Early Absolute Lymphocyte Count Recovery Research Articles

Absolute Lymphocyte Count Is an Independent Survival Predictor in Patients with Acute Myeloid Leukemia Treated with Intensive Chemotherapy

Background Absolute lymphocyte count (ALC)is known to be an independent prognostic factor for overall survival (OS) in patients receiving autologous transplantation for Hodgkin's and non-Hodgkin's lymphomas, multiple myeloma and breast cancer. In acute myeloid leukemia (AML) patients, enhanced ALC recovery after intensive chemotherapy (IC) has been associated with superior OS and leukemia-free survival (LFS). However, few if any data correlated ALC recovery with novel therapies as well as with updated prognostic factors, such as European Leukemia Net (ELN) risk-classification. Aims Our study aims at evaluating the predictive value of ALC recovery in newly diagnosed AML patients who obtained complete remission (CR) to IC by analysing its impact through different patient subgroups according to therapy response, type of chemotherapy regimen and the use of allogeneic stem cell transplantation (HSCT). Methods We evaluated 156 responsive AML patients treated with IC at Bologna Seràgnoli Hematology Institute since 2007. We defined 4 ALC time-points (TPs): at 15, 21 and 28 days from the start of induction chemotherapy and before consolidation therapy (CC). ALC cut-off was established at 500/mm3. In addition to the assessment of the single TP, patients were also grouped in those who obtained ≥500/mm3ALC in all 4 TPs and those who had<500/mm3ALC in at least one TP. Median follow-up was 65 months. Results When ALC recovery was assessed in whole population, both at single TPs and ALC recovery achievement at all TPS vs others, no statistically significant association with better OS and LFS has been shown. Then we subdivided patients according to IC regimen administered: "3+7-based" regimen (52,6%) versus those who were treated with "fludarabine-based" regimen (47,4%). Considering "3+7" patients, at TP day 15 a significant correlation with OS (p=0.047) of patients with ≥500/mm3ALC (34,6%) vs those who had<500/mm3ALC (17,9%) was observed (instead for ALC-21 p value was 0.078). A similar trend (p=0.021) was shown for those who obtained ≥500/mm3 ALC in all 4 TPs (27,5%) compared to those who had <500/mm3ALC in at least one TP (25%). Of note, FLT3-ITD positive patients in this subgroup, who achieved early ALC recovery at day 15 and at all 4 TPs assessment, had better outcomes, despite with p=0.27 and p=0.19 respectively, because of the meager number of patients. Among patients treated with "fludarabine-based" regimens, ALC recovery assessment did not show remarkable correlation with outcome, even when considering the NPM1 mutated subgroup. We, then, analysed in whole population the impact of post-chemotherapy ALC recovery in patients who received HSCT (63,5%) vs those who did not (36,5%) (Fig.1). As expected, transplanted patients had globally better outcome than patients who received only chemotherapy. In patients who received HSCT the impact of ALC recovery after chemotherapy was minimal (blue and purple curve). In contrast, patients who had ALC <500/mm3 ALC in at least one TP and did not undergo HSCT had the worst outcome (green curve). Interestingly, patients who were not transplanted but had ≥500/mm3ALC in all 4 TPs (red curve) had a better OS, comparable to transplanted patients. Conclusions Our study indicates ALC recovery after IC as a promising survival predictor in AML patients, especially in those who do not undergo HSCT. It is reasonable to underline the impact of fludarabine, as for its lymphocytolytic effect, in order to explain the different results in the subgroup fludarabine-based. The outcome trends in different prognostic subgroups according to ELN classification, such as FLT3, NPM1, adverse cytogenetics, need a caseload expansion. In the path that aims to investigate the complex interaction between leukemia and the immune system, our study may provide the clinical rationale for the construction of an immunological score to be integrated in the current disease-centered risk classification system. Future studies in larger cohorts addressing the impact of ALC recovery in association with the use of novel agents and minimal residual disease status are highly warranted. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Clinical impact of early recovery of peripheral blood absolute lymphocyte count after frontline autologous stem cell transplantation for diffuse large B-cell lymphoma.

