Recovery of blood lymphocytes and serum immunoglobulins after treatment of solid tumors in children

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.

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.

Baseline CD3+CD56+ (NKT-like) Cells and the Outcome of Influenza Vaccination in Children Undergoing Chemotherapy

Background

In children undergoing chemotherapy yearly influenza vaccination is recommended by treatment protocols. We investigated the relationship between cellular immunity and the antibody response to inactivated influenza vaccines.

Methods

25 patients (age: 2-18 years) undergoing chemotherapy for different malignancies participated in our study. Flow cytometric detection of peripheral blood lymphocyte subpopulations together with hemagglutination inhibition antibody titers were measured before and 21-28 days after vaccination. We examined the ratio and total numbers of CD3+, CD4+, CD8+ T cells, activated helper (CD3+CD4+CD25^low), regulatory (CD3+CD4+CD25^high), naive (CD3+CD45RA+) and memory (CD3+CD45RO+) T cells, CD56+NK, and CD3+CD56+ (NKT-like) cells. Relationships between specific antibody responses (seroprotection, seroconversion, geometric mean titer (GMT), geometric mean fold increase (GMFI)) and the ratios and counts of lymphocyte subpopulations were evaluated using one-way ANOVA and the paired sample t test after dichotomization according to age-related reference values.

Results

Patients with CD4+ lymphocyte levels in the normal age-specific range showed significantly better response regarding postvaccination GMT elevation for H1N1 and H3N2 strains (97.52 vs. 19.2, p=0.019, 80 vs. 14.43, p=0.021, respectively). GMFI results were significant only against B strain (2.69-fold vs. 1.23-fold, p=0.046). Prevaccination CD3+CD56+ (NKT-like) cells above predicted values according to age showed significant associations both in postvaccination GMT elevation (H1N1: 75.11 vs. 14.14, p=0.010; H3N2: 62.18 vs. 11.22, p=0.012; B: 22.69 vs. 6.67, p=0.043) and GMFI against all three strains (H1N1: 3.76-fold vs. 1.06-fold, p=0.015; H3N2: 2.74-fold vs. 1, p=0.013; B: 2.57-fold vs. 1, p=0.008). By one-way ANOVA, we found a positive relation between absolute lymphocyte cell count above 1000/µl and the postvaccination GMT elevation against H3N2 (12.81 vs. 56.56, p=0.032), and GMFI regarding H1N1 (1.22-fold vs. 3.48-fold, p=0.044).

Conclusions

In addition to verifying the predictive value of absolute lymphocyte count above 1000/µl, our results suggest an association between NKT-like cell counts and the specific antibody response against all three investigated influenza strains in highly immunosuppressed patients. Furthermore, prevaccination CD4+ lymphocyte levels in the normal age-specific range may influence seroresponse.

Fine Particulate Matter and Respiratory Healthcare Encounters among Survivors of Childhood Cancers

Some chemotherapies that treat childhood cancers have pulmonary-toxic properties that increase risk for adverse respiratory-health outcomes. PM_2.5 causes similar outcomes but its effect among pulmonary compromised cancer survivors is unknown. This case-crossover study identified the PM_2.5-associated odds for primary-respiratory hospitalizations and emergency department visits among childhood cancer survivors in Utah. We compared risk among chemotherapy-treated survivors to a cancer-free sample. We calculated 3-day-average PM_2.5 by ZIP code and county for event and control days. Conditional logistic regression estimated odds ratios. Models were stratified by cause of admission (infection, respiratory disease, asthma), previous chemotherapy, National Ambient Air Quality Standard (NAAQS), and other variables. Results are presented per 10 µg/m³ of PM_2.5. 90% of events occurred at 3-day PM_2.5 averages <35.4 µg/m³, the NAAQS 24-h standard. For survivors, PM_2.5 was associated with respiratory hospitalizations (OR = 1.84, 95% CI = 1.13⁻3.00) and hospitalizations from respiratory infection (OR = 2.09, 95% CI = 1.06⁻4.14). Among chemotherapy-treated survivors, the PM_2.5-associated odds of respiratory hospitalization (OR = 2.03, 95% CI = 1.14⁻3.61) were significantly higher than the cancer-free sample (OR = 0.84, 95% CI = 0.57⁻1.25). This is the first study to report significant associations between PM_2.5 and respiratory healthcare encounters in childhood cancer survivors. Chemotherapy-treated survivors displayed the highest odds of hospitalization due to PM_2.5 exposure and their risk is significantly higher than a cancer-free sample.

