Impaired B-cell reconstitution in children after chemotherapy for standard or medium risk acute precursor B-lymphoblastic leukemia

Phase II Study of Responses to Vaccination in Pediatric Cancer Survivors Following Standard-of-Care Non-HSCT Chemotherapy

INTRODUCTION

Survivors of childhood cancer exhibit variable humoral immunity to vaccine-preventable diseases (VPDs) following cancer treatment. An increasing number of children are surviving a cancer diagnosis, making it imperative to document the extent to which survivors are at risk for VPDs and their response to vaccinations.

METHODS

This Phase II prospective study included 65 pediatric patients diagnosed with cancer and treated with intensive chemotherapy without transplantation. Serum vaccine antibody concentrations were determined for 12 VPDs: tetanus, diphtheria, pertussis, polio, Haemophilus influenzae, pneumococcus, hepatitis B, meningococcus A, measles, mumps, rubella, and varicella following completion of cancer treatment and after vaccination.

RESULTS

Many patients lacked protective antibody levels to VPDs at the end of treatment. After vaccination, 87%-100% of patients had protective antibody titers against inactivated vaccines. The percentage of patients protected against the live attenuated vaccines was lower: measles (79%), mumps (83%), rubella (85%), and varicella (82%). Differences in response rates to vaccinations were not statistically significant for age (<7 vs. ≥7 years of age), diagnosis (hematologic disease vs. solid tumor), the time between the end of treatment and vaccination (3-6 vs. >6 months for inactivated vaccines), or between absolute lymphocyte count or CD4+ T-cell count at baseline.

CONCLUSION

For pediatric cancer survivors, a single dose of inactivated vaccines given 3 months following the end of treatment protects against these VPDs without the need for assessment of serostatus after inoculation. For live attenuated vaccines, patients require two inoculations for protection, and we recommend an assessment of serostatus to inform patients and providers of their risk for acquiring one of these communicable VPDs.

Clinical analysis of immune reconstitution after chemotherapy in children with acute lymphoblastic leukemia

OBJECTIVES

The aim of this retrospective study was to investigate the influence of chemotherapy on the immune status of individual patients diagnosed with acute lymphoblastic leukemia (ALL) and to elucidate the clinical characteristics of immune reconstitution in ALL patients following chemotherapy.

METHODS

Clinical data of children with ALL were gathered, including information on the number of lymphocyte subsets prior to chemotherapy, at the end of therapy, six months, and one year after the end of the treatment.

RESULTS

A total of 146 children with ALL were included, and T cells, B cells, and NK cells all decreased to various degrees prior to treatment. The abnormal CD3 + T cell numbers group experienced a considerably higher mortality (21.9% vs. 6.1%) and recurrence rate (31.3% vs. 11.4%) compared to the normal group (P < 0.05). T cells, B cells, and NK cells were all significantly compromised at the end of therapy compared to the beginning of chemotherapy, with B cells being more severely compromised (P < 0.001). At the end of treatment, levels of B cells, CD4 + T cells, CD4/CD8, IgG and IgM in low risk (LR) group were significantly higher than those in intermediate risk (IR) group (P < 0.01), and levels of NK cells in LR group were evidently lower than those in IR group (P < 0.001). Six months after the end of therapy, all the above indicators recovered (P < 0.001) except CD4/CD8 ratio (P = 0.451).

CONCLUSIONS

The immune systems of the ALL patients were severely compromised upon therapy withdrawal, particularly the B cells. At six months after the therapy ended, the B cells were basically restored to normal level, while the T-cell compartment was not. The impaired numbers of CD3 + T cell may contribute to a weakened anti-tumor response, potentially leading to a poorer prognosis.

Treatment intensity affects immune reconstitution even after childhood cancer not treated with hematopoietic stem cell transplantation

BACKGROUND

Only a few previous studies examine immune system recovery after completed cancer treatment.

AIMS

The aim of this study was to analyze immune reconstitution after childhood cancer therapy in a non-hematopoietic stem cell transplantation setting.

