Early lymphocyte recovery predicts clinical outcome after HSCT with mycophenolate mofetil prophylaxis in the Japanese population

Early reversal of the lymphocyte-to-monocyte ratio after allogeneic-hematopoietic stem cell transplantation is associated with reduced relapse and improved prognosis

BACKGROUND

The early recovery of lymphocyte and monocyte cells is associated with a favorable prognosis after allogeneic stem cell transplantation (allo-HSCT); however, it is not clear whether the balance of lymphocyte and monocyte recovery affects the post-transplant prognosis.

METHODS

We examined whether the time-point at which the number of lymphocytes exceeded the number of monocytes, which we termed lymphocyte-to-monocyte ratio reversal (LMRR), affected the prognosis after allo-HSCT. We retrospectively evaluated 235 patients who underwent their first allo-HSCT at our institution.

RESULTS

The median number of days from HSCT to LMRR was 46 (range, 0-214), and the patients were divided into two groups according to the occurrence of LMRR by day 45 (LMRR45). In a multivariate analysis, early LMRR contributed favorably to overall survival (hazard ratio [HR] .519; 95% confidence interval [CI] .332-.812; p = .004) with fewer post-transplant relapses (HR .462; 95% CI, .274-.777; p = .004). Differences in the timing of LMRR did not affect non-relapse mortality (HR 1.477; 95% CI .779-2.80; p = .23) or the incidence of grade II-IV acute GVHD (LMRR45(+): 25.0% vs. LMRR45(-) 35.2%. p = .111). In subgroup analyses, LMRR45(+) was found to be a favorable factor for survival with less relapse, regardless of the disease risk, stem cell source, or the recovery of either lymphocyte or monocyte counts.

CONCLUSIONS

An early LMRR may be a novel factor that is associated with reduced relapse and improved survival after allo-HSCT.

Prognostic impact of the simple L-index and absolute lymphocyte count early after allogeneic hematopoietic stem cell transplantation

BACKGROUND AIMS

The L-index, designed as a quantitative parameter to simultaneously assess the duration and severity of lymphopenia, and absolute lymphocyte count (ALC) have a prognostic impact after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, discrepancies have been reported in the impact of ALC, and limited information is currently available on the L-index.

METHODS

To search for a better clinical tool, the authors retrospectively compared the simple L-index at 30 days (sL-index(30)), which aims to make the original L-index more compact, and ALC at 30 days (ALC(30)) after allo-HSCT in 217 patients who underwent allo-HSCT at the authors' institutions.

RESULTS

Median sL-index(30) was 11 712 (range, 4419-18 511) and median ALC(30) was 404 (range, 0-3754). In a multivariate analysis, higher sL-index(30) was associated with a significantly higher cumulative incidence of relapse (CIR) (hazard ratio [HR], 1.01, 95% confidence interval [CI], 1.00-1.02, P = 0.02 for every increase of 100 in sL-index(30)) as well as non-relapse mortality (NRM) (HR, 1.02, 95% CI, 1.00-1.03, P = 0.01 for every increase of 100 in sL-index(30)). Although higher ALC(30) was associated with significantly lower CIR (HR, 0.94, 95% CI, 0.89-1.00, P = 0.04 for every increase of 100/μL in ALC(30)), it was not extracted as an independent risk factor for NRM (HR, 0.96, 95% CI, 0.88-1.05, P = 0.39). Higher sL-index(30) was associated with a slightly higher rate of grade 3-4 acute graft-versus-host disease (GVHD) (HR, 1.02, 95% CI, 1.00-1.04, P = 0.12 for every increase of 100 in sL-index(30)) but not chronic GVHD (HR, 1.00, 95% CI, 0.99-1.01, P = 0.63). ALC(30) was not associated with rates of grade 3-4 acute GVHD (HR, 1.02, 95% CI, 0.88-1.17, P = 0.81) or chronic GVHD (HR, 1.02, 95% CI, 0.98-1.06, P = 0.34). In a receiver operating characteristic curve, the cutoff values of sL-index(30) and ALC(30) for CIR were 9000 and 500, respectively, and the cutoff value of sL-index(30) for NRM was 12 000.

