Increased Serum Interleukin-9 Levels in Rheumatoid Arthritis and Systemic Lupus Erythematosus: Pathogenic Role or Just an Epiphenomenon?

Andréa Tavares Dantas,Angela Luzia Branco Pinto Duarte,Laurindo Ferreira Da Rocha Junior,Pablo Ramon Gualberto Cardoso,Maira Galdino Da Rocha Pitta,Moacyr Jesus Barreto De Melo Rego,Ivan Da Rocha Pitta,Mariana Brayner Cavalcanti,Sayonara Maria Calado Gonçalves,Claudia Diniz Lopes Marques,Henrique De Ataide Mariz

doi:10.1155/2015/519638

Andréa Tavares Dantas, Angela Luzia Branco Pinto Duarte + Show 9 more

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https://doi.org/10.1155/2015/519638

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Abstract

The purpose of this paper was to evaluate the levels of IL-9 in patients with SLE and RA compared with controls and the association of IL-9 levels with clinical and laboratory parameters. IL-9 levels were assessed in 117 SLE patients, 67 RA patients, and 24 healthy controls by ELISA. Clinical and laboratory parameters were recorded. The IL-9 serum levels were significantly higher in RA patients (4,77 ± 3,618 pg/mL) and in SLE patients (12,26 ± 25,235 pg/mL) than in healthy individuals (1,22 ± 0,706 pg/mL) (p < 0,001). In SLE patients, there were no statistically significant associations or correlations between the levels of IL-9 and SLEDAI or other clinical and laboratorial parameters, with the exception of disease time, which showed a statistically significant negative correlation with IL-9 levels (r = −0,1948; p = 0,0378). In RA patients, no association or statistically significant correlation was observed with disease duration, DAS28, HAQ, rheumatoid factor positivity, or erosions on radiography. These data demonstrated increased serum levels of IL-9 in SLE and RA patients, but further studies are needed to clarify the precise role of this cytokine and its potential use as therapeutic target.

Highlights

The imbalance between effector and regulatory cell populations (Treg) is of critical importance in the pathogenesis of various autoimmune disorders
Serum IL-9 levels were significantly higher in rheumatoid arthritis (RA) patients (4,77 ± 3,618 pg/mL) and in systemic lupus erythematosus (SLE) patients (12,26 ± 25,235 pg/ mL) than in healthy individuals (1,22 ± 0,706 pg/mL) (p < 0, 001) (Figure 1)
The present study revealed that the IL-9 levels are significantly increased in SLE and RA patients compared to healthy controls; it has not demonstrated association with clinical or laboratory parameters in both diseases, with the exception of a negative correlation with disease duration in SLE patients

Summary

Introduction

The imbalance between effector and regulatory cell populations (Treg) is of critical importance in the pathogenesis of various autoimmune disorders. According to the current paradigm, the proinflammatory axis of Th1 and Th17 cells is counter balanced by the cell populations Th2 cells and Treg [1]. Interleukin-9 (IL-9) is a member of the gamma-chain family of cytokines, first described as a member of a growing number of cytokines that have crucial roles in the development, proliferation, survival, and differentiation of multiple cell lineages of both the innate and adaptive immune systems [2]. It is known that, under specific conditions, regulatory (Tregs), Th1, and Th17 subset of T cells express IL-9. It has been shown that IL-9-producing CD4+ T cells may represent the T helper subset Th9 cells. In vivo T cells produce IL-9 in both proinflammatory and antiinflammatory environments [3]

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