An association between delirium and reduced release of TNFα (OR 0.29, 95%CI 0.11–0.72, P = 0.01), IP-10 (OR 0.25, 95%CI 0.08–0.73, P = 0.01), IL-1β (OR 0.42, 95%CI 0.20–0.89, P = 0.02), and IL-12 (OR 0.07, 95%CI 0.01–0.70, P = 0.02) as well as the increased plasma IL-6 (OR 1.61, 95%CI 1.00–2.58, P = 0.04) remained significant after adjusting for stroke severity (NIHSS score on admission), pneumonia, and urinary tract infection. This evidence concerns the gene IL1B and susceptibility to pneumonia measurement.