MY4 expression on B-lymphocyte malignancies may be associated with a more adverse prognosis

We have noted what other preliminary reports have also described as a new specificity of the MY4 monoclonal antibody from Coulter Immunology which previously was designated to only have myelogenous CD14 specificity. The MY4 marker appears to characterize a subpopulation of some B-lymphocytic malignancies that are CD19, CD20, surface immunoglobulin as well as MY4 positive. The results occurred when other myelogenous markers such as CD11b, CD13 and CD33 were unreactive. Another monoclonal antibody marker of CD14 specificity, MO2, did not demonstrate a similar reactivity. Various other monoclonal antibodies of the same IgGI subclass as MY4 were also not reactive and thereby excludes non-specific adsorption as an explanation of the results. The six patients described in this report represented five non-Hodgkin's lymphoma cases and one chronic lymphocytic leukemia case. Fifteen B-lymphocytic leukemias and 30 other B-lymphocytic non-Hodgkin's lymphomas analysed during the same period were not MY4 positive. In reviewing the clinical course of the six patients compared to the general behavior of these types of malignancies and making a speculative generalization from the small group of cases, the MY4 antigen appeared to be expressed by low to intermediate grade B-lymphocytic malignancies of a type that were more rapidly progressive and/or had a greater tendency to undergo a transformation of their malignancy. Two of the three transformed cases were proceeded by chronic lymphocytic leukemia.