LAUSR

Granulomas are inflammatory infiltrates consisting primarily of macrophages, histiocytes, and lymphocytes that contain and limit insulting agents. They often develop in response to chronic infection, but may also be a manifestation of type IV delayed-type hypersensitivity reaction in response to noninfectious agents, including drugs and foreign bodies. Whenever microbial or noninfectious causes of granulomas cannot be identified, granulomas are defined as idiopathic. Granulomatous lesions involving the skin or other organs are particularly common among patients with inborn errors of immunity (IEI), for which their overall prevalence is estimated to be 1% to 4%. This prevalence is highest among patients with combined immune deficiency (CID), common variable immune deficiency (CVID), and chronic granulomatous disease.1 Furthermore, while granulomas involving sinopulmonary, gastrointestinal, and other visceral locations are more common in patients withCVIDandchronicgranulomatousdisease,theskinrepresents theprimarysiteofgranulomatousmanifestationsinpatientswith CID.1 In this issue of JAMA Dermatology, Wanat et al2 report the presence of rubella virus (RuV) in idiopathic skin granulomas from 4 clinically immunocompetent adults. In 3 of these cases, vaccine-derived RuVs were detected, whereas wild-type RuV was present in the fourth patient.2 Rubella is typically a mild disease, but when contracted during pregnancy, it may cause miscarriage or serious birth defects, collectively termed congenital rubella syndrome (CRS). Before development of the RuV vaccine, during a major rubella epidemic in Europe and the US from 1962 to 1964, CRS left more than 11 000 infants with deafness, more than 3500 with blindness, and nearly 2000 with intellectual disability.3 In rare cases, persistent RuV infection in adults is associated with an increased risk of Fuchs uveitis, encephalitis, and arthritis. Vaccination with the RA27/3 strain, which is used in most countries as live-attenuated vaccine against rubella in combination w ith measles and mumpsattenuated viruses and more recently with varicella virus vaccine, is effective and safe and has substantially contributed to global elimination of rubella and prevention of CRS.3