Immunology is one of the most recent subjects to have emerged as a separate discipline in biomedical science. Therefore, many clinicians currently practising will have received little or no basic or clinical training in this subject, while those who have will find that much has changed in the past five to 10 years. Access to this important aspect of medicine is hampered by the profligate use of acronyms and jargon, but some attempt has been made to bring order where chaos threatened. The CD (cluster of differentiation) system defines cell surface molecules and now stretches to CD161. The interleukin system of cytokine nomenclature (now up to interleukin 18) has rid the literature of BCGF (B cell growth factor) and other acronyms. The genetic age has brought with it a new nomenclature for the HLA system, which may be difficult for clinicians who are required to adapt from the old one but will be beneficial to new generations of clinicians. The reality is that immunology can no longer be avoided. Its relevance spans from pregnancy to senescence and from vaccination to cancer, a fact recognised by the 10 Nobel prizes for medicine or physiology awarded for key immunological advances, most recently to Zinkernagel and Doherty for their work on the specificity of cell mediated immune defence.