We conducted a retrospective study to evaluate the clinical impact of an early recovery of posttransplant absolute lymphocyte count (ALC) on the outcome of frontline autologous stem cell transplantation (ASCT) for diffuse large B-cell lymphoma (DLBCL). We reviewed 65 DLBCL patients who underwent frontline ASCT after primary chemotherapy based on cyclophosphamide, doxorubicin, vincristine, and prednisone. A receiver operating characteristic analysis was performed to determine the optimal cut point (0.4×109 /L) for an ALC at 15days after ASCT (ALC-15). Both event-free survival and overall survival rates of the higher-ALC-15 group were significantly better than those of the lower-ALC-15 group (event-free survival, P=.008; overall survival, P=.013). The infused CD34+ cell count was significantly associated with the recovery of ALC-15 (>0.4×109 /L) after ASCT (P=.028). A multivariate analysis confirmed that a higher infused CD34+ cell dose (>5.0×106 cells/kg) was an independent factor affecting an early recovery of ALC after ASCT (odds ratio, 4.145; 95% confidence interval, 1.106-15.528; P=.035). In conclusion, an early recovery of ALC after ASCT can be regarded as a good prognostic marker in patients with DLBCL who have undergone frontline ASCT. We found that the infused CD34+ cell dose for ASCT was associated with the recovery of ALC.

Effect of Immune Reconstitution on Survival after Autologous Hematopoietic Cell Transplant for B-Cell Non-Hodgkin Lymphoma

Autologous hematopoietic cell transplant (AHCT) plays an important role in the treatment of B-cell Non-Hodgkin lymphoma (B-NHL), both in the upfront and relapsed/refractory settings. In addition to patient and disease-related factors (age, Charlson comorbidity index, disease status pre-AHCT, IPI score at AHCT and high-dose regimen), composition of the infused cell product (higher dendritic cell content, lymphocyte to monocyte ratio < 1) and immune reconstitution after AHCT have emerged as independent predictors of AHCT outcomes. Early absolute lymphocyte count recovery (ALC > 500 cells/μL by day +15 post AHCT) has previously been reported to correlate with superior progression-free survival (PFS) and overall survival (OS) in B-NHL. We conducted a prospective single institution study to further understand the effect of various immune cell subsets and recovery patterns on AHCT outcomes.A comprehensive immunophenotyping panel including 35 cell subsets was performed in a cohort of 120 consecutive B-NHL patients [Diffuse large B-cell lymphoma (DLBCL) 54%, Mantle cell lymphoma (MCL) 38%] who received AHCT between 1/2008 and 11/2014, at a median of 28 days before AHCT (N=120), and at day +100 (N=95) post-AHCT. Specifically, the immunophenotyping panel included total numbers of T cells, B cells, NK cells and dendritic cells; T cell subsets included the relative proportions of double positive (CD4+CD8+), double negative (CD4-CD8-), CD4+ and CD8+ naïve, CD4+ and CD8+ central memory, CD4+ and CD8+ effector memory, recent thymic emigrants, and T-regulatory cells; B cell subsets included proportions of naïve and memory cells. B-NHL response to AHCT, recovery of ALC by day +15 post-AHCT, PFS and OS were examined and correlated with various immune subsets.Characteristics in 120 patients pre-AHCT were: median age 59 (range 24-77) years; 71% males; 84% KPS ≥80; disease status pre-AHCT- CR1 43%, ≥CR2 32%, never in CR 13% and relapse ≥1 13%; mobilization regimens: plerixafor+G-CSF 40% and G-CSF alone 60%; high dose regimens: CBV 48% and BuCy 62%. 118 (98%) patients survived beyond day +100 post-AHCT. Day +100 responses: achieved or maintained CR: 83%, less than CR: 3%, disease progression: 15%. Median follow-up was 22.5 (3-42) months. The frequency of different immune subsets either pre-AHCT or at day +100 post-AHCT, PFS or OS were independent of disease histology (DLBCL/MCL) and use of plerixafor as part of mobilization. Unlike an earlier study (Porrata et al, BBMT, 2008), early ALC recovery (by peripheral blood differential count) was not associated with significantly improved PFS or OS in either the whole cohort or individual DLBCL/MCL cohorts. There was no correlation between pre-AHCT immune cell subsets and post-AHCT outcomes. Higher proportions of CD8 central memory (CM) or effector memory (EM) T-cells at day+ 100 post-AHCT were associated with worse PFS and OS (see figures 1 and 2). The frequencies of other immune cell subsets (including NK cells) at day +100 post-AHCT were not associated with attaining CR status post-AHCT, PFS or OS. Further analyses are ongoing to evaluate the association between immune cell subsets in the stem cell product and AHCT outcomes.This is the first study to examine detailed lymphocyte subsets following AHCT for B-NHL and report a correlation between higher levels of CD8 EM/CM T-cells and decreased PFS and OS after AHCT. Whether relative elevations in CD8 memory T cells directly contribute to disease progression after AHCT for B-NHL or are reflective of an underlying process related to disease progression is uncertain. However, our data suggest that frequency of CD8 memory cells could serve as a biomarker for high risk disease after AHCT for B-NHL. [Display omitted] [Display omitted] DisclosuresPaiva:Sanofi: Consultancy; Millennium: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Onyx: Consultancy; Binding Site: Consultancy; BD Bioscience: Consultancy; EngMAb AG: Consultancy. McCarthy:Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; The Binding Site: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees. Hahn:Novartis: Equity Ownership; NIH/NHLBI: Research Funding.

