6 and n = 7 for TG and LM mice, respectively).