IL17A and chronic obstructive pulmonary disease: In contrast, absolute macrophage counts and the proportion of macrophages were markedly reduced in simvastatin treatment compared with placebo treatment, possibly resulting from the reduction in IL-17A that contributes to macrophage recruitment by activating IL-17A receptors on macrophages.38 In keeping with the finding of a reduced sputum macrophage count with simvastatin in COPD, a clinical trial in asthma reported atorvastatin treatment, compared with placebo, was associated with a reduction in the absolute sputum macrophage count.39