Optimal Primer Selection for Clonality Assessment by Polymerase Chain Reaction Analysis: II. Follicular Lymphomas

Prior studies have shown variable success in amplification of monoclonal B-cell populations from follicular lymphomas (FLs) of germinal center cell origin using the polymerase chain reaction (PCR). We examined 60 FLs by the PCR to determine optimal primer selection for detection of clonal immunoglobulin heavy chain gene (IgH) rearrangements in this common group of B-cell lymphomas. Each primer set included a 3' IgH joining region consensus primer; the 5' primer was different in each reaction. The first-line panel included the following: Set 1, bcl-2 major breakpoint region (mbr) primer; Set 2, bcl-2 minor cluster region (mcr) primer; Set 3, IgH variable region framework III consensus primer; and Set 4, seven separate IgH variable region framework I family-specific primers. A reserve panel also was used. The efficiency of monoclonal B-cell population amplification differed among primer sets. The bcl-2-targeted primer pairs (Sets 1 and 2) were most efficient and amplified 42 (70%) of 60 cases. Of these, the mbr and mcr primer sets detected monoclonality in 38 and four cases, respectively. Set 3 amplified monoclonal B-cell in 38 and four cases, respectively. Set 3 amplified monoclonal B-cell populations in 31 (52%) cases and Set 4 detected similar populations in only 27 (45%) samples. When results from primer Sets 1, 2, and 3 were combined, 49 of 60 (82%) FLs showed evidence of B-cell monoclonality by the PCR. Three of the 11 negative cases were documented as monoclonal with primer Set 4, and three additional samples were amplified only with our reserve panel.(ABSTRACT TRUNCATED AT 250 WORDS)