Recovery of natural killer cells after chemotherapy for childhood acute lymphoblastic leukemia and solid tumors

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.

ATRX is a predictive marker for endocrinotherapy and chemotherapy resistance in HER2-/HR+ breast cancer through the regulation of the AR, GLI3 and GATA2 transcriptional network

Drug resistance in breast cancer (BC) is a clinical challenge. Exploring the mechanism and identifying a precise predictive biomarker for the drug resistance in BC is critical. Three first-line drug (paclitaxel, doxorubicin and tamoxifen) resistance datasets in BC from GEO were merged to obtain 1,461 differentially expressed genes for weighted correlation network analysis, resulting in identifying ATRX as the hub gene. ATRX is a chromatin remodelling protein, therefore, ATRX-associated transcription factors were explored, thereby identifying the network of AR, GLI3 and GATA2. GO and KEGG analyses revealed immunity, transcriptional regulation and endocrinotherapy/chemotherapy resistance were enriched. Moreover, CIBERSORT revealed immunity regulation was inhibited in the resistance group. ssGSEA showed a significantly lower immune status in the ATRX-Low group compared to the ATRX-High group. Furthermore, the peaks of H3K9me3 ChIP-seq on the four genes were higher in normal tissues than in BC tissues. Notably, the frequency of ATRX mutation was higher than BRCA in BC. Moreover, depressed ATRX revealed worse overall survival and disease-free survival in the human epidermal growth factor receptor 2 (HER2)-/hormone receptor (HR)+ BC. Additionally, depressed ATRX predicted poor results for patients who underwent endocrinotherapy or chemotherapy in the HER2-/HR+ BC subgroup. A nomogram based on ATRX, TILs and ER exhibited a significantly accurate survival prediction ability. Importantly, overexpression of ATRX significantly inhibited the IC50 of the three first-line drugs on MCF-7 cell. Thus, ATRX is an efficient predictive biomarker for endocrinotherapy and chemotherapy resistance in HER2-/HR+ BC and acts by suppressing the AR, GLI3 and GATA2 transcriptional network.

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.

Arsenic Trioxide Enhances the NK Cell Cytotoxicity Against Acute Promyelocytic Leukemia While Simultaneously Inhibiting Its Bio-Genesis

Natural killer cells (NK) contribute significantly to eradication of cancer cells, and there is increased interest in strategies to enhance it’s efficacy. Therapeutic agents used in the treatment of cancer can impact the immune system in a quantitative and qualitative manner. In this study, we evaluated the impact of arsenic trioxide (ATO) used in the management of acute promyelocytic leukemia (APL) on NK cell reconstitution and function. In patients with APL treated with single agent ATO, there was a significant delay in the reconstitution of circulating NK cells to reach median normal levels from the time of diagnosis (655 days for NK cells vs 145 and 265 days for T cells and B cells, respectively). In vitro experiments demonstrated that ATO significantly reduced the CD34 hematopoietic stem cell (HSC) differentiation to NK cells. Additional experimental data demonstrate that CD34⁺ sorted cells when exposed to ATO lead to a significant decrease in the expression of IKZF2, ETS1, and TOX transcription factors involved in NK cell differentiation and maturation. In contrast, exposure of NK cells and leukemic cells to low doses of ATO modulates NK cell receptors and malignant cell ligand profile in a direction that enhances NK cell mediated cytolytic activity. We have demonstrated that NK cytolytic activity toward NB4 cell line when exposed to ATO was significantly higher when compared with controls. We also validated this beneficial effect in a mouse model of APL were the median survival with ATO alone and ATO + NK was 44 days (range: 33–46) vs 54 days (range: 52–75). In conclusion, ATO has a differential quantitative and qualitative effect on NK cell activity. This information can potentially be exploited in the management of leukemia.

Immunization status in childhood cancer survivors: A hidden risk which could be prevented

BACKGROUND

A limited number of studies have examined the vaccine-specific antibody status of children with cancer. There are disagreements over the guidelines for postcancer immunization strategy.

