Restricted use of T-cell receptor V beta genes in posttransfusion graft-versus-host disease.

BACKGROUND

Posttransfusion graft-versus-host disease (PT-GVHD) is a pathophysiological process of the immune system. Mature donor T cells that have survived the host defense mechanisms recognize recipient allo-antigens through antigen-specific T-cell receptors and mount an immune attack against certain host antigens.

STUDY DESIGN AND METHODS

To characterize the T cells involved in PT-GVHD, expression of the T-cell receptor V beta genes in peripheral blood T cells isolated from four PT-GVHD patients was analyzed. T-cell receptor beta chain cDNA derived from mRNA extracted from peripheral blood lymphocytes was amplified by an inverse polymerase chain reaction method, and the cDNA was subsequently cloned and sequenced.

RESULTS

The cDNA clones derived from patients with PT-GVHD showed remarkable differences in the distribution of T-cell receptor V beta gene use from that in normal controls. Very restricted T-cell receptor V beta gene repertoires and preferential expression of certain V beta gene segments were revealed in the peripheral blood lymphocytes of each patients. Shared V beta gene use among the patients was not observed, probably because of HLA differences among the patient-donor combinations.

CONCLUSION

This restricted use reflected in vivo expansion of a limited number of engrafted T-cell clones at the onset of PT-GVHD and suggested that those oligoclonal donor T cells may be involved in the induction of PT-GVHD.