Interestingly, HDM also induced the accumulation of CD11b+ cells expressing high (hi) or intermediate (int) levels of Gr-1 and resembling myeloid-derived suppressor cells (MDSCs, identified as CD11b+Gr-1hi cells in lung tissues and CD11b+Gr-1intF4/80+ cells in the BALF) (Fig. 3L–N, Supplemental Fig. 3H–J), and of CD11b+ cells expressing programmed cell death protein 1 (PD-1, identified as CD11b+PD-1+ cells in lung tissues) (Fig. 3O–Q, Supplemental Fig. 3K–M), which are both known to inhibit anti-tumor immunity and to promote tumor development [55, 56]. The gene discussed is PDCD1; the disease is neoplasm.