Recovery of blood B-lymphocytes and serum immunoglobulins after chemotherapy for childhood acute lymphoblastic leukemia

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.

Mimicking Natural Metabolisms: Cell-Free Flow Preparation of Dopamine

The biosynthesis of dopamine (DA) from L-tyrosine as starting material is an excellent yet challenging strategy. Here we developed a versatile, multi-enzymatic platform for the biocatalytic preparation of DA in a continuous mode with excellent conversion (90 %) and reaction time (45 min). The system exploits the immobilization of a decarboxylase from Bacillus pumilis (Fdc) and a tyrosinase from Agaricus bisporus (Tyr), which were combined to mimic the in-vivo synthesis of DA (both primary and secondary metabolisms) giving rise to an efficient strategy with a considerable reduction of process associated costs and environmental impact. To enhance the system automation, an in-line purification via catch-and-release procedure was added.

Vaccination of Immunocompromised Cats

Immunocompromise is a common condition in cats, especially due to widespread infections with immunosuppressive viruses, such as feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV), but also due to chronic non-infectious diseases, such as tumours, diabetes mellitus, and chronic kidney disease, as well as treatment with immunosuppressive drugs, such as glucocorticoids, cyclosporins, or tumour chemotherapy. In this review, the European Advisory Board on Cat Diseases (ABCD), a scientifically independent board of experts in feline medicine from eleven European countries, discusses the current knowledge and rationale for vaccination of immunocompromised cats. So far, there are few data available on vaccination of immunocompromised cats, and sometimes studies produce controversial results. Thus, this guideline summarizes the available scientific studies and fills in the gaps with expert opinion, where scientific studies are missing. Ultimately, this review aims to help veterinarians with their decision-making in how best to vaccinate immunocompromised cats.

Vaccination coverage in hematological patients undergoing chemotherapy: Should we move towards personalized vaccination?

INTRODUCTION

Immunocompromised patients are at high-risk for severe influenza and invasive pneumococcal diseases (IPD). Despite the French Public Health Council (FPHC) and the 7th European Conference on Infections in Leukaemia (ECIL7) recommendations, vaccination coverage remains insufficient. This study aimed to estimate the coverage and determinants of influenza, pneumococcal and diphtheria-tetanus-poliomyelitis (dTP) vaccinations in hematological patients underlying chemotherapy.

METHODS

A survey was distributed to all patients of the hematology day hospital assessing vaccine uptakes and general opinion about vaccination. Vaccine uptakes were collected from medical and vaccination records; knowledge of and attitudes towards vaccinations in immunocompromised patients were evaluated for each general practitioner (GP) by phone call. Adequacy between vaccine uptakes and indication or not to vaccinate according to ECIL7 guidelines was assessed. Factors associated with vaccine uptakes were assessed by multivariate logistic regression.

RESULTS

Among 145 patients, 66 % were aged 65 years or older, 40 % were followed for lymphoma and 38 % for multiple myeloma, 39 % were treated with anti-CD20 antibodies. Vaccination coverage was suboptimal for influenza (45-56 %), dTP (44 %) and IPD (16-19 %) regardless of the guidelines followed, with a wide variation in rates by information source (19-76 %). Adequacy rate with ECIL7 recommendations were 63 % and 87 % for influenza and IPD respectively. Information of patients on specific vaccinations was positively associated with flu and IPD vaccinations, as well as favorable attitude toward vaccination and age ≥ 65 years for flu vaccination, and recommendation by hematologist for pneumococcal vaccination.

CONCLUSION

Despite vaccination opportunities, the complexity of these specific recommendations and the lack of communication between the health actors could explain the suboptimal vaccination coverage in this high-risk population. A proactive attitude of all actors in the city and hospital, including better patient information and a personalized and evolving vaccination schedule to help GPs to coordinate vaccination would allow to improve vaccine coverage.

Prospective clinical trial of hepatitis B vaccination for children with hematological malignancies: a study on the safety and immunogenicity efficacy

