Anti-CD3D monoclonal antibody, clone VDIU2 [Cy5]

T cells recognize antigens via their cell surface TCR and are classified as either alpha beta or gamma delta depending on the variable chains in their TCR, alpha and beta or gamma and delta, respectively. Both alpha beta and gamma delta TCRs also contain several invariant chains, including CD3 delta, which support surface TCR expression and transduce the TCR signal. Mutations in variable chains would be expected to affect a single T cell lineage, while mutations in the invariant chains would affect all T cells. Consistent with this, all CD3 delta-deficient patients described to date showed a complete block in T cell development. However, CD3 delta-KO mice have an alpha beta T cell-specific defect. Here, we report 2 unrelated cases of SCID with a selective block in alpha beta but not in gamma delta T cell development, associated with a new splicing mutation in the CD3D gene. The patients' T cells showed reduced CD3D transcripts, CD3 delta proteins, surface TCR, and early TCR signaling. Their lymph nodes showed severe T cell depletion, recent thymus emigrants in peripheral blood were strongly decreased, and the scant alpha beta T cells were oligoclonal. T cell-dependent B cell functions were also impaired, despite the presence of normal B cell numbers. Strikingly, despite the specific loss of alpha beta T cells, surface TCR expression was more reduced in gamma delta than in alpha beta T cells. Analysis of individuals with this CD3D mutation thus demonstrates the contrasting CD3 delta requirements for alpha beta versus gamma delta T cell development and TCR expression in humans and highlights the diagnostic and clinical relevance of studying both TCR isotypes when a T cell defect is suspected.

Currently, the pathogenesis of chronic GVHD is unclear. To elucidate the molecular characteristics underlying chronic GVHD, we analyzed the gene expression profiles of 21 mononuclear cell samples from allogeneic hematopoietic stem cell transplantation (HSCT) recipients. Self organizing map (SOM) clustering showed that the entire expression profiles of chronic GVHD samples were clearly different from those of the non-GVHD samples, and significance analysis of microarray (SAM) demonstrated that 120 genes, including PTDSS1, VAV1 and CD3D, were up-regulated, and 5 genes, including calnexin, were down-regulated in GVHD patients. Gene ontology annotation revealed that these genes are related to the phosphorous metabolism and lipid biosynthesis. Quantitative real time polymerase chain reaction (qRT-PCR) experiments validated the up-regulation of PTDSS1, VAV1 and CD3D in separate samples. Pathway-wise global test revealed that differential gene expression in cell cycle and T cell immune-associated pathways were significant between GVHD patients and non-GVHD patients. Seventeen classifier genes selected using a PAM (prediction analysis of microarray) algorithm showed favorable performance (prediction accuracy 0.85) for identifying patients with chronic GVHD. In conclusion, we identified differentially expressed genes and pathways in chronic GVHD patients using microarray analysis, and we also selected diagnostic genes predicting chronic GVHD status.