Inflammatory markers in patients after hematopoietic stem cell transplantation

The Role of Complement in HSCT-TMA: Basic Science to Clinical Practice

Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (HSCT-TMA) is a common complication occurring post-HSCT and is associated with substantial morbidity and mortality if not promptly identified and treated. Emerging evidence suggests a central role for the complement system in the pathogenesis of HSCT-TMA. The complement system has also been shown to interact with other pathways and processes including coagulation and inflammation, all of which are activated following HSCT. Three endothelial cell-damaging “hits” are required for HSCT-TMA genesis: a genetic predisposition or existing damage, an endothelial cell-damaging conditioning regimen, and additional damaging insults. Numerous risk factors for the development of HSCT-TMA have been identified (including primary diagnosis, graft type, and conditioning regimen) and validated lists of relatively simple diagnostic signs and symptoms exist, many utilizing routine clinical and laboratory assessments. Despite the relative ease with which HSCT-TMA can be screened for, it is often overlooked or masked by other common post-transplant conditions. Recent evidence that patients with HSCT-TMA may also concurrently present with these differential diagnoses only serve to further confound its identification and treatment. HSCT-TMA may be treated, or even prevented, by removing or ameliorating triggering “hits”, and recent studies have also shown substantial utility of complement-targeted therapies in this patient population. Further investigation into optimal management and treatment strategies is needed. Greater awareness of TMA post-HSCT is urgently needed to improve patient outcomes; the objective of this article is to clarify current understanding, explain underlying complement biology and provide simple tools to aid the early recognition, management, and monitoring of HSCT-TMA.

Orthostatic intolerance syndromes after hematopoietic cell transplantation: clinical characteristics and therapeutic interventions in a single-center experience

Background

Hematopoietic cell transplantation (HCT) is an established and potentially curative therapeutic option for hematologic cancers. HCT survivors are at risk of developing long-term complications impacting on morbidity and mortality. Orthostatic hypotension (OH) and postural tachycardia syndrome (POTS) have been anecdotally described after HCT. However, the incidence and clinical characteristics of patients with OH and POTS after HCT has not been well defined.

Methods

This retrospective study included 132 patients who had HCT between March 2011 and July 2018 and were referred to Cardio-oncology clinic. Patients were screened for OH and POTS. Using logistic regression analysis we evaluated the association between clinical factors and the incidence of OH and POTS.

Results

Median age was 58 (47–63) years, 87 (66%) patients were male, 95 (72%) were Caucasian. OH was diagnosed in 30 (23%) subjects and POTS in 12 (9%) after the HCT. No significant differences in demographic characteristics were found when comparing patients with and without OH or POTS. The two groups did not differ for cardiovascular diseases prevalence nor for the prior use of antihypertensive drugs. Previous radiotherapy and treatment with specific chemotherapy drugs were found to be associated with the incidence of OH or POTS, but none of the factors maintained the significance in the multivariate model. Pharmacological therapy was required in 38 (91%) cases, including a b-adrenergic blocker (n = 24, 57%), midodrine (n = 24, 57%) and fludrocortisone (n = 7, 18%).

Conclusion

Orthostatic intolerance syndromes are commonly diagnosed in patients referred to the cardiologist after HCT, involving approximately 1/3 of patients and requiring pharmacological therapy to cope with symptoms in the majority of cases. Risk factors specific to this population are identified but cannot fully explain the incidence of POTS and OH after HCT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40959-021-00126-7.

Advances in preclinical hematopoietic stem cell models and possible implications for improving therapeutic transplantation

Hematopoietic stem cell transplantation (HSCT) is a treatment for many malignant, congenital, and acquired hematologic diseases. Some outstanding challenges in the HSCT field include the paucity of immunologically‐matched donors, our inability to effectively expand hematopoeitic stem cells (HSCs) ex vivo, and the high infection risk during engraftment. Scientists are striving to develop protocols to generate, expand, and maintain HSCs ex vivo, however these are not yet ready for clinical application. Given these problems, advancing our understanding of HSC specification, regulation, and differentiation in preclinical models is essential to improve the therapeutic utility of HSCT. In this review, we link biomedical researchers and transplantation clinicians by discussing the potential therapeutic implications of recent fundamental HSC research in model organisms. We consider deficiencies in current HSCT practice, such as problems achieving adequate cell dose for successful and rapid engraftment, immense inflammatory cascade activation after myeloablation, and graft‐vs‐host disease. Furthermore, we discuss recent advances in the field of HSC biology and transplantation made in preclinical models of zebrafish, mouse, and nonhuman primates that could inform emerging practice for clinical application.

Profound but Transient Changes in the Inflammatory Milieu of the Blood During Autologous Hematopoietic Stem Cell Transplantation

Little is known about the inflammatory milieu in the blood during autologous hematopoietic stem cell transplantation (AHSCT) and how it is affected by the stem cell mobilization, collection, and reinfusion and conditioning regimen. In this study, we analyzed 92 proteins connected to inflammation at 10 time points during and after AHSCT in 16 patients with multiple sclerosis (MS). Serum from 29 patients with newly diagnosed MS and 15 healthy controls were included for comparative analysis. There were no significant differences in inflammatory serum protein levels between patients with newly diagnosed MS and healthy controls, but 29 out of 73 detectable proteins were significantly altered between at least 2 adjacent sampling time points during AHSCT. The predominant changes occurred after the conditioning regimen had been administered, whereas stem cell mobilization, collection, and reinfusion appeared to have less impact. Two distinct response patterns could be discerned, likely representing loss of basal cytokine production and homeostasis. The analyzed serum proteins gradually returned to baseline levels after treatment, with no remaining differences at 3 months after AHSCT. We conclude that treatment with AHSCT has a major but transient impact on the inflammatory milieu of peripheral blood.

