Whole Exome Sequencing for Detection of Genetic Variants to Predict Chronic Lung Allograft Dysfunction

Markus Schmitt GATC Biotech AG, Germany

Abstract
Schmitt M, Pison C, Wahl B, Magnan A, Royer PJ, Botturi K, Sève M, Roux A, Reynaud Gaubert M, Kessler R, Dromer C, Mussot S, Tissot A, Mal H, Guillemain R, Mornex J-F, Dahan M, Benden C, Koutsokera A, Auffray C, Marsland BJ, and Nicod LP on behalf of the SysClad consortium
SysCLAD, an European union-funded project under the FP-7, aims to identify biomarkers and personalized signatures in recipients of lung transplants to predict Chronic Lung Allograft Dysfunction (CLAD) including its subtypes Bronchiolitis Obliterans Syndrome (BOS) and Restrictive Allograft Syndrome (RAS).
A study containing DNA from 64 stable lung transplant recipients and 56 patients with diagnosed BOS (n=35) and RAS (n=21) was carried out. Exome sequencing was performed using an improved post capture enrichment protocol. All libraries were sequenced using 100 bp paired-end sequencing by synthesis technology with approximately 70 – 100 million reads. The coverage was on average between 90 – 120x per sample. Genetic variants were determined by in-house analysis pipelines. A commercial software was used to compare the relative distribution of variants between various combinations of the three designated phenotypic groups: stable, BOS and RAS. Identification of variant combinations predominant within the respective patient group was conducted by processing the resulting data in a newly developed analysis-pipeline. A median number of about 5 to 10 of such distinguishing variants were present per patient in each of the groups.
The results presented will be utilized in a panel comprising several of such variants that could identify, and possible predict, lung transplant recipients at higher risk of suffering from CLAD. A diagnostic tool with such a high sensitivity and specificity could help to reduce the number of lung transplant rejections in future.