The impact of HBO on early ALC recovery following high-dose therapy and autologous transplantation.

7034 Background: Historically, early absolute lymphocyte count (ALC) recovery (defined as ALC of 500 cells/microL day 15 of transplant) is seen in around 50% of patients receiving autologous stem c...

Early Lymphocyte Recovery Predicts Superior Disease Free Survival and Overall Survival after High Dose Chemotherapy and Autologous Stem Cell Transplantation in Non-Hodgkin Lymphoma Patients

Introduction. An early absolute lymphocyte count (ALC) recovery after high dose therapy (HDT) and autologous hematopoietic stem cell transplantation (HSCT) in non Hodgkin lymphoma (NHL), Hodgkin lymphoma (HL), multiple myeloma and acute leukemia patients has been related with an improved outcome due to a better immune restoration. In this retrospective study we analyze a population of NHL patients to evaluate ALC recovery after autologous HSCT and its relation with post-transplant survival.Patients and methods. Fifty-three consecutive adult NHL patients received HDT followed by autologous HSCT in a single center between 2000 and 2012. Only individuals with at least 6 months post-transplant follow up were included. All patients received the same conditioning regimen (BEAM: carmustine, etoposide, cytarabine and melphalan) followed by peripheral blood stem cells previously collected by leukapheresis. Median CD34+ cell dose was 4.13 x 106/kg (1.62 – 12.58). Patients were divided into two groups: ALC at day +15 inferior than 500/mm3 (group 1) and ALC at day +15 superior or equal than 500/mm3 (group 2). Differences between groups were analyzed using t-Student and Chi-Square tests, with statistical significance determined at p<0.05. Progression-free survival (PFS) and overall survival (OS) were analyzed by Kaplan Meier method. Differences in survival between the two groups were determined by log-rank test.Results. No differences were observed between groups regarding gender, histology, disease status at transplant and cell dose. Patients into group 1 were older and more heavily pre-treated. Neutrophil and platelet engraftment were significantly faster in group 2 (Table 1). After a median follow-up of 56 months, progression-free survival (PFS) and overall survival (OS) were superior in group 2 patients. Median PFS was 47 months and not reached (p=0.013) and OS was 51 months and not reached (p=0.016) in groups 1 and 2 respectively (figures 1 and 2).Discussion. An early ALC recovery after autologous HSCT is associated with a better PFS and OS in NHL patients. Patients with ALC major or equal than 500/mm3 had a shorter time to neutrophil and platelet recovery and a shorter stay at transplant unit. In this study, CD34+ cell dose does not appears as a determinant factor for lymphocyte recovery. The extent of pre-transplant chemotherapy may influence ALC recovery after transplant. These results confirm the association between lymphocyte recovery and outcome in NHL patients after autologous HSCT. Table 1Patient characteristics and comparison between groups 1 and 2.Group 1Group 2pALC< 500 /mm3> 500/mm3N2528Age, median (range)57 (29 - 66)41 (15 - 65)0.008Female gender (n)1214NSHistology (n)DLBCL1316NSFollicular lymphoma62Mantle cell lymphoma32Peripheral T cell lymphoma13Indolent lymphoma12Others13Individuals who received two or more lines of pre-transplant treatment (n)1180.01Disease status at transplant (n)Complete remission711NSPartial remission1613Progressive disease21CD34+ cells dose, median (range) (10E6/kg)3.45 (1.62 - 9.12)4.40 (2.28 - 12.58)NSMononuclear cells dose, median (range) (10E8/kg)8,84 (3,55 - 18,74)6,7 (1,94 - 27)NSDays to achieve ANC > 500/mm3, median (range)11 (7 - 30)8 (3 - 16)0.034Days to achieve platelets > 20.000/mm3, median (range)9 (2 - 49)5 (1 - 10)0.003Length of stay in transplant unit, days, median (range)30 (20 - 59)24 (20 - 35)0.001 [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Analysis Of Immune Cell Populations Before and After Autologous Hematopoietic Stem Cell Transplant For Multiple Myeloma: Association With Early Recovery Of Absolute Lymphocyte Count and Progression-Free Survival

