Retroviruses, immunosuppression and osteopetrosis.

Since decades, retroviruses are known to induce the formation of dense bones (osteopetrosis) in animals, either by increasing osteoblastic proliferation (ALVs viruses) or by decreasing osteoclastic bone resorption (FeLV virus). The latter is a good model of the inherited disease since neonatally infected cats die from wasting disease, like mutant op/op rats and children suffering from juvenile-malignant osteopetrosis. These similarities have prompted this review of retrovirus-induced osteopetrosis in animals. We suggest the possibility that retroviruses might be involved, at least in part, in the induction of the human disease.