OPTIMAL PRIMER SELECTION FOR CLONALITY ASSESSMENT BY POLYMERASE CHAIN-REACTION ANALYSIS .1. LOW-GRADE B-CELL LYMPHOPROLIFERATIVE DISORDERS OF NONFOLLICULAR CENTER CELL-TYPE

Recent polymerase chain reaction (PCR)-based studies focused on the de tection of immunoglobulin heavy chain gene (IgH) rearrangements have s uggested that clonal populations may be amplified more easily from cer tain categories of B-cell neoplasia than others and that primer makeup can be a critical factor in successful amplification. However, these particular reports contained relatively few-low grade B-cell lymphopro liferative disorders of nonfollicular center cell type (LG-BLPD) and u sed only a limited panel of available primer sets for PCR amplificatio n of monoclonal B-cell populations. To address this issue more extensi vely we evaluated 156 samples of LG-BLPD by the PCR to determine optim al primer selection in this setting. All cases were classified accordi ng to standard morphological and immunophenotypic criteria, with monoc lonality documented by Ig light chain restriction analysis. The LG-BLP D included 33 cases of chronic lymphocytic leukemia (CLL), 57 cases of smalt lymphocytic lymphoma (SLL), 10 cases of atypical CLL, 32 cases of mantle cell lymphoma (MCL), 17 plasma cell neoplasms (PCNs), and se ven cases of hairy cell leukemia (HCL). All primer sets included a 3' IgH joining region consensus primer, whereas the 5' IgH variable regio n (VH) primer was different in each set. The first-line panel included the following: Set 1, MI-framework III consensus primer, and Set 2, s even separate MI-framework I family-specific primers. A reserve panel of alternate MI consensus primers directed at framework II or III regi ons was used only when Set 1 showed no evidence of B-cell monoclonalit y. Overall, monoclonal B-cell populations were amplified in 153 of 156 (98%) neoplasms by the PCR; two PCNs and one plasmacytoid SLL were ne gative with all primer pairs. Higher amplification efficiency was obta ined with Set 1 primers than Set 2 primers in the entire series (96% v 84%) as well as within each subtype of LG-BLPD. In each diagnostic ca tegory monoclonal B-cell populations were detected by Set 1 in 96% or more of neoplasms, the only exception being plasma cell neoplasms wher e the monoclonality detection rate was 76% (ie, 13 of 17 cases). With the additional use of Set 2 and the reserve panel primer sets, 15 of 1 7 (88%) PCNs were shown to contain PCR-detectable monoclonal B-cell po pulations. Our data suggest that the vast majority of CLLs, SLLs, MCL, and HCL samples fan be successfully genotyped by the PCR with a singl e primer set (Set 1). In contrast, plasma cell tumors and rare SLL sam ples appear to require more extensive analysis (ie, additional primer sets) to adequately assess B-cell clonality. Copyright (C) 1994 by W.B . Saunders Company