We studied the degree and the pattern of skewing of the variable region of beta-chain (VB) T-cell receptor (TCR) repertoire in aplastic anemia (AA) at initial presentation and after immunosuppression using a high-resolution analysis of the TCR VB complementarity-determining region 3 (CDR3).
We found sequence identity for complementarity determining region 3 (CDR3) among a majority of CD4 clones; the same sequence was present in marrow lymphocytes from four other patients with AA but was not detected in controls.
To determine whether the antigen-driven T-cell response is involved in the pathogenesis of aplastic anemia (AA), we examined the complementarity-determining region 3 (CDR3) size distribution of T-cell receptor (TCR) beta-chain (BV) subfamilies in the bone marrow (BM) of untreated AA patients.
Unique rearrangements detected in the CDR3 region are suggestive of a limited process of an antigen-driven (oligo)clonal T cell expansion which may take place over the overwhelmingly polyclonal repertoire of T lymphocytes at the onset of severe AA.