Recent research in the area of neuroimmunology has focused on the role of immune cells, such as autoimmune T cells and microglial cells, in the initiation and progression of particular neurological diseases, such as multiple sclerosis and Alzheimer's disease. In addition, there have been important advances in our understanding of the effects of an inflammatory response in the brain owing to infection or injury. This Focus highlights these recent advances and their therapeutic implications.

Given the different biological functions of the known CD4+ T-cell subsets, an important current area of research is to determine the factors that control T helper (TH)-cell differentiation pathways in different conditions, with a view to understanding how these pathways might be manipulated for therapeutic benefit. This Focus describes the molecular pathways that govern the differentiation of TH1, TH2, TH17 and regulatory T cells.

As we learn more about how immune responses occur in situ, it is becoming clear that the characteristics of the tissue microenvironment can be as important as immune cells in determining the initiation, progression and resolution of an immune response. In October 2008, Nature Reviews Immunologywill begin a series of articles related to tissue–specific immune responses. These articles will consider aspects of immune responses in the context of the tissue in which they occur, highlighting how tissue cells or tissue–derived factors in different organs can shape the outcome of these responses.

Most infectious, allergic and inflammatory diseases in humans involve mucosal surfaces, including the gastrointestinal, reproductive and respiratory tracts. To maintain health, the mucosal immune system must provide protection against pathogens while being tolerant of commensal bacteria and harmless antigens. This Focus highlights the latest advances in our understanding of host-microbe interactions at mucosal sites and the consequences of immune dysregulation at these sites.

Millions of people worldwide suffer from respiratory diseases such as allergies, asthma and chronic obstructive pulmonary disease, and these diseases constitute a major public health burden. This Focus issue highlights the latest advances in our understanding of the immune bases of these diseases and outlines how this knowledge can be translated into more effective treatment strategies.

Immune tolerance is a built-in control mechanism to prevent the immune system from attacking self tissues, but when it goes awry autoimmune diseases can ensue. This Focus highlights the latest advances in our understanding of immune tolerance and anergy, and how this knowledge can be translated into effective immunotherapies.

Cytokines act as key communicators for immune cells and maintaining a delicate balance in the level of these communicators is vital for health. This special Focus issue highlights the latest advances in cytokine research and the application of these findings for clinical intervention.

From September 2006, a series of articles on tumour immunology will appear in Nature Reviews Immunology. Each article in this series will explore the dynamic interactions between tumour cells and immune cells, the mechanisms by which an immune response to tumours might be generated and maintained, how tumour cells escape detection and destruction by the immune system and how this knowledge can lead to new therapeutic targets and treatments for cancer. We hope that this Article Series will give you a taste of the diversity of topics that form part of this rapidly moving field.

Immunology is one of the few disciplines that straddle both basic sciences and applied medicine, and translating what we observe in the laboratory to the clinic is an increasingly important goal for many immunologists. This Focus highlights how basic research findings are being translated and applied to the treatment of cancer, and autoimmune and infectious diseases.

All the cells of the immune system are derived from precursor cells in the bone marrow. However, full development to become a T cell is completed in the thymus, not in the bone marrow as is the case for B cells. This Focus highlights our current understanding of several steps that are crucial for the complex process of early lymphocyte development.

Cells of the immune system communicate by cell–cell contact and through the production of soluble factors that bind cognate receptors expressed at the surface of target cells. This Focus on immune-cell communication highlights some of the diverse mechanisms of immune-cell communication.

Innate immunity is the first line of defence against pathogens and is initiated rapidly after recognition of microbial products by receptors such as the Toll-like receptors (TLRs). We outline the signalling cascades initiated by TLR triggering and the therapeutic potential of targeting this pathway, as well as relevant Highlight articles from the journal.