[PCR analysis of T cell antigen receptor genes for human lymphoid malignancies]

T-cell receptor genes encode proteins related to their specific recognition structures. As is true for immunoglobulins, T-cell receptor genes consist of separate germ line segments that encode the variable and constant regions of the chain. The variable region genes are assembled from two or three separate germ line segments that somatically rearrange during differentiation. The diversity in the variable region of T-cell receptors results from germ line diversity of V, (D), and J sequences, combinatorial joining of the segments, junctional diversity leading to codon changes at the end of gene segments, N-region diversity arising from addition of template independent nucleotides at junction. Each T-cell clone has its own unique structure of the variable region, and in T-cell malignancies, this variable region is retained after malignant transformation. This enables the nucleotide sequences of the variable region genes to be used as a molecular marker for the malignant clone. By amplification of these sequences of variable genes, it is now possible to study the pathological features of the leukemic clones in vivo, as well as to follow the patients for minimal residual disease.