>Hello everybody, > >We use a kappa/lambda/CD19 triple to establish clonality for B cells, >but we are noticing that some of our cases of Hairy cell leukaemia >appear "double stained" for kappa and lambda. We use 2% bovine serum >albumin in our wash buffer and have tried blocking with various >reagents, but no luck so far. Has anyone come across this problem, or >have any ideas? > >Thanks in advance > >Steve Couzens >(Couzens@cf.ac.uk) Dear Steve, We find it is not uncommon to see both kappa and lambda staining with hairy cell leukaemia, in fact it is a pointer to that diagnosis. I gather it is due to cytophilic immunoglobulin bound to the cell membrane. One method to remove it is to acetate wash cells. There is a method in Methods in Haematology: The Leukaemic Cell. page 145. Ed by Catovsky First Edition 1981. Can't find it in the later edition. The reference given is Habeshaw et al,1979, Brit J Cancer 40: 11.Briefly: Cells are incubated in Acetate buffer ph 5.5 at 37C for 10 minutes with occasional shaking, washed twice , resuspended in medium for 2 hours at 37C. Washed twice ,then repeat the test. An alternative which works well is to perform kappa and lambda staining on cytospins by APAAP technique. This invariably confirms monoclonality and is useful if the hairy cells are a minority population. Hope this helps Jan Jan Nelson Molecular Haematology Department of Molecular Medicine The University of Auckland Phone: (+64)(9) 373-7599 ext 6381 Fax: (+64)(9) 373-7292
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