METHODS AND RESULTS

We analyzed children (N = 79) who received chemotherapy with/without irradiation for cancer diagnosed between 2014 and 2019 at Turku University Hospital, Finland. We retrospectively collected data on baseline parameters and post-treatment immunological recovery, namely neutrophil and lymphocyte counts, IgG levels, CD19, CD4 and natural killer cell counts. Immunological parameters were followed until their normalization. Treatment intensity was stratified according to the Intensity of Treatment Rating Scale (ITR-3). We analyzed the effects of treatment intensity on normalization of immunological parameters across the entire treatment range. Treatment intensity had a major effect on immune system recovery after completion of treatment. Most patients had normal immunological parameters 1-4 months post-treatment both in high- and low-intensity treatment groups, but patients classified in the high-intensity group had low parameters more often than patients in the low-intensity group.

CONCLUSION

Our data suggest a fast recovery of studied immunological parameters after the majority of current pediatric oncologic treatments. Treatment for high-risk acute lymphoblastic leukemia, acute myeloid leukemia, medulloblastoma, and mature B-cell lymphoma was associated with prolonged recovery times for a substantial proportion of cases. High treatment intensity was associated with prolonged immunological recovery.

Loss of humeral immunity in childhood cancer survivors not having undergone hematopoietic stem cell transplantation

BACKGROUND

Data are limited and conflicting regarding loss of immunity in childhood cancer survivors who did not undergo hematopoietic stem cell transplantation. The purpose of this retrospective, single center study is to provide further data to help build unifying revaccination guidelines post-chemotherapy in childhood cancer survivors not having undergone hematopoietic stem cell transplantation.

METHODS

This retrospective study included 28 childhood cancer survivors, 14 males and 14 females, whose treatment consisted of at least 3 months of chemotherapy and with confirmation of completing their primary vaccination series prior to therapy. The rate of vaccine titer seropositivity for cancer survivors was compared with the expected general population, based on long-term studies of anti-body persistence.

RESULTS

Decreased seropositivity for measles, mumps, rubella, varicella, tetanus, and hepatitis B was found in patients across all categories of malignancy compared with the general population. However, tetanus was not statistically significant. Results were more pronounced for those with hematological malignancies.

CONCLUSIONS

This study indicates that pediatric cancer survivors, especially those with hematological malignancies, may have greater loss of protective antibodies from primary vaccinations. Further studies are needed to provide guidelines for revaccination of both hematologic malignancies and solid tumor childhood cancer survivors who did not undergo hematopoietic stem cell transplantation.

Temporal evolution and differential patterns of cellular reconstitution after therapy for childhood cancers

The cellular reconstitution after childhood cancer therapy is associated with the risk of infection and efficacy of revaccination. Many studies have described the reconstitution after stem cell transplantation (SCT). The recovery after cancer treatment in children who have not undergone SCT has mainly been investigated in acute lymphoblastic leukemia (ALL), less for solid tumors. Here, we have examined the temporal evolution of total leukocyte, neutrophil and lymphocyte counts as surrogate parameters for the post-therapeutic immune recovery in a cohort of n = 52 patients with ALL in comparison to n = 58 patients with Hodgkin's disease (HD) and n = 22 patients with Ewing sarcoma (ES). Patients with ALL showed an efficient increase in blood counts reaching the age-adjusted lower limits of normal between 4 and 5 months after the end of maintenance therapy. The two groups of patients with HD and ES exhibited a comparably delayed recovery of total leukocytes due to a protracted post-therapeutic lymphopenia which was most pronounced in patients with HD after irradiation. Overall, we observed a clearly more efficient resurgence of total lymphocyte counts in patients aged below 12 years compared to patients aged 12 to 18 years. Our results underline that the kinetics of cellular reconstitution after therapy for HD and ES differ significantly from ALL and depend on treatment regimens and modalities as well as on patient age. This suggests a need for disease, treatment, and age specific recommendations concerning the duration of infection prophylaxis and the timing of revaccination.

Do Not Forget About the Ticks: An Unusual Cause of Fever, GI Distress, and Cytopenias in a Child With ALL

We report the case of a 5-year-old male with B-cell acute lymphoblastic leukemia in remission, receiving maintenance chemotherapy, who presented with fever, emesis, diarrhea, headache, and lethargy. He developed rapidly progressive cytopenias and was found to have acute human granulocytic anaplasmosis as well as evidence of past infection with Babesia microti. The case highlights the need to maintain a broad differential for infection in children undergoing chemotherapy or other immunosuppressive therapies with possible or known tick exposure.