The treatment of transplant-eligible, multiple myeloma (MM) patients usually consists of induction therapy followed by autologous hematopoietic stem cell transplant (ASCT). In addition to typical cytogenetic and biochemical prognostic factors, there are other risk factors that predict for relapse and progression after ASCT. This includes absolute lymphocyte count (ALC) recovery (>0.5 cells/μL) by day +15 post ASCT, which has previously been shown to correlate with prolonged progression-free (PFS) and overall survival (OS). In a cohort of 70 MM patients who received high dose melphalan with ASCT between 8/2007 and 9/2012, we performed a comprehensive immunophenotyping panel including 35 T-, B-, NK- and Dendritic Cell (DC)-cell subsets a median of 25 days before ASCT (N=70), at day +30 post-ASCT (N=40) and at day +100 (N=51) post-ASCT. Specifically, the immunophenotyping panel included total numbers of T cells (CD3+, CD4+, CD8+), B cells (CD19+, CD20+), NK cells (CD56+CD16+) and myeloid (CD11c+) and plasmacytoid (CD123+) dendritic cells. T cell subsets included the relative proportions of double positive (CD3+CD4+CD8+), double negative (CD3+CD4-CD8-), CD4+ and CD8+ Naïve (CD3+ CD45RA+ CD45RO- CD27+), CD4+ and CD8+ central memory (CD3+ CD45RA- CD45RO+ CD27+), CD4+ and CD8+ effector memory (CD3+ CD45RA- CD45RO+ CD27-), recent thymic emigrants (CD3+ CD4+ CD45RA+ CD31+), and T-regulatory cells (CD3+ CD4+ CD25(br), CD3+CD4+CD25+CD127(d), CD3+CD4+CD25+CD127-HLADr+). B cell subsets included proportions of naïve (CD19+ CD27-), and memory (CD19+ CD27+, pre-switch CD19+ IgD+ CD27+, post-switch CD19+ IgD- CD27) cells. All patients survived to day +100. We examined MM response to ASCT, recovery of ALC by day +15 post-ASCT, clinically significant infections, PFS and OS. Characteristics in 70 patients pre-ASCT were: median (range) age 60 (28-75) yrs; 54% females; 26% KPS ≥90; response to most recent therapy was 13% in CR/sCR, 40% in VGPR, 41% in PR, 6% stable disease. MM responses at day + 100 included: 51% achieved or maintained CR/sCR, 17% VGPR, 10% PR, 24% SD and 6% progressed. The frequency of different immune cell subsets at either pre-ASCT or day +100 post-ASCT were not associated with CR/sCR status at day 100 post-AHSCT. ALC recovery by day +15 post-ASCT was associated with significantly longer median PFS (651 vs 288 days, P=0.001) and OS (804 vs 391 days, P=0.02) than those who did not recover ALC by day 15. For patients showing early recovery of ALC, the absolute numbers of T-cells pre-ASCT (P=0.08), as well as the proportion of CD4+ naïve (P=0.07) and CD8+ NK (CD8+/CD16+/CD56+, P=0.06) populations tended to be higher, whereas the absolute counts of gamma-delta T cells (P=0.02), CD4+ helper (P=0.03, See Figure), CD8+ effector (P=0.02) T-cells and total B-cell count (P=0.05) were significantly higher as compared to patients who did not achieve ALC recovery by day +15. Of note, within the T-cell compartment, CD4+ central memory (P=0.02, see Figure), CD8+ central memory (P=0.05), T-regulatory (T reg) (P=0.02, CD4+25+) populations were significantly lower. The distribution of different immune cell subsets pre-ASCT was not associated with development of clinically significant infections before day +100 post-AHCT; however, the proportion of memory B cells measured at day+100 was significantly higher (p=0.02) in patients who had experienced an infection before day +100. In the present study we show that the distribution of different immune cell populations correlates with ALC recovery in MM. Moreover, we also confirmed the association of ALC recovery with prolonged PFS and OS. The increase in the relative proportions of CD4+ and CD8+ effector cell subpopulations and the decrease in CD4+ and CD8+ central memory and T-reg populations demonstrate that the pre-ASCT effector cell phenotype contributes to faster ALC recovery, and improved PFS/OS. Therapeutic strategies to alter the pre-ASCT and/or day + 100 immune phenotype may improve outcomes after ASCT. [Display omitted] [Display omitted] Disclosures:McCarthy:Janssen: Honoraria; Celgene: Consultancy.

Measures of immune recovery following autologous stem cell transplantation for multiple myeloma and outcome.

