Evidence for both respiratory syncytial virus and measles virus antigens in the osteoclasts of patients with Paget's disease of bone.

Recent ultrastructural and immunohistochemical evidence supports the hypothesis that Paget's disease of bone is a slow viral infection of the Paramyxoviridae family. Conflicting evidence for the presence of respiratory syncytial virus (RSV), a pneumovirus, or measles, a morbillivirus, has been reported. By the indirect fluorescent antibody assay, four RSV antisera were compared with four measles antisera on serial sections of pagetic bone or replicate coverslips of cells from pagetic bone grown in culture from 30 patients. Results produced positive immunofluorescence for RSV in 28 of 29 patients and positive immunofluorescence for measles in 11 of 22 patients. Of the 20 patients from whom comparable samples could be tested for antigens, 11 were found to harbor both antigens. These studies support the hypothesis that Paget's disease of bone is a slow viral infection of the Paramyxoviridae family more closely related to the pneumoviruses than the morbilliviruses.