Effect of GATA3 rs3824662 gene polymorphism in Han Chinese children with pre-B-cell acute lymphoblastic leukemia with 10 years follow-up

PURPOSE

To evaluate the influence of GATA3 rs3824662 on pre-B-cell acute lymphoblastic leukemia (pre-B-cell ALL) susceptibility and long-term prognosis in Han Chinese children with pre-B-cell ALL treated with the CCLG-2008 protocol at the Children's Hospital of Soochow University.

METHODS

A total of 256 patients with childhood pre-B-cell ALL under the CCLG-2008 protocol were enrolled in this study, and 174 healthy children were used as case controls. GATA3 rs3824662 genotyping was performed using a polymerase chain reaction, followed by Sanger sequencing. The association of genotype with clinical characteristics, treatment response, adverse events, and outcomes were analyzed.

RESULTS

The A allele frequency of GATA3 rs3824662 in patients with pre-B cell ALL was significantly higher than that in healthy children (OR = 1.41, 95% CI = 1.042-1.908; P = 0.026). Among patients with pre-B-cell ALL, the GATA3 rs3824662 AA genotype was associated with poor prednisolone response and high blast cell burden on day 15 of the induction therapy (P = 0.011 and 0.007, respectively). Patients with the rs3824662 AA variant suffered more episodes of sepsis than those with the CC or CA variants (P = 0.021). The GATA3 rs3824662 AA genotype was significantly associated with sepsis [hazard ratio (HR) = 3.375; P = 0.01]. No significant differences were found in the cumulative incidence of relapse, overall survival, and event-free survival among all genotypes.

CONCLUSION

GATA3 rs3824662 was associated with susceptibility in Han Chinese children with pre-B-cell ALL and could be a possible risk factor for poor early treatment response and treatment-related sepsis.

Short NK and naïve T-cell telomere length is associated with thyroid cancer in childhood cancer survivors: A report from the Childhood Cancer Survivor Study

BACKGROUND

Survivors of childhood cancer are at risk for therapy-related subsequent malignant neoplasms (SMN), including thyroid SMN. Telomere length (TL) is associated with cancer risk, but the relationship between TL and SMN risk among survivors is less clear.

METHODS

We conducted a nested, matched case-control study of radiation-exposed 15-year+ adult survivors of childhood cancer with thyroid SMN (cases) and without SMN (controls). 46 cases were matched to 46 controls by primary diagnosis, chemotherapy (yes/no), radiation field, and follow-up duration. Lymphocyte TL (LTL) was measured by telomere flow-FISH cytometry using blood samples banked at a mean of 38.9 years (cases), 39.2 years (controls). Genetic variation in telomere genes was assessed by whole genome sequencing. Point estimates for LTL <10th percentile were determined for cases and controls.

RESULTS

Cases had shorter median LTL than controls in three out of four leukocyte subsets. Cases were more likely to have NK cell LTL <10th percentile (p=0.01), and 2.8-fold more likely to have naïve T-cell LTL <10th percentile than controls (CI 1.07, 8.78). Five out of 15 cases with a rare indel or missense variant had naïve T-cell LTL <10th percentile, compared with one out of 8 controls.

CONCLUSIONS

Long-term survivors have shorter than expected LTL, a finding that is more pronounced among survivors with thyroid SMN.

IMPACT

The long-term impact of childhood cancer treatment on immune function is poorly understood. Our findings support immune function studies in larger survivor cohorts to assess long-term deficits in adaptive and innate immunity that may underlie SMN risk.

Immune function in childhood cancer survivors: a Children's Oncology Group review

Childhood cancer and its treatment often impact the haematopoietic and lymphatic systems, with immunological consequences. Immunological assessments are not routinely included in surveillance guidelines for most survivors of childhood cancer, although a robust body of literature describes immunological outcomes, testing recommendations, and revaccination guidelines after allogeneic haematopoietic cell transplantation. Survivorship care providers might not fully consider the impaired recovery of a child's immune system after cancer treatment if the child has not undergone haematopoietic cell transplantation. We did a scoping review to collate the existing literature describing immune function after childhood cancer therapy, including both standard-dose chemotherapy and high-dose chemotherapy with haematopoietic cell rescue. This Review aims to summarise: the principles of immunology and testing of immune function; the body of literature describing immunological outcomes after childhood cancer therapy, with an emphasis on the risk of infection, when is testing indicated, and preventive strategies; and knowledge gaps and opportunities for future research.