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.

An assessment of selected immune parameters of patients with Hodgkin's disease

Malignancy and oncologic treatment lead to various secondary immune disorders. In particular, little is known regarding immune reconstitution following cancer therapy. Lymphocytes, their subpopulations and immunoglobulin serum concentrations were assessed in patients with Hodgkin's disease at diagnosis (group I, 26 patients), cessation of therapy (group II, 21 patients) and 2 years after treatment (group III, 18 patients). Absolute lymphocyte count was significantly decreased in group II only (15/21 vs. 6/26 and 0/18 patients). In group I, the absolute count of the following subsets were decreased: Cluster of differentiation 19⁺ (CD19⁺) (18/26 patients), CD3⁺ (13/26), CD3⁺CD4⁺ (11/26) and CD3⁺CD8⁺ (7/26). In group II, the reduction of CD19⁺, CD3⁺ and CD3⁺CD4⁺ cell counts was evident (12/21, 16/21 and 19/21 patients, respectively), with the CD3⁺CD4⁺/CD3⁺CD8⁺ ratio distinctly lowered in the majority of patients (16/21). Similar changes in the percentages of lymphocyte subsets were observed. In the majority of patients in group III, the percentage of lymphocyte subsets were normal, but absolute lymphocyte counts were elevated (CD19⁺ in 11/18, CD3⁺ in 12/18, CD3⁺CD4⁺ in 13/18 and CD3⁺CD8⁺ in 11/18 patients). In half the patients at diagnosis, immunoglobulin G (IgG) was significantly elevated. In conclusion, disorders assessed in the percentage distribution and individual subpopulations of lymphocytes was applicable mainly to patients at the time of the diagnosis and shortly following completion of treatment. The analysis of time-distant consequences showed disorders only in the content of the percentage of CD4⁺ memory cells. The concentration of IgG at the time of diagnosis was significantly elevated in half the patients, which is possibly associated with the pathogenesis of the disease. The treatment does not appear to noticeably affect the production of IgG, IgA and IgM.

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.

Immune response to conjugated meningococcal C vaccine in pediatric oncology patients

BACKGROUND

Following outbreaks of meningococcal disease in Quebec in 1991-1993 and 2000-2001, a mass vaccination campaign was performed. In 2001-2002, children aged 2 months to 20 years were immunized with the Meningococcal CRM197 vaccine (Menjugate). We examined the response of pediatric oncology patients during or following maintenance chemotherapy and post-bone-marrow transplantation to Meningococcal C vaccine.

PROCEDURE

This was an open label descriptive study of a cohort of patients from the oncology clinic at the Montreal Children's Hospital. A positive vaccine response was defined as a fourfold increase in specific IgG from baseline and a bactericidal assay using human complement (hBCA) titer >1:4.

RESULTS

Of the 25 patients with ALL, 13 had a serologic response (average 60-fold increase). The serologic responders had a higher mean B cell count (0.262) compared to non-responders 0.068 x 10.9/L [t(23) = 2.843 (P < 0.05)]. Eleven of the 12 non-responders and 4 of the responders were on maintenance chemotherapy. In addition, two of the five patients post-bone-marrow transplant, responded. Fifteen of the 34 patients (44%) had an adequate hBCA response (mean titer 61). The group included 14/18 serologic responders with hBCA response (P < 0.001) and 16/17 non-serologic responders with no hBCA response (P < 0.001).

CONCLUSIONS

Meningococcal C-conjugate vaccine produced variable responses in children with common cancers. Proximity to chemotherapy and total B cell number may help predict likelihood of response.

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.

Impairment of nasal mucociliary clearance after radiotherapy for childhood head cancer

BACKGROUND

Radiotherapy of the head region in children is known to cause long-term sequelae, such as facial, dental, and ocular abnormalities. We investigated whether a decreased nasal mucociliary function occurs after radiotherapy of the head in children.

METHODS

A saccharin/charcoal test was performed in 20 children treated with radiotherapy of the head and in 20 controls, age-matched and gender-matched.

