Evaluation of B-cell clonality in archival skin biopsy samples of cutaneous B-cell lymphoma by immunoglobulin heavy chain gene polymerase chain reaction

Polymerase chain reaction (PCR)-based detection of clonal T- and B-cells is widely used in the diagnosis of various lymphomas, including those of the skin. A large number of corresponding methods have been published. Recently, for the first time, standardized PCR protocols were developed in common by 14 European centers of lymphoma diagnosis and research (Biomed-2 protocols). Here, we have applied Biomed-2 immunoglobulin heavy chain (IgH)-PCR for clonality detection in primary cutaneous B-cell lymphoma (CBCL) and compared it with previously established methods. The DNA of 43 paraffin-embedded lesional skin biopsies of confirmed CBCL cases 27 follicle center cell lymphoma (FCCL), 11 marginal zone B-cell lymphoma/immunocytoma (MZL/IC) and five large CBCL of the lower leg (CBCL-LL)] were amplified by the Biomed-2 IgH-PCR protocols as well as using four other assays, priming also the three IgH framework regions (FR) 1-3. All PCR products were analysed by fluorescence fragment analysis. Twenty-nine of 43 (67%) CBCL samples (5/5, 100% of CBCL-LL; six of 11, 54.5% of IC/MZL; 18 of 27, 66.7% of FCCL) showed monoclonal B-cell presence complementary in all of the IgH-PCR. The three Biomed-2 PCR indicated together clonality in 24 of 43 samples (56%). Considering each method separately, the Biomed-2 FR3-PCR showed the highest rate of clonality detection (20 of 43, 47%). In conclusion, the Biomed-2 FR3-PCR is recommended for detecting B-cell clonality in archival skin samples of CBCL but should be completed by FR1- and/or FR2-PCR.