Skewed T-cell receptor usage and junctional heterogeneity among isletitis alpha beta and gamma delta T-cells in human...

Because of anatomical limitations, molecular characterization of islet-inflammatory T-cells in human insulin-dependent diabetes mellitus (IDDM) has remained elusive. We have isolated isletitis T-cells from pancreas graft biopsies of two patients (syngeneic and allogeneic, respectively) shortly after onset of recurrent IDDM and have characterized their repertoire by sequencing T-cell receptor (TcR)-specific cDNAs. Histopathological analysis of the grafts revealed selective beta-cell loss and isletitis characteristic of recurrent disease with no evidence of chronic inflammation or rejection. Most of the in vivo-activated isletitis T-cells were CD8+TcR alpha beta+ and CD4-CD8-TcR gamma delta+ in both patients. Comparison of the different TcR alpha,beta,gamma, and delta sequences revealed V(D)J junctional heterogeneity but skewed TcR usage within patients. Eighth of 13 different isletitis TcR beta sequences (19 of 26 cDNAs) from the syngeneic graft of patient 1 were V beta 3+, as opposed to only 1 of 31 peripheral TcR beta sequences (1 of 31 cDNAs) (61.5 vs. 3.2%, P < 0.0001). Of the 19 different isletitis TcR alpha clonotypes of this patient (24 of 42 cDNAs), 5 were V alpha 14+. The isletitis TcR beta clonotypes of the human leukocyte antigen-identical allogeneic graft of patient 2 showed selective J beta, but not V beta, gene usage. Two of three predominant isletitis clonotypes of patient 2 were V alpha 22+ (19 of 28 cDNAs) and the other (5 of 28 cDNAs) was also V alpha 14+.(ABSTRACT TRUNCATED AT 250 WORDS)