Impact of influenza A infection on house dust mite-specific Th-cytokine responses. Separate groups of 8-day-old mice were infected with influenza virus or given PBS alone. Seven days later, PBS- and Flu-infected groups are exposed either to 3 weeks of HDM or Sal and killed 72 h after the last HDM exposure. Splenocytes from individual mice were cultured in medium alone (□) or stimulated with HDM in vitro (▪) and Th1-, Th2-, and Th17-associated cytokine production measured by ELISA. For all data, n=4–10 mice per group. Data represent mean±s.e.m. P<0.05 compared with *Sal, ‡Flu, and §HDM, respectively. ELISA, enzyme-linked immunosorbent assay; HDM, house dust mite; PBS, phosphate-buffered saline.