Diet and Hygiene in Modulating Autoimmunity During the Pandemic Era

Abstract

The immune system is an efficiently toned machinery that discriminates between friends and foes for achieving both host defense and homeostasis. Deviation of immune recognition from foreign to self and/or long-lasting inflammatory responses results in the breakdown of tolerance. Meanwhile, educating the immune system and developing immunological memory are crucial for mounting defensive immune responses while protecting against autoimmunity. Still to elucidate is how diverse environmental factors could shape autoimmunity. The emergence of a world pandemic such as SARS-CoV-2 (COVID-19) not only threatens the more vulnerable individuals including those with autoimmune conditions but also promotes an unprecedented shift in people's dietary approaches while urging for extraordinary hygiene measures that likely contribute to the development or exacerbation of autoimmunity. Thus, there is an urgent need to understand how environmental factors modulate systemic autoimmunity to better mitigate the incidence and or severity of COVID-19 among the more vulnerable populations. Here, we discuss the effects of diet (macronutrients and micronutrients) and hygiene (the use of disinfectants) on autoimmunity with a focus on systemic lupus erythematosus.

Keywords: COVID-19; autoimmunity; diet; hygiene; immune homeostasis; immunomodulation.

Figure 1

The interplay between environmental factors and genetic susceptibilities in shaping immune dysregulation. Genetic susceptibilities could lead to immune dysregulation via different mechanisms including (1) defective apoptotic cell clearance, (2) defective apoptosis, and (3) loss of suppressive regulatory controls. Collectively they lead to disrupted cytokine signals and hyperactivation of autoreactive T and B cells, invigorating a series of tissue damage in various manifestations. In SLE, the manifestations could be presented as splenomegaly, lymphadenopathy, nephritis and arthritis. Environmental triggers either augment or mitigate these mechanisms to shape the autoimmunity.

Figure 2

The immunomodulatory effects of vitamins D and A on T cells. Following their binding to DNA responsive elements of target genes, both vitamins differentially modulate key transcription factors and stimulatory cytokine signals to shape the commitment and functional responses of multiple T-cell subsets including Th1, Th2, Th17, and Treg.