METHODS

Our study was an observational, cross-sectional retrospective review of data collected on children who were seen in the outpatient clinic at King Abdullah Medical City, Oncology Center, Jeddah, the Kingdom of Saudi Arabia. Our aim was to evaluate the seropositive status to vaccine-preventable diseases: measles, mumps, rubella, diphtheria, tetanus, polio, and Haemophilus influenzae type B (HIB) in childhood cancer survivors at our center in order to plan future vaccination for these children and establish a simple revaccination schedule.

RESULTS

Forty-seven patients (21 boys and 26 girls) were included in the study. Age at the time of cancer diagnosis (mean±standard deviation) was 5.68±3.79 years and age at test sampling was 10.68±3.79 years. Acute leukemia was the most common cancer (49% of patients), followed by lymphoma (28%), brain tumors (13%), and solid tumors (10%). Treatment intensities (according to the Treatment Intensity Rating Scale, version 3.0; ITR-3) were 2, 3, and 4 for 26 patients (55%), 20 patients (43%), and one patient (2.1%), respectively. We found that 93% of our patients were considered seronegative (unprotected) for at least one vaccine-preventable disease. The seronegative rates for measles, mumps, rubella, diphtheria, tetanus, polio, and HIB were 46.8%, 36.2%, 36.2%, 46.8%, 61.7%, 17.1%, and 42.6%, respectively. Criteria including age at diagnosis, age at sampling, type of malignancy, and treatment intensity were not significantly different between seropositive and seronegative patients.

CONCLUSION

Seronegative rates for vaccine-preventable diseases were very high in childhood cancer survivors, which represented a subpopulation of high-risk patients who could benefit from revaccination. We suggest a universal revaccination approach for all childhood cancer survivors, which is easily applicable and of low cost.

Immune Dysfunction After Completion of Childhood Leukemia Therapy

BACKGROUND

Children with leukemia suffer immune dysfunction from their malignancy and chemotherapy. The immune system components most affected, the degree to which immune suppression occurs, and the duration of immunodeficiency are incompletely characterized. This study measures immunologic parameters following completion of therapy.

METHODS

This is a prospective, single institution cohort study. Eligible children with acute myelogenous or acute lymphoblastic leukemia diagnosed between 1 and 21 years of age were enrolled at therapy completion. Immune parameters were assessed at the end of therapy and 6 months later: complete blood counts, immunoglobulin levels, quantitative lymphocyte subsets, mitogen-induced lymphocyte proliferation, natural killer cell function, and vaccine titers.

RESULTS

Twenty patients were evaluated; 13 (65%) were female, 15 had acute lymphoblastic leukemia (75%). Mean age at diagnosis was 7.9 years. At end of therapy, all patients had some degree of immune dysfunction. At 6 months posttherapy, persistent abnormalities included: leukopenia (25%), neutropenia (15%), lymphopenia (5%), hypogammaglobulinemia (25%), one or more subtherapeutic vaccine titers (100%), abnormal lymphocyte subset levels (20%), decreased (15%), or absent (10%) natural killer cell function and abnormal lymphocyte proliferative responses (25%).

CONCLUSIONS

All patients had multiple abnormalities at end of therapy, and all patients had some degree of persistent immune dysfunction at 6 months after completion of therapy. Clinical implications of these laboratory abnormalities are currently unknown; longer term evaluations are ongoing. We demonstrate that survivors of childhood cancer have lasting quantitative and functional immunologic defects and may remain at risk for infectious complications after completion of therapy.

