Abstract
The incidence of post-infectious autoimmune diseases has been on the rise following the COVID-19 pandemic. Recently, an autistic patient was admitted to the hospital presenting with a mild upper respiratory system COVID-19 infection. Months after recovery and polymerase chain reaction negativity, the patient developed HEp-2 cell positivity and presented with relapsing polychondritis (RP), a rare autoimmune disease. The mechanism of this autoimmune invasion is ultimately caused by activating a myriad of immune reactions. Lymphocytopenia almost always accompanies various clinical forms of COVID-19; however, it may drive the lymphocytopenia-induced proliferation of autoreactive T cells via the activation of interleukin-6 (IL-6). Moreover, high levels of neutrophils during infection promote autoimmune disease by releasing cytokine and chemokine cascades that accompany inflammation, and neutrophil extracellular traps regulating immune responses through cell-cell interactions. Furthermore, autism spectrum disorder patients display an altered immune system that includes an augmented inflammatory cytokine milieu leading to an increased pro-inflammatory Th1/Th2 ratio. In addition, the pathophysiology of RP is majorly associated with a cell-mediated immune reaction; thus, the predisposing exaggerated immune system of such patients must also be considered as a predisposing factor to the development of post-infectious autoimmune diseases. LEARNING POINTS: COVID-19 infection is a potential trigger for relapsing polychondritis, an autoimmune disease affecting cartilage, and must be considered as a rare post-COVID complication.The hyperactive immune system in autism spectrum disorder (ASD) is an important predisposing factor to the induction of more autoimmune diseases after the occurrence of post-infectious dysregulation.Lymphocytopenia-induced proliferation possibly initiates the post-infection immune dysregulation.