Increase of CALLA-positive stimulated lymphoid cells in transient erythroblastopenia of childhood.

In 1986 and 1987 11 children with TEC (transient erythroblastopenia of childhood) were referred to our hospital. Bone marrow aspirations were performed to exclude haematological malignancy. There was a marked reduction of erythropoiesis in 9 cases (1%-8%), two children had already recovered (33% and 44% erythropoiesis). Eight patients exhibited high percentages of stimulated lymphoid cells. The subsequent immunotyping revealed the expression of CALLA (common acute lymphoblastic leukaemia antigen) on these cells but there was no other sign for malignancy. The patients recovered without any specific treatment except transfusions of packed red cells. Eight patients were followed up 11-18 months after initial presentation and were all found to be in good health. A prominent increase of CALLA-positive stimulated lymphoid cells has also been found in other haematological diseases such as neutropenia and immune thrombocytopenia. The expression of CALLA in bone marrow lymphocytes is a general reactive change to various alterations.