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.

Prognostic Role of Cell Blood Count in Chronic Myeloid Neoplasm and Acute Myeloid Leukemia and Its Possible Implications in Hematopoietic Stem Cell Transplantation

Numerous prognostic indexes have been developed in hematological diseases based on patient characteristics and genetic or molecular assessment. However, less attention was paid to more accessible parameters, such as neutrophils, lymphocytes, monocytes, and platelet counts. Although many studies have defined the role of neutrophil-to-lymphocyte or platelet-to-lymphocyte in lymphoid malignancies, few applications exist for myeloid neoplasm or hematopoietic stem cell transplantation procedures. In this review, we synthesized literature data on the prognostic value of count blood cells in myeloid malignancies and hematopoietic stem cell transplantation in the context of classical prognostic factors and clinical outcomes.

Early reconstitution of lymphocytes after allogenic hematopoietic stem cell transplantation affects chronic graft-versus-host disease

BACKGROUND

Lymphocyte reconstitution after hematopoietic stem cell transplantation (HSCT) is important for the prevention of infections, as well as for the reduction of recurrence, by its graft versus tumor effect. However, these lymphocytes may also play a role in the development of graft-versus-host disease (GVHD). Few studies have investigated the association between lymphocyte reconstitution and clinical outcomes after HSCT.

METHODS

This issue was investigated by retrospectively analyzing pediatric patients who received their first allogeneic-HSCT using a newly developed parameter, the LD-index, which evaluates both the intensity and duration of lymphopenia. A total of 101 patients underwent allo-HSCT from April 2007 to August 2019 in our hospital. Excluding patients who died before lymphocyte recovery or underwent multiple HSCT, 78 patients were analyzed for associations between the LD-index with various factors relating to HSCT.

RESULTS

A significantly high association was observed between a low LD-index and the incidence of chronic GVHD (P = 0.0019). Analysis of predictive factors for chronic GVHD was carried out using univariate analysis. Lower LD-index, donor source and duration of lymphopenia were found to be significant factors associated with chronic GVHD. Multivariate analysis, however, only identified an association between a lower LD-index and an increased incidence of chronic GVHD (P = 0.00081).

CONCLUSIONS

Early reconstitution of lymphocytes after allo-HSCT is associated with a higher incidence of chronic GVHD.

The microbiome and human cancer

Microbial roles in cancer formation, diagnosis, prognosis, and treatment have been disputed for centuries. Recent studies have provocatively claimed that bacteria, viruses, and/or fungi are pervasive among cancers, key actors in cancer immunotherapy, and engineerable to treat metastases. Despite these findings, the number of microbes known to directly cause carcinogenesis remains small. Critically evaluating and building frameworks for such evidence in light of modern cancer biology is an important task. In this Review, we delineate between causal and complicit roles of microbes in cancer and trace common themes of their influence through the host's immune system, herein defined as the immuno-oncology-microbiome axis. We further review evidence for intratumoral microbes and approaches that manipulate the host's gut or tumor microbiome while projecting the next phase of experimental discovery.

Natural killer cell-based immunotherapy for acute myeloid leukemia

Despite considerable progress has been achieved in the treatment of acute myeloid leukemia over the past decades, relapse remains a major problem. Novel therapeutic options aimed at attaining minimal residual disease-negative complete remission are expected to reduce the incidence of relapse and prolong survival. Natural killer cell-based immunotherapy is put forward as an option to tackle the unmet clinical needs. There have been an increasing number of therapeutic dimensions ranging from adoptive NK cell transfer, chimeric antigen receptor-modified NK cells, antibodies, cytokines to immunomodulatory drugs. In this review, we will summarize different forms of NK cell-based immunotherapy for AML based on preclinical investigations and clinical trials.

Association of the areas over and under the lymphocyte curve with cytomegalovirus reactivation after allogeneic hematopoietic stem cell transplantation

BACKGROUND

We retrospectively compared the impact of the areas over and under the lymphocyte curve (L_AOC vs L_AUC) on cytomegalovirus (CMV) reactivation after allogeneic hematopoietic stem cell transplantation (HSCT).

METHODS

Among 394 consecutive patients who underwent their first allogeneic HSCT at our center between 2007 and 2018, 301 patients met the inclusion criteria. L_AOC was calculated as the area over the lymphocyte curve during lymphopenia (absolute lymphocyte count [ALC] <700/μL). We calculated L_AOC and L_AUC from day 0 to day 15 (L_AOC15, L_AUC15) and from day 0 to day 30 (L_AOC30, L_AUC30).