Children with hematological malignancies are at increased risk of hepatitis B virus infection. This study assessed the immunogenicity and safety profile of HBV vaccination in pediatric hemato-oncological children. A nonrandomized interventional study was conducted from January 2017 to February 2020 in Shanghai, China. Seventy-three pediatric hemato-oncological children with hepatitis B surface antibody (anti-HBs) titers <10 mIU/ml were recruited. The participants received three doses of recombinant HBV vaccine according to the 0-, 1-, and 6- month immunization schedule. Adverse events following immunization and anti-HBs titers (at baseline, 1 month, and 6 months after inoculation) were recorded. Forty-three males and thirty females with median ages of 9.12 and 9.60 years, respectively, were included. The mean anti-HBs titer was 4.88 ± 2.61 mIU/ml, 893.12 ± 274.12 mIU/ml, and 711.45 ± 337.88 mIU/ml at baseline, one month, and six months after inoculation, respectively (P< .001). A total of fourteen adverse events following immunization were reported, and among them, 5 (6.85%), 5 (6.85%), and 4 (5.48%) events were reported after the first, second, and third inoculation, respectively (P= .927). In conclusions, the HBV vaccine is immunogenic and safe in children with hematological malignancies. It is worth noting that the anti-HBs titer was decreased at the 6-month follow-up, and periodic monitoring of the anti-HBs titer accompanied by timely booster vaccination should be carefully considered.Abbreviations: AEFI: Adverse events following immunization; HBV: Hepatitis B virus; Anti-HBs: Antibody against hepatitis B surface antigen; HBsAg: Hepatitis B surface antigen; APC: Antigen-presenting cell; HSCT: Hemopoietic stem cell transplantation; COVID-19: Corona Virus Disease 2019.

Immunization status and re-immunization of childhood acute lymphoblastic leukemia survivors

Intensive chemotherapy can cause long-lasting immunosuppression in children who survived cancer. The immunosuppression varies according to the type of cancer, intensity of chemotherapy and age of the patient. A sufficient immune reconstruction when has been completed in childhood cancer survivors, the re-vaccination program can achieve sufficient antibody levels for some of the life-threatening vaccine-preventable infectious diseases. This study evaluates the serological status of pediatric acute lymphoblastic leukemia (ALL) cases before and after the intensive chemotherapy treatment. Antibodies against measles, mumps, rubella, varicella, hepatitis A and B were tested with the enzyme-linked immunosorbent assay (ELISA) method. Antibody titers were measured firstly at the leukemia diagnosis time when the chemotherapy was not started. The second evaluation of antibody titers was studied at 6 months after the cessation of chemotherapy for all patients. Forty-six patients with the mean age of 6.1 ± 4.5 years were participated in this study. Changing to seronegative after treatment was significantly different in measles, rubella, hepatitis A and hepatitis B (p < .05). Seventy-eight (28%) antibody levels in the patients were non-protective for all diseases. Only three (7%) patients had protective antibody levels for all diseases in the sixth month of chemotherapy cessation. There was a negative correlation between patient's age and losing protective antibody levels for any vaccine-preventable disease (p < .05). Antibody levels against vaccine-preventable diseases have evident that reduced after ALL treatment at childhood. Pediatric ALL survivors must be re-vaccinated for vaccine-preventable diseases after achieving immune reconstruction.

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.

Changes in hepatitis B antibody status after chemotherapy in children with acute lymphoblastic leukemia

BACKGROUND

Children with cancer may be at an increased risk of infection with hepatitis B virus (HBV) when levels of hepatitis B antibodies are reduced owing to chemotherapy-induced immunosuppression. This study evaluated the changes in HBV antibody status and HBV infections after chemotherapy in children with acute lymphoblastic leukemia (ALL).

PROCEDURE

The data of patients with ALL diagnosed between April 2007 and March 2013 were retrospectively collected. Hepatitis B surface antibody (HBsAb) titers were defined as negative at levels <10 IU/L. The HBsAb titers were individually compared before and after chemotherapy.

RESULTS

A total of 88 patients were included in this study. At the time of diagnosis, 32 (36.4%) and 56 (63.6%) patients were HBsAb negative and HBsAb positive, respectively. The 56 HBsAb-positive patients were categorized into two groups, namely, group A with 44 patients (78.6%, 44/56) who became HBsAb negative after chemotherapy, and group B with 12 patients (21.4%) who remained HBsAb positive. On multivariate analysis, lower initial levels of HBsAb titers were associated with HBsAb negativity after chemotherapy (relative risk: 1.003, 95% confidence interval: 1.001-1.006; P = .009).

CONCLUSION

This study demonstrated that patients with a low level of prechemotherapy HBsAb titers were likely to become HBsAb negative after chemotherapy. Therefore, evaluation of HBsAb status may be necessary after the completion of chemotherapy in children with ALL.