RESULTS

We found a decreased nasal mucociliary clearance (lower percentage of responses (p = 0083) and longer mucociliary transport times (p =.0001) in the patients compared with the controls. The radiotherapy dosage influenced the response to the test (p =.0046).

CONCLUSIONS

Irradiation of the head in children may cause impairment of mucociliary function, even permanently, which may predispose children to upper respiratory infections. We would suggest careful monitoring of such patients to detect as early as possible the clinical effects of the functional changes and to prevent the evolution to chronic diseases.

[Immunization for children treated for solid tumors: what are the guidelines?]

There is no agreement on immunization of children treated with chemotherapy (CT) for solid tumors. Based on a review of the literature, we have attempted to establish guidelines on this subject. Except for hepatitis B vaccine, there is no argument to support the use of vaccine during CT. After a standard CT, a 3-month washout period appears to be necessary before starting an immunization program for a child not previously vaccinated, or to proceed with the recommended booster injections for diphteria anatoxin, tetanus vaccine, poliomyelitis inactivated vaccine, pertussis vaccine, and haemophilus influenza type b vaccine if the child is less than 5 years old. For mumps, measles, and rubella live vaccines, a longer post-CT washout of 6 months is suggested for the initial immunization, or for a revaccination of a child proved to be negative for all three serologies. Following high-dose CT a minimal 12-months term and a normalization of the blood lymphocytes count is necessary before planning booster injections once having checked for antidiphteria, tetanic, polio, measles, mumps, rubella and +/- haemophilus antibody titles. We don't find any reason to recommend a systematic varicella immunization in pediatric oncology. Pneumococcal vaccine is recommended in case of asplenia. Any other vaccination (BCG, influenza, yellow fever) must be evaluated individually.

Military service of male survivors of childhood malignancies

BACKGROUND

The objective of this study was to assess the eligibility for and the course of compulsory military service of childhood cancer survivors.

METHODS

The medical, military recruitment, conscription, and military service data of male Finnish childhood cancer survivors were collected from manually filed records. Inclusion criteria were: survivors born 1977 or earlier, treated for a malignancy between birth and age 15 years, and followed by a pediatrician until at least age 18 years. The documents of 207 survivors from the Pediatric Clinics of Finnish University Hospitals were examined, and 130 of these survivors were considered eligible for military service. Demographic factors, the predictors of fitness for military service, factors associated with service interruption, the attained level of military training, and the health status of conscripts during service were evaluated. Comparisons were made with the Finnish male population of the same age and with conscripts serving at the corresponding time.

RESULTS

Approximately 60% of studied survivors were enlisted. Positive predictors of fitness for service were year of birth of 1973 or later (odds ratio [OR], 3.2), height at call-up age of 170-174.9 cm (OR, 3.6), and the man's own positive opinion of his fitness for service (OR, 62.3). Negative predictors were age at diagnosis > or = 11 years (OR, 0.5), central nervous system radiotherapy (OR, 0.3), limb defects (OR, 0.02), and the group of sequelae concerning neurologic, cardiopulmonary, and gastrointestinal systems, or secondary malignancies (OR, 0.3). Survivors interrupted their service more often (20%) (P < 0.001). Leukemia survivors were less likely to interrupt their service (7%) compared with other survivors (P = 0.04). Factors associated with service interruption were: diagnosis (P = 0.04), the man's own opinion of his fitness for service (P = 0.013), surgery (P = 0.003), and height (P = 0.049), weight (P = 0.019), and body mass index (P = 0.035) at the beginning of military service. The attained level of military training was equal to that of controls. The survivors visited the garrison physician less frequently in total (mean, 5.9 times) (P < 0.001), visited because of infections as much as controls, and were off duty more (mean, 11.9 days) (P = 0.012) than controls.

CONCLUSIONS

The current study found that childhood cancer survivors were less likely to meet the requirements set for military service in Finland. The causes of rejection usually were obvious, but approximately 30% were rejected merely on the basis of a former cancer diagnosis. However, enlisted survivors coped well with military service if their treatment sequelae were taken into consideration carefully at the time of enlistment. Vocational opportunities within the armed forces might be an appropriate career option even for survivors of childhood malignancies.