While HIF-1α, HO-1, NOS-2, phosphor-p38-MAPK and VEGF-A were markedly upregulated in the lungs within 24 h pi in animals infected with either of the reassortants or with H5N1, and remained highly expressed in the latter group throughout the course of the study (Fig. 4 , and data not shown), no consistent pattern was discernable in the expression of these inflammatory markers in the lymphoid tissues. Nevertheless, all five markers were markedly upregulated above control levels at one or more time points postinfection in all lymphoid tissues of all infection groups (data not shown).