Implication of therapeutic outcomes associated with molecular characterization of paediatric aplastic anaemia

Severe aplastic anemia is characterized by a hypocellular bone marrow and peripheral cytopenia. Mesenchymal stem cells (MSCs) play a crucial role in haematopoietic stem cells (HSCs) development and the development of microenvironment suitable for hematopoiesis. Molecular characterization of telomere maintenance pathway and gene expression profiling of MSCs can be important for the therapeutic interventions among paediatric aplastic anaemia patients.

The study involved paediatric aplastic anaemia patients (n = 10) and age matched paediatric healthy donors (n = 8). Peripheral blood samples were collected from the individuals. Average leucocyte telomere length and gene expression of the telomere maintenance genes were determined by quantitative real time PCR. Microarray based gene expression profiles (GSE33812) of MSCs for five paediatric aplastic anaemia patients were analyzed compared to five healthy controls and the data was downloaded from the GEO database.

The telomere length was significantly shorter among paediatric AA patients compared to age matched healthy donors. Interestingly, one subgroup (n = 2) of paediatric AA patients has moderate telomere length comparable to age matched healthy donors. Based on the gene expression analysis of telomere maintenance pathway, TERF2 was significantly downregulated among paediatric patients with shorter telomere length but not among paediatric patients with moderate telomere length. Gene expression profiling of MSCs revealed three differentially expressed genes (GAS2L3, MK167 and TMSB15A) among the patients and was associated with therapeutic outcome.

Telomere length estimation and gene expression patterns of the MSCs and telomere length maintenance pathway may serve as a potential biomarker and could be associated with therapeutic choice of paediatric aplastic anaemia patients.