Background/Purpose:  Biological DMARDs (bDMARDs) such as adalimumab (ADA), infliximab (IFX), ustekinumab (UST) and secukinumab (SEC) become available and efficacious in patients with psoriatic arthritis (PsA). However, it remains unclear how we can differentially use these bDMARDs to individual patients. We assessed peripheral immune cell phenotypes in PsA patients treated with bDMARDs and tried to subdivide patients by the lymphocyte phenotypic difference.

Methods:  44 PsA patients with inadequate response to conventional therapy were treated with bDMARDs (IFX 15, ADA 17, certolizumab pegol 1, UST 7, SEC 4 cases) and PASI score, SDAI, DAS28(ESR) were evaluated. Peripheral immune cell phenotypes were assessed by 8-color flow cytometric analysis for human immune system termed by NIH and FOCIS in 20 patients with PsA who showed.

Results:  Baseline characteristics of patients with PsA were; mean age 47.7 years, the male/female 27/17, mean disease duration 139.2 months, respectively. All of patients had already been treated with topical therapy, corticosteroid, DMARDs and/or immunosuppressant. Following treatment with bDMARDs, the PASI score, SDAI, DAS28(ESR) were significantly decreased from 8.8/17.7/4.38 at baseline to 3.3/8.6/2.28 at 6 months, respectively, and 29.5 % of patients achieved both SDAI remission and PASI clear at 6 months. No statistical difference in clinical efficacy among bDMARDs was observed. Among CD4⁺ T cells, although expression of differentiation markers such as CCR7/CD45RA and proportion of Th1 cells were comparable between PsA and HC, activated Th17 cells were significantly higher in patients with PsA than in HC. Contrarily, the proportion of naïve CD8⁺ T cells were lower, that of central memory CD8⁺ T cells, effector memory CD8⁺ T cells, activated CD8⁺ T cells were significantly higher in patients with PsA than in HC, and the proportion of activated CD8⁺ T cells correlated with PASI score. In addition, 20 patients with PsA were categorized to 4 different subgroups according to phenotypic difference in CD4⁺CD45RA^– T helper subsets: CXCR3⁺CCR6^–CD38⁺HLA-DR⁺ activated Th1 dominant (3　cases), CXCR3^–CCR6⁺ activated-Th17 dominant (6), CXCR3⁺CCR6⁺ activated-Th1/Th17 high (4), and CXCR3^–CCR6^– activated-Th1/Th17 low (7). After the 6 month-treatment, the proportions of central memory CD8⁺ T cells, effector memory CD8⁺ T cells, activated CD8⁺ T cells, activated Th1 cells and activated Th17 cells were remarkably decreased in patients who showed clinical improvement.

Conclusion:  Our study proved that peripheral activated CD4⁺ helper T cells could divided to 4 patterns; Th1-high, Th17-high, both-high and both-low in patients with PsA. Furthermore, the proportion of activated CD8⁺ memory T cells and activated Th17 cells was characteristically high, but it was decreased by the treatment with bDMARD, indicating these subsets may contribute to the pathogenesis in PsA. Immunophenotypic analysis is, therefore, useful for evaluation of the therapeutic target and prediction of the response to bDMARDs in patients with PsA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/characteristic-phenotypes-of-peripheral-t-cells-and-efficacy-of-biological-dmards-in-patients-with-psoriatic-arthritis/