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Background Tocilizumab blocks pro-inflammatory activity of interleukin-6 (IL-6), involved in pathogenesis of pneumonia the most frequent cause of death in COVID-19 patients. Methods A multicenter, single-arm, hypothesis-driven trial was planned, according to a phase 2 design, to study the effect of tocilizumab on lethality rates at 14 and 30 days (co-primary endpoints, a priori expected rates being 20 and 35%, respectively). A further prospective cohort of patients, consecutively enrolled after the first cohort was accomplished, was used as a secondary validation dataset. The two cohorts were evaluated jointly in an exploratory multivariable logistic regression model to assess prognostic variables on survival. Results In the primary intention-to-treat (ITT) phase 2 population, 180/301 (59.8%) subjects received tocilizumab, and 67 deaths were observed overall. Lethality rates were equal to 18.4% (97.5% CI: 13.6–24.0, P = 0.52) and 22.4% (97.5% CI: 17.2–28.3, P < 0.001) at 14 and 30 days, respectively. Lethality rates were lower in the validation dataset, that included 920 patients. No signal of specific drug toxicity was reported. In the exploratory multivariable logistic regression analysis, older age and lower PaO2/FiO2 ratio negatively affected survival, while the concurrent use of steroids was associated with greater survival. A statistically significant interaction was found between tocilizumab and respiratory support, suggesting that tocilizumab might be more effective in patients not requiring mechanical respiratory support at baseline. Conclusions Tocilizumab reduced lethality rate at 30 days compared with null hypothesis, without significant toxicity. Possibly, this effect could be limited to patients not requiring mechanical respiratory support at baseline. Registration EudraCT (2020-001110-38); clinicaltrials.gov (NCT04317092).

Take home message: utility and safety of bronchoscopy during SARS-CoV-2 outbreak Funding: the work is funded by Università degli Studi di Milano in the context of the Registry for COVID19 Emergency (RECOVER) electronic database

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Approximately 5% of the population in Western countries is affected by autoimmune diseases (AID), with a significantly higher prevalence in women. Genetic factors are known to be crucial determinants of susceptibility as shown by family and twin studies, although no specific genes predisposing women to autoimmunity have been identified thus far. Several studies indicate that X chromosome abnormalities, such as inactivation patterns, characterize some female-predominant AID. We herein review the most recent evidence on the role of the X chromosome in the breakdown of immune tolerance and discuss its potential implications. Future efforts will help to identify specific X chromosome regions containing candidate genes for disease susceptibility.

There has been a rapid growth in our understanding of the molecular bases of primary biliary cirrhosis (PBC). These efforts were initiated when the immunodominant mitochondrial autoantigen was cloned and sequenced. Using the recombinant cloned antigen as a tool, research has focused on the effector mechanisms of disease and the uniqueness of the primary target tissue, the intrahepatic bile ducts. Most recently, there have been experimental data suggesting that innate immunity changes may be critical to the initiation and perpetuation of the autoimmune injury, as in the case of the enhanced response of monocytes and memory B cells to infectious stimulation and environmental mimics. These observations are important as they help fill in the many gaps which remain on the most difficult subject of autoimmunity, etiology. Indeed, based on the available data, several experimental models of PBC have been developed. These models illustrate and suggest that PBC can be initiated by several mechanisms, all of which lead to loss of tolerance to the mitochondrial antigens. However, once this adaptive response develops, it appears that much of the subsequent pathology is exacerbated by innate responses. We suggest that future therapeutic efforts in PBC will depend heavily on understanding the nature of this innate immune responses and methodology to blunt their cytotoxicity.

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease, predominantly occurring in women of childbearing age. SLE, like several other autoimmune diseases, is characterized by a striking female predominance and, although sex hormone influences have been suggested as an explanation for this phenomenon, definitive data are still unavailable. Our group recently reported an increased X monosomy in lymphocytes of women, affected with primary biliary cirrhosis (PBC), systemic sclerosis (SSc), and autoimmune thyroiditis (AITD) in comparison to healthy women, thus suggesting the involvement of this chromosome in female predominance and in the deregulation of the immune system that characterizes autoimmunity. We have now evaluated X monosomy rates in SLE using fluorescence in situ hybridization (FISH) on peripheral mononuclear white blood cells (PBMCs) from female patients compared to healthy age-matched controls. In addition, because of a previous finding of microchimerism as a pathogenetic cause of a number of autoimmune diseases, we investigated the presence of cells carrying the Y chromosome. We did not identify an increased X monosomy in women with SLE compared to controls (P = 0.3960, SLE vs. HCs, Student's t-test), thus suggesting that a different mechanism of immune deregulation might be predominant in the female population of patients with SLE.

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