8581 Background: Autologous stem cell transplant (ASCT) improves survival in patients with multiple myeloma (MM). Recent studies have elucidated the relationship in ASCT between absolute lymphocyte count (ALC) recovery and improved survival, highlighting the importance of immune recovery. We conducted a retrospective analysis of patients with multiple myeloma to observe the impact of different measures of immune recovery at day 100 post-ASCT on outcome. Methods: Retrospective analysis of data from the existing clinical databases identified 1184 patients with multiple myeloma that underwent ASCT at Mayo Clinic between 1987-2011. Markers of immune recovery analyzed on day 100 status-post ASCT included ALC, monocyte count, and immunoglobulin levels. Kaplan Meier analysis was performed to determine progression free survival (PFS) and overall survival (OS). Results: Among the 1184 patients, median age at diagnosis of multiple myeloma was 57 (range, 23-75 yr), and median age at time of transplantation was 59 (range, 24-75 yr); 59% were male. The median OS and PFS post-transplant were 80 months and 34 months respectively. 62% of patients were alive 5-years post-transplant. The median OS was not improved with normal vs. abnormal IgG levels at day 100 (p=.298). In contrast, monocyte recovery was a significant predictor of OS. Patients with normal monocyte counts of greater than 0.3 x 10⁹ cells/L at day 100 showed superior survival (65 vs. 37 months, p= .001). Similarly, patients with normal monocyte recovery at day 15 post-transplant showed a significant survival benefit (68 vs. 50 months, p=.007). Early ALC recovery, which has been shown to be a positive prognostic indicator at day 15 post-transplant, was not prognostic at day 100 (p= .960). Conclusions: The present study further elucidates prognostic indicators after ASCT for MM highlighting the importance of various markers of immune recovery. Immunoglobulin recovery was not associated with superior survival, while monocyte recovery at day 15 and day 100 post-transplant translated to an improved survival and requires further study. It may be hypothesized that early immune system reconstitution may have a positive effect against disease post-transplant.

Leukemia burden delays lymphocyte and platelet recovery after allo-SCT for AML

Lymphocyte and platelet recovery may influence outcomes of allo-SCT for treatment of AML. It is not clear, however, if this impact is independent of patient and transplant characteristics. To investigate this question, we evaluated the influence of pre- or post transplant factors on day +30 absolute lymphocyte count (ALC) and the speed of platelet engraftment. We studied 106 AML patients treated with fludarabine and melphalan reduced-intensity conditioning and allo-SCT. Twenty nine percent of patients were in CR at the initiation of the conditioning, 39% had active disease with circulating blasts and 32% had active disease without circulating blasts. The graft source was peripheral blood from a matched sibling donor in 55% and BM from a matched unrelated donor in 45%. Our data showed that the presence of circulating blasts before transplantation is significantly correlated with low post-SCT day +30 ALC and slow platelet engraftment. This finding suggests that the impact of early ALC and platelet recovery on transplant outcome may not be independent of disease status at transplantation.

High CD8+ lymphocyte dose in the autograft predicts early absolute lymphocyte count recovery after peripheral hematopoietic stem cell transplantation

Early lymphocyte recovery (ELR) after autologous peripheral hematopoietic stem cell transplantation (ASCT) is an independent predictor for survival in patients with hematological and non-hematological cancers. Sixty-five ASCT for hematological cancers were retrospectively analyzed to identify the factors associated with ELR and to assess the impact of different mobilization regimens on the pre-collection absolute lymphocyte count (ALC). The CD8+ lymphocyte dose in the autograft and the pre-mobilization ALC were independently associated with ELR (P < 0.001 and P = 0.008, respectively). CD8+ lymphocyte doses higher than 0.1 x 10(9)/kg were strongly associated with ELR [P < 0.001, odds ratio 25.22, 95% confidence interval (CI) 4.98-127.69] and this cutoff may be used to predict ELR (P = 0.001, area under the curve 0.75, 95% CI 0.62-0.88). Mobilization with granulocyte colony-stimulating factor (G-CSF) alone, the pre-collection ALC and the number of apheresis sessions were independently associated with the CD8+ lymphocyte dose (P = 0.04, P = 0.001, and P < 0.001, respectively). The number of aphereses was the variable with the strongest correlation to the CD8+ lymphocyte dose (r(s) = 0.68, P < 0.001). Median pre-mobilization ALC was higher than pre-collection ALC in the subgroup of patients without ELR mobilized with chemotherapy followed by G-CSF (1090 vs. 758 lymphocytes/microL; P < 0.001). This reduction was not significant in the subgroup with ELR mobilized with chemotherapy plus G-CSF (1920 vs. 1539/microL, respectively; P = 0.23). These results suggest that the CD8+ lymphocyte dose in the autograft is critical for ELR after ASCT and also demonstrates that mobilization with chemotherapy followed by G-CSF significantly decreases the pre-collection ALC, especially in patients with low pre-mobilization ALC.

Early Absolute Lymphocyte Count Recovery after Autologous Peripheral Hematopoietic Stem Cell Transplantation Depends on the Pre-Mobilization Absolute Lymphocyte Count and the Lymphocyte Dose in the Autograft.

