Tumor necrosis factor (TNF)-alpha and TNF receptors in viral pathogenesis

Severe Acute Respiratory Syndrome Coronavirus 2 and the Use of Biologics in Patients With Psoriasis [Formula: see text]

Coronavirus disease (COVID-19), a respiratory disease caused by a novel coronavirus designated severe acute respiratory syndrome coronavirus 2, has rapidly spread worldwide and has been recognized as a pandemic by the World Health Organization. Patients with altered immunologic function are at higher risk of acquiring COVID-19. In patients with psoriasis, inhibition of select pro-inflammatory cytokines through the use of biologic agents has been shown to be an effective treatment option. Pro-inflammatory cytokines have key immunomodulatory effects and are known to be involved in the hosts' immune response to a variety of viral infections. Though little is currently known about the role of inflammatory cytokines in COVID-19, early reports have shown patients with severe disease to have elevated serum levels of select inflammatory cytokines such as tumor necrosis factor alpha. This review will summarize key information that is currently known about COVID-19, the role of select cytokines in viral defense, and important considerations for patients with psoriasis using biologic agents during this pandemic. Currently, there is insufficient evidence to discontinue biologic therapy in patients with psoriasis who have not tested positive for COVID-19. The decision to pause biologic therapy should be considered on a case-by-case basis in patients in higher risk populations, and should take into account individual risk and benefit. Until more is known about the impact of biologic therapy on COVID-19 outcomes, we recommend patients with psoriasis who test positive for COVID-19 be instructed to discontinue or postpone biologic treatment until they have recovered from infection.

Pathobiology of A/chicken/Hong Kong/220/97 (H5N1) avian influenza virus in seven gallinaceous species

Direct bird-to-human transmission, with the production of severe respiratory disease and human mortality, is unique to the Hong Kong-origin H5N1 highly pathogenic avian influenza (HPAI) virus, which was originally isolated from a disease outbreak in chickens. The pathobiology of the A/chicken/Hong Kong/220/97 (H5N1) (HK/220) HPAI virus was investigated in chickens, turkeys, Japanese and Bobwhite quail, guinea fowl, pheasants, and partridges, where it produced 75-100% mortality within 10 days. Depression, mucoid diarrhea, and neurologic dysfunction were common clinical manifestations of disease. Grossly, the most severe and consistent lesions included splenomegaly, pulmonary edema and congestion, and hemorrhages in enteric lymphoid areas, on serosal surfaces, and in skeletal muscle. Histologic lesions were observed in multiple organs and were characterized by exudation, hemorrhage, necrosis, inflammation, or a combination of these features. The lung, heart, brain, spleen, and adrenal glands were the most consistently affected, and viral antigen was most often detected by immunohistochemistry in the parenchyma of these organs. The pathogenesis of infection with the HK/220 HPAI virus in these species was twofold. Early mortality occurring at 1-2 days postinoculation (DPI) corresponded to severe pulmonary edema and congestion and virus localization within the vascular endothelium. Mortality occurring after 2 DPI was related to systemic biochemical imbalance, multiorgan failure, or a combination of these factors. The pathobiologic features were analogous to those experimentally induced with other HPAI viruses in domestic poultry.