Abstract
Juvenile myelomonocytic leukemia (JMML) is a well-characterized malignant hematopoietic disorder in early childhood. Onset age above 2 years, thrombocytopenia, high HbF value and cytogenetic abnormalities are known to be poor prognostic factors. However, there currently exist no readily available laboratory markers that reflect disease activity. While blast transformation of peripheral blood mononuclear cells stimulated by concanavalin A or phytohemagglutinin is widely used to evaluate immune function, attention is seldom paid to the control (without mitogen) values which indicate the level of spontaneous blast formation (SBF). During the treatment of three cases of JMML, we found SBF values, significantly high at diagnosis, to be a good marker of disease activity where clinical exacerbation or improvement was associated with a change in SBF values. Determination of the SBF values appears to be a good marker of JMML activity, although its evaluation is warranted in a large study.