Noninvasive Detection of Antibodies to Human T-Cell Lymphotropic Virus Types 1 and 2 by Use of Oral Fluid

Human T-lymphotropic viruses type 1 and 2 (HTLV-1/2) are prevalent in endemic clusters globally, and HTLV-1 infects at least 5 to 10 million individuals. Infection can lead to inflammation in the spinal cord, resulting in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), or adult T cell leukemia/lymphoma (ATL). Obtaining venous blood for serological screening, typically performed using enzyme immunoassays (EIAs), is invasive, sometimes socially unacceptable, and has restricted large-scale seroprevalence studies. Collecting oral fluid (OF) is a noninvasive alternative to venesection. In this study, an IgG antibody capture EIA was developed and validated to detect anti-HTLV-1/2 IgG in OF. OF and plasma specimens were obtained from seropositive HTLV-1/2-infected patients attending the National Centre for Human Retrovirology (n = 131) and from HTLV-1/2-uninfected individuals (n = 64). The assay showed good reproducibility and high diagnostic sensitivity (100%) and specificity (100%) using both OF and plasma. The Murex HTLV I+II commercial assay was evaluated and did not detect anti-HTLV-1/2 IgG in 14% (5/36) of OF specimens from seropositive donors. The reactivities of OF and plasma in the IgG capture correlated strongly (r = 0.9290) and were not significantly affected by delayed extraction when held between 3°C and 45°C for up to 7 days to simulate field testing. The use of OF serological screening for HTLV-1/2 infection could facilitate large-scale seroprevalence studies, enabling active surveillance of infection on a population level.

Seroprevalence of Hepatitis A Virus in Pediatric Patients with Hematologic Malignancies after Chemotherapy and Hematopoietic Cell Transplantation

This retrospective study was performed to determine the seroprevalence of hepatitis A virus (HAV) in children and adolescents with hematologic malignancies after the completion of chemotherapy and hematopoietic cell transplantation (HCT). Of 97 enrolled patients, 60 (61.9%) were seropositive for HAV. The seroprevalences in patients undergoing chemotherapy and HCT were 60.3% (41/68) and 65.5% (19/29), respectively (P = 0.628). No significant factors associated with seropositivity for HAV after chemotherapy and HCT were identified. Anti-HAV tests and HAV re-vaccinations can be considered in children and adolescents with underlying hematologic malignancies after chemotherapy and HCT based on the anti-HAV results.

Postchemotherapy Immunization Practices for Non-HSCT Pediatric Oncology Patients

Pediatric oncology patients treated with antineoplastic therapy have impaired immune systems that lead to loss of protective antibodies. They require reimmunization to protect against vaccine-preventable diseases. There are a paucity of studies on the clinical practice of pediatric oncologists and the available recommendations are heterogenous. This study describes current reimmunization practices among pediatric oncologists. We surveyed the Children's Oncology Group (COG)-identified principle investigators to capture clinical practices among pediatric oncologists within their institutions regarding reimmunization of non-hematopoietic stem cell transplantation patients. The majority of respondents did not routinely assess vaccine-related immune status; those who did most frequently assessed 6 months after cessation of therapies. Methods of assessment included type of therapy received, vaccine titers, and absolute lymphocyte counts. Providers from smaller institutions were more likely to check vaccine titers than those from larger institutions. More than half of the surveyed institutions did not have standardized guidelines available for practitioners. There are variations in reimmunization practices among pediatric oncologists despite available guidelines on recommended schedules. Further research is needed to identify the safest and most cost-effective way to insure immunity to infectious disease after the treatment of childhood cancer.

Assessment of Humoral Immunity to Hepatitis B, Measles, Rubella, and Mumps in Children After Chemotherapy

BACKGROUND

Cancer survival rates and longevity of patients after therapy have significantly improved during the last few decades. Therefore, lasting protection against infections should be provided.

PROCEDURE

A total of 162 children diagnosed with acute lymphoblastic leukemia, acute myelogenous leukemia, solid tumors, non-Hodgkin lymphoma, and Hodgkin lymphoma were enrolled in the study. Antibody levels against hepatitis B virus was assessed both at the time of diagnosis and within 6 months after completion of chemotherapy. However, measles, mumps, and rubella (MMR) antibodies levels were measured just within 6 months after completion of chemotherapy.

RESULTS

Anti-HBs antibody titers had decreased below the protective level after treatment in 25 of 96 patients having protective antibody levels for hepatitis B virus before therapy. In 66 patients without pretreatment protective levels of antibody, in spite of the immunization during chemotherapy, only 6 of them were found to be anti-HBS positive after treatment. In 153 patients previously vaccinated with MMR, 19 had protective antibody titers after treatment. MMR seropositivities were negatively correlated to age as expected.

CONCLUSIONS

Our data demonstrate that a significant number of children lose preexisting humoral immunity against MMR and hepatitis B after completion of chemotherapy.

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.

