Poxviridae Pneumonia.

Poxviridae family includes several viruses that infecting humans usually causes skin lesions only, but in some cases their clinical course is complicated by viral pneumonia (with or without bacterial superinfections). Historically variola virus has been the poxviridae most frequently associated with the development of pneumonia with many large outbreaks worldwide before its eradication in 1980. It is still considered a biological threat for its potential in biological warfare and bioterrorism. Smallpox pneumonia can be severe with the onset of acute respiratory distress syndrome (ARDS) and death. Vaccinia virus, used for vaccination against smallpox exceptionally, in immunocompromised patients, can induce generalized (with also lung involvement) severe disease after vaccination. MPXV virus occasionally can cause pneumonia particularly in immunocompromised patients. The pathophysiology of poxviridae pneumonia is still an area of active research; however, in animal models these viruses can cause both direct damage to the lower airways epithelium and a hyperinflammatory syndrome, like a cytokine storm. Multiple mechanisms of immune evasion have also been described. The treatment of poxviridae pneumonia is mainly based on careful supportive care. Despite the absence of randomized clinical trials in patients with poxviridae pneumonia there are antiviral drugs, such as tecovirimat, cidofovir and brincidofovir, FDA-approved for use in smallpox and also available under an expanded access protocol for treatment of MPXV. There are 2 (replication-deficient modified vaccinia Ankara and replication-competent vaccinia virus) smallpox vaccines FDA-approved with the first one also approved for prevention of MPXV in adults that are at high risk of infection.

Impaired antiviral activity of monocytes from patients on hemodiafiltration.

BACKGROUND: The aim of our study was to determine whether intermittent hemodiafiltration (HDF) leads to an alteration in monocyte antiviral activity as well as in the in vitro release of cytokines such as interleukin-12 (IL-12), tumor necrosis factor-alpha (TNF-alpha) and interferon-alpha (IFN-alpha) by the same cells. METHODS: We enrolled 25 patients undergoing HDF for 3.5-4 hours 3 times a week (12 men, 13 women; mean age 58 +/- 6.7 years) and 25 healthy donors (ND) (12 men, 13 women; mean age 57 +/- 8 years). Monocytes from peripheral blood mononuclear cells were isolated with a Monocyte Isolation Kit II. Monocytic cells were infected with herpes simplex virus type 2 (HSV-2). Cytokines were assayed in supernatants. RESULTS: The in vitro antiviral activity of monocytes from HDF patients was significantly impaired with respect to ND. Furthermore, monocytes from post-HDF patients were more prone to viral infection. Lipopolysaccharide (LPS) stimulation induced significant viral inhibition only in monocytes from NDs (p<0.05). The cytokine pattern (TNF-alpha, IFN-alpha and IL-12) in monocytes stimulated with LPS was markedly inhibited in HDF patients compared with ND (p<0.05). A basal production of TNF-alpha was found in monocytes from pre-HDF and post-HDF patients. No IFN-alpha production was found in LPS-stimulated and HSV-2-infected monocytes from pre-HDF and post-HDF patients. IL-12 production appeared significantly decreased after HDF in all experimental conditions (p<0.05). CONCLUSIONS: The significant increase of viral replication in monocytes from HDF patients compared with healthy donors could be related to a significant reduction of cytokine production. Moreover, the dialytic session influenced the intrinsic antiviral activity of monocytes, favoring viral replication.