Expression of CD10, CD19 and CD34 markers in bone marrow samples of children with precursor B-cell acute lymphoblastic leukemia in clinical and hematological remission.

Long-term follow-up of the rate of CD10, CD19 and CD34 antigens expression compared with the percentage of lymphocytes and blastic cells in 196 bone marrow specimens of 91 children with early B-cell acute lymphoblastic leukemia has been performed. It was shown that during a five year period there were no significant differences concerning the percentage of CD markers and the percentage of lymphocytes and blastic cells except those in the 4th year of clinical and immunological follow-up--when increase of lymphocytes and CD19 marker percentage have been observed. Consensus, i.e. more than 20% CD markers positivity associated with more than 5% blasts (positive consensus) or less than 20% CD markers positivity combined with less than 5% blasts (negative consensus) was ascertained in 92.8% of cases. Disagreement, i.e. the rate of CD markers over 20% combined with less than 5% blasts was found in 14 (7.2%) patients. This finding present in the initial phase of the disease could be considered as a sign of not complete remission, in contrast to the finding in children who completed chemotherapy and were in long-term hematological remission, in which the increase of CD markers could be considered as a sign of increased regeneration activity of bone marrow after chemotherapy induced medullary aplasia. Anyway, the increase of CD10, CD19 and CD34 antigens in bone marrow samples over 20% should be evaluated with caution. In these cases, mainly in children with long-term hematologic remission the examination should be repeatedly performed and/or more sensitive methods for detection of minimal residual disease should be applied. In control group of 20 children without leukemia the rate of CD markers in the bone marrow was always under 20%.