RESULTS

CMV antigenemia was defined as more than 3 cells/2 slides by the C10/11 method and detected in 204 cases (CMV reactivation) at a median of 39 days after HSCT. Although there were significant differences in L_AOC15, L_AOC30, L_AUC15, and L_AUC30 between patients with and without CMV reactivation, there was no difference in accuracy for predicting CMV reactivation between L_AOC and L_AUC. In a multivariate analysis, L_AOC15 and L_AUC15 were each identified as independent predictive factors for CMV reactivation, along with advanced age and CMV serostatus. However, ALC at day 14 or day 21 was as accurate as area-based indexes such as L_AOC15 and L_AUC15. L_AOC15 and L_AUC15 were significantly associated with longer duration of anti-CMV antiviral therapy while ALC was not.

CONCLUSIONS

L_AOC15 and L_AUC15 had similar impacts on CMV reactivation. Although these area-based indexes were not superior to ALC for predicting CMV reactivation, they might predict patients who need longer duration of antiviral therapy more accurately.

Prospective phase 2 trial of ixazomib after nonmyeloablative haploidentical peripheral blood stem cell transplant

Proteasome inhibition results in extensive immunomodulatory effects that augment natural killer cell cytotoxicity and inhibit aspects of T-cell, B-cell, and dendritic cell function. We performed a phase 2 study that examined the effects of ixazomib for graft-versus-host disease (GVHD) prophylaxis (up to 12 cycles) with posttransplant cyclophosphamide and tacrolimus after standard nonmyeloablative haploidentical donor transplantation (HIDT). Ixazomib was started on day +5 (4 mg on days 1, 8, and 15 of a 28-day cycle), with dose reductions allowed in future cycles for toxicity. All patients received peripheral blood stem cells. Twenty-five patients were enrolled with a median age of 62 years (range, 35-77 years) who had acute leukemia (4), myelodysplastic syndrome (7), non-Hodgkin lymphoma/Hodgkin lymphoma/chronic lymphocytic leukemia (8), and myeloma (6). The hematopoietic cell transplant comorbidity index was ≥3 in 68% of the patients. After a median follow-up of 33.5 months, the cumulative incidence of relapse/progression at 1 year was 24% and 44% at 3 years, which failed to meet the statistically predefined goal of decreasing 1-year risk of relapse. Engraftment occurred in all patients with no secondary graft failure, and 3-year nonrelapse mortality (NRM) was 12%. Cumulative incidence of grade 3 to 4 acute GVHD was 8%, whereas moderate-to-severe chronic GVHD occurred in 19%. Nineteen patients survive with an estimated 1-year overall survival (OS) of 84% and 3-year OS of 74%. Hematologic and cutaneous toxicities were common but manageable. The substitution of ixazomib for mycophenolate mofetil (MMF) post-HIDT results in reliable engraftment, comparable rates of clinically significant GVHD, relapse and NRM, and favorable OS. This trial was registered at www.clinicaltrials.gov as # NCT02169791.

Prospective validation of the L-index reflecting both the intensity and duration of lymphopenia and its detailed evaluation using a lymphocyte subset analysis after allogeneic hematopoietic stem cell transplantation

We prospectively validated the previously reported L-index, which reflects both the intensity and duration of lymphopenia, and further evaluated it using a lymphocyte subset analysis after allogeneic hematopoietic stem cell transplantation (HSCT) (n = 30). The L-index was defined as the area over the lymphocyte curve during lymphopenia (<700/μl), and calculated from the start of conditioning to day30 (L-index(30)) and day100 (L-index(100)). The lymphocyte subset including CD3, CD4, CD8, CD19 and CD56 was analyzed before and at 14, 21, 28, 42, 56, 70, and 84 days after HSCT. Cytomegalovirus (CMV) antigenemia was detected as >3 cells/2 slides by the C10/11 method in 21 cases (CMV-AG ≥3 group) at a median of 34 days. L-index(30) was significantly higher in the CMV-AG ≥3 group than in the CMV-AG <3 group (median 20,358 vs 17,235, P = .028). Recovery of the CD4+ and CD56+ cell counts between days 14 and 28 after HSCT was impaired in the CMV-AG ≥3 group. Regarding graft-versus-host disease (GVHD), grade II-IV acute GVHD was identified in 14 patients (GVHD group) at a median of 31 days. L-index(30) was significantly lower in the GVHD group (median 19,048 vs 22,256, P = .043). Recovery of CD3+ cells including both CD4+ and CD8+ cells between days 14 and 28 tended to be better in the GVHD group. In conclusion, L-index(30) was significantly associated with CMV reactivation and grade II-IV acute GVHD, but its clinical significance seemed to differ according to the results of a lymphocyte subset analysis.