Efficacy of Compound Kushen Injection in Combination with Induction Chemotherapy for Treating Adult Patients Newly Diagnosed with Acute Leukemia

We assessed the clinical effectiveness and safety of CKI (compound Kushen injection) plus standard induction chemotherapy for treating adult acute leukemia (AL). We randomly assigned 332 patients with newly diagnosed AL to control (n = 165, receiving DA (daunorubicin and cytarabine) or hyper-CVAD (fractionated cyclophosphamide, doxorubicin, vincristine, and dexamethasone)) or treatment (n = 167, receiving CKI and DA or hyper-CVAD) groups. Posttreatment, treatment group CD3+, CD4+, CD4+/CD8+, natural killer (NK) cell, and immunoglobulin (IgG, IgA, and IgM) levels were significantly higher than those of the control group (p < 0.05), and CD8+ levels were lower in the treatment group than in the control group (p < 0.05). Treatment group interleukin- (IL-) 4 and IL-10 levels were significantly higher compared to the control posttreatment (both p < 0.05) as were complete remission, overall response, and quality of life (QoL) improvement rates (p < 0.05). The control group had more incidences of grade 3/4 hematologic and nonhematologic toxicity (p < 0.05). Responses to induction chemotherapy, QoL improvement, and adverse events incidence between control group patients with acute myeloid leukemia and acute lymphocytic leukemia were not significantly different. CKI plus standard induction chemotherapy is effective and safe for treating AL, possibly by increasing immunologic function.

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.

Vaccinations in patients with hematological malignancies

Patients with hematological malignancies are at risk for a number of infections that are potentially preventable by vaccinations such as pneumococcal infections and influenza. Treatment, especially with anti-B-cell antibodies and hematopoietic stem cell transplantation (HSCT), negatively impacts the response to vaccination for several months. It is therefore recommended that patients be vaccinated before initiating immunosuppressive therapy if possible. The risk of side-effects with inactivated vaccines is low, but care has to be taken with live vaccines, such as varicella-zoster virus vaccine, since severe and fatal complications have been reported. HSCT patients require repeated doses of most vaccines to achieve long-lasting immune responses. New therapeutic options for patients with hematological malignancies that are rapidly being introduced into clinical practice will require additional research regarding the efficacy of vaccinations. New vaccines are also in development that will require well-designed studies to ascertain efficacy and safety.

[Seroconversion in response to a reinforced primary hepatitis B vaccination in children with cancer]

INTRODUCTION

Immune response against vaccine antigens may be impaired in children with cancer. The aim of this study was to evaluate the seroconversion response against hepatitis B vaccination (HBV) at the time of chemotherapy onset and/or remission in children with cancer.

PATIENTS AND METHOD

Prospective, two-centre, controlled, non-randomised study conducted on children recently diagnosed with cancer, paired with healthy subjects. Cases received HBV at time 0, 1 and 6 months with DNA recombinant HBV at a dose of 20 and 40 μg if < or > than 10 years of age, respectively, at the time of diagnosis for solids tumours and after the remission in case of haematological tumours. Controls received the same schedule, but at of 10 and 20 μg doses, respectively. HBs antibodies were measured in serum samples obtained at 2, 8 and 12 months post-vaccination. Protective titres were defined as > 10 mIU/ml at 8th month of follow up.

RESULTS

A total of 78 children with cancer and 25 healthy controls were analysed at month 8th of follow up. Seroconversion rates in the cancer group reached 26.9%, with no differences by age, gender or type of tumour (P = .13, .29, and .44, respectively). Control group seroconversion was 100% at the 8th month, with P < .0001 compared with the cancer group. At month 12 of follow up, just 31.9% of children with cancer achieved anti-HBs antibodies > 10 mIU/ml.

CONCLUSIONS

Vaccination against hepatitis B with three doses of DNA recombinant vaccine at an increased concentration, administrated at the time of onset of chemotherapy and/or remission provided an insufficient immune response in a majority of children with cancer. More immunogenic vaccines should be evaluated in this special population, such as a third generation, with more immunogenic adjuvants, enhanced schedules at 0, 1, 2, 6 month, evaluation of antibody titres at month 8 and 12h to evaluate the need for further booster doses.

Varicella zoster immune status in children treated for acute leukemia

Children treated for acute leukemia are at increased risk of severe infection with varicella zoster virus (VZV). We studied the VZV sero-status of children with acute leukemia prior to starting chemotherapy and after completion of chemotherapy. VZV sero-status was assessed using time resolved fluorescence immunoassay (TRFIA) before starting treatment and 6 months after completion of treatment. Prior to starting treatment for acute leukemia, a significant proportion of children (35%) are VZV seronegative. On completion of treatment most patients maintained protective VZV antibody levels; however, 35% had reduced/loss VZV antibody to a level considered non-protective and susceptible to VZV infection.

