Detection of clonal VDJ rearrangements in PMBL.

DNA from PMBL tissue was submitted to a PCR with primer combination FR1. Cases that did not reveal clonal signals with FR1 were reanalyzed with an alternative primer set FR2. Monoclonal rearrangements are identified by a sharp, distinct band in comparison with diffuse signals generated from polyclonal control samples (P). In cases 8a, 8b, and 11, specific PCR products are indicated by an arrowhead. Additional bands detectable in these cases proved to be nonspecific upon sequence analysis. M indicates molecular size marker.