Background: Early absolute lymphocyte count (ALC) recovery after autologous peripheral hematopoietic stem cell transplantation (ASCT) has been reported as an independent prognostic factor for overall survival and progression-free survival for patients with hematological and non-hematological cancers. Early immune reconstitution appears to have a protective effect against residual disease after ASCT.End points: Assessment of factors impacting on early ALC recovery after ASCT.Methods: Retrospective analysis of the ASCT procedures done between 2000 and 2007 in Hemorio. Early lymphocyte recovery (ELR) was defined as an ALC ≥500/μL at day 12 after ASCT.Results: A total of 53 of 66 consecutive ASCT (80,3%) were eligible for this study. Of the 53 ASCT, 9 were for lymphoma, 22 for multiple myeloma and 22 for acute myelogenous leukemia. Median age of the group was 34 years (range: 13–65). All patients except one were mobilized with chemotherapy plus granulocyte colony-stimulating factor (G-CSF). ELR was observed in 41% of the patients. Univariate analysis identified an association between the following factors and ELR: median pre-mobilization ALC (1920 vs 1060 lymphocytes/μL; p=0.003), pre-collection ALC (1637 vs 747 lymphocytes/μL; p<0.001), dose of leukocytes infused (1.21 x 109 vs 0.65 x 109 leukocytes/kg; p=0.002), dose of lymphocytes infused (0.26 x 109 vs 0.10 x 109 lymphocytes/kg; p<0.001), dose of CD4+ lymphocytes infused (0.075 x 109 vs 0.034 x 109 CD4+ lymphocytes/kg; p<0.001) and dose of CD8+ lymphocytes infused (0.11 x 109 vs 0.03 x 109 CD8+ lymphocytes/kg; p<0.001) were all higher in the ELR group. Patient diagnosis, number of previous cycles of chemotherapy and number of CD34+ cells collected were not correlated with ELR. Forward stepwise regression identified the pre-mobilization ALC and the number of lymphocytes in the autograft as factors related to ELR (p=0.013 and p<0.001; respectively). Multivariate analysis demonstrated that the lymphocyte dose in the graft can be predicted by the pre-collection ALC and the number of aphereses carried out (p<0.001 for both). Median pre-mobilization ALC was higher than pre-collection ALC (1335 vs 975 lymphocytes/μL respectively; p=0.013). This difference was most significant in the group of patients without ELR (1060 vs 747 lymphocytes/μL respectively; p=0.004). Among patients with ELR, the difference was not significant (1920 vs 1637 lymphocytes/μL respectively; p=0.53).Conclusions: These results indicate that ELR after ASCT depends on the pre-mobilization ALC and the lymphocyte dose in the autograft. The number of aphereses performed for stem cell collection and the pre-collection ALC predict the number of lymphocytes collected. Stem cell mobilization with chemotherapy and G-CSF significantly reduces the ALC at the time of collection, specially in patients with lower ALC at the time of the mobilization. Strategies to improve immunologic recovery may have an impact on the results of ASCT. [Display omitted]

Early Recovery of Absolute Lymphocyte Count (ALC) Is a Predictor of Long-Term Outcome Following Related Allogeneic Peripheral Blood Stem Cell Transplantation in Adults with AML/MDS.

Background: Early recovery of absolute lymphocyte count (ALC) is associated with improved outcomes following allogeneic and autologous stem cell transplantation for various hematological malignancies. The mechanism(s) underlying this observation is (are) unknown, but lymphocyte recovery may be a marker of immune reconstitution or graft-versus-leukemia activity. Objective: We assessed the incidence of early ALC recovery (defined as ALC ≥ 0.5 x 109/l by day+30) after peripheral blood stem cell transplantation (PBSCT) in recipients transplanted for AML or MDS and investigated its role as a potential prognostic marker for post PBSCT outcomes. Methods: We reviewed the cases of 110 consecutive patients who underwent first allogeneic PBSCT from related donors for a diagnosis of AML (n=92) or MDS (n=18) at the Princess Margaret Hospital (Toronto, Canada) between 2000 and 2007. All patients received related donor transplants (matched related, n=103; mismatched related, n=7) and were alive at day+30. The primary outcome measure was incidence of early ALC recovery at day +30 post PBSCT. Endpoints were overall survival (OS), non-relapse mortality (NRM) and relapse incidence (RI) after PBSCT according to day +30 ALC ≥ 0.5 x 109/l (high ALC group) or &lt; 0.5 x 109/l (low ALC group). Results: The cohort included 51 women and 59 men. Median age at PBSCT was 51.7 years (range 18–71 years). Myeloablative conditioning (MAC) was employed in 65 (59%) patients (TBI based, n=62; Busulfan based, n=3), and 45 (41%) received reduced intensity conditioning (RIC). Median follow-up for survivors was 32 months. ALC ≥ 0.5 x 109/l by day+30 was reached by 72 patients (66%). There was no association between recipients’ gender, age at PBSCT or type of conditioning regimen and the probability of attaining ALC ≥ 0.5 x 109/l by day+30. Two-year OS in the entire cohort was 61%. Two-year OS of the high ALC group was superior to that of the low ALC group (72% vs. 40%, p=0.0003) (Figure 1A). The high ALC group also had significantly lower NRM (16% vs. 35%, p=0.005) (Figure 1B) and RI (21% vs. 42%, p=0.003) compared to the low ALC group (Figure 1C). No association between early ALC recovery and the incidences of acute or chronic graft-versus-host disease or incidence of CMV reactivation was observed. On multivariate analyses, low ALC at day +30 (ALC &lt; 0.5 x 109/l) was an independent prognostic factor for inferior OS (p=0.02, HROS=2.27), higher RI (p= 0.01, HRRI=3.18), and higher NRM (p=0.03, HRNRM=2.1). Conclusion: In AML and MDS early lymphocyte recovery by day 30 is associated with improved OS. Failure to attain early ALC recovery may identify patients with higher risk of relapse and NRM after PBSCT. Figure 1. Comparison of transplant outcomes between groups with high and low ALC counts at day 30 in terms of survival (A), non-relapse (C). Figure 1. Comparison of transplant outcomes between groups with high and low ALC counts at day 30 in terms of survival (A), non-relapse (C).

