IL17A and infection: Drucker et al. demonstrated that, in older adults with psoriatic disease, the incidence of serious infections was 1.4 per 100 patient-years among those treated with newer biologic agents targeting IL-12, IL-23, or IL-17, compared to 2.5–2.7 per 100 patient-years among those treated with conventional systemic therapies such as methotrexate or cyclosporine [24].