Background/Purpose: Methotrexate (MTX) is the most commonly used DMARD in rheumatoid arthritis (RA) patients. Since the first reports of the efficacy of low-dose MTX in RA, several studies have established its central role in the treatment of RA. Activated T CD4+ lymphocytes play a pivotal role secreting cytokines initiating and perpetuating the chronic inflammation characteristic for this disease. The role of circulating CD4⁺T lymphocytes in early RA is under discussion and is not well understood. The objective is evaluate the number of IFNγ, IL-4, IL-9 and IL-17 producing CD4⁺ T lymphocytes and in their CD4⁺ naïve T cells (T_N), central memory (T_CM), non-terminated effector memory (T_NTEM) and terminated effector memory (T_TEM) T cells activation/differentiation subsets in a population of recently diagnosed DMARD naïve RA patients along the first 6 months of methotrexate (MTX) treatment.

Methods: The number of IFNγ, IL-4, IL-9 and IL-17 producing CD4+ T lymphocytes, and in their T_N, T_CM, T_NTEM and T_TEMsubsets in forty untreated patients with RA before MTX treatment and at 3 and 6 months of treatment were assayed using a multiparametric flow cytometry. We have obtained peripheral blood mononuclear cells (PBMC) from AR patients. PBMC were stimulated during six hour with phorbol-myristate-acetate and ionomycin. To study the intracellular cytokine production of CD4+ T lymphocytes we used the next surface antigens: CD3, CD4, CD45RA, CD27, cells were fixed and permed, and simultaneously stained with the next intracellular cytokines: IFNγ, IL-4, IL-9 and IL-17. We acquired in a FacsAria-II flow cytometer and analyzed in Diva and Flow-Jo software. We also studied twenty-five age and sex-matched healthy subjects as controls.

Results: MTX treatment provoke a significant decrease of the IFNγ CM, NTEM and TEM effector producing T CD4 lymphocytes but not in naïve T CD4+ cells at 3 and 6 months of MTX treatment. However, the IL-17 naïve producing T CD4 lymphocytes were significant expanded along the 6 months of MTX treatment. In other hand, IL-17 CM and NTEM producing T CD4 lymphocytes were significant decreased at 6 months of MTX treatment. The intracellular expression of IL-4 and IL-9 do not shown alterations in RA naïve patients along the MTX treatment.

Conclusion: MTX treatment show immunomodulatory effects on circulating IFNγ and IL-17 producing T CD4 lymphocytes activation/differentiation stage subsets along the first 6 months of MTX treatment. Therefore, MTX are able to reduce the inflammation produce by Th1 effector T CD4 lymphocytes at 6 months. However, MTX are able to reduce Th17 in central memory but not in naive T CD4 lymphocytes, that appear increased, at 6 months of treatment.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/metrotexate-treatment-inmunomodulate-the-abnormal-cytokine-expression-present-in-naive-rheumatoid-arthritis-patients/