Mouse erythrocyte rosette formation with malignant human B‐lymphocytes re‐evaluated: still a useful marker for differentiating mature B‐cell malignancies

摘要

Summary.We have re‐evaluated mouse rosette formation (MRF) as a marker for B‐CLL by estimating the fraction of mouse rosette forming B‐lymphocytes (identified by CD20 monoclonal antibodies) in normal donors and malignant CD20 + cell proliferations (ALL, AML, B‐NHL, B‐HCL and B‐CLL). Whereas this ratio was increased in B‐CLL, all other CD20 positive malignancies showed mean ratios of less than 0·1. As part of a Danish multi‐centre study, we furthermore prospectively analysed 86 patients and found that the mouse/CD20 ratio divided the 78 patients with monoclonal B‐cell populations suspected of B‐CLL in two distinct groups. In the low ratio group, three patients were categorized as leukaemized B‐NHL and one as PLL. The remaining three patients with low ratio were clinically and immunologically (by Smlg density and CD5 expression) B‐CLL patients suggesting a frequency of MR‐negative B‐CLLs of approximately 5. In the high ratio group two of 70 patients were diagnosed as B‐NHLs. Thirdly, MRF was a valuable parameter in patients, where transformation of disease is suspected, since it preceded clinical changes by several months. Thus, MRF is still a useful marker in th