Value Of The In Vitro Study Of Osteoclasts Progenitors In A Case Of Severe Infantile Osteopetrosis Treated By Bone Marrow Transplantation

Background. - Pathogenesis of osteopetrosis is still debated. Testing the ability osteoclastic progenitors to support the proliferation of functional cells may be useful in understanding pathogenesis.Case report and methods. - A diagnosis of osteopetrosis was made in a girl 1 month-old, born to consanguuineous parents. Bone marrow transplantation was uneffective at the age of 3 months but a second engraftment was successful at 5 months. Unfortunatly, the patient died from severe thrombocytopenia at the age of 8 months. Long-term cultures of mononucleated cells from the patient's blood were performed before and after the bone marrow transplantation, with or without growth factors such as vitamin D3, IL-6 and IL-1. Similar studies were made from die patient's marrow obtained after transplantation; all results, were compared with those obtained after culturing control cells from cord blood umbilical.Results. - Production of osteoclastic cells was mild in peripheral blood cultures; it was important in bone marrow cultures in presence of growth factors.Conclusion. - These results suggest that osteopetrosis in our patient resulted from an intrinsic defect in progenitors of osteoclasts.