A Case of CD3+, CD4−, CD8−, WT31− Acute T-Cell Leukemia

The article reports a case of acute T-cell leukemia (T-ALL) with the unusual CD3+, WT31− phenotype. On surface marker analysis, the blast cells were found to be CD7+, CD2−, CD5−, CD1−, CD4−, CD8−, CD3+ and negative for B-lymphoid and myeloid lineage. The cells had both TCR β and TCRγ gene rearrangement but had negative results with the monoclonal antibody WT31, which reacts with a framework epitope on the T α/β heterodimer (Ti) of the conventional T-cell receptor (TCR). This suggests an association of the CD3 molecular complex with a different polypeptide (the alternate TCR γ ). In two similar reported cases of T-ALL (WT31−, CD3+, CD4−, CD8−), the CD3 molecular complex was found to be associated with a product of the Tγ gene.