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Autoimmune Disease
Published in Gia Merlo, Kathy Berra, Lifestyle Nursing, 2023
Nanette Morales, Jessica Landry, Christy McDonald Lenahan, Janine Santora
Molecular mimicry involves activation of autoreactive T or B cells by a foreign antigen, such as infections or chemical agents that cause autoimmunity (Rojas et al., 2018). Examples include C. jejuni infection preceding Guillain-Barre syndrome, bovine milk protein butyrophilin preceding MS, and Escherichia coli (E. coli), hepatitis C & B, HIV, or Epstein-Barr virus preceding RA. Molecular mimicry cross-reactivity combines environmental and genetic factors triggering autoimmunity. The molecular mimicry theory may explain why some foods trigger or worsen ADs (Houghton, 2021).
Therapeutic Application of Monoclonal Antibodies in the Rheumatic Diseases
Published in Thomas F. Kresina, Monoclonal Antibodies, Cytokines, and Arthritis, 2020
The HLA-B27-associated arthropathies (seronegative spondyloarthropathies) comprise ankylosing spondylitis (AS), Reiter’s syndrome (RS) and reactive arthritis (ReA), psoriatic arthritis (PsA), and the arthropathy of inflammatory bowel disease (AIBD). There is a highly significant association of these disorders with the class I MHC allele, HLA-B27. Approximately 96% of patients with the prototype disease, AS, are B27 positive (130) and significant proportions (60–80%) of patients with RS, ReA, PsA, and AIBD also carry this allele, depending in part on the presence or absence of spondylitis (131). The exact relationship between the B27 allele and the immunopathology of these disorders is uncertain (132,133). One hypothesis concerning the role of B27 in these diseases relates to “molecular mimicry” and implicates sequences on the hypervariable region of the B27 molecule that are homologous with antigenic determinants associated with certain infectious agents, particularly enteric pathogens (134,135). The molecular mimicry model, however, has been re-examined recently in AS (135,136) as well as in other diseases in this category (137).
Acute Infective Endocarditis and Its Mimics in the Critical Care Unit
Published in Cheston B. Cunha, Burke A. Cunha, Infectious Diseases and Antimicrobial Stewardship in Critical Care Medicine, 2020
The most effective mimics of ACCUIE are the following: Marantic endocarditis or non-bacterial thrombotic endocarditis (NBTE), viral myocarditis, systemic lupus erythematosus (SLE), and atrial myxoma. These processes are included in this discussion of ACCUIE, because they may closely resemble NIE.
PANDAS – a rare but severe disorder associated with streptococcal infections; Awareness is needed
Published in Acta Oto-Laryngologica Case Reports, 2023
Karin Frånlund, Charbél Talani
PANDAS was first described by Swedo et al. in 1998 in 50 cases with sudden onset of obsessive-compulsive disorder (OCD) and behavioural disorders in a group of children with B-haemolytic streptococcal infection. It affects males more frequently than females 2:1, and occurs most frequently among children aged between 3 and 12 [1,2]. PANDAS is considered an autoimmune disease based on a streptococcal infection with a verified immune response. Molecular mimicry is the most frequent physio-pathological mechanism, where a foreign antigen shares structural or sequence similarities with self-antigens [3]. Streptococcal infections hide from the host immune system by mimicking host cells. This causes the production of cross-reactive antibodies that can cross the blood–brain barrier. Anti-neuronal autoantibodies react with autoantigens in the basal ganglia and cortical structures, causing the onset of neuropsychiatric symptoms [4].
COVID Vaccine-Associated Uveitis
Published in Ocular Immunology and Inflammation, 2023
Zohar Habot-Wilner, Piergiorgio Neri, Annabelle A. Okada, Rupesh Agrawal, Ng Xin Le, Shai Cohen, Naomi Fischer, Fionn Kilmartin, Amy Coman, Dara Kilmartin
The exact cause of ocular inflammation associated with inactivated COVID-19 is not yet understood. It has been suggested that the potential mechanisms could involve molecular mimicry and antigen-specific hypersensitivity reactions mediated by cells and antibodies.20,88,89 Antigen-specific hypersensitivity reactions are a type of immune response where T cells and antibodies specifically target a specific antigen, such as the SARS-Cov-2 viral protein. In the context of COVID-19, it is possible that viral proteins used in SARS-Cov-2 vaccines may stimulate a hypersensitivity reaction in the eye, leading to inflammation and other ocular symptoms.90 Differently, molecular mimicry is a phenomenon where a foreign substance, such as a virus/virus protein, can resemble a self-antigen, mistakenly causing the body’s immune system to attack its own healthy cells. In the context of COVID-19, it is possible that the inactivated virus used in vaccines may share similarities with certain ocular tissues, leading to an autoimmune response and subsequent inflammation in the eye.90 Regarding vaccines and the eye, although no definite causal link may be proven, there have been several reports of mild ocular side-effects such as conjunctivitis or eye irritation following vaccination to more severe such as uveitis and scleritis. Also, as with any vaccine or medical intervention,90 it is important to be aware of potential side-effects and report any concerns to a healthcare provider as appropriate.
Acute motor axonal neuropathy following SARS-CoV-2 infection in the third trimester of pregnancy
Published in Baylor University Medical Center Proceedings, 2022
Mohamed M. G. Mohamed, Amar Jadhav, Polo Banuelos, Alexandre Lacasse, Vikas Kumar
GBS is a heterogenous group of disorders characterized by flaccid ascending paralysis.4 It is the most common cause of flaccid paralysis in the US and worldwide.4 GBS is hypothesized to be of autoimmune origin, often preceded by an infectious process. Molecular mimicry appears to play a role in its pathophysiology, with different targets leading to different subtypes.3–5 Since pregnancy is usually associated with a dampened immunological response, GBS is an uncommon disorder in pregnancy.4,6 SARS-CoV-2 infection has also been implicated in patients presenting with GBS.2,3 Although AMAN has been previously reported in pregnant patients,7,8 its diagnosis following SARS-CoV-2 infection has not been widely reported.