Severe, persistent, and fatal T-cell immunodeficiency following therapy for infantile leukemia

We describe five cases of children who completed chemotherapy for infantile acute lymphoblastic leukemia (ALL) and soon after were diagnosed with severe T-cell, non-HIV immunodeficiency, with varying B-cell and NK-cell depletion. There was near absence of CD3(+) , CD4(+) , and CD8(+) cells. All patients developed multiple, primarily opportunistic infections. Unfortunately, four patients died, although one was successfully treated by hematopoietic stem cell transplantation. These immunodeficiencies appeared to be secondary to intensive infant ALL chemotherapy. Our report highlights the importance of the early consideration of this life-threatening immune complication in patients who received chemotherapy for infantile ALL.

Phenotype of NK Cells Determined on the Basis of Selected Immunological Parameters in Children Treated due to Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most frequent pediatric malignancy. The chemotherapy for ALL is associated with a profound secondary immune deficiency.We evaluated the number and phenotype of natural killer (NK) cells at diagnosis, after the intensive chemotherapy and following the completion of the entire treatment for patients with ALL. The fraction, absolute number, and percentage of NK cells expressing interferon-γ were determined in full blood samples. The fraction of NK cells expressing CD158a, CD158b, perforin, A, B, and K granzymes was examined in isolated NK cells.We have shown that patients assessed at ALL diagnosis showed significantly lower values of the fraction of NK cells and percentage of NK cells with the granzyme A expression. Additionally, the absolute number of NK cells, the expression of CD158a, CD158b, perforin, and granzyme A were significantly lower in patients who completed intensive chemotherapy. Also, there was a significantly higher fraction of NK cells expressing granzyme K in patients who completed the therapy.Abnormalities of NK cells were found at all stages of the treatment; however, the most pronounced changes were found at the end of intensive chemotherapy.

Autoimmune diseases in Adult Life after Childhood Cancer in Scandinavia (ALiCCS)

Objectives

The pattern of autoimmune diseases in childhood cancer survivors has not been investigated previously. We estimated the risk for an autoimmune disease after childhood cancer in a large, population-based setting with outcome measures from comprehensive, nationwide health registries.

Methods

From the national cancer registries of Denmark, Iceland and Sweden, we identified 20 361 1-year survivors of cancer diagnosed before the age of 20 between the start of cancer registration in the 1940s and 1950s through 2008; 125 794 comparison subjects, matched by age, gender and country, were selected from national population registers. Study subjects were linked to the national hospital registers. Standardised hospitalisation rate ratios (SHRRs) and absolute excess risks (AERs) were calculated.

Results

Childhood cancer survivors had a significantly increased SHRR of 1.4 (95% CI 1.3 to 1.5) of all autoimmune diseases combined, corresponding to an AER of 67 per 100 000 person-years. The SHRRs were significantly increased for autoimmune haemolytic anaemia (16.3), Addison's disease (13.9), polyarteritis nodosa (5.8), chronic rheumatic heart disease (4.5), localised scleroderma (3.6), idiopathic thrombocytopenic purpura (3.4), Hashimoto's thyroiditis (3.1), pernicious anaemia (2.7), sarcoidosis (2.2), Sjögren's syndrome (2.0) and insulin-dependent diabetes mellitus (1.6). The SHRRs for any autoimmune disease were significantly increased after leukaemia (SHRR 1.6), Hodgkin's lymphoma (1.6), renal tumours (1.6) and central nervous system neoplasms (1.4).

Conclusions

Childhood cancer survivors are at increased risk for certain types of autoimmune diseases. These findings underscore the need for prolonged follow-up of these survivors.

Cytotoxicity of CD56-positive lymphocytes against autologous B-cell precursor acute lymphoblastic leukemia cells

