Clinical significance of HLA-DR+, CD19+, CD10+ immature B-cell phenotype and CD34+ cell detection in bone marrow lymphocytes from children affected with immune thrombocytopenic purpura.

In children with immune thrombocytopenic purpura (ITP), bone marrow lymphocytes can express the common acute lymphoblastic leukemia antigen (CALLA) pattern with no evidence of leukemia or lymphoma. Bone marrow lymphocytes from 23 children and 20 adults affected with ITP were studied to determine the incidence and the clinical impact of lymphocytes with the immature B-cell phenotype and CD34+ cell expression. In this investigation we identified a group consisting of 52% of the children who showed the immature B phenotype, while the remaining 48%, similarly to adult ITP displayed an increase of T-cell antigens. CD34 was positive in 53% of children, but it was present in only half of the patients with the immature B phenotype and it was always absent in adults. IgH genes disclosed a germline configuration in all six patients in the immature B phenotype group. No difference was found in the two groups of children in terms of age, presentation of the disease or final outcome. Finally, no patient in either children's group has developed an acute lymphoproliferative disorder.