Evaluation of lymphocyte and macrophage scores in relation to the use of daily co-trimoxazole in patients with GPA with negative nose cultures for S. aureus; no significant differences were found in CD3+, CD20+, CD68+, CD86+ or CD163+ cells in the airways between patients with GPA who were or were not on daily co-trimoxazole. The gene discussed is CD86; the disease is granulomatosis with polyangiitis.