Precursor B-lineage acute lymphoblastic leukemia (pre-B ALL) affects hematopoietic development and therefore is associated with immune deficiencies that can be further exacerbated by chemotherapy. It is unclear if and when monoclonal antibodies (mAbs) that stimulate antibody-mediated cellular cytotoxicity (ADCC) can be used for treatment because this depends on the presence of functional effector cells. Here, we used flow cytometry to determine that patient samples at diagnosis, post-induction and relapse contain detectable numbers of CD56+ cells. We were able to selectively expand CD56+ immune effector cells from bone marrow and peripheral blood samples at diagnosis and at various stages of treatment by co-culture with artificial antigen-presenting K562 clone 9.mbIL-21 cells. Amplified CD56+CD3- cells had spontaneous and anti-BAFF-R mAb-stimulated ADCC activity against autologous ALL cells, which could be further enhanced by IL15. Importantly, matched CD56+ effector cells also killed autologous ALL cells grown out from leukemia samples of the same patient, through both spontaneous as well as antibody-dependent cellular cytotoxicity. Since autologous cell therapy will not be complicated by graft-versus-host disease, our results show that expanded CD56+ cells could be applied for treatment of pre-B-ALL without transplantation, or for purging of bone marrow in the setting of autologous bone marrow transplants.

Infections among long-term survivors of childhood and adolescent cancer: a report from the Childhood Cancer Survivor Study

BACKGROUND

Little is known about infections among adult survivors of childhood cancer. The authors report the occurrence of infections and risk factors for infections in a large cohort of survivors of childhood cancer.

METHODS

The Childhood Cancer Survivor Study cohort was used to compare incidence rates of infections among 12,360 5-year survivors of childhood cancer with the rates of 4023 siblings. Infection-related mortality of survivors was compared with that of the US population. Demographic and treatment variables were analyzed using Poisson regression to determine the rate ratios (RRs) and corresponding 95% confidence intervals (CIs) for associations with infectious complications.

RESULTS

Compared with the US population, survivors were at an increased risk of death from infectious causes (standardized mortality ratio [SMR], 4.2; 95% CI, 3.2-5.4), with the greatest risk observed among females (SMR, 3.2; 95% CI, 1.5-6.9) and among those who had been exposed to total body irradiation (SMR, 7.8; 95% CI, 1.8-33.0). Survivors also reported higher rates than siblings of overall infectious complications (RR, 1.3; 95% CI, 1.2-1.4) and higher rates of all categories of infection.

CONCLUSIONS

Survivors of childhood cancer remain at elevated risk for developing infectious-related complications, and they have a higher risk of infection-related mortality years after therapy. Further investigation is needed to provide insight into the mechanisms for the observed excess risks.

2013 IDSA clinical practice guideline for vaccination of the immunocompromised host

An international panel of experts prepared an evidenced-based guideline for vaccination of immunocompromised adults and children. These guidelines are intended for use by primary care and subspecialty providers who care for immunocompromised patients. Evidence was often limited. Areas that warrant future investigation are highlighted.

The effect of red ginseng extract on inflammatory cytokines after chemotherapy in children

Ginseng has been used as an herbal medicine, widely used in Asian countries, for long time. Recently, beneficial effects for immune functions of Korean red ginseng (KRG) have been reported in adults. This study was performed to investigate the effects of ginseng on immune functions in children after cessation of chemotherapy or stem cell transplantation for advanced cancer. Thirty patients, who were diagnosed and treated for leukemia and solid cancer at the department of pediatrics and adolescence of the Yeungnam University Hospital from June 2004 to June 2009, were enrolled for the study. The study group consisted of 19 patients who received KRG extract (60 mg/kg/d) for 1 yr and 11 patients who did not receive KRG extract were the control group. Blood samples were collected every 6 mo. Immune assays included circulating lymphocyte subpopulation, serum cytokines (IL- 2, IL-10, IL-12, TNF-alpha, and IFN-gamma), and total concentrations of serum IgG, IgA, and IgM subclasses. Age at diagnosis ranged from 2 mo to 15 yr (median 5 yr). Nine patients received stem cell transplantation. The cytokines of the KRG treated group were decreasing more rapidly than that of the control group. Lymphocyte subpopulations (T cell, B cell, NK cell, T4, T8, and T4/ T8 ratio) and serum immunoglobulin subclasses (IgG, IgA, and IgM) did not show significant differences between the study and the control groups. This study suggests that KRG extract might have a stabilizing effect on the inflammatory cytokines in children with cancer after chemotherapy.