Early lymphocyte recovery following autologous peripheral stem cell transplantation is associated with better survival in younger patients with lymphoproliferative disorders

Early absolute lymphocyte count (ALC) has become an important end point for engraftment in patients undergoing autologous peripheral stem cell transplantation (APSCT). In this retrospective study, we evaluate the prognostic significance of early recovery of ALC (≤0.5 cells × 109/l on or before day 15) following APSCT in predicting transplant outcome in 72 patients with lymphoproliferative disorders, including non-Hodgkin's lymphoma (n = 30), Hodgkin's lymphoma (n = 8) and multiple myeloma (n = 34). The median quantities of CD34+ stem cells and lymphocytes infused were 4.97 × 106/kg (range 0.64 – 11.7) and 11.3 × 107/kg (range 1.11 – 110) respectively. After a median follow-up of 18 months (range 2–68), 28 patients had experienced a relapse and 16 had died. Of the 72 patients, 27 (37%) demonstrated early recovery of ALC. Early recovery of ALC was strongly associated with long-term overall and disease-free survival in patients aged less than 50 years (P < 0.001). In both univariate and multivariate survival analyses, a shorter time from diagnosis to APSCT was associated with early recovery of ALC (P = 0.03). These findings indicate that early recovery of ALC may contribute to longer survival in younger patients with lymphoproliferative disorders. A shorter time from diagnosis to APSCT may favor recovery of ALC independent of the infused stem cell or lymphocyte doses.

Cellular Composition of Allogeneic and Autologous PBPC Grafts and Patient Engraftment.

We studied the influence of graft populations on the hematological recovery of PBPC transplants. The data shown is a retrospective study of 36 patients (median age 41, range 16–67) who underwent allogeneic transplant from HLA-matched siblings and 29 patients (median age 25, range 20–68) who underwent autologous PBPC transplants between June 2002 and July 2005. The cell populations studied were: total nucleated cells (TNC), CD34+ cells, T cells (CD3+) and NK cells (CD3−/CD56+). The hematological engraftment was evaluated by the following parameters: time to absolute neutrophil count (ANC)>0.5x109/L, platelets>20x109/L, absolute lymphocyte count (ALC)>0.5x109/L and ALC at day +15. The median cell doses infused in patients are summarised in Table 1Table 1-PBPC cell population infused per Kg of patient body weightTNC x 108CD34+ cells x 106T cells x 108NK cells x 106Allogeneic12.8 *7.53.236.83.6 – 30.7 **3.4 – 10.50.7 – 9.84.2 – 136.6Autologous123.263.5294.1– 51.02.2 – 7.00.1– 0.47.4 – 351*median **rangeSpearman correlation analysis showed for the allogeneic PBPC grafts, correlation between TNC and NK cells collected (p=0.002), whereas for the autologous grafts there was correlation between TNC and NK cells (p=0.000) and CD34+ cells (p=0.004) collected.To asses the importance of cell dose infused in the hematologic engraftment of the two patient groups, neutrophil, platelet and lymphocyte recovery was determined (Table 2).Table 2-Patient engraftmentDay to ANC>0.5x109/LDay to platelets>0.2x109/LDay to ALC>0.5x109/LALC day +15 cell/μlAllogeneic11 *12117158 – 15 **8 – 292 – 14190 – 4670Autologous11111211787 – 138 – 1810 – 21230 – 4410*median **rangeFor both groups of patients, engraftment occurred within the expected time and ALC day +15 cell/μl was different (median 715 cell/μl and 1178 cell/μl for allogeneic and autotransplanted patients respectively).For the allogeneic transplanted patients, Spearman correlation analysis showed that the dose of NK cells infused was significantly correlated with ALC at day +15 (p=0.021). There was also correlation between the time to platelets and ANC engraftment (p=0.008) and time to platelets engraftment and ALC at day +15 (p=0.046).For the autologous patients there was no correlation between cell populations of the grafts and the hematologic engraftment. Our data provide evidence that in allogeneic transplants the NK dose influences early ALC recovery. However, it is important to continue this study to balance the importance of cell population doses both in allogeneic and autologous transplants.

