Table 5– Inter-patient variability of sputum inflammatory mediators and cell counts in matched stable patients with usual chronic obstructive pulmonary disease (COPD) and α₁-antitrypsin deficiency (A1ATD)

	IL-8	MPO	LTB₄	Sputum neutrophils	Sputum macrophages
A1ATD	78.9	230.1	51.1	29.1	35.7
COPD	99.3	78.3**	71.1	20.6	58.0

Data are presented as coefficient of variance (CV) as %. The inter-patient (between patients) CV is derived from individual patient's mediator-specific mean and sd (from logged data), calculated using data from nine visits. IL: interleukin; MPO: myeloperoxidase; LTB₄: leukotriene B₄. **: p<0.01.