CD73 (5′-ectonucleotidase) is expressed by two distinct mouse CD4 T cell populations: CD25+ (FoxP3+) T regulatory (Treg) cells that suppress T cell proliferation but do not secrete IL-2, and CD25− uncommitted primed precursor Th (Thpp) cells that secrete IL-2 but do not suppress in standard Treg suppressor assays. CD73 on both Treg and Thpp cells converted extracellular 5′-AMP to adenosine. Adenosine suppressed proliferation and cytokine secretion of Th1 and Th2 effector cells, even when target cells were activated by anti-CD3 and anti-CD28. This represents an additional suppressive mechanism of Treg cells and a previously unrecognized suppressive activity of Thpp cells. Infiltration of either Treg or Thpp cells at inflammatory sites could potentially convert 5′-AMP generated by neutrophils or dying cells into the anti-inflammatory mediator adenosine, thus dampening excessive immune reactions.

Extracorporeal membrane oxygenation (ECMO) refers to specific mechanical devices used to temporarily support the failing heart and/or lung. Technological advances as well as growing collective knowledge and experience have resulted in increased ECMO use and improved outcomes. Veno-arterial (VA) ECMO is used in selected patients with various etiologies of cardiogenic shock and entails either central or peripheral cannulation. Central cannulation is frequently used in postcardiotomy cardiogenic shock and is associated with improved venous drainage and reduced concern for upper body hypoxemia as compared to peripheral cannulation. These concerns inherent to peripheral VA ECMO may be addressed through so-called triple cannulation approaches. Veno-venous (VV) ECMO is increasingly employed in selected patients with respiratory failure refractory to more conventional measures. Newer dual lumen VV ECMO cannulas may facilitate extubation and mobilization. In summary, the pathology being addressed impacts the ECMO approach that is deployed, and each ECMO implementation has distinct virtues and drawbacks. Understanding these considerations is crucial to safe and effective ECMO use.

Although type 2 immune responses contribute to allergy and asthma, these responses are essential for clearing intestinal helminth infestations by mechanisms that include increased epithelial shedding. We show that T helper 2 cells (T(H)2), but not other T cell subsets, express amphiregulin, a member of the epidermal growth factor (EGF) family. EGF receptor ligands directly induce epithelial cell proliferation, and lack of amphiregulin delayed expulsion of the nematode Trichuris muris. This newly recognized link between T(H)2 cells and epithelial proliferation should help in planning therapeutic interventions for helminth infections and other diseases that involve both cell proliferation and allergy, such as asthma.