In addition to soluble mediators, surface cellular markers such as CD69 (an early lymphocyte activation marker), lung homing related CD62L, Triggering Receptor Expressed on Myeloid cells (TREM)-1 and HLA-DR have been useful for inflammation analysis in influenza infections (22), inflammatory systemic syndrome (23) and hypersensitivity states (24). The gene discussed is TREM1; the disease is influenza.