Toll-like receptor (TLR9) -1486 T/C (rs187084) gene polymorphism in Egyptian patients with rheumatoid arthritis

Toll-Like Receptor 9 (TLR9) Gene C/T (rs352140) Polymorphisms in Adult Primary Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by low platelet count and increased bleeding risk. The initial event(s) leading to antiplatelet autoimmunity remains unclear. Toll-like receptors (TLRs) are the most well-characterized pattern recognition receptors and are a transmembrane protein coded by the Toll genes family. In addition to their protective role in immunity, it is also becoming clear that TLRs exhibit homeostatic roles. Toll-like receptors play potential roles in the development of disease and its maintenance. The objective of this study is to evaluate the distribution of TLR9 gene C/T (rs352140) polymorphisms and its possible association with clinicopathological finding in Egyptian adult primary ITP. This study was carried out at Internal Medicine Department, Menoufia University Hospital, Egypt, from August 2018 to January 2020. Eighty adults (≥ 18 years) were enrolled in the study; 40 patients with primary ITP and 40 healthy individuals as controls. Identification of the TLR9 C/T (rs352140) polymorphic variant was performed by polymerase chain reaction–restriction fragment length polymorphism. In our study, we excluded any other causes of secondary ITP. Distribution of the TLR9 C/T genotypes did not exhibit significant deviation between patients and controls. There was no significant difference between studied groups as regards allele (C and T) frequency. There was no significant difference regarding TLR9 gene C/T (rs352140) polymorphisms between Egyptian adult with primary ITP and controls. TLR9 gene C/T (rs352140) polymorphisms have no relation to any of the clinicohematological variables in primary ITP in Egyptians.

TLR9 and COVID-19: A Multidisciplinary Theory of a Multifaceted Therapeutic Target

By mapping the clinical pathophysiology of the novel coronavirus disease 2019 (COVID-19) against insights from virology, immunology, genomics, epidemiology and pharmacology, it is here proposed that the pathogen recognition receptor called toll like receptor 9 (TLR9) might have a pivotal role in the pathogenesis of COVID-19. Severe Acute Respiratory Syndrome Coronavirus 2, is causing the greatest global social and economic disruption since world war II. Lack of a vaccine, lack of successful treatment and limitations of the healthcare workforce and resources needed to safeguard patients with severe COVID-19 on the edge of life, demands radical preventive measures. It is urgently needed to identify biomarkers and drug candidates so that vulnerable individuals can be recognized early and severe multi-organ complications can be prevented or dampened. The TLR9 COVID-19 hypothesis describes a mechanism of action that could explain a wide spectrum of manifestations observed in patients with severe COVID-19. The introduced hypothesis proposes biomarkers for identification of vulnerable individuals and positions TLR9 as a promising multifaceted intervention target for prevention and/or treatment of COVID-19. TLR9 agonists might have value as prophylactic vaccine adjuvants and therapeutic immune stimulators at the early onset of disease. Additionally, in this current manuscript it is proposed for the first time that TLR9 could be considered as a target of "inhibition" aimed to dampen hyperinflammation and thrombotic complications in vulnerable patients that are at risk of developing late stages of COVID-19. The readily availability of TLR9 modulating drug candidates that have reached clinical testing for other disorders could favor a fast track development scenario, an important advantage under the current high unmet medical need circumstances regarding COVID-19.