Hello Wal, Within European Working Group on Clinical cell Analysis we have performed phenotyping of plasma cells on approx 100 myeloma, MGUS and normal BM collected in 6 laboratories. In normal BM plasma cells showed "dim" CD 19 expression. In myeloma and MGUS in 90% of cases the CD19 expression was negative or much lower than in normal/reactive plasma cells. The best differentiation between normal and pathological plasma cells was obtained by CD56 expression which was negative in normal plasma cells but positive in approx. 80% of myeloma/MGUS cases. When it comes to differentiation between MGUS and myeloma our experience supports the previous findings of Dr Orfao's group (Am J Pathol. 1998 Jun;152(6):1655-65) showing that in MGUS the normal plasma cells are also present while in myeloma there is a total dominance of the pathological plasma cell population. Kind regards Anna At 13:16 2001-10-06 +0100, you wrote: > >Eyup me owd Flowers (Yorkshire slang), > >I'd like to try and get a consensus on two related topics - > >1) Is CD19 positivity in plasma cells definitive of Myeloma or can you get >reactive plasma cells showing the same ? > >2) Does the list believe that even a small number of these cells in bone >marrow justifies the diagnosis of Myeloma when clinical evidence (or rather, >lack of it) would normally support MGUS ? > >I have my own thoughts on the matter but I thought it would be interesting >to get wider opinions. > >Wal Sharp >Yorkshire >UK > > > Anna Porwit Hematopathology Lab. Department of Pathology, Radiumhemmet Karolinska Hospital, 171 76 Stockholm, Sweden Anja.Porwit@ks.se tel.:+46-851774518 fax.:+46-851775843
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