Influence of chemotherapy for lymphoma in canine parvovirus DNA distribution and specific humoral immunity

In man, the combination of cancer and its treatment increases patients' susceptibility to opportunistic infections, due to immune system impairment. In veterinary medicine little information is available concerning this issue. In order to evaluate if a similar dysfunction is induced in small animals undergoing chemotherapy, we assessed the complete blood count, leukocytic, plasma and fecal canine parvovirus (CPV) viral load, and anti-CPV protective antibody titers, in dogs with lymphoma treated with CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone) protocol, before and during chemotherapy. There was no evidence of decreased immune response, either at admission or after two chemotherapy cycles, indicating that the previously established immunity against CPV was not significantly impaired, supporting the idea that immunosuppression as a result of hematopoietic neoplasms and their treatment in dogs requires further investigation and conclusions cannot be extrapolated from human literature.

Assessment of immune response following immunization with DTP/Td and MMR vaccines in children treated for acute lymphoblastic leukemia

BACKGROUND

This study was performed to determine the antibody titers against diphtheria-tetanus-pertussis, and measles-mumps-rubella before and after re-vaccination in different periods of time in patients with acute lymphoblastic leukemia (ALL) to provide a suitable vaccination schedule.

METHODS

Ninety patients with ALL were studied in three stages, including newly diagnosed patients, patients on maintenance therapy, and 1 to 12 months after cessation of therapy. Baseline antibody titers were assessed in all participants. Postimmunization antibody titers to DTP/Td and MMR vaccines were evaluated 3 weeks after vaccination.

RESULTS

Patients on maintenance therapy had considerable decreased in seropositivity rate; they achieved seroconversion rate of 100% for diphtheria and tetanus and of 71.4% for pertussis following DTP/Td vaccination. In patients after one month off therapy, the seroconversion rates for diphtheria, tetanus, and pertussis were 71.4%, 80%, and 100%, respectively. The amounts of seroconversion in patients after 3 months off therapy were 66.5%, 80%, and 66.5% for measles, mumps, and rubella, respectively. In patients after 6 months off therapy, the seroconversion rates were 85.7% for diphtheria, 100% for pertussis and tetanus, 83.3% for mumps, 50% for rubella, and 41.6% for measles. Patients after 12 months off therapy achieved seroconversion rate of 100% for diphtheria, tetanus, pertussis, and mumps, of 71.5% for rubella, and of 63.5% for measles.

CONCLUSION

Administration of one dosage of DTP/Td vaccine during maintenance therapy and after cessation of therapy could be recommended, while one dosage of MMR vaccine at least three months after completion of therapy could be safe and beneficial.

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.

Guidelines on vaccinations in paediatric haematology and oncology patients

OBJECTIVE

Vaccinations are the most important tool to prevent infectious diseases. Chemotherapy-induced immune depression may impact the efficacy of vaccinations in children.

PATIENTS AND METHODS

A panel of experts of the supportive care working group of the Italian Association Paediatric Haematology Oncology (AIEOP) addressed this issue by guidelines on vaccinations in paediatric cancer patients. The literature published between 1980 and 2013 was reviewed.

RESULTS AND CONCLUSION

During intensive chemotherapy, vaccination turned out to be effective for hepatitis A and B, whilst vaccinations with toxoid, protein subunits, or bacterial antigens should be postponed to the less intensive phases, to achieve an adequate immune response. Apart from varicella, the administration of live-attenuated-virus vaccines is not recommended during this phase. Family members should remain on recommended vaccination schedules, including toxoid, inactivated vaccine (also poliomyelitis), and live-attenuated vaccines (varicella, measles, mumps, and rubella). By the time of completion of chemotherapy, insufficient serum antibody levels for vaccine-preventable diseases have been reported, while immunological memory appears to be preserved. Once immunological recovery is completed, usually after 6 months, response to booster or vaccination is generally good and allows patients to be protected and also to contribute to herd immunity.

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.

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

Chemotherapy for childhood acute lymphoblastic leukemia (ALL) is a highly effective treatment, but at the same time causes significant suppression of the patient's immunity. Immune reconstitution was studied in a homogeneous cohort of 48 children with standard or medium risk ALL treated according to the ALL-Berlin-Frankfurt-Münster (BFM) protocol. Whereas the T-cell compartment was only moderately affected and recovered to normal levels quickly after treatment cessation, B-cells were significantly reduced during and after therapy. In particular, the naive B-cell compartment declined. Even 5 years after the end of therapy, B-cell distribution was disturbed and patients showed an ongoing reconstitution. Thus, even standard regimens for chemotherapy cause severe B-cell depletion that resolves only gradually.

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.