Severe infections following treatment for childhood cancer: a report from CYP-C

Little is known about infections occurring after childhood cancer treatment. We assessed the risk of severe infection postcancer therapy in survivors of leukemia compared to other cancer types. We performed a population-based cohort study of children <15 years of age diagnosed with cancer (2001-2016), alive and relapse-free 30 days after treatment completion. The risk of severe infection in both groups was estimated using subdistribution proportional hazard regression. We identified 6148 survivors (1960 with leukemia). The cumulative incidence (95% confidence interval) of severe infections at 3 years was 0.70% (0.40-1.2%) in leukemia and 0.51% (0.32-0.79%) in other cancers. The risk of severe infection was not statistically different in leukemia survivors compared to other cancer types in univariate and multivariate analysis (adjusted hazard ratio: 1.40, 95% CI: 0.69-2.85). No significant association was found between a history of leukemia and an increased risk of severe infection after treatment, compared to other cancer types.

Immune reconstitution in children following chemotherapy for acute leukemia

Although survival rates for pediatric acute lymphoblastic leukemia are now excellent, this is at the expense of prolonged chemotherapy regimens. We report the long-term immune effects in children treated according to the UK Medical Research Council UKALL 2003 protocol. Peripheral blood lymphocyte subsets and immunoglobulin levels were studied in 116 participants, at six time points, during and for 18-month following treatment, with 30-39 patients analyzed at each time point. Total lymphocytes were reduced during maintenance chemotherapy and remained low 18 months following treatment completion. CD4 T cells remained significantly reduced 18 months after treatment, but CD8 cells and natural killer cells recovered to normal values. The fall in naïve B-cell numbers during maintenance was most marked, but numbers recovered rapidly after cessation of treatment. Memory B cells, particularly nonclass-switched memory B cells, remained below normal levels 18 months following treatment. All immunoglobulin subclasses were reduced during treatment compared to normal values, with IgM levels most affected. This study demonstrates that immune reconstitution differs between lymphocyte compartments. Although total B-cell numbers recover rapidly, disruption of memory/naïve balance persists and T-cell compartment persist at 18 months. This highlights the impact of modern chemotherapy regimens on immunity, and thus, infectious susceptibility and response to immunization.

Infections as a potential long-term risk following childhood leukemia

Leukemia is the most common childhood cancer. While infections are a frequent and potentially severe complication while on treatment, less is known about the risk for infections following therapy completion. In this article, we propose that leukemia survivors might be at increased risk of infections following therapy completion than the general population, independently of potential confounders such as age, sex and Down syndrome. This association is conceivably due to several factors. First, therapy-induced immune dysfunction of both the humoral and cellular compartments appears to last for several years following anti-cancer therapy and after hematopoietic stem cell transplantation. Second, clinical and epidemiological research has shown leukemia survivors are disproportionally affected by comorbidities related to leukemia treatment and its complications, such as diabetes and obesity, which may induce secondary immunodeficiency and infections. Last, differences in health-related behaviors between leukemia survivors and the general population (such as re-vaccination practices) may affect the baseline risk of infections. Although under-represented in the epidemiological literature as a possible late effect of childhood leukemia and its treatment, it is plausible that leukemia survivors are at increased risk of infections for several years when compared to the general population and their siblings. Further research is needed to empirically test these hypotheses.

Long-Term Risk of Infections After Treatment of Childhood Leukemia: A Population-Based Cohort Study Using Administrative Health Data

PURPOSE

Infections are a frequent complication during childhood leukemia treatment. Little is known about the infectious risk in survivors. We compared the relative rate (RR) of infections after treatment completion between pediatric leukemia survivors and the general population.

METHODS

We performed a retrospective, population-based cohort study of children diagnosed with leukemia between 1992 and 2015 in Ontario, Canada, who were alive and relapse free 30 days after treatment completion (index date). Leukemia survivors were matched 5:1 with the general population by year of birth, sex, and rural status and stratified by initial treatment, including and excluding hematopoietic stem-cell transplantation (HSCT). The primary outcome was time to infections, as identified using validated diagnostic codes from administrative databases. Individuals were censored at the earliest of death, first relapse, loss to follow-up, or end of study.