Superior Survival Associated with Early Lymphocyte Regeneration after Cytoreductive Chemotherapy in Childhood Acute Lymphoblastic Leukemia.

Post autologous stem cell transplantation (ASCT) studies have demonstrated that early absolute lymphocyte count (ALC) recovery is associated with prolonged survival. A potential explanation for the survival advantage associated with ALC recovery after ASCT is the possibility that early immune reconstitution may have a protective effect against residual disease progression. This is analogous to the graft -versus-tumor effect in allogeneic bone marrow transplantation recipients whereby the donor immune system is responsible for the eradication of residual disease in the host. If true then ALC following cytoreductive chemotherapy without transplantation could help predict patients at increased risk of relapse. The relationship of ALC with clinical outcomes following cytoreductive chemotherapy for childhood acute lymphoblastic leukemia (ALL) is unknown. We evaluated all 91 children treated according to BFM 95 protocol at a single center with ALL from 1997 to 2002.We studied if the recovering ALC post induction (Day33) in all patients, post consolidation (Day79) in standard risk patients and day +28 from commencement of 1st high risk block of chemotherapy for high risk patients can predict clinical outcome. These time points correlate with minimal residual disease as per recent studies. Of the 91 patients 77 were standard risk, 7 were high risk and remaining 7 had very high risk disease as per BFM 95 criteria. Patients were analyzed according to overall and disease free survival. Mean lymphocyte counts were calculated and survival curves drawn based on a median count for all patients. The study shows that post chemotherapy recovery of ALC correlates with overall survival at all time points studied. Post induction (Day 33) mean ALC in disease free survivors v patients who had relapsed was 1.89 v 1.10 x 109/L.Similarly for these groups the recovering ALC was higher on post consolidation (Day 79) 1.28 v 0.97 x 109/L. Post 1st high risk block also showed a significant difference between survivors and relapsing high risk patients 1.47 v 0.96 x 109/L. Post Day 33 patients were split into those with ALC greater or less than 1.0 x 109/L. Overall survival was 94 % for patients with ALC greater than 1.0x 109/L on day 33 and 52 % for patients with ALC less than 1.0x 109/L on day 33 at median follow up of 3 years (median survival not reached v 20 months). If lymphocyte numbers are influencing outcome by an autologous immune anti-tumor effect, this knowledge could be used to influence and benefit future therapies to treat ALL in children. In conclusion, we confirm the association between early ALC recovery and superior survival after cytoreductive chemotherapy in children with ALL. Since the limitations of a retrospective analysis, our results should be viewed with caution and prospective studies that attempt to link specific lymphocytes subsets and outcome after cytoreductive chemotherapy in ALL are needed before any firm conclusions are drawn.

Lymphocyte recovery as a positive predictor of prolonged survival after autologous peripheral blood stem cell transplantation in T-cell non-Hodgkin's lymphoma.

We performed a retrospective study on recovery and survival of patients with T-cell NHL after autologous peripheral blood stem cell transplantation (APBSCT). Of a total of 39 patients with high-risk T-cell NHL, 33 were analyzed. Six patients who experienced early treatment mortality without full lymphocyte recovery were excluded. We chose absolute lymphocyte count (ALC) recovery as 1000 cells/microl as a cutoff value. ALC recovery day was defined as the first of 3 consecutive days with ALC above 1000 cells/microl. Univariate analysis revealed that age younger than 45 years, good international prognostic index, chemosensitive disease prior to APBSCT, and early ALC recovery (1000 cells/microl within 25 days of APBSCT) were predictors of prolonged survival. Multivariate analyses confirmed that chemosensitive disease prior to APBSCT and early ALC recovery were strongly associated with better overall survival (OS) (P=0.005 and 0.011, respectively) and progression-free survival (PFS) (P<0.001 and P=0.013, respectively). Our finding, that ALC recovery > or =1000 cells/microl is an independent predictor of OS and PFS in T-cell NHL after APBSCT, suggests that earlier immune recovery may contribute to longer survival.