HLA-G expression in acute lymphoblastic leukemia: a significant prognostic tumor biomarker

Human leukocyte antigen G (HLA-G) is a non-classical major histocompatibility class Ib antigen with multiple immune regulatory functions including the induction of immune tolerance in malignancies. The goal of our study was to investigate the expression of membrane form of HLA-G in acute lymphoblastic leukemia (ALL) before and after therapy in a trial to evaluate its role as a tumor escape mechanism and prognosis. So we measured its expression by reverse transcription (RT)-PCR in peripheral blood mononuclear cells of 25 (ALL) patients and 15 healthy controls and correlated our findings with a variety of clinical and laboratory variables and two important cytokines, IL-10 and INF-γ, and with natural killer (NK) cells. Serum levels of IL-10 and INF-γ were measured by ELISA. NK cells were quantitated by flow cytometry. The best cutoff values for the investigated markers were determined by ROC curve. The current study showed that membrane-bound HLA-G expression levels and positivity rates above the cutoff value 0.37 were significantly higher in ALL patients at diagnosis compared to after therapy and both showed significant higher levels than in normal control group (P < 0.01). Moreover, IL-10 and INF-γ serum levels were significantly elevated in ALL patients at time of diagnosis compared to healthy controls with a significant reduction in their levels in ALL patients after receiving chemotherapy. Membrane HLA-G expression showed a significant positive correlation with lactate dehydrogenase, peripheral and bone marrow blast cells and with IL-10 and INF-γ. The positive correlation of membrane HLA-G expression with both IL-10 and INF-γ serum levels supports the speculation that both cytokines may be involved in the control of HLA-G expression. HLA-G showed a negative correlation with NK cells confirming its importance in tumor escape through down-regulation of NK cells. In conclusion, HLA-G expression could be used as a prognostic tumor marker to monitor disease state and improvement in ALL.

Immunomodulatory effects of low dose chemotherapy and perspectives of its combination with immunotherapy

Given that cancer is one of the main causes of death worldwide, many efforts have been directed toward discovering new treatments and approaches to cure or control this group of diseases. Chemotherapy is the main treatment for cancer; however, a conventional schedule based on maximum tolerated dose (MTD) shows several side effects and frequently allows the development of drug resistance. On the other side, low dose chemotherapy involves antiangiogenic and immunomodulatory processes that help host to fight against tumor cells, with lower grade of side effects. In this review, we present evidence that metronomic chemotherapy, based on the frequent administration of low or intermediate doses of chemotherapeutics, can be better than or as efficient as MTD. Finally, we present some data indicating that noncytotoxic concentrations of antineoplastic agents are able to both up-regulate the immune system and increase the susceptibility of tumor cells to cytotoxic T lymphocytes. Taken together, data from the literature provides us with sufficient evidence that low concentrations of selected chemotherapeutic agents, rather than conventional high doses, should be evaluated in combination with immunotherapy.

EXERCISE in pediatric autologous stem cell transplant patients: a randomized controlled trial protocol

Background

Hematopoietic stem cell transplantation is an intensive therapy used to improve survivorship and cure various oncologic diseases. However, this therapy is associated with high mortality rates and numerous negative side-effects. The recovery of the immune system is a special concern and plays a key role in the success of this treatment. In healthy populations it is known that exercise plays an important role in immune system regulation, but little is known about the role of exercise in the hematological and immunological recovery of children undergoing hematopoietic stem cell transplant. The primary objective of this randomized-controlled trial (RCT) is to study the effect of an exercise program (in- and outpatient) on immune cell recovery in patients undergoing an autologous stem cell transplantation. The secondary objective is to determine if an exercise intervention diminishes the usual deterioration in quality of life, physical fitness, and the acquisition of a sedentary lifestyle.