RESULTS

A total of 2,204 leukemia survivors were included and matched with 11,020 controls. The rate of infections was elevated after treatment completion compared with controls (RR, 1.51; 95% CI, 1.45 to 1.57) and at less than 1 year (RR, 1.77; 95% CI, 1.69 to 1.86); 1 to 4.99 years (RR, 1.66; 95% CI, 1.62 to 1.71), and 5 or more years (RR, 1.29; 95% CI, 1.22 to 1.36) from the index date. Among those whose initial treatment excluded HSCT, the rate remained elevated more than 5 years from the index date (RR, 1.29; 95% CI, 1.23 to 1.35). Infection-related death was significantly increased in leukemia survivors both among the entire cohort (hazard ratio, 149.3; 95% CI, 20.4 to 1,091.9) and among those without HSCT (hazard ratio, 92.7; 95% CI, 12.4 to 690.7).

CONCLUSION

A significant association was found between a history of leukemia therapy and an increased risk of infections. Additional study is needed to establish which exposures in patients with leukemia lead to late infections.

Absolute lymphocyte counts at end of induction correlate with distinct immune cell compartments in pediatric B cell precursor acute lymphoblastic leukemia

Several retrospective studies in children with B cell precursor (BCP) acute lymphoblastic leukemia (ALL) provided clinical evidence that higher absolute lymphocyte counts (ALC) early into treatment significantly correlated with improved relapse-free and overall survival. It still remains unknown, however, whether the predictive role of higher ALCs reflects general bone marrow recovery or a more specific attribute of immune function. To investigate this question, we implemented a prospective observational cohort study in 20 children with BCP ALL on day 29 (D29) of induction chemotherapy and immunophenotyped their lymphoid (T, B and natural killer cells) and myeloid (neutrophils, monocytes, dendritic cells) compartments. In a first evaluation of a cohort treated with Children's Oncology Group-based induction chemotherapy, the immune cell compartments were differentially depleted at D29. Neither gender, risk status, minimal residual disease, nor bone marrow recovery markers correlated with D29 ALC. In contrast, both CD3+ T cell and dendritic cell compartments, which did not correlate with age, significantly correlated with D29 ALC (p < 0.0001). In addition, subset complexity of cellular immune compartments was preserved at D29. This study reveals that D29 ALC significantly correlates with distinct immune cell compartments but not with bone marrow recovery markers, suggesting that higher D29 ALCs may contribute to leukemia control by inducing specific host immune activity.

Understanding the reconstitution of the B-cell compartment in bone marrow and blood after treatment for B-cell precursor acute lymphoblastic leukaemia

A better understanding of the reconstitution of the B-cell compartment during and after treatment in B-cell precursor acute lymphoblastic leukaemia (BCP-ALL) will help to assess the immunological status and needs of post-treatment BCP-ALL patients. Using 8-colour flow cytometry and proliferation-assays, we studied the composition and proliferation of both the B-cell precursor (BCP) population in the bone marrow (BM) and mature B-cell population in peripheral blood (PB) during and after BCP-ALL therapy. We found a normal BCP differentiation pattern and a delayed formation of classical CD38^dim -naive mature B-cells, natural effector B-cells and memory B-cells in patients after chemotherapy. This B-cell differentiation/maturation pattern was strikingly similar to that during initial B-cell development in healthy infants. Tissue-resident plasma cells appeared to be partly protected from chemotherapy. Also, we found that the fast recovery of naive mature B-cell numbers after chemotherapy was the result of increased de novo BCP generation, rather than enhanced B-cell proliferation in BM or PB. These results indicate that post-treatment BCP-ALL patients will eventually re-establish a B-cell compartment with a composition and B-cell receptor repertoire similar to that in healthy children. Additionally, the formation of a new memory B-cell compartment suggests that revaccination might be beneficial after BCP-ALL therapy.

