Serial study of T lymphocytes in childhood leukemia during remission

Clinical characteristics and risk factors of acute lymphoblastic leukemia in children with severe infection during maintenance treatment

BACKGROUND

Infection is the most common adverse event of acute lymphoblastic leukemia (ALL) treatment and is also one of the main causes of death.

METHODS

To investigate the clinical characteristics and risk factors of severe infections during the maintenance phase of ALL treatment, we conducted a retrospective study.

RESULTS

A total of 181 children were eligible and 46 patients (25.4%) suffered from 51 events of severe infection, most of which occurred in the first half year of the maintenance phase (52.9%). The most common infection was pulmonary infection (86.3%) followed by bloodstream infection (19.6%). The main symptoms of ALL patients with pulmonary infection were fever, cough, and shortness of breath. The main manifestations of computer tomography (CT) were ground glass shadow (56.8%), consolidation shadow (27.3%), and streak shadow (25%). Multivariate binary logistic regression analysis showed that agranulocytosis, agranulocytosis ≥7 days, anemia, and low globulin level were independent risk factors for severe infection during the maintenance phase (all p < 0.05).

CONCLUSIONS

Taken together, blood routine examinations and protein levels should be monitored regularly for ALL patients in the maintenance phase, especially in the first 6 months. For ALL patients with risk factors, preventive anti-infective or supportive therapies can be given as appropriate to reduce the occurrence of severe infections.

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.

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.

Cytomegalovirus disease in children with acute lymphoblastic leukemia

Viral infections are an underrecognized problem in children on standard chemotherapy for acute lymphoblastic leukemia (ALL). In countries with high baseline seroprevalence of cytomegalovirus (CMV) such as India, it may be an important pathogen leading to fever, end-organ damage, and cytopenia. Data regarding the incidence and manifestations of CMV disease in pediatric ALL patients are scanty. The authors prospectively assessed all children on chemotherapy for ALL with prolonged febrile neutropenia (FN) for CMV disease over a 3-year period. Children with end-organ damage, including pneumonia, retinitis, and colitis, were also evaluated. Quantitative and qualitative polymerase chain reaction (PCR) from blood, body fluids, or tissue was done along with ophthalmologic evaluation. CMV disease was detected in 10% of the children with prolonged FN. In addition, other children were identified due to end-organ damage, lung and eye being the common organs of involvement. Time of CMV reactivation was essentially during nonintense phase of chemotherapy. Lymphopenia was present in most children, and prolonged lymphopenia was associated with relapse of CMV infection after therapy. The authors conclude that CMV is an important pathogen in children on standard chemotherapy for ALL. It has a good outcome with early detection and directed therapy. Parenteral ganciclovir is needed for a period of 14-21 days to prevent recurrence.

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.

Decreased numbers of CD4+ T lymphocytes in peripheral blood after treatment of childhood acute lymphoblastic leukemia

Treatment-related immunosuppression in patients with acute lymphoblastic leukemia (ALL) is associated with increased susceptibility to infectious diseases, also after the treatment. The aim of the present study was the detailed evaluation of T lymphocyte subsets in peripheral blood in children after treatment of ALL. All children were treated according to the BFM 90 protocol. The patients were divided into 5 groups of 30 children in each, depending on the time from cessation of the ALL treatment. A control group consisted of 30 healthy children subjected to elective "1-day" surgery. The children's age ranged from 6 to 18 years. The examinations were performed in FACScan flow cytometer with the use of wide set of monoclonal antibodies: CD3, CD4, CD8, TCRalphabeta, TCRgammadelta, CD19, CD25, CD45RA, CD45RO, CD69, HLA-DR, CD16 and CD56, which particularly allowed detailed analysis of T lymphocytes. The results showed that most parameters in children 1 year after ALL treatment completion were similar to healthy children. However, we observed persistently low CD4+ T cell numbers, both CD45RA+ as well as CD45RO+ subsets as compared to the control group. This might reflect decreased regenerative potential of immunological system in children 1 year after ALL treatment.

