Monocytes show immunoregulatory capacity on CD4+ T cells in a human in ‐vitro model of extracorporeal photopheresis

In this study, we established anin ‐vitro ECP model focusing on ECP ‐treated monocytes in co‐culture with CD4+ T cells as knowledge on the role of monocytes in ECP is particularly controversial and should be further investigated. We found thatin ‐vitro ECP treatment of monocytes (1) significantly induced proinflammatory T cell types dependent on cell ‐contact, whereas anti‐inflammatory T cells were unaffected, (2) significantly reduced proliferation rates of co‐cultured T cells in a cell‐contact‐dependent manner partially due to PD‐L1–PD‐1 interactions as (3) blockade of this interaction by antibodies led to a slight but signific ant recovery of T cell proliferation. SummaryExtracorporeal photopheresis (ECP) is a widely used immunomodulatory therapy for the treatment of various T cell ‐mediated disorders such as cutaneous T cell lymphoma (CTCL), graft‐versus‐host disease (GvHD) or systemic sclerosis. Although clinical benefits of ECP are already well described, the underlying mechanism of action of ECP is not yet fully understood. Knowledge on the fate of CD14+ monocytes in the context of ECP is particularly limited and controversial. Here, we investigated the immunoregulatory function of ECP treated monocytes on T cells in anin ‐vitro ECP model. We show that ECP ‐treated monocytes significantly induce proinflammatory T cell types in co‐cultured T cells, while anti‐inflammatory T cells remain unaffected. Furthermore, we found significantl...
Source: Clinical and Experimental Immunology - Category: Allergy & Immunology Authors: Tags: Original Article Source Type: research