In touch with mucosal immunity

Two articles in this issue consider the interrelationships between the mucosal immune system and other tissues and organ systems. Maria Rescigno reminds us of the important influence of the neuroendocrine system on mucosal homeostasis and immune function, and Peggy Jacques and Dirk Elewaut explore the link between mucosal inflammation and arthropathy. See pages 328 and 364

Insights into the intestinal epithelium

Richard Blumberg and colleagues provide an insightful Commentary on findings presented at a recent workshop on local influences on the health and repair of the intestinal epithelium. See page 330

Evolving concepts of Th17 cells and associated cytokines

Kevin Maloy and Marika Kullberg review the evolving roles played by cells producing the cytokines interleukin (IL)-23 and IL-17 in intestinal inflammation and immunity to pathogens. In a related Commentary, Wenjun Ouyang specifically addresses the paradoxical role of IL-22, a Th17 cytokine, in immune protection and inflammation. See pages 339 and 335

Frustrated granulocytes

Andrew Leitch and colleagues discuss the role of granulocyte apoptosis in the regulation of lung inflammation and implicate novel therapeutic strategies directed at the induction of granulocyte apoptosis and the enhancement of granulocyte clearance. See page 350

Importance of microenvironment

John Forrester and colleagues review the concept of “immune privilege.” They note the importance of understanding this phenomenon in the context of promoting it to prevent graft rejection or disrupting it to induce tumor rejection. This topic is further highlighted in one of this issue's primary articles, in which Akiko Kobayashi and colleagues provide clues to how a developing immunosuppressive environment may allow chronic infection with human papillomavirus, leading to cervical cancer. See pages 372 and 412

T-cell replenishment after HIV therapy

HIV infection depletes intestinal CD4+ T cells, which in most patients are not efficiently reconstituted following treatment. However, in this issue, Prameet Sheth and colleagues report surprising results in a subgroup of patients on long-term highly active antiretroviral therapy with undetectable blood HIV RNA for at least 4 years who have complete CD4+ T-cell reconstitution in the sigmoid colon. See page 382

Human T-cell responses to oral typhoid vaccine

Existing vaccines against Salmonella typhi confer some protection but require repeated administration. In this issue, Rezwanul Wahid and colleagues demonstrate the ability of a new vaccine strain to induce memory and effector T cells with the capacity to localize to mucosal and systemic sites after a single oral dose. See page 389

Biomarkers for Crohn's disease

Razvan Arsenescu and colleagues have employed a panel of biomarkers of innate immune activation for the classification of patients with Crohn's disease, which may help to inform and target therapy. See page 399