Involvement of Virus-Induced Interferon Production in IgG Autoantibody-Mediated Anemia.

Infection with viruses, such as the lactate dehydrogenase-elevating virus (LDV), is known to trigger the onset of autoimmune anemia through the enhancement of the phagocytosis of autoantibody-opsonized erythrocytes by activated macrophages. Type I interferon receptor-deficient mice show enhanced anemia, which suggests a protective effect of these cytokines, partly through the control of type II interferon production. The development of anemia requires the expression of Fcγ receptors (FcγR) I, III, and IV. Whereas LDV infection decreases FcγR III expression, it enhances FcγR I and IV expression in wild-type animals. The LDV-associated increase in the expression of FcγR I and IV is largely reduced in type I interferon receptor-deficient mice, through both type II interferon-dependent and -independent mechanisms. Thus, the regulation of the expression of FcγR I and IV, but not III, by interferons may partly explain the exacerbating effect of LDV infection on anemia that results from the enhanced phagocytosis of IgG autoantibody-opsonized erythrocytes.

Interventions to reduce contaminated aerosols produced during dental procedures for preventing infectious diseases: A cochrane review

BACKGROUND Many dental procedures produce aerosols that harbour various pathogenic micro-organisms and may pose a risk for the spread of infections between dentist and patient. The COVID-19 pandemic has led to greater concern about this risk. OBJECTIVES To assess the effectiveness of methods used during dental treatment procedures to minimize aerosol production and reduce or neutralize contamination in aerosols. SEARCH METHODS The following databases were searched on 17 September 2020: Cochrane Oral Health’s Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (in the Cochrane Library, 2020, Issue 8), MEDLINE Ovid (from 1946);Embase Ovid (from 1980);the WHO COVID-19 Global literature on coronavirus disease;the US National Insti tutes of Health Trials Registry (ClinicalTrials.gov);the Cochrane COVID-19 Study Register. SELECTION CRITERIA AND OUTCOMES We included randomized controlled trials (RCTs) and controlled clinical trials (CCTs) on aero sol-generating procedures (AGPs) performed by dental healthcare providers that evaluated methods to reduce contaminated aerosols in dental clinics (excluding pre-procedural mouthrinses). The primary outcomes were incidence of infection in dental staff or patients, and reduction in volume and level of contaminated aerosols in the operative environment. The secondary outcomes were cost, accessibility and feasibility. MAIN RESULTS We included 16 studies with 425 participants aged 5 to 69 years (8 studies at high risk of bias). No studies measured infection. All studies measured bacterial contamination using the surrogate outcome of colony-forming units (CFU). The results described below should be interpreted with caution, as the evidence is very low certainty due to heterogeneity, risk of bias, small sample sizes and wide confidence intervals. Moreover, we do not know the minimal clinically important difference in CFU. Use of a high-volume evacuator (HVE) may reduce bacterial contamination in aerosols less than one foot from a patient’s mouth, but not at longer distances (3 splitmouth RCTs, 122 participants). One RCT (50 participants) found that there may be no difference in CFU between a combination system (Isolite) and a saliva ejector during AGPs or after AGPs. One split-mouth RCT (10 participants) found that there may be a reduction in CFU with rubber dam at one metre and two-metre distance. One RCT of 47 dental students found use of rubber dam may make no difference in CFU at the forehead and occipital region of the operator. One split-mouth RCT (21 participants) found that rubber dam plus HVE may reduce CFU more than cotton roll plus HVE on the patient’s chest and dental unit light. One split-mouth CCT (2 participants) used a local stand-alone air cleaning system (ACS), which may reduce aerosol contamination during cavity preparation or ultrasonic scaling. Another CCT (50 participants) found that laminar flow in the dental clinic combined with a HEPA filter may reduce contamination approximately 76 cm from the floor and 20 cm to 30 cm from the patient’s mouth. Two RCTs evaluated use of anti microbial coolants during ultra sonic scaling. Compared with dis tilled water, coolant-containing chlorhexidine (CHX), cinnamon extract coolant or povidone iodine may reduce CFU. AUTHORS’ CONCLUSIONS We found no studies that evaluated disease transmission via aerosols in a dental setting;and no evidence about viral contamination in aerosols. All of the included studies measured bacterial contamination using CFU. There appeared to be some benefit from the interventions, but the available evidence is very low certainty so we are unable to draw reliable conclusions. © 2020 EDRA SpA. Tutti i diritti riservati.