ADA and chronic obstructive pulmonary disease: ABA, abatacept; ADA, adalimumab; ETA, etanercept; INF, infliximab; LEF, leflunomide; MTX, methotrexate; RIT, rituximab; SSZ-HCQ, sulfasalazine/hydroxychloroquine; SD, standard deviation; HBV, hepatitis B virus; COPD, chronic obstructive pulmonary disease.