RAS mutations contribute to evolution of chronic myelomonocytic leukemia to the proliferative variant.

Purpose: The biological and clinical heterogeneity of chronic myelomonocytic leukemia features renders its classification difficult. Moreover, because of the limited knowledge of the mechanisms involved in malignant evolution, chronic myelomonocytic leukemia remains a diagnostic and therapeutic challenge and a poor prognosis disease. We aimed to verify the biological and clinical significance of the discrimination, based on the leukocyte count, between myelodysplastic chronic myelomonocytic leukemia (MD-CMML) and myeloproliferative chronic myelomonocytic leukemia (MP-CMML).

Study of complement-mediated anaphylaxis in humans. The role of IgG subclasses (IgG1 and/or IgG4) in the complement-activating capacity of immune complexes.

The role of Ig classes and subclasses in complement activation has been investigated both in vitro and in experimental animals, but not in humans. This study was conducted to determine the immunologic events of post-transfusion anaphylaxis in humans, and the effects of immune complexes of different IgG subclass compositions on complement activation. The ability of immune complexes containing mixed IgG1 and IgG4 or IgG4 Ab only to activate complement was investigated in two patients with von Willebrand's disease (a congenital bleeding disorder).