Cytogenetics and granulopoietic effects of bone marrow fibroblastic cells in Fanconi's anaemia.

To determine if abnormalities exist in the bone marrow stroma in Fanconi's anaemia, we studied the cytogenetic composition of in vitro bone marrow fibroblastic cells (FC) from a patient with this disorder and compared it to those obtained from skin fibroblasts, peripheral blood lymphocytes, and direct bone marrow preparations. The presence of granulocytic progenitors in bone marrow and T lymphocyte colonies in peripheral blood was also determined in addition to the ability of this patient's FC to stimulate normal granulocytic progenitors. We found that the FC had far fewer chromosomal abnormalities and stimulated normally the growth of granulocyte colonies. Granulocyte progenitors were not found, but T lymphocyte colonies were abundant. These results support the concept that a defect in haematopoietic stromal elements is not responsible for the aplasia developing in the disorder.