IL-18 associated with lung lymphoid aggregates drives IFNγ production in severe COPD

Table 2 IL-18 immunoreactivity of lung macrophages and dendritic cells

Definition of abbreviations: Mac, macrophages; DCs, dendritic cells; mDCs, myeloid dendritic cells. IL-18 positive cells were identified in the lung of COPD patients (see Additional file 1: Table S2) by multi-color immunofluorescence staining using a panel of cell markers. There was no IL-18 staining associated with ECP⁺ eosinophils, MPO⁺ neutrophils, tryptase⁺ mast cells, CD3⁺ T cells, CD20⁺ B cells and CD138⁺ plasma cells. Interleukin-18 positivity was scored as follows: - absent staining, + weak light chromogen staining; ++, clear and moderate immunoreactivity; +++ intense dark staining (brackets are used to indicate where the higher scoring was seen only in certain patients and not all of those analysed)