RELATIVE EXPRESSION OF IFN-alpha BIOSYNTHETIC PATHWAY GENES IN PERIPHERAL BLOOD CELLS OF PATIENS WITH IgG4-RELATED DISEASE

ATTALLAH, C; CASAFÚ, H; COSTA, L; OGGERO, M; FERNANDEZ, E; PAIRA, S

Buenos Aires

Congreso; 20° Pan-American Congress of Reumathology (PANLAR); 2018

Pan-American League of Associations for Reumathology

Objectives: IgG4-related disease (IgG4-RD) is a multisystem fibroinflammatory condition with characteristic histopathological findings in the organs involved. Although previous data provide strong evidence that plasmacytoid dendritic cells (pDCs) activation and IFN-alpha production are prominent features of IgG4-related Type 1 Autoimmune Pancreatitis, IgG4-RD immunopathogenesis is scarcely known. The aim of this study was to evaluate the relative expression of IFN-alpha biosynthetic pathway genes in patients with different manifestations of IgG4-RD.Methods: The study was conducted on 9 diagnosed IgG4-RD patients aged between 23-75 years (median 59.0 [IQR, interquartile range: 42.0, 61.50]), and 8 healthy subjects aged between 27-70 years (median 46.5 [IQR 34.25, 60.25]). Patients were diagnosed according to the comprehensive diagnostic criteria for IgG4-RD (2011), resulting as definite (n=7) and probable (n=2). Written informed consent was obtained from all subjects. Patients were further sub divided into two groups: group I included patients with mono organic involvement (n=1) and group II included patients with multi organic involvement (n=8). The treatment profiles of patients at the moment of blood sampling were as follows: non-treated (n=2) and under the treatment with: steroids (n=1), steroids and methotrexate (n=5), and steroids and azathioprine (n=1). TLR7, TLR9, IRF5, IRF7, Foxp3 and Fas gene expression was analyzed using the real-time reverse transcriptase polymerase chain reaction (RT-PCR). From total RNA of peripheral blood mononuclear cells the expression level was quantitated by real-time quantitative PCR (qPCR) and normalized with the values of the housekeeping control of the -actin gene. Relative gene expression was calculated using the comparative 2-Ct method. A melting curve was done to increase sensibility and specificity of the test. Statistical analysis was performed using the nonparametric Mann-Whitney U test. Results were considered significant when the p value was less than =0.05. Statistical analysis was carried out using the Graph-Pad software (Prism).Results: Neither the genes involved in IFN-alpha biosynthetic pathway (IRF5, IRF7, TLR7 and TLR9) nor the Fas or transcription factor Foxp3 showed differences in the relative expression of their transcripts between patients and healthy donors.Conclusions: Although these results are preliminary due to the small number of analyzed patients, no differences were found in the gene expression of IFN-alpha biosynthetic pathway members. It is interesting to continue this study since innate immunity was presented as having a central role in the development of the disease by other authors.