Céline Gregoire

Mesenchymal Stromal Cell Therapy in Ischemia/Reperfusion Injury.

Ischemia/reperfusion injury (IRI) represents a worldwide public health issue of increasing incidence. IRI may virtually affect all organs and tissues and is associated with significant morbidity and mortality. Particularly, the duration of blood supply deprivation has been recognized as a critical factor in stroke, hemorrhagic shock, or myocardial infarction, as well as in solid organ transplantation (SOT). Pathophysiologically, IRI causes multiple cellular and tissular metabolic and architectural changes. Furthermore, the reperfusion of ischemic tissues induces both local and systemic inflammation. In the particular field of SOT, IRI is an unavoidable event, which conditions both short- and long-term outcomes of graft function and survival. Clinically, the treatment of patients with IRI mostly relies on supportive maneuvers since no specific target-oriented therapy has been validated thus far. In the present review, we summarize the current literature on mesenchymal stromal cells (MSC) and their potential use as cell therapy in IRI. MSC have demonstrated immunomodulatory, anti-inflammatory, and tissue repair properties in rodent studies and in preliminary clinical trials, which may open novel avenues in the management of IRI and SOT.

Review article: mesenchymal stromal cell therapy for inflammatory bowel diseases.

Inflammatory bowel diseases (IBD) are chronic relapsing diseases in which pro‐inflammatory immune cells and cytokines induce intestinal tissue damage and disability. Mesenchymal stromal cells (MSCs) exert powerful immunomodulatory effects and stimulate tissue repair.

Yellow nail syndrome after allogeneic haematopoietic stem cell transplantation in two patients with multiple myeloma

OBJECTIVE AND IMPORTANCE: Yellow nail syndrome (YNS) is a rare disorder of unknown aetiology characterized by the triad of yellow nails, lymphoedema and respiratory manifestations. About 200 cases have been reported, but a lot of patients probably elude proper diagnosis because of both variability of symptoms and ignorance of this syndrome by many physicians. The pathogenesis remains unclear, and could involve functional lymphatic abnormalities, microvasculopathy or lymphocyte deficiency, but none of these hypotheses seems fully satisfactory. CLINICAL PRESENTATION: We report for the first time two cases of YNS associated with multiple myeloma relapsing after non-myeloablative haematopoietic cell transplantation (HCT). In these two cases, onset or worsening of YNS symptoms followed graft-versus-host disease (GvHD) manifestations. INTERVENTION: Corticosteroids given to treat GvHD also improved YNS manifestations. CONCLUSION: YNS after HCT might be a microvascular manifestation of endothelial GvHD and corticosteroids might be an effective treatment.

In vitro Th17-polarized human CD4+ T cells exacerbate xenogeneic graft-versus-host disease

Acute graft-versus-host disease (aGVHD) is a severe complication of allogeneic hematopoietic stem cell transplantation. The role of Th17 cells in its pathophysiology remains a matter of debate. In this study, we assessed whether enrichment of human peripheral blood mononuclear cells (PBMCs) with in vitro Th17-polarized CD4+ T cells would exacerbate xenogeneic GVHD (xGVHD) into NOD-scid IL-2Rγ null (NSG) mice. Naive human CD4+ T cells were stimulated under Th17-skewing conditions for 8 to 10 days and then coinjected in NSG mice with fresh PBMCs from the same donor. We observed that Th17-polarized cells engrafted and migrated toward xGVHD target organs. They also acquired a double-expressing IL-17A+IFNγ+ profile in vivo. Importantly, cotransfer of Th17-polarized cells (1 × 106) with PBMCs (1 × 106) exacerbated xGVHD compared with transplantation of PBMCs alone (2 × 106). Furthermore, PBMC cotransfer with Th17-polarized cells was more potent for xGVHD induction than cotransfer with naive CD4+ T cells stimulated in nonpolarizing conditions (Th0 cells, 1 × 106 + 1 × 106 PBMCs) or with Th1-polarized cells (1 × 106 + 1 × 106 PBMCs). In summary, our results suggest that human Th17-polarized cells can cooperate with PBMCs and be pathogenic in the NSG xGVHD model.