CONCLUSIONS

sL-index(30) is a promising tool that may be applied to various survival outcomes. A large-scale prospective study is needed to clarify whether medical interventions based on sL-index(30) values will improve the clinical prognosis of patients.

The Composite Immune Risk Score predicts overall survival after allogeneic hematopoietic stem cell transplantation: A retrospective analysis of 1838 cases

There has been little consensus on how to quantitatively assess immune reconstitution after hematopoietic stem cell transplantation (HSCT) as part of the standard of care. We retrospectively analyzed 11 150 post-transplant immune profiles of 1945 patients who underwent HSCT between 2012 and 2020. 1838 (94.5%) of the cases were allogeneic HSCT. Using the training set of patients (n = 729), we identified a composite immune signature (integrating neutrophil, total lymphocyte, natural killer, total T, CD4+ T, and B cell counts in the peripheral blood) during days 91-180 after allogeneic HSCT that was predictive of early mortality and moreover simplified it into a formula for a Composite Immune Risk Score. When we verified the Composite Immune Risk Score in the validation (n = 284) and test (n = 391) sets of patients, a high score value was found to be associated with hazard ratios (HR) of 3.64 (95% C.I. 1.55-8.51; p = .0014) and 2.44 (95% C.I., 1.22-4.87; p = .0087), respectively, for early mortality. In multivariate analysis, a high Composite Immune Risk Score during days 91-180 remained an independent risk factor for early mortality after allogeneic HSCT (HR, 1.80; 95% C.I., 1.28-2.55; p = .00085). In conclusion, the Composite Immune Risk Score is easy to compute and could identify the high-risk patients of allogeneic HSCT who require targeted effort for prevention and control of infection.

Human cytomegalovirus infection: A considerable issue following allogeneic hematopoietic stem cell transplantation

Cytomegalovirus (CMV) is an opportunistic virus, whereby recipients are most susceptible following allogeneic hematopoietic stem cell transplantation (allo-HSCT). With the development of novel immunosuppressive agents and antiviral drugs, accompanied with the widespread application of prophylaxis and preemptive treatment, significant developments have been made in transplant recipients with human (H)CMV infection. However, HCMV remains an important cause of short- and long-term morbidity and mortality in transplant recipients. The present review summarizes the molecular mechanism and risk factors of HCMV reactivation following allo-HSCT, the diagnosis of CMV infection following allo-HSCT, prophylaxis and treatment of HCMV infection, and future perspectives. All relevant literature were retrieved from PubMed and have been reviewed.

Immune reconstitution following hematopoietic stem cell transplantation using different stem cell sources

Introduction: Adequate immune reconstitution post-HSCT is crucial for the success of transplantation, and can be affected by both patient- and transplant-related factors. Areas covered: A systematic literature search in PubMed, Scopus, and abstracts of international congresses is performed to investigate immune recovery posttransplant. In this review, we discuss the pattern of immune recovery in the post-transplant period focusing on the impact of stem cell source (bone marrow, peripheral blood stem cells, and cord blood) on immune recovery and HSCT outcome. We examine the impact of serotherapy on immune reconstitution and the need to tailor dosing of serotherapy agents when using different stem cell sources. We discuss new techniques being used particularly with cord blood and haploidentical grafts to improve immune recovery in each scenario. Expert opinion: Cord blood T cells provide a unique CD4+ biased immune reconstitution. Initial studies using targeted serotherapy with cord grafts showed improved immune recovery with limited alloreactivity. Two competing haploidentical approaches have developed in recent years including TCRαβ/CD19 depleted grafts and post-cyclophosphamide haplo-HSCT. Both approaches have comparable survival rates with limited alloreactivity. However, delayed immune reconstitution is still an ongoing problem and could be improved by modified donor lymphocyte infusions from the same haploidentical donor.