Figure 4

Cigarette smoke (CS) exposure prior to influenza infection results in reduced BAFF and secretory IgA (S-IgA). Mice were exposed to room air (RA) or CS for 3 months and then infected with influenza virus or vehicle control. They were sacrificed and evaluated on day 7 after infection. (A) The relative mRNA levels of keratinocyte-derived chemokine (KC) in the lung, (B) the total leukocyte counts, (C) BAFF protein levels and (D) influenza-specific S-IgA levels in bronchoalveolar lavage (BAL) fluid are shown (n = 5 mice/group). RA + Flu, RA-exposed mice with influenza virus infection; CS + Flu, CS-exposed mice with influenza virus infection; #, not detected; *P < 0.05.