Assessment of serologic immunity to diphtheria-tetanus-pertussis after treatment of Korean pediatric hematology and oncology patients

The aim of this study was to investigate the diphtheria-tetanus-pertussis antibody titers after antineoplastic treatment and to suggest an appropriate vaccination approach for pediatric hemato-oncologic patients. A total of 146 children with either malignancy in remission after cessation of therapy or bone marrow failure were recruited. All children had received routine immunization including diphtheria-tetanus-acellular pertussis vaccination before diagnosis of cancer. The serologic immunity to diphtheria, tetanus and pertussis was classified as: completely protective, partially protective, or non-protective. Non-protective serum antibody titer for diphtheria, tetanus and pertussis was detected in 6.2%, 11.6%, and 62.3% of patients, respectively, and partial protective serum antibody titer for diphtheria, tetanus and pertussis was seen in 37%, 28.1%, and 8.9% of patients. There was no significant correlation between the severity of immune defect and age, gender or underlying disease. Revaccination after antineoplastic therapy showed significantly higher levels of antibody for each vaccine antigen. Our data indicates that a large proportion of children lacked protective serum concentrations of antibodies against diphtheria, tetanus, and pertussis. This suggests that reimmunization of these patients is necessary after completion of antineoplastic treatment. Also, prospective studies should be undertaken with the aim of devising a common strategy of revaccination.

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.

Immune reconstitution in children following chemotherapy for haematological malignancies: a long-term follow-up

Modern intensive chemotherapy for childhood haematological malignancies has led to high cure rates, but has detrimental effects on the immune system. There is little knowledge concerning long-term recovery of the adaptive immune system. Here we studied the long-term reconstitution of the adaptive immune system in 31 children treated for haematological malignancies between July 2000 and October 2006. We performed detailed phenotypical and functional analyses of the various B and T cell subpopulations until 5 years after chemotherapy. We show that recovery of newly-developed transitional B cells and naive B and T cells occurred rapidly, within months, whereas recovery of the different memory B and T cell subpopulations was slower and incomplete, even after 5 years post-chemotherapy. The speed of B and T cell recovery was age-independent, despite a significant contribution of the thymus to T cell recovery. Plasmablast B cell levels remained above normal and immunoglobulin levels normalised within 1 week. Functional T cell responses were normal, even within the first year post-chemotherapy. This study shows that after intensive chemotherapy for haematological malignancies in children, numbers of several memory B and T cell subpopulations were decreased on the long term, while functional T cell responses were not compromised.

Measles, mumps, and rubella antibody status and response to immunization in children after therapy for acute lymphoblastic leukemia

Seventy-seven patients with acute lymphoblastic leukemia (ALL) who were in complete remission and whose therapies had been stopped for at least 6 months before enrollment in this study were retrospectively analyzed regarding their antibody status for measles, mumps, and rubella, with the aim to demonstrate the seropositivity rate after treatment in the authors' group. Each patient's serum samples were analyzed by enzyme-linked immunosorbent assay (ELISA) method to determine the antibody titers before and after immunization. Measles serology was available in 77 children; 45 (58%) were seronegative. Initial ages of measle-seronegative patients were statistically lower than those of seropositive cases (median 3.29 versus 4.91 years, respectively). Mumps serology was available in 76 children; 36 (47%) were seronegative. Mumps-seropositive cases tended to have more frequent previous history of infection than seronegative cases (55.0% versus 28.6%, respectively, P = .05). Rubella serology was available in 76 children, and 20 (26.3%) were seronegative. It was determined that initial ages of rubella-seronegative patients were statistically lower than those of seropositive cases (median 3.03 versus 4.32 years, respectively). The authors concluded based on the results of their study that at a median of 3.31 years after completion of chemotherapy for ALL, the majority of cases had antibody levels lower than protective values for measles (58.4%); however, these values were 47.3% for mumps and 26.3% for rubella. Seroconversion rates after measles (55%) and mumps vaccination (57.1%) were still low. However, in the available cases, relatively adequate response to rubella vaccination (92.3%) was observed.

Impact of influenza-like illness and effectiveness of influenza vaccination in oncohematological children who have completed cancer therapy

In order to evaluate the impact of influenza-like illness and the effectiveness of influenza vaccination in children with oncohematological disease who have completed cancer therapy, 182 children with a diagnosis of oncohematological disease were divided into two subgroups on the basis of the length of time off therapy (<6 months or 6-24 months) and randomised 1:1 to receive influenza vaccination or not. The controls were 91 otherwise healthy children unvaccinated against influenza. The results show that the clinical and socioeconomic impact of influenza-like illnesses and the effectiveness of influenza vaccination in oncohematological children who have completed cancer therapy are related to the length of the off therapy period, and seem to be significantly greater in those who have been off therapy for less than 6 months in comparison with healthy controls. This suggests that the administration of influenza vaccination should be strongly recommended only among oncohematological children who have been off therapy for less than 6 months.

