Cellular immune function monitoring after allogeneic haematopoietic cell transplantation: evaluation of a new assay

Abstract

SummaryManaging the patient's immune system after haematopoietic cell transplantation (HCT) is a challenge, mainly in the unstable period immediately after the transplant. Currently there is no standardized non-invasive diagnostic tool for the evaluation of immunological complications such as graft-versushost disease (GVHD) and for managing the cellular immune function of the transplant recipient. The ImmuKnow assay for cellular immune function monitoring has been incorporated successfully into the clinical follow-up routine of solid organ transplant recipients. This study aims to explore the relevance and potential contribution of immune monitoring using the assay in the setting of HCT. We found that ImmuKnow-level measurement can distinguish between states of immune function quiescence and between events of acute GVHD. ImmuKnow levels were significantly higher in patients going through GVHD than the levels measured for the same patients during immunological stability. Moreover, we demonstrate a patient case where longitudinal monitoring using the ImmuKnow assay provided a trustworthy depiction of the patient's cellular immune function post-HCT. In conclusion, we provide evidence for the potential contribution of the ImmuKnow assay for longitudinal individualized cellular immune function monitoring of patients following HCT. Further studies are necessary in order to establish the optimal practice for utilizing the assay for this purpose.

Low T-Cell Responses to Mitogen Stimulation Predicts Poor Survival in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation

“…The Cylex ImmuKnow ® is another immune monitoring assay, which after stimulation with PHA measures intracellular adenosine triphosphate levels in CD4+ T-cells ( 24 ). Several studies in the HSCT population did not demonstrate any additional clinical value of the ImmunKnow assay ( 11 , 25 , 26 ). More complex biomarkers such as T-cell immunoglobulin and mucin-domain containing 3 (TIM3), interleukin-6, soluble tumor necrosis factor receptor 1, and plasma suppression of tumorigenicity 2 have shown some promise in predicting AGVHD and NRM ( 3 , 5 ).…”

“…Potential biomarkers should ideally be easy to perform, be reproducible, and accurately predict outcomes such as AGVHD ( 3 , 5 ), infection ( 9 , 22 ), and survival ( 3 , 9 ). Candidate biomarker targets have included T-cell subsets ( 7 , 23 ), functional immune assays ( 11 , 23 ), inflammatory cytokines ( 22 ), and interleukin receptors ( 5 ). T-cell subset numbers, particularly higher CD8+ T-cells but not CD4+ T-cells, at day 90 were recently observed to predict enhanced survival in a cohort of HSCT recipients but immune function was not assessed ( 7 ).…”

“…Following HSCT, clinicians often need to balance the risk of acute graft versus host disease (AGVHD) against infection, with both complications contributing significantly to transplant-related mortality. Potential candidate biomarkers used to predict mortality or AGVHD outcomes include levels of inflammatory cytokines ( 5 ), T-cell subset number (CD4+ or CD8+ T-cells) or rate of recovery ( 7 , 8 ), C-reactive protein ( 9 ), interleukin receptors ( 3 ), ferritin ( 10 ), and functional immune assays ( 11 ).…”

Functional immune reconstitution early after allogeneic haematopoietic cell transplantation: A comparison of pre‐ and post‐transplantation cytokine responses in stimulated whole blood

“…Besides infections, another detrimental complication to HCT is acute GvHD, where alloreactive donor‐derived T cells recognize recipient cells as foreign and initiates a cytotoxic and inflammatory response resulting in organ damage, typically in the skin, gut and/or liver 44 . A previous study of CD4+ T cell reactivity found that patients with acute GvHD had a markedly increased immune response to phytohemagglutinin stimulation 24 . In our study, a single patient had acute GvHD at the time of whole blood sampling, and while this patient had higher‐than‐average signatures of cytokine responses to R848 and HKCA stimuli, other GvHD‐free patients exhibited similar patterns.…”

“…Previous clinical studies of the functional immune reconstitution at different timepoints after HCT have investigated (a) the reactivity of CD4+ T cells based on the amount of adenosine phosphate secreted upon phytohemagglutinin stimulation [21][22][23][24] ; (b) the virus-specific reactivity of CD8+ T cells based on the release of interferon-γ upon stimulation with viral antigens [25][26][27][28][29][30] ; (c) the pathogen-specific proliferative and cytokine responses of peripheral blood mononuclear cells after culturing 31 ; or (d) the phagocytic, migratory and stimulusspecific oxidative capacity of neutrophils and monocytes 32,33 ; among other approaches. While these approaches-to evaluate the post-HCT functional immune reconstitution-are valuable when investigating pathogen-or immune cell-specific responses, our study demonstrates the feasibility of obtaining a more global screening of the circulating immune cells post-HCT, revealing a broad array of cytokine responses elicited through multiple immunologic signalling pathways.…”