Methods

This RCT has received approval from The Conjoint Health Research Ethics Board (CHREB) of the University of Calgary (Ethics ID # E-24476). Twenty-four participants treated for a malignancy with autologous stem cell transplant (5 to 18 years) in the Alberta Children’s Hospital will be randomly assigned to an exercise or control group. The exercise group will participate in a two-phase exercise intervention (in- and outpatient) from hospitalization until 10 weeks after discharge. The exercise program includes strength, flexibility and aerobic exercise. During the inpatient phase this program will be performed 5 times/week and will be supervised. The outpatient phase will combine a supervised session with two home-based exercise sessions with the use of the Wii device. The control group will follow the standard protocol without any specific exercise program. A range of outcomes, including quantitative and functional recovery of immune system, cytokine levels in serum, natural killer (NK) cells and their subset recovery and function, and gene expression of activating and inhibitory NK cell receptors, body composition, nutrition, quality of life, fatigue, health-related fitness assessment and physical activity levels will be examined, providing the most comprehensive assessment to date.

Discussion

We expect to find improvements in immunological recovery and quality of life, and decreased acquisition of sedentary behavior and fitness deconditioning. The comprehensive outcomes generated in this RCT will provide preliminary data to conduct a multisite study that will generate stronger outcomes.

Trial registration

Gov identification # NCT01666015

Multivariate analysis of the relation between immune dysfunction and treatment intensity in children with acute lymphoblastic leukemia

BACKGROUND

Immunoreconstitution following childhood acute lymphoblastic leukemia (ALL) is a complex process during which various immune functions recover differentially. This process is difficult to elucidate since variables are interrelated and require simultaneous evaluation, rendering conventional statistical methods inappropriate.

PROCEDURE

We used principal components analysis (PCA) and projection of latent structures (PLS) to evaluate immune competence in 32 children treated for ALL. One or 6 months after completion of therapy, the relation between lymphocyte subpopulations, lymphocyte function and response to vaccination with tetanus, diphtheria and hemophilus influenzae, was investigated.

RESULTS

PCA demonstrated that increasing treatment intensity correlated with progressive immune dysfunction. Children treated with high intensity had poor response to vaccination associated with loss of humoral memory, decreased CD4(+) 45RA(+) T-lymphocytes and increased CD5+ B-lymphocytes. Patients treated with intermediate intensity had better preservation of humoral memory but decreased CD4(+) 45RA(+) T-cells. Patients with a low intensity regimen had similar vaccination response and lymphocyte levels as controls.

CONCLUSIONS

Our findings demonstrate the utility of PCA and PLS in detecting hidden structures in complex data and suggest that, even 6 months after therapy, patients treated with intermediate and high intensity have attenuated responses to de novo antigens whereas those with high intensity also respond poorly to recall antigens.

Immunization after the elective end of antineoplastic chemotherapy in children

The aim of the present commentary is to discuss the multifaceted topic of vaccinations after treatment for cancer in the pediatric age. Publications in this field reveal conflicting data and opinions; no evidence-based guidelines currently exist. However, in spite of several discrepancies some commonly accepted information and conclusions exist. Efforts to find a common strategy of re-immunization should be directed towards setting up prospective studies on sufficient numbers of patients to obtain statistically relevant end points.

Longitudinal assessment of immunological status and rate of immune recovery following treatment in children with ALL

BACKGROUND

We prospectively evaluated the immunological status, immune recovery and risk of infection in pediatric ALL patients treated on the BFM 95 protocol.

PROCEDURE

Humoral and cellular immunity were evaluated in 72 children with ALL at the end of intensive therapy and values were compared to those at the completion of therapy and 6-monthly. Parameters investigated included lymphocyte subpopulation by flow cytometry, immunoglobulin levels by nephelometry, antibody titers to previous immunizations and delayed hypersensitivity with skin testing. Immune responses were correlated to duration of therapy, CNS radiotherapy, age and sex.