Maintenance Therapy With Interleukin-2 for Childhood AML: Results of ELAM02 Phase III Randomized Trial

Despite significant progress in the treatment of pediatric acute myeloblastic leukemia (AML), relapse remains the commonest cause of death. Randomized ELAM02 trial questioned if maintenance therapy with interleukin-2 (IL2), for 1 year, improves disease-free survival (DFS). Patients aged 0 to 18 years, with newly diagnosed AML (excluding patients with acute promyelocytic leukemia or down syndrome AML) were enrolled. They received 1 course of induction treatment (cytarabine and mitoxantrone) and 3 courses of consolidation treatment (high-dose cytarabine in courses 1 and 3). According to the cytogenetics risk, patients not undergoing hematopoietic stem cell transplantation, still in complete remission (CR) after the third course of consolidation treatment, were eligible for randomization to 1 year of maintenance therapy with monthly courses of IL2 or no maintenance treatment. There were 438 evaluable patients, 154 of whom were randomized to the IL2/no maintenance groups. Relapse occurred in 28 patients from the IL2+ group and 29 patients in the IL2- group. Survival was similar in the 2 groups, with a 4-year DFS of 62% without IL2 and 66% with IL2 (P = 0.75). In the CBF population, 4-year DFS was 55% without IL2 and 78% with IL2 (P = 0.07). No deaths from toxicity or excess of serious adverse events related to IL2 treatment were recorded. Prolonged IL2 for maintenance therapy after intensive chemotherapy is feasible and safe in pediatric AML patients in their first CR. Such treatment did not improve DFS in this study, but a positive trend was observed in favor of IL2 maintenance therapy among core binding factor acute myeloblastic leukemia.

Early CD8+-recovery independently predicts low probability of disease relapse but also associates with severe GVHD after allogeneic HSCT

In this single-center study we retrospectively evaluated the impact of early reconstitution of different lymphocyte subsets on patient outcomes after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We found that CD8+ T-cell counts exceeding 50x10(6)/l as early as on day 28 post-transplantation correlated significantly with decreased relapse risk, with three-year relapse rates of 17.0% and 55.6% (P = 0.002), but were also associated with severe acute and chronic GVHD. Incidence of grade III-IV acute GVHD was 30.5% for those with early CD8+ T-cell recovery compared to 2.1% for those with lower CD8+ T-cell counts on day 28 post-transplant (HR = 20.24, P = 0.004). Early CD8+ T-cell reconstitution did not, however, affect the overall survival. Multivariate analysis showed that slow CD8+ T-cell reconstitution was strongly associated with increased risk of relapse (HR = 3.44, P = 0.026). A weaker correlation was found between CD4+ reconstitution and relapse-risk, but there was no such association with CD19+ B-cells or NK-cells. In conclusion, the early CD8+ T-cell recovery on day 28 post-transplant is associated with the lower risk of relapse but also predicts the impending severe GVHD, and thus could be useful in guiding timely treatment decisions.

Nutritional Support from the Intestinal Microbiota Improves Hematopoietic Reconstitution after Bone Marrow Transplantation in Mice

Bone marrow transplantation (BMT) offers curative potential for patients with high-risk hematologic malignancies, but the post-transplantation period is characterized by profound immunodeficiency. Recent studies indicate that the intestinal microbiota not only regulates mucosal immunity, but can also contribute to systemic immunity and hematopoiesis. Using antibiotic-mediated microbiota depletion in a syngeneic BMT mouse model, here we describe a role for the intestinal flora in hematopoietic recovery after BMT. Depletion of the intestinal microbiota resulted in impaired recovery of lymphocyte and neutrophil counts, while recovery of the hematopoietic stem and progenitor compartments and the erythroid lineage were largely unaffected. Depletion of the intestinal microbiota also reduced dietary energy uptake and visceral fat stores. Caloric supplementation through sucrose in the drinking water improved post-BMT hematopoietic recovery in mice with a depleted intestinal flora. Taken together, we show that the intestinal microbiota contribute to post-BMT hematopoietic reconstitution in mice through improved dietary energy uptake.

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

Immune reconstitution affects clinical outcomes after allogeneic hematopoietic stem cell transplantation (HSCT), and it has been suggested that lymphocyte recovery affects survival after HSCT. However, few studies have examined lymphocyte recovery in Asian patients who received mycophenolate mofetil (MMF) prophylaxis for graft-versus-host disease. We retrospectively evaluated early lymphocyte recovery after HSCT among Japanese adults who received MMF prophylaxis. Patients were divided into two groups according to their median absolute lymphocyte count (ALC) on day 28 after HSCT as follows: the "low ALC group" (≤ 0.22 × 10⁹ cells/L) and the "high ALC group" (> 0.22 × 10⁹ cells/L). With a median follow-up of 317 days, the high ALC group showed significantly better overall survival than the low ALC group (at 1 year: 62 vs. 46%, P = 0.02). The high ALC group also tended to have better non-relapse mortality than the low ALC group (at 1 year: 13 vs. 23%, P = 0.08). There was no significant difference in relapse rate between the high and low ALC groups (at 1 year: 29 vs. 35%, P = 0.2). We conclude that among Japanese patients who received MMF prophylaxis, ALC on day 28 after HSCT was effective in predicting overall survival and non-relapse mortality.

