The authors selected articles published in the literature from January 2004 through December 2004 that were relevant to the areas of basic and clinical immunology. Several articles explored the development of TH1 or TH2 response and the role of the monocyte-T cell interaction. Others were articles describing the action of drugs commonly used in asthma to inhibit cytokine responses and the anti-inflammatory role of nonimmune pulmonary cells present in the lung. Several reports show how dendritic cells are being developed as vehicles for DNA vaccines aimed at stimulating cellular responses, an advance of great importance for HIV researchers working on vaccines, who are concerned about the different ways HIV evades the immune response. Other publications described Toll-like receptors in diverse cells, including mast cells and CD4+ T cells, for the recognition of viruses and bacteria. In the area of clinical immunology, an updated classification for primary immunodeficiencies with more than 100 identified genes responsible for these diseases and the report on the second clinical trial of gene therapy for X-linked severe combined immunodeficiency syndrome were published. Significant advances included the clinical prognosis in common variable immunodeficiency for patients presenting with lung pathology, the safety of live vaccines in partial DiGeorge syndrome, the report of patients with complete DiGeorge syndrome with the presence of peripheral blood T cells, the clinical spectrum of patients with NF-kappaB essential modifier (NEMO) gene deficiency, the publication of a consensus algorithm for the management of hereditary angioedema, and the report of immune restoration syndrome in pediatric HIV infection.