Immunological Reconstitution in Children After Completing Conventional Chemotherapy of Acute Lymphoblastic Leukemia is Marked by Impaired B-cell Compartment

Humoral and cellular immunity were studied in 28 children completing conventional treatment of standard-risk (SR) or intermediate-risk (IR) acute lymphoblastic leukemia (ALL). Both naïve and memory B cells were most severely affected and showed slow recovery during the 2-year follow-up, while the T-cell compartment showed only minor changes. Immunoglobulins and IgG subclasses, components, and antibodies against vaccine-preventable diseases were not significantly affected. In conclusion, immune recovery after conventional chemotherapy for SR and IR ALL is marked by B-cell depletion, but otherwise did not show any severe deficiencies in lymphocyte function.

Redirection of CD4+ and CD8+ T lymphocytes via an anti-CD3 × anti-CD19 bi-specific antibody combined with cytosine arabinoside and the efficient lysis of patient-derived B-ALL cells

Background

B-acute lymphoblastic leukemia (B-ALL) is derived from B cell progenitors. Recently, the development of appropriate combinations of chemotherapy and immunotherapy represents a promising approach for eliminating cancer. We previously constructed an anti-CD3 × anti-CD19 bi-specific antibody in a diabody configuration and its disulfide-stabilized format (ds-diabody). The combination of the diabody or ds-diabody and Ara-C was highly effective in enhancing the cytotoxicity of T cells against the CD19+ human leukemia cell-line, Nalm-6, both in vitro and in vivo. This study verified whether B-ALL patient-derived cells were sensitive to the diabody or ds-diabody and low-dosage Ara-C combination.

Methods

This study aimed to detect the B7 family members B7.1 (CD80) and B7.2 (CD86) that were expressed in B-ALL patient-derived cells pre-treated by Ara-C (0.25 μM) and to determine the targeted killing ability of T cell subtypes induced by the diabody or ds-diabody combination with Ara-C both in vitro and in vivo. We also determined the levels of the cytokines that were released by activated CD4+ or CD8+ T cells during therapy.

Result

Low-dose Ara-C enhanced CD80 and CD86 expression in nearly 50 % of specimens of B-ALL patient-derived cells. A combination of diabody or ds-diabody and Ara-C enhanced T cell against B-ALL cells in vitro and in vivo. Both CD8+ and CD4+ T cells were potently activated. Expression of CD25 and CD69 was augmented equally by CD4+ or CD8+ T cells. However, CD8+ T cells made the major contribution by redirecting target cell lysis in a granzyme B and perforin-dependent mechanism. CD4+ T cells played an important immunomodulatory role by secreting IL2. Consequently, IL3, IL6, TNFα, and IFNγ were also released by CD4+ or CD8+ T cells following diabody-mediated T cell activation.

Conclusion

T cell therapy induced by diabody or ds-diabody combined with low dose of Ara-C was effective against cancer cell-lines and in clinical trials. In vivo, the ds-diabody was more efficient than its parent diabody due to its enhanced stability.

TGFβ and IL10 have an impact on risk group and prognosis in childhood ALL

BACKGROUND

Cytokines and their genes have been described to have an influence on incidence and prognosis in malignant, infectious and autoimmune disease. We previously described the impact of cytokine production on prognosis in paediatric standard-risk acute lymphoblastic leukaemia (ALL).

PROCEDURE

In this study, we investigated the influence of cytokine gene polymorphisms (TNFα, TGFβ, IL10 and IFNγ) on frequency, risk group and prognosis in 95 paediatric ALL-patients. We further report on intracellular production of these cytokines in T-cells.

RESULTS

IL10 high-producer-haplotypes were reduced in ALL-patients compared with healthy controls and resulted in a reduced relapse rate compared with low-producer haplotypes. TGFβ high-producer-haplotypes were correlated with a high initial blast-count (codon 25: G/G) and were elevated in high-risk ALL-patients (codon 10: T/T). IL10 was positively and IFNγ-production was negatively correlated with initial blast-count. At diagnosis the expression of TNFα and IFNγ was reduced in patients compared with healthy controls. This was more pronounced in high-risk and in T-ALL-patients.

CONCLUSION

We conclude that gene-polymorphisms of the regulatory/anti-inflammatory cytokines, TGFβ and IL10, but not of the pro-inflammatory cytokines, IFNγ and TNFα, have an impact on prognosis and risk-group of ALL. However, the reduced capacity to produce pro-inflammatory cytokines at diagnosis may serve as another important, functional risk factor. These data may help in further risk stratification and adaptation of therapy-intensity in paediatric patients with ALL.