T Cell Depletion as an Alternative Approach for Patients 55 Years or Older Undergoing Allogeneic Stem Cell Transplantation as Curative Therapy for Hematologic Malignancies

T cell-depleted (TCD) allogeneic hematopoietic stem cell transplantation (HSCT) is curative treatment for hematologic malignancies in adults, shown to reduce graft-versus-host disease (GVHD) without increased relapse. We retrospectively reviewed a single-center, 11-year experience of 214 patients aged ≥ 55 years to determine tolerability and efficacy in the older adult. Most patients (70%) had myeloid diseases, and most acute leukemias were in remission. Median age was 61 years, with related and unrelated donors ≥8/10 HLA matched. Hematopoietic cell transplantation-specific comorbidity index scores were intermediate and high for 84%. Conditioning regimens were all myeloablative. Grafts were peripheral blood stem cells (97%) containing CD3 dose ≤103-4/kg body weight, without pharmacologic GVHD prophylaxis. With median follow-up of 70 months among survivors, Kaplan-Meier estimates of overall and relapse-free survival were 44% and 41%, respectively (4 years). Cumulative incidence of nonrelapse mortality at day +100 was only 10%. Incidence of GVHD for acute (grades II to IV) was 9% at day +100 and for chronic was 7% at 2 and 4 years (8 extensive, 1 overlap). Median Karnofsky performance status for patients > 2 years post-transplant was 90%. As 1 of the largest reports for patients ≥2 aged ≥55 years receiving TCD HSCTs, it demonstrates curative therapy with minimal GVHD, similar to that observed in a younger population.

Lymphocyte recovery is an independent predictor of relapse in allogeneic hematopoietic cell transplantation recipients for acute leukemia

AIM

To examine the optimal absolute lymphocyte count (ALC) cut-off utilizing receiver operator characteristics (ROC) in addition to graft characteristics associated with early ALC recovery.

METHODS

Patients who received T-cell replete peripheral hematopoietic cell transplantation (HCT) for acute leukemia were identified. ALC cut-off was established using ROC analysis and subsequently the cohort was stratified. Time to endpoint analysis and cox regression modelling was computed to analyze outcomes.

RESULTS

A total of 72 patients met the inclusion criteria and were analyzed. Optimal ALC cut-off was established to be on day 14 (D14) with ALC > 0.3 × 10⁹/L. At 2 years, cumulative incidence of relapse was 16.9% vs 46.9% (P = 0.025) for early and delayed lymphocyte recovery cohorts, respectively. Chronic graft vs host disease was more prevalent in the early lymphocyte recovery (ELR) group at 70% vs 27%, respectively (P = 0.0006). On multivariable analysis for relapse, ELR retained its prognostic significance with HR = 0.27 (0.05-0.94, P = 0.038).

CONCLUSION

ELR is an independent predictor for relapse in patients receiving allogeneic HCT for acute leukemia. ELR was influenced by graft characteristics particularly CD34 count.

Optimal Threshold and Time of Absolute Lymphocyte Count Assessment for Outcome Prediction after Bone Marrow Transplantation

The recovery pace of absolute lymphocyte count (ALC) is prognostic after hematopoietic stem cell transplantation. Previous studies have evaluated a wide range of ALC cutoffs and time points for predicting outcomes. We aimed to determine the optimal ALC value for outcome prediction after bone marrow transplantation (BMT). A total of 518 patients who underwent BMT for acute leukemia or myelodysplastic syndrome between 1999 and 2010 were divided into a training set and a test set to assess the prognostic value of ALC on days 30, 60, 90, 120, 180, as well as the first post-transplantation day of an ALC of 100, 200, 300, 400, 500, and 1000/μL. In the training set, the best predictor of overall survival (OS), relapse-free survival (RFS), and nonrelapse mortality (NRM) was ALC on day 60. In the entire patient cohort, multivariable analyses demonstrated significantly better OS, RFS, and NRM and lower incidence of graft-versus-host disease (GVHD) in patients with an ALC >300/μL on day 60 post-BMT, both including and excluding patients who developed GVHD before day 60. Among the patient-, disease-, and transplant-related factors assessed, only busulfan-based conditioning was significantly associated with higher ALC values on day 60 in both cohorts. The optimal ALC cutoff for predicting outcomes after BMT is 300/μL on day 60 post-transplantation.