[Value of in vitro study of osteoclast precursors in the case of severe infantile osteopetrosis treated by bone marrow graft].
BACKGROUND
Pathogenesis of osteopetrosis is still debated. Testing the ability of osteoclastic progenitors to support the proliferation of functional cells may be useful in understanding pathogenesis.


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. Unfortunately, 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 the 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.


CONCLUSIONS
These results suggest that osteopetrosis in our patient resulted from an intrinsic defect in progenitors of osteoclasts.
Gourdin
A
A
Unité d'hémato-oncologie, hôpital universitaire des enfants Reine-Fabiola, Bruxelles, Belgique.
Demulder
A
A
Ferster
A
A
Fondu
P
P
D001773:Blood Cells / Q000473:pathology; D001853:Bone Marrow / Q000473:pathology; D016026:Bone Marrow Transplantation; D002454:Cell Differentiation; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007223:Infant; D010010:Osteoclasts / Q000473:pathology*; D010022:Osteopetrosis / Q000473:pathology* / Q000628:therapy*; D011184:Postoperative Period