Background During pregnancy, most patients with psoriatic arthritis (PsA) experience a natural improvement of their symptoms. This might be due to the immunological changes that occur in normal pregnancy to allow tolerance to the semiallogeneic fetus. Pregnancy induces a down-regulation of the adaptative immune system and generates a specific cytokine milieu. The balance between T helpers cells (Th), Th1/Th2/Th17, depends on the cytokine milieu and interleukin (IL) 23 promotes the expansion and survival of Th17 cells. The IL23-IL17 axis is up-regulated in PsA.
Objectives The aim of our study is to investigate changes of the cytokines pattern with focus on the IL23-IL17 immune axis during and after pregnancy in PsA patients compared with non-pregnant PsA patients and healthy controls (HC).
Methods Nineteen PsA patients (10 pregnant, 9 non-pregnant) and 19 HC (11 pregnant and 8 non-pregnant) were prospectively studied. Clinical assessment and blood sampling was done in pregnant women before, during and after pregnancy and once in the non-pregnant group. Sera were analyzed for levels of C reactive protein (CRP) and high sensitive CRP (hsCRP) by enzyme linked immunoassay. The following cytokines and regulatory molecules were measured by magnetic bead-based multiplex immunoassay: the activation marker soluble CD40 ligand (sCD40L), the Th1 cytokines tumor necrosis factor α (TNFα) and Interleukin (IL)-1β, the Th2 cytokines IL-4, IL-10, IL-31, IL-33, IL-25 and the Th 23/17 pathway cytokines IL-6, IL-17A, IL-17F, IL-21, IL-22, IL23.
Results In the non-pregnant groups we observed that patients with PsA had higher levels of hsCRP, sCD40L, TNFα, IL-1β, IL-33, Il-6 and IL-22 than HC.
Though pregnant PsA patients had inactive or mild disease activity with normal CRP levels, the hsCRP levels were higher than those of pregnant HC.
In the HC group, pregnant women at the third trimester showed higher levels of IL-10, Il-33 and TNFα than at the postpartum time point. Moreover, healthy women at the third trimester had higher levels of IL-1β, IL-33 and IL-22 than age-matched non-pregnant women.
At the third trimester of pregnancy, patients with PsA displayed higher levels of hsCRP, sCD40L, TNFα and IL-6 than HC. Interestingly, pregnant PsA patients did not show any differences in the cytokine pattern compared to non-pregnant PsA patients.
Most differences appeared when comparing PsA and HC at the postpartum time point. Postpartal patients with PsA showed higher levels of sCD40L, TNFα, IL-1β,IL-10, IL-33, IL-31, IL-6 and IL-22 compared to HC
Conclusions Pregnancy induces no predominance of circulating Th2 cytokines but rather a coexistence of Th1, Th2 and Th17 cytokines. Patients with PsA present a more pronounced inflammatory profile consisting of elevated hsCRP levels, Th1 and Th17 cytokines during pregnancy and postpartum. Thus, inactive disease in pregnant PsA patients was associated with persisting immunological activity including the IL-23 /Th17 immune axis.
Disclosure of Interest None declared
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