Decrease of CD4 + and B-Lymphocyte Populations Is Not Associated with Severe Infectious Complications in Children with Acute Lymphoblastic Leukemia during Maintenance

The suppression of lymphopoiesis and immune competence during the maintenance phase in children with acute lymphoblastic leukemia (ALL) and the occurrence of infectious complications remain an unexplored area. In this study we assessed lymphocyte subpopulation disturbances during maintenance for childhood ALL along with the incidence, type, and severity of infections that occur during that period in the absence of neutropenia. Twenty-eight children (13 boys, 15 girls) with ALL aged 3-14 years (median 7 years) and treated according to the ALL-BFM 90/95 protocol were studied during maintenance for ALL. Complete white blood cell (WBC) counts and peripheral blood lymphocyte (PBL) analyses were performed. Major lymphocyte subsets (CD19+, CD3+CD4+, CD3-CD8+, CD3-CD16+CD56+, CD45RA-, CD45RO+) and markers of T-cell activation (CD25, CD38, CD69, HLA-DR) were analyzed with flow cytometry. Serum immunoglobulin G (IgG), IgA, and IgM levels were measured by a nephelometric assay. All infectious episodes during the study period were recorded in detail. Additionally, 41 age-matched immunocompetent children were used as controls. Absolute WBC counts (median, 3627/microL) and PBL counts (median, 1206/microL) were significantly below the age-adjusted control values (7400/microL and 2673/microL, respectively; P < .0001). B-lymphocyte, total CD4+, and memory CD4+ (CD4+CD45RO+) subsets were also significantly decreased (33/microL versus 377/microL [P < .0001], 531/microL versus 1045/microL [P < .01], and 80/microL versus 299/microL [P < .001], respectively). Significantly lower immunoglobulin levels were found in all patients. Twenty-two of the 28 patients presented with 74 episodes of a variety o minor infections (mostly respiratory viral [39], skin [7], and gastrointestinal [3]), none demanding prolonged hospital treat ment. Our findings demonstrate a profound immunosuppression throughout maintenance therapy in children with ALL tha has no major clinical impact in terms of increased incidence or severity of systemic infections.

Immunologic monitoring of maintenance therapy for acute lymphoblastic leukaemia in children-preliminary report

BACKGROUND

In the study we evaluated immune reconstitution during maintenance therapy for acute lymphoblastic leukaemia (ALL) in relation to different treatment protocols and response of the immune system to the accompanying infections.

PROCEDURE

The study group consisted of 40 children. The BFM protocol'90 was used in the standard risk group, while the New York protocol-in the high risk group. Assessment of the immune system was based on the analysis of peripheral blood mono-nuclear cells by flow cytometry and concentrations of immunoglobulins: G, M, A and IgE. Each patient was examined at 1-3 months' intervals.

RESULTS

Following cessation of intensive therapy, the successive months of maintenance treatment showed: (1) a considerable depletion of B lymphocytes, a durable decrease in IgM, IgA and gradually increasing IgG; (2) a correlation between the time passing from the cessation of intensive therapy and increased numbers and percentage of B cells, and the helper/suppressor cell ratio. In the group of children treated according to the high risk protocol, compared to the low-risk group patients, we found lower levels of the following parameters: IgG, % lymphocytes: B and T lymphocytes (including CD4/CD8 ratio and "naive"/"memory" ratio) and NK cells (% and count). During infection: (1) a significant increase was noted in the percentage of T cells with HLA co-expression and monocytes with ICAM-1 co-expression, (2) the percentage of CD3(+)CD45RO(+) "memory" T cells was found to increase.

CONCLUSIONS

Our findings indicate quantitative and qualitative changes of the immunity in children with ALL during maintenance therapy.

Imaging and quantitative analysis of tritium-labelled cells in lymphocyte proliferation assays using microchannel plate detectors originally developed for X-ray astronomy

Microchannel plate detectors have been used in many astronomical X-ray telescopes. Recently we have begun to use similar detectors to image electron emission from radiolabelled biological assays. Here we show how a microchannel plate (MCP) detector can be used to image tritium uptake in T lymphocyte proliferation assays. Quantitative analysis using the MCP detector has the same sensitivity and speed as conventional liquid scintillation counter (LSC) analysis whilst obviating the need for scintillation fluid. In addition the system permits the imaging of whole plate harvests from a range of plate sizes. Here we present data obtained with 96-well plates and Terasaki plates.

Non-tuberculous mycobacterial infection in children with cancer

Reported here is the clinical presentation and management of patients with rapidly growing non-tuberculous mycobacterial infection diagnosed in a paediatric oncology unit. A retrospective analysis that correlated patient isolates with the children's cancer registry revealed two cases of non-tuberculous mycobacterial infection; both had been observed within the last 6 years and were due to Mycobacterium chelonae. The first case was line-associated and the second was a disseminated infection. In both cases the patients were lymphopenic and had had indwelling vascular catheters. Neither patient was neutropenic. The literature on mycobacterial infection in children with cancer is also reviewed.