IL1B and chronic obstructive pulmonary disease: The case-control and case-only association studies identified three coding SNPs, so far not analyzed in this context, that were associated with COPD disease severity and IL-1β concentration in the serum: NLRP1 (rs12150220, L155H), NLRP4 (rs12462372, R708H) and NLRP8 (rs306481, K937R).