Discovery and validation of biomarkers for chronic graft-versus-host disease in patients submitted to hematopoietic stem cell transplantation

Abstract

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the most effective tumor immunotherapy available. Although allo-HSCT provides beneficial graft-versus-tumor effects, graft versus host disease (GVHD) is the primary source of morbidity and mortality after HSCT. GVHD can be classified as acute or chronic, based on the clinical, laboratorial and histological presentation. The diagnosis of GVHD is typically based on clinical symptoms in one or more of the main target organs. In acute GVHD the target organs involved are skin, liver, and gastrointestinal. Chronic GVHD most common organs are skin, gastrointestinal, liver, lung and mouth. The current available diagnostic and staging tools of GVHD fail to identify patients at higher risk of GVHD progression, unresponsiveness to therapy, or death. In addition, there are shortcomings in the prediction of GVHD before clinical signs develop indicating the urgent need for noninvasive and reliable laboratory tests. Saliva contains many components of adaptive and innate immune response crucial for local host defenses. Changes in salivary constituents could reflect systemic processes such as immune reconstitution and development of GVHD that occur post-transplant. This is an ongoing project which the objective is to discovery and validate a panel of salivary proteins candidates as biomarkers for cGVHD already discovered. Saliva samples of 20 allo-HSCT patients were prospectively collected before the initiation of the conditioning regimen (pre-HSCT), on day D+8 and on day D+100 post-HSCT. An extra saliva sample was collected on cGVHD onset if it occurred anytime up D+100 post-HSCT. Patients were divided into 2 groups: with cGVHD (n=5) and non-GVHD (n=15). Saliva samples were submitted to the mass spectrometry evaluation and a panel of 60 proteins was identified. The odds ratio statistical analysis between those 2 groups of patients selected a panel of 4 proteins which are commonly observed on the cGVHD group (Lactoferroxin-B; Cystatin-AS; Cystatin-S and Protein S100-A9). Other 2 proteins (Lipocalin-1 and Isoform 1 of Delete in Malignant Brain Tumors 1 Protein) were chose based on the results of the t-Student test applied in every collection time. The validation study will be done by Ensyme Linked Immuno Sorbent Assay (ELISA). (AU)