Clinical Use of Next-Generation Sequencing of TRG Gene Rearrangements Has Arrived

Abstract

In this issue of the Journal , Schumacher and colleagues1 describe important principles to consider when applying next-generation sequencing (NGS) for the identification of clonal sequences to support the diagnosis of T-cell neoplasms. NGS has been shown to be clinically useful in identifying germline mutations in hereditary conditions and somatic mutations in numerous cancers. In 2009, one of the first reports of the use of NGS methods to describe the repertoire of TRB gene rearrangements was published.2 Since then, it has been used to characterize the T-cell repertoire in patients with various diseases. The next application described was the identification of unique sequences of minimal residual disease in acute lymphoblastic leukemia.3,4 It was a logical step to go from defining a T-cell repertoire to the application of NGS in clonality detection, whether at diagnosis1 or in follow-up.3,4 One must aim for certain goals in preparing unbiased libraries based on polymerase chain reaction (PCR) amplified products of any gene targets. The first desirable goal is to use primers that give proportional representation of the variable (V) and joining (J) region genes that are used in the TRG gene rearrangements. Second, the primers selected and the products produced must have equal amplification efficiencies. Proportional representation for each of the V and J gene groups is largely achieved by the primers selected, but it will be less than 100%, since specific primers for each of the individual group I variable genes were not designed in the set of primers that the …