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A practical strategy for the routine use of BIOMED‐2 PCR assays for detection of B‐ and T‐cell clonality in diagnostic haematopathology

BIOMED‐2 polymerase chain reaction (PCR) assays for clonality analysis of immunoglobulin (IG) and T‐cell receptor (TCR) gene rearrangements were evaluated in routine haematopathological practice where paraffin‐embedded tissues constitute the majority of specimens. One hundred and twenty‐five fresh/frozen and 316 paraffin specimens were analysed for DNA quality and clonality. Seventy‐nine per cent of paraffin specimens yielded PCR products of over 300 bp. These specimens and all fresh/frozen specimens were analysed with the complete set of BIOMED‐2 reactions for IG (8 reactions) and/or TCR (6 reactions) gene rearrangements. The rate of detection of clonality was 96% in mature B‐cell neoplasms and 98% in mature T‐cell neoplasms and there were no significant differences in these rates between paraffin and fresh/frozen specimens. As the value of sole use of any individual BIOMED‐2 reaction in clonality detection was limited, we assessed combinations of reactions that gave the greatest sensitivity with fewest reactions and were applicable for both fresh/frozen and paraffin specimens. For IG gene rearrangements, three reactions combining one targeting the IG heavy chain framework‐2 region and two targeting the IG kappa locus achieved a 91% detection rate. For TCR gene rearrangements, the two TCR gamma reactions gave a 94% detection rate. We therefore recommend this strategy as the first‐line assays for routine B‐ and T‐cell clonality analysis in diagnostic haematopathology.