Prospective Validation of a Chronic GvHD-Specific Proteome Pattern (cGvHD-MS14) Post Allogeneic Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment for many hematologic malignancies and non-malignant hematopoietic disorders, but is associated with significant morbidity and mortality with focus on acute and chronic graft-versus-host disease (GvHD). Chronic GvHD (cGvHD) occurs with increasing frequency, hampering quality of life of patients post-allogeneic HSCT and leading to increased morbidity and mortality even years after allogeneic HSCT. Diagnosis of chronic GvHD is based on clinical features and histology. Here we present the generation of cGvHD-specific proteomic pattern (cGvHD-MS14) using capillary electrophoreses and mass spectrometry to analyze urine sample collected prospectively after allogeneic HSCT.

A proteomic pattern (cGvHD-MS14) was developed in order to diagnose cGvHD, to differentiate acute versus cGvHD, and to predict onset and severity of cGvHD prior to clinical diagnosis of cGVHD as a non-invasive, unbiased laboratory test for diagnosis of cGvHD. This pattern was prospectively evaluated on 329 patients (1034 urine samples) after allogeneic HSCT at MHH and 3 collaborating transplant centers. The majority of the patients had acute leukemias prior to transplantation (n=210) and were transplanted from matched unrelated or related donors (MUD n=134; MRD n=125). Reduced intensity conditioning regimens were used in about 75% of all patients and the majority (80%) received ATG (anti-thymocyte globulin) as GVHD-prophylaxis prior to transplantation and a calcineurin-inhibitor based prophylaxis afterwards.

Prospective and blinded evaluation revealed the correct classification of patients developing cGvHD with a sensitivity 78% and specificity of about 71% at time of diagnosis. Differentiation between late onset acute GvHD and chronic GvHD was achieved in 3 patients in this validation set. Acute GvHD prior to day 100 is not recognized by cGvHD-MS14, since aGvHD-specific peptides had been excluded during cGvHD-pattern generation. The pattern consists of 14 differentially excreted peptides, differentiating chronic GvHD from tolerant patients. Four of 14 peptides have been sequenced to date, 2 are fragments from collagen 1, 1 is from inter-alpha trypsin inhibitor heavy chain 4 and 1 is a fragment from the fibrinogen ß-chain.

The proteomic pattern of urine proteomics enables diagnosis of cGvHD as well as differentiation of acute versus chronic GvHD. Further prospective evaluation of the cGvHD-specific pattern cGvHD-MS14 for organ specificity as well as severity prediction is currently ongoing.

Taken together our results indicate that diagnosis of cGvHD is possible using CE/MS analysis of prospectively collected urine samples with high sensitivity and specificity.

Metzger:mosaiques-diagnostics GmbH: Employment. Krons:mosaiques-diagnostics GmbH: Employment.