Since atopy is associated with fewer CD8+ T cells [46], and most participants in this study were atopic (of the 334 severe asthmatics, atopy information was available for 308, of whom 234 were positive (76.0%); of the 87 controls, atopy information was available for 76, of whom 32 were positive (42.1%)), their atopic status rather than their asthma may explain the reduced CD8+ proportions. Here, CD8A is linked to asthma.