Author/Authors :
Arandi, Nargess Department of Immunology - School of Public Health - Tehran University of Medical Sciences, Tehran , Mirshafiey, Abbas Department of Immunology - School of Public Health - Tehran University of Medical Sciences, Tehran , Jeddi-Tehrani, Mahmood Monoclonal Antibody Research Center - Avicenna Research Institute - ACECR, Tehran , Shaghaghi, Mohammadreza Research Center for Immunodeficiency - Pediatrics Center of Excellence - Children’s Medical Center - Tehran University of Medical Sciences, Tehran , Sadeghi, Bamdad Research Center for Immunodeficiency - Pediatrics Center of Excellence - Children’s Medical Center - Tehran University of Medical Sciences, Tehran , Abolhassani, Hassan Research Center for Immunodeficiency - Pediatrics Center of Excellence - Children’s Medical Center - Tehran University of Medical Sciences, Tehran , Sharifian, Ramazan Ali Clinic of Hematology and Oncology - Vali-Asr Hospital - Faculty of Medicine - Tehran University of Medical Sciences, Tehran , Rahiminejad, Mohammad Saeid Division of Pediatric Hematology Oncology - Children's Medical Center - Tehran University of Medical Sciences, Tehran , Aghamohammadi, Asghar Research Center for Immunodeficiency - Pediatrics Center of Excellence - Children’s Medical Center - Tehran University of Medical Sciences, Tehran
Abstract :
Immune thrombocytopenic purpura (ITP) is an autoimmune bleeding disorder characterized by
production of auto-antibodies against platelet antigens. It is obvious that regulatory T cells (Tregs)
have a major role in controlling immune homeostasis and preventing autoimmunity.
To investigate the frequency and functions of Tregs, twenty ITP patients and twenty age- and sexmatched
healthy controls were recruited. The peripheral blood mononuclear cells were isolated and
the proportion of Tregs was defined by flow cytometry method. The expression of immune-regulatory
markers, cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) and glucocorticoid induced tumor
necrosis factor receptor (GITR) were also assessed by quantitative Real-time polymerase chain
reaction TaqMan method. For evaluation of Treg function, Tregs were enriched and their ability to
inhibit proliferation of T cells was measured and levels of immune-regulatory cytokines IL-10 and
Transforming growth factor beta (TGF-.) were also measured.Results showed that the frequency of
Tregs and the mean fluorescence intensity of forkhead box P3 (FOXP3) protein significantly
decreased in ITP patients compared to those in healthy controls. In addition, there was a significant
reduction in relative expression of both CTLA-4 and GITR mRNA in ITP patients (p=0.02 and
p=0.006, respectively). The suppressive function of Tregs also diminished in ITP patients compared to
controls. Both IL-10 and TGF-. cytokines were produced in lower amounts in ITP patients than
controls.
It could be concluded that alteration in Treg frequency and functional characteristics might be
responsible for loss of self-tolerance and subsequently destructive immune responses observed in ITP
patients.
