Virome and Inflammasomes, a Finely Tuned Balance with Important Consequences for the Host Health

The virome is a multifaceted network of viruses inhabiting humans in health and disease. The virome forms a conspicuous portion of the so-called microbiome. Massive amount of data recently emerging demonstrates that the microbiome, once generically referred to as human (or animal) flora, is not a static entity but closely reflects what we eat, how and where we live, what we do, and many other unexpected variables. Composition, location, and amount of the microbiome have a direct impact on innate and adaptive host immune defences. Indeed, the microbiome may activate inflammasomes, multiprotein complexes that assemble in most human cells and that are responsible for the downstream effects of sensing microorganisms. Depending on their interplay with microbes, inflammasomes instruct host defences to tolerate or forfeit a specific microorganism. Indeed, the microbiome not only colonizes the gut and facilitates food digestion and absorption, but also shapes human immune defences and contributes to inflammatory processes by quenching or increasing them. Viruses that make up the virome play their part in shaping the immune system. Anelloviruses, one of the recently discovered families that are part of the virome, form a large fraction of human virome. They are present in most, if not all, human beings, where they replicate persistently without causing apparent disease. This review illustrates the role of the virome in modulating inflammation in cancer and various degenerative diseases and provides strong evidence for Anelloviruses as useful and practical molecular markers to monitor inflammatory processes and immune system competence.