A Comprehensive Analysis of the Expression Profiles of KCTD Proteins in Acute Lymphoblastic Leukemia: Evidence of Selective Expression of KCTD1 in T-ALL

Acute leukemia is the most common pediatric cancer. In most cases, this disease results from the malignant transformation of either the B-cell (B-ALL) or, less frequently, T-cell progenitors (T-ALL). Recently, a marked overexpression of KCTD15, a member of the emerging class of the potassium (K) channel tetramerization domain-containing proteins (KCTDs) has been detected in both patients and continuous cell lines as in vitro model systems. Because there is growing evidence of the key, yet diversified, roles played by KCTDs in cancers, we here report an exhaustive analysis of their expression profiles in both B-ALL and T-ALL patients. Although for most KCTDs, no significant alterations were found in these pathological states, for some members of the family, significant up- and down-regulations were detected in comparison with the values found in healthy subjects in the transcriptome analysis. Among these, particularly relevant is the upregulation of the closely related KCTD1 and KCTD15 in T-ALL patients. Interestingly, KCTD1 is barely expressed in both unaffected controls and B-ALL patients. Therefore, not only does this analysis represent the first study in which the dysregulation of all KCTDs is simultaneously evaluated in specific pathological contexts, but it also provides a promising T-ALL biomarker that could be suitable for clinical applications.

Expression profile of HLA-B*38:55Q allele

The identification of null or questionably expressed HLA allelic variants is a major issue in HLA diagnostics, because the mistyping of the aberrant expression of such alleles can have a major impact on the outcome of both hematopoietic stem cell transplantation (HSCT) and solid organ transplants. It is debated how questionable (Q) alleles, because of their unknown expression profile, should be considered in an allogenic HSCT setting. The HLA-B*38:55Q allele was detected as an HLA-B blank specificity; DNA sequencing identified a single polymorphism at position 373 in exon 3 (TGC > CGC), which results in the replacement of cysteine 101 with an arginine in the HLA-B heavy chain, thus, impairing disulfide bridge formation in the alpha-2 domain, essential for the normal expression of the HLA molecules. In order to determine the RNA and protein expression profile of this allelic variant, we analyzed antigenic expression at different levels, transcriptional and transductional, using a combination of cellular methods, such as serological testing and flow cytometric analysis, polymerase chain reaction (PCR) sequence-specific primer (SSP) cDNA group-specific amplification and immunocytochemical assay, demonstrating the prevalent cytoplasmatic distribution of the HLA-B*38:55Q protein. Our findings suggest that in matching process the HLA-B*38:55Q allele needs to be considered as a low expressed allele, able to elicit an allogenic T-cell response in vivo and impair the transplant outcome.