How major fungal infections can initiate severe autoimmune diseases.

Several autoimmune diseases have long been linked to viral and bacterial infections. In contrast, the possibility of fungal infections causing autoimmune diseases has received almost no attention. However, major fungal infections can cause severe autoimmune diseases, by decreasing TREG cells and increasing production of interleukin-23, CD4 TH17 T-cells, interleukin-17 and other cytokines, including interleukin-22. Several factors can cause fungal infections, including antibiotic usage. Bacterial and fungal populations compete in mammalian oropharyngeal, respiratory, gastrointestinal, and genitourinary tracts. Antibiotic usage decreases bacteria and thereby favors fungal populations over bacterial populations. This leads to an explanatory hypothesis for the pathogenesis of severe autoimmune diseases by major fungal infections. The increase in fungal populations in individuals susceptible to major fungal infections can also explain the higher incidence of autoimmune diseases. CD4 TH17 T-cells and certain interleukins can be one path of pathogenesis between major fungal infections and increased incidences of major autoimmune diseases, including type 1 diabetes, multiple sclerosis, and various types of arthritis.