Introduction and Objective: Immune
Thrombocytopenias (ITPs) are a heterogeneous group of disorders recognized by platelet devastation resulting from an immune reaction against platelets. In general, ITPs are categorized into primary,also known as idiopathic,and secondary, which results from infections, medications, malignancies, or vaccination. ITP, which happens after vaccination,is known as vaccine-related ITP (VITP).This systematic review aims to Examination on thrombocytopenia as a complication of
SARS-CoV-۲ vaccination.Search Method: This study was performed by using the collected article in English that were available on details of the main topic from ۲۰۰۰ to ۲۰۲۲ in Scopus, PubMed, and Web of Science with keywords ITP, vaccination, and SARS-CoV-۲, all in title/abstract field. This study was performed based on the PRISMA guideline. Articles were selected based on the exclusion criteria and included in the study after reviewing.Results: After excluding duplicated papers, ۳۶۴ results were admitted to the screening step. Finally, ۱۹ studies were entered into the study.Thrombocytopenia due to vaccination happens ۴ to ۱۶ days following exposure to the vaccine but, if facing the immunogenic agent or emerging naturally occurring antibodies happen sooner, it can manifest earlier. Some of the mechanisms that may lead to the development of ITP after administration of
SARS-CoV-۲ vaccines such as Covishield, Pfizer,and Moderna are Molecular mimicry; Host generation of cross-reactive anti-platelet antibodies (anti-GP IIb/IIIa, GP-Ib/IX, or GP-V); Direct viral infection; immune dysregulation with Direct effect of cytotoxic CD۸+ T cells on platelets and Low or dysfunctional regulatory CD۴+ T cells;Release of self-antigens following tissue damage and epitope spreading; Homology between
SARS-CoV-۲ immunogenetic proteins and proteins essential to the adaptive immune system;Increased C-reactive protein (CRP) in COVID-۱۹-associated hyperinflammatory state which binds to platelet phosphorylcholine residues and facilitating IgG-mediated phagocytic responses against platelets; and Heterozygous SOCS ۱ (suppressor of cytokine signaling ۱) loss of function mutations.Conclusion: Therefore, vaccines produced to resist coronavirus infection, such as Covishield, Pfizer,and Moderna,probably induce de-novo ITP and despite the need for vaccination, special attention should be paid to the occurrence of post-vaccination severe thrombocytopenias.