Humoral immunity to diphtheria, tetanus, measles, and hemophilus influenzae type b in children with acute lymphoblastic leukemia and response to re-vaccination

OBJECTIVE

Loss of immunity to previous vaccination and timing of re-vaccination in children receiving chemotherapy remains controversial. The aim of this study was to investigate the immunity to vaccine preventable diseases in children with acute lymphoblastic leukemia (ALL).

PROCEDURE

Sixty-one patients with ALL and 13 healthy siblings were enrolled. Three study groups included newly diagnosed patients (group 1), patients on maintenance chemotherapy (group 2), and patients that completed chemotherapy (group 3). Blood samples for baseline antibody titers were obtained from all the patients and controls. Patients in group 2 were vaccinated with diphtheria, tetanus, and hemophilus influenzae type b (Hib). Patients in group 3 and controls received the measles vaccine in addition to all the above vaccines. In groups 2 and 3, post-vaccination antibody titers were also obtained.

RESULTS

Patients and controls had no Hib vaccine during primary vaccination. After chemotherapy median antibody levels against diphtheria, tetanus, measles, and Hib were decreased but tetanus antibodies were still at the protective levels. Proportions of the patients with protective levels were 11.1%, 83.3%, 16.7%, and 16.7% for diphtheria, tetanus, Hib, and measles, respectively. Vaccination achieved protective antibody levels in 81%, 100%, 89.5%, and 70% of the patients for diphtheria, tetanus, Hib, and measles, respectively. Vaccine responses during maintenance were also satisfying.

CONCLUSION

We recommend re-vaccination after 3 months of cessation of chemotherapy. Administration of Hib vaccine may be beneficial after the first 3 months of maintenance chemotherapy especially in children with no primary vaccination followed by a second booster dose after cessation of therapy to increase immunity.

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.

Humoral immune response after post-chemotherapy booster diphtheria-tetanus-pertussis vaccine in pediatric oncology patients

BACKGROUND

The role of post-chemotherapy booster vaccination in pediatric oncology children remains to be established. In this randomized controlled study, we studied the effect of immune responses to diphtheria-tetanus-pertussis (DTP) booster vaccination in children 6 months after completing chemotherapy.

METHODS

Children 1-18 years old with chemotherapy completed for 6 months (baseline) were eligible. Subjects were randomized into vaccine and control group. In the former, three doses of DTP vaccine (Aventis Pasteur Inc., Lyon, France) were administered. IgG antibody titers against diphtheria, tetanus, pertussis, hepatitis B, measles, mumps, and rubella antibodies were measured serially in vaccine and control groups. Subsets of circulating lymphocytes (CD3(+), CD4(+), CD8(+), CD19(+), and CD16/56(+)) were quantified by flow cytometry using fluorescence-labeled monoclonal antibodies.

RESULTS

Fifty-six children (28 vaccinees; 28 controls) were enrolled. Protective antibody levels against diphtheria, tetanus, pertussis were found at baseline in 83.6%, 96.5%, 96.1% of them respectively. After three doses of DTP, all vaccinees demonstrated a sustain rise in antibody levels and the antibody titers were significantly higher than control group. 35.8% of subjects were susceptible to measles mumps and rubella infection and 69% showed anti-HBs antibody titer less than protective level up to 18 months after stopping chemotherapy.

CONCLUSIONS

Post-chemotherapy booster vaccinations produced a strong and sustained effect in humoral immunity against vaccine-preventable infectious diseases.

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.

Vaccinations in children treated with standard-dose cancer therapy or hematopoietic stem cell transplantation

Most children with cancer are immunocompromised during therapy and for a variable period after completion of therapy. They are at an increased risk of infections, including vaccine-preventable infections. There is a reduction in immunity to vaccine-preventable diseases after completion of standard-dose chemotherapy and after hematopoietic stem cell transplant. It is important to protect these children against vaccine-preventable diseases by reimmunization.

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.

Loss of antibody titers and effectiveness of revaccination in post-chemotherapy pediatric sarcoma patients

BACKGROUND

Little is known about the effects of chemotherapy on patient antibody titers to vaccine-preventable infectious diseases; thus, there is no standard protocol for revaccinating post-chemotherapy patients.

PROCEDURES

To assess losses of detectable antibody titers due to chemotherapy, we retrospectively examined antibody titers for tetanus, varicella, measles, mumps, rubella, hepatitis B, and polio in 109 pediatric sarcoma patients. We also evaluated revaccination data to determine current practices and efficacy of revaccination. We limited our sample to osteosarcoma, Ewing sarcoma, and rhabdomyosarcoma patients to control for the chemotherapy regimen patients received.