Protein dysregulation in graft versus host disease

Allogeneic hematopoietic stem cell transplantation is a well-established treatment for many malignant and non-malignant hematological disorders. As a frequent complication in up to 50% of all patients, graft-versus-host disease is still the main cause for morbidity and non-relapse mortality. Diagnosis is usually done clinically, even though confirmation by pathology is often used to support the clinical findings. Effective treatment requires intensified immunosuppression as early as possible. Although several promising biomarkers have been proposed for an early diagnosis, no internationally-recognized consensus has yet been established. Protein-based biomarkers represent an interesting tool since they have been recently reported to be an important regulator of various cells, including immune cells such as T cells. Therefore, we assume that protein dysregulation is important in the pathogenesis of acute graft versus host disease and their detection might be an possibility in the early diagnosis and monitoring. In this review, we aim to summarize the previous reports of protein biomarkers, focusing on the pathogenesis of the disease and possible implications in diagnostic approaches.

The clinical value of biomarkers in respiratory complications in hematopoietic SCT

To determine the role of biomarkers in the clinical management of respiratory complications (RC) in hematopoietic stem cell transplantation (HSCT) recipients, we have prospectively evaluated a cohort of 175 patients followed-up for 1 year after HSCT. To avoid misinterpretation, we have excluded both unidentified respiratory infections (RI) and mixed RI. A total of 64 RC were included. Plasma levels of C-reactive protein (CRP), procalcitonin (PCT) and proadrenomedullin (proADM) were measured at diagnosis and on day 3 and 7. Different cytokines were evaluated in serum on the first day. No HSCT recipients without RC were included as a control group. Compared with RI, non-infectious RC showed a significant increase in CRP, proADM and interleukin 6 on day 0 (P=0.005; P=0.03 and P=0.04, respectively). When only RI were considered, we observed that bacterial–fungal PI showed higher levels of CRP (P=0.02), PCT (P=0.04) and proADM (P<0.01). Persistent low levels of proADM biomarkers suggest viral infection (specificity and positive predictive value 100%). Patients dying of RC had PCT and proADM levels higher than survivors (P=0.002 and P=0.03, respectively). In HSCT recipients biomarkers increase in both infectious and non-infectious RC. They may have utility in the assessment of the severity of RC and in suspecting a viral etiology.

Impact of pre-transplant pulmonary infection developed in horizontal laminar flow unit on the outcome of subsequent allogeneic hematopoietic stem cell transplantation

BACKGROUND

So far, there is very little literature on how pre-transplant pulmonary infection developed in horizontal laminar flow unit (HLFU) affects outcomes of allogeneic hematopoietic stem cell transplantation (allo-HSCT).

METHODS

A retrospective analysis was performed on allo-HSCT recipients who were diagnosed with pre-transplant pulmonary infection developed in HLFU between January 2012 and December 2012. Various tests were analyzed to evaluate the overall survival (OS) and pulmonary infection rate after allo-HSCT.

RESULTS

Among 317 patients who received allo-HSCT from related donors, 7 cases of human leukocyte antigen (HLA)-haploidentical transplantation reported a fever, cough, and other symptoms before transplantation. Chest radiography findings showed pulmonary infection, and the C-reactive protein (CRP) level was higher than normal, which confirmed pulmonary infection (incidence rate 2.21%). The Breslow test suggested that the early survival rate was lower in the group with pre-transplant pulmonary infection than in the group without pre-transplant pulmonary infection (OS: 28.4 vs. 42.4 months; P=0.023); the early survival rate was lower in patients with a pulmonary infection accompanied by bilateral pleural effusion than in patients without pleural effusion (OS: 1.5 vs. 36.3 months; P=0.010). In the first month after transplantation, the difference in the CD4CD45RO+CD45RA- and CD4CD45RO-CD45RA+ between the groups with and without pre-transplant pulmonary infection was statistically significant (P<0.05). Patients with pre-transplant pulmonary infection who survived >3 years had a higher rate of pulmonary infection in the first 2 months after allo-HSCT than those without pre-transplant pulmonary infection [100% (5/5 patients) vs. 38.1% (118/310); χ(2)=5.542, P=0.019].

CONCLUSIONS

Development of pre-transplant pulmonary infection in the HLFU in patients with hematological malignancies who receive HLA-haploidentical HSCT is associated with an increased risk of recurrent pulmonary infection in the early period after transplantation; however, there is no impact on patients' long-term survival rate.

MicroRNAs as biomarkers for graft-versus-host disease following allogeneic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (HCT) is a well-established treatment for many malignant and non-malignant hematological disorders. As frequent complication in up to 50 % of all patients, graft-versus-host disease (GVHD) is still the main cause for morbidity and non-relapse mortality. Diagnosis of GVHD is usually done clinically, even though confirmation by pathology is often used to support the clinical findings. Effective treatment requires intensified immunosuppression as early as possible. Although several promising biomarkers have been proposed for an early diagnosis, no internationally recognized consensus has yet been established. Here, microRNAs (miRs) represent an interesting tool since miRs have been recently reported to be an important regulator of various cells, including immune cells such as T cells. Therefore, we could assume that miRs play a key role in the pathogenesis of acute GVHD, and their detection might be an interesting possibility in the early diagnosis and monitoring of acute GVHD. Recent studies additionally demonstrated the implication of miRs in the pathogenesis of acute GVHD. In this review, we aim to summarize the previous reports of miRs, focusing on the pathogenesis of acute GVHD and possible implications in diagnostic approaches.