RESULTS

Humoral immunity was severely depressed by the end of intensive therapy with low immunoglobulin levels and CD19, improved after therapy cessation. Cellular immune responses were normal at the end of intensive treatment but declined significantly by the end of therapy and both CD4 and CD8 remained low at later evaluation points whereas CD4/CD8 ratio was increasing. Duration of therapy and CNS radiotherapy did not affect the rate of immune recovery whereas female had higher CD19, CD45RO, and IgM and children >7 years had higher CD19 and lower CD16 and CD3DR. Among immunized children, 86.7% maintained protective antibodies to MMR and 63% to polio. Despite impairment of immunity, infections outside the neutropenic periods were common viral illnesses.

CONCLUSION

Humoral immunity was depressed in children with ALL at the end of intensive therapy but began to recover after cessation of therapy. In contrast, cellular immunity declined significantly by the end of therapy and remained abnormal for at least 1 year post-therapy.

Monitoring of inosine monophosphate dehydrogenase activity in mononuclear cells of children with acute lymphoblastic leukemia: enzymological and clinical aspects

BACKGROUND

Inosine 5'-monophosphate dehydrogenase (IMPDH; EC1.1.1.205) catalyzes the rate-limiting step in guanine nucleotide biosynthesis, and may play an important role in treatment of patients with antipurines.

METHODS

We used an HPLC method to measure the IMPDH activity in peripheral blood and bone marrow mononuclear cells (MNC). IMPDH activities were determined in children who were diagnosed with and treated for acute lymphoblastic leukemia (ALL), and in a group of control children.

RESULTS

The median IMPDH activity for control children was 350 pmol/10(6) pMNC/hr (range 97-896; n = 47). No gender or age differences were observed. IMPDH activity at diagnosis of ALL was correlated with the percentage of peripheral blood lymphoblasts (r = 0.474; P < 0.001; n = 71). The median IMPDH activity at diagnosis was 410 pmol/10(6) pMNC/hr (range 40-2009; n = 76), significantly higher than for controls (P = 0.012). IMPDH activity significantly decreased after induction treatment, and during treatment with methotrexate (MTX) infusions (median 174 pmol/10(6) pMNC/hr; range 52-516; n = 21). The activity remained low during maintenance treatment with 6-mercaptopurine (6MP) and MTX, at a significantly lower level than for controls (P < 0.004). One year after cessation of treatment IMPDH activity returned to normal values.

CONCLUSION

The decrease of IMPDH activity at remission of ALL seems to be at least partly due to the eradication of lymphoblasts with the type 2 isoform of the enzyme.

Immune thrombocytopenia following successful treatment of cancer in children

A predisposition to developing immune thrombocytopenia (ITP) has not been reported in survivors of childhood cancer. We report a case series of childhood cancer survivors who developed an isolated thrombocytopenia in the presence of a normocellular bone marrow. Five children, two with endodermal sinus tumors and three with acute lymphoblastic leukemia, developed ITP at a median of 4 years (range: 0.2-8 years) after completion of therapy. We suggest the association of ITP in survivors of childhood malignancy may not be co-incidental as chemotherapy may cause persistent immune dysfunction.

Immune reconstitution after childhood acute lymphoblastic leukemia is most severely affected in the high risk group

OBJECTIVE

The aim was to examine the immune reconstitution after current chemotherapy for childhood ALL, with a special focus on finding immunologic variables that predict a poor immune response to vaccinations.

PROCEDURE

In a cross-sectional study of 31 children after treatment with the NOPHO ALL-1992 protocol peripheral blood lymphocyte subsets, T- and B-cell function in vitro and serum immunoglobulins (Ig) were measured. All patients were examined once, at 1 or at 6 months after cessation of chemotherapy, immediately before vaccination with DT and Hib.