RESULTS

Patients had pre-treatment detectable antibody titer that fell within the range of healthy children's antibody titers. However, 71% of patients had post-chemotherapy negative titers for at least one infectious disease. Patients most commonly had negative titers for hepatitis B (64%). Few patients had negative titers for measles (14%), mumps (9%), rubella (4%), polio 1 (0%), polio 2 (2.9%), polio 3 (4.8%), tetanus (5%), or varicella (11%). Revaccinations most frequently administered were hepatitis B and polio.

CONCLUSIONS

Our findings suggest that post-chemotherapy patients may need to be revaccinated against certain vaccine-preventable diseases including hepatitis B, tetanus, varicella, polio, measles, mumps, and rubella. Larger studies need to be performed to establish guidelines for revaccinating post-chemotherapy pediatric patients.

Revaccination of Children after Completion of Standard Chemotherapy for Acute Leukemia

BACKGROUND

After the treatment of patients with acute leukemia, there is a decrease in vaccine-specific antibody and an increased susceptibility to certain vaccine-preventable diseases. A simple revaccination schedule is warranted.

METHOD

Fifty-nine children (age, 1-18 years) who had completed standard chemotherapy in accordance with Medical Research Council of United Kingdom protocols were recruited. All children received a single dose of Haemophilus influenzae type b (Hib), tetanus, diphtheria, acellular pertussis, meningococcus C, polio, measles, mumps, and rubella vaccines > or = 6 months after completion of treatment. Antibody concentrations were measured before vaccination and 2-4 weeks and 12 months after vaccination.

RESULTS

Prevaccination antibody levels were protective for all patients for tetanus (geometric mean concentration [GMC], 0.13 IU/mL; 95% CI, 0.1-0.17 IU/mL), for 87% for Hib (GMC, 0.5 microg/mL; 95% CI, 0.37-0.74 microg/mL), for 71% for measles (GMC, 301 mIU/mL; 95% CI, 163-557 mIU/mL), for 12% for meningococcus C (geometric mean titer [GMT], 1:2.9; 95% CI, 1:2.2 to 1:3.9), and for 11% for all 3 poliovirus serotypes. Revaccination resulted in a significant increase in levels of antibody to each vaccine antigen, with 100% of patients achieving optimal antitetanus antibody concentrations (defined as > 0.1 IU/mL; 1.5 IU/mL; 95% CI, 1.1-2.1 IU/mL), 93% achieving optimal antibody concentrations to Hib (defined as > 1.0 microg/mL; 6.5 microg/mL; 95% CI, 5.1-8.2 microg/mL), 94% achieving optimal antibody concentrations to measles (defined as > or = 120 mIU/mL; 2720 mIU/mL; 95% CI, 1423-5198 mIU/mL), 96% achieving optimal antibody concentrations to meningococcus C (defined as > or = 1:8; 1:1000; 95% CI, 1:483-1:2064), and 85% achieving optimal antibody concentrations to all the 3 poliovirus serotypes (defined as > or = 1:8). For the majority of subjects, protection persisted for at least 12 months after vaccination.

CONCLUSION

Revaccination of children after standard chemotherapy is important, and protection can be achieved in the majority of these children using a simple schedule of 1 vaccine dose at 6 months after completion of leukemia therapy.

Loss of antibodies and response to (re-)vaccination in children after treatment for acute lymphocytic leukemia: a systematic review

Intensified chemotherapy regimens resulting in improved survival of children with acute lymphocytic leukemia (ALL) lead to concerns about therapy-induced immune damage reflected by the loss of protection of previous immunizations and the efficacy of (re-)vaccination. The severity of secondary immunodeficiency, however, is not clear and knowledge is based on a limited number of studies. We performed a systematic review on literature concerning vaccination data of children with ALL published since 1980. Eight studies fulfilled the inclusion criteria. Regarding antibody titers after treatment, the number of children who had preserved the defined protection level for antibodies differed widely, ranging from 17 to 98% for diphtheria, 27 to 82% for Bordetella pertussis, 20 to 98% for tetanus, 62 to 100% for poliomyelitis, 35 to 100% for Haemophilus influenzae type B (HiB), 29 to 92% for mumps, 29 to 60% for measles and 72 to 92% for rubella. Most patients however responded to revaccination, demonstrating immunological recovery. Although the designs and results of the included studies varied widely, it can be concluded that cytostatic therapy for ALL in children results in a temporarily reduction of specific antibody levels. Memory is preserved but revaccination may be warranted. This is the first systematic review and the best possible current approximation of chemotherapy-induced immune damage in children after ALL treatment.

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.