Figure 3From: Reduced rhinovirus-specific antibodies are associated with acute exacerbations of chronic obstructive pulmonary disease requiring hospitalisation Circulating IL-21 is lower in exacerbation-prone COPD patients Plasma IL-21 levels are plotted for (A) stable and exacerbation-prone COPD patients with the median indicated and (B) against the number of hospital admissions. Significant differences are indicated.Back to article page