IL-17 levels were positively correlated with IL-1α (r = 0.31), IL-13 (0.32), and RANTES (r = 0.37) levels in the lungs of sensitized mice (P < 0.05), whereas IL-17 levels were inversely correlated with IL-4 levels in the lungs of mice without pneumococcal pneumonia, a finding which approached statistical significance (r = −0.29, P = 0.05). Here, IL4 is linked to pneumococcal pneumonia.