RESULTS

Lymphocytes, T-cells, and CD4+ T-cells were low at 6 months after treatment. Naive T-cell subsets were more reduced than memory subsets. In the high risk (HR) ALL group, CD8+ T-cells were reduced at 6 months. NK-cells were low at 1 month, but normal at 6 months; however, the CD3+CD56+ (NKT) subset was reduced at both time points. Total B-cell number was low at 1 month, but normal at 6 months. A relative increase of CD5+ B-cells (B-1 cells) was evident, particularly in the HR group. Antigen-independent T- and B-cell function in vitro were affected at 1 month, but virtually normalized at 6 months. Serum IgM level was decreased at 1 month and IgG3 level was increased at 1 and 6 months.

CONCLUSIONS

This study shows that immune reconstitution after childhood ALL is slower than previously reported and emphasizes the influence of treatment intensity. The most intensively treated patients still have persistent abnormalities in T-, B-, and NK-cell subsets at 6 months post therapy and show a poor response to immunization with T-cell dependent antigens. In the HR group, routine re-immunizations before this time point are of limited benefit, and the effect of repeated vaccinations should be evaluated.

A nine-year experience of immunoprophylaxis against hepatitis B virus infection in children with cancer: results from a single institution in Poland

The results of a nine-year study of immunoprophylaxis against HBV infection in children with cancer during anticancer therapy are presented. Three hundred and fifty-three children entered the study. The preventive strategy involved three different patterns of passive and active prophylaxis. Specific anti-HBV immunoprophylaxis introduced simultaneously with anticancer therapy resulted in protection of 95.2% of children; 62% of patients produced antibodies. Long-term follow-up confirmed stable protection. Better results were obtained in children who received the last dose of vaccine after chemotherapy. The overall infection rate was 5.4% (19/353). Thirteen (68.4%) of the 19 infections occurred in patients who had not received hepatitis B immunoglobulin at the beginning of anticancer therapy. Children vaccinated before chemotherapy (during a neonatal vaccination programme) showed continuous protection after one dose of vaccine in 94% cases. In three cases, both HBsAg and anti-HBs was observed. A preventive strategy for viral hepatitis in children with cancer that includes passive and active HBV immunoprophylaxis from the beginning of chemotherapy is effective.

Immune recovery in children with malignancy after cessation of chemotherapy

PURPOSE

To study longitudinally the extent and recovery of cellular and humoral immune alterations in children with cancer after completion of their therapy.

PATIENTS AND METHODS

Using standard immune assays, cellular and humoral immunity was measured in 43 infants and children with cancer at completion of therapy and every 3 months thereafter for 1 year. There were 17 patients with acute lymphoblastic leukemia, 9 with Hodgkin disease, and 17 with solid nonhematopoietic tumors. All children had received standard childhood immunizations before diagnosis of cancer. Immune assays performed included circulating lymphocyte subpopulations, in vitro antigen-induced responses, and total concentrations of serum immunoglobulin G (IgG), IgM, IgA, and IgG subclasses, and specific antibodies against diphtheria, tetanus, pertussis, and poliovirus types I, II, and III.

RESULTS

At completion of therapy, the majority of patients had low circulating lymphocyte subpopulations and antigen-induced responses. Serum antibody concentrations were low in up to 89% of patients regardless of the underlying malignancy. Although improvement occurred during the year of follow-up, 35 of 43 (81%) patients continued to exhibit one or more immune abnormalities 9 to 12 months after cessation of chemotherapy. Younger patients had more persistent alterations. Other risk factors studied (including gender, duration of therapy, and underlying malignancy) did not correlate with the severity of the immune defects. With the exception of poliovirus antibodies, specific antibody titers against common childhood vaccine antigens were deficient at completion of therapy and 9 to 12 months later in a substantial proportion of patients.

CONCLUSION

Children with malignancy have persistent specific and nonspecific immune alterations 9 to 12 months after cessation of chemotherapy. The clinical implications of these in vitro observations are unclear and require further evaluation.