Immune reconstitution after autologous purged bone marrow transplantation in children

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

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

Bronchiectasis following treatment for high-risk neuroblastoma: A case series

High-risk (HR) neuroblastoma remains a very challenging disease to treat and long-term cure is only possible with intensive, multimodal treatment including chemotherapy, high-dose therapy, radiotherapy, surgery, and immunotherapy. As a result, treatment-related morbidity and late effects are common in survivors. This report outlines a case series of six patients who developed a chronic productive cough following treatment for HR neuroblastoma. High-resolution computed tomography scanning confirmed the diagnosis of bronchiectasis. Two of the patients who have undergone immunological testing demonstrate hypogammaglobulinaemia and impaired vaccine response. Persistent cough in patients treated for neuroblastoma warrants investigation and consideration of immunological referral.

Infectious complications in the first year following autologous hematopoietic progenitor cell rescue for children with brain tumors

BACKGROUND

High-dose chemotherapy with autologous hematopoietic progenitor cell rescue (AuHPCR) for pediatric patients with brain tumors has become an important therapeutic modality to avoid or delay the long-term effects of cranial irradiation. Data on post-AuHPCR infectious complications in this population are lacking. This single institution retrospective review reports the prophylactic practices and infections in the first year following AuHPCR in pediatric patients with brain tumors.

PROCEDURE

The medical record of patients who underwent AuHPCR for the treatment of a malignant brain tumor at Children's Hospital Los Angeles between 1988 and 2010 were reviewed. Patients without prior irradiation who were free of disease at 1 year without additional chemotherapy were evaluated for all infectious disease complications occurring from time of neutrophil engraftment to 1 year post-AuHPCR.

RESULTS

Forty-three of the 115 eligible patients were included. The median time to neutrophil engraftment was 11 days (range: 8-43 days), and 20 Grade III/IV (no Grade V) infectious episodes developed in 15 patients (35%). Fourteen episodes of bacteremia (70%) were catheter-related, predominantly gram-negative (71%), and polymicrobial (50%). There were no fungal or pneumocystis infections and only 1 of 25 (4%) at-risk patients developed VZV reactivation.

CONCLUSIONS

These data suggest patients with brain tumors undergoing AuHPCR have few late-occurring non-catheter-related post-transplant infections indicating that prophylaxis practices were sufficient. Central lines should be removed soon after engraftment, but those with central line infections should receive adequate treatment including gram-negative coverage. In addition, only at-risk patients who receive further irradiation may benefit from VZV reaction prophylaxis.

Mass spectrometry based phospholipidomics of mammalian thymus and leukemia patients: implication for function of iNKT cells

In previous studies phospholipids have been proved to be involved in biochemical, physiological, and pathological processes. As a special class of phospholipids, peroxisome-derived lipids (PDLs) have been proved to be potential ligands of invariant natural killer T (iNKT) cells in recent studies. Here, on the basis of phospholipidomics, we focused on the relative quantity of PDLs extracted from mammalian thymus or bone marrow using electrospray ionization mass spectrometry (MS). In phospholipid analysis, we identified 12 classes of phospholipids and accounted for their relative quantities by comparing their relative abundances in the MS(1) map. Our results show that PDLs are present in mammalian thymus as well as mouse spleen and liver. Interestingly, the relative quantity of PDLs extracted from human acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) bone marrows is higher than that extracted from bone marrow of healthy donors. Our results may help to explain the close correlation between PDLs and iNKT cell function in thymus, spleen, liver, and especially in leukemia patients. We think that our phospholipidomics work may reveal a function of iNKT cells.

Dynamics in children and adolescents who experience varicella zoster virus infections after haematopoietic stem cell transplantation: a case-control study

We evaluated the incidence of varicella-zoster virus (VZV) infections, including herpes zoster (HZ), and investigated the associated risk factors for HZ and compared lymphocyte subsets of these patients at 1, 3 and 6 months following haematopoietic stem cell transplantation (HSCT) in a case-control study in children and adolescents. The incidence of HZ infection at the first year after HSCT was 17/125 (13·6%). The cumulative incidence of HZ infection was 22/125 (17·6%). Sixteen (73%) cases with HZ and 11 (32%) cases in the control group had a diagnosis of malignant disorder. No significant difference was noted between the HZ group and the control group in absolute lymphocyte number and subsets (except WBC) at the pre-transplant evaluation. Pre-transplant WBC count was statistically lower in the HZ group (P<0·05). The CD4/CD8 ratios were lower in the HZ group during the first 6 months after HSCT, and the decrease was statistically significant at 6 months compared to the control group. In conclusion, patients undergoing HSCT for a malignant disorder had a significantly higher risk of VZV infection than those with non-malignant disorders and pretransplant donor characteristics were not helpful in predicting risk of post-transplant VZV infection.

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

OBJECTIVE

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

PROCEDURE

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

RESULTS

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

CONCLUSIONS

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

Immune restoration following hematopoietic stem cell transplantation: an evolving target

Hematopoietic stem cell transplantation (HSCT) is the definitive cure for many malignant and nonmalignant diseases. However, delays in immune reconstitution (IR) following HSCT significantly limit the success of transplantation and increase the risk for infection and disease relapse in the transplant recipient. Therefore, ways to measure and to manipulate immune recovery following HSCT are emerging and their success depends directly upon an enhanced understanding for the underlying mechanisms responsible for reconstituted immunity and hematopoiesis. Recent discoveries in the activation, function, and regulation of dendritic cell (DC), natural killer (NK) cell, and T-lymphocyte subtypes have been critical in developing immunotherapies used to prevent graft-versus-host disease and to enhance graft-versus-leukemia. For example, regulatory T cells that induce tolerance and NK receptor-tumor ligand disparities that result in tumor lysis are being used to minimize GVHD and tumor burden, respectively. Furthermore, expansion and modulation of immune effector cells are being used to augment hematopoietic and immune recovery and to decrease transplant-related toxicity in the transplant recipient. Specifically, DC expansion and incorporation into antitumor and anti-microbial vaccines is fast approaching application into clinical trials. This paper will review our current understanding for IR following HSCT and the novel ways in which to restore immune function and decrease transplant-related toxicity in the transplant recipient.

Inflammatory myofibroblastic tumor following hematopoietic stem cell transplantation: report of two pediatric cases

Inflammatory myofibroblastic tumors are benign neoplasms histologically composed of lymphocytes, histiocytes, macrophages, foam cells, and plasma cells among a spindle-shaped stroma. Their etiology and potential for metastatic spread is controversial. Numerous predisposing factors have been suggested, including preceding infections, radiotherapy, and local trauma. We present two cases of pseudotumors that developed in children following hematopoietic stem cell transplantation. These are the first cases after hematopoietic transplant reported in the literature. As these neoplasms are difficult to diagnose and are often confused with highly aggressive tumors, our cases demonstrate that a high index of suspicion for such lesions must be maintained when evaluating masses in post transplant patients.

Immune reconstitution, infectious complications and post transplant supportive care measures after autologous blood and marrow transplantation in children

We retrospectively analyzed data on T- and B-cell reconstitution and infectious complications in 58 children undergoing ABMT, in order to evaluate post-transplant supportive care measures used during the study period. Normalization of T-cell number and lymphocyte proliferative responses to phytohemagglutinin (PHA) and alloantigen (MLC) occurred in two-thirds of children by 6 months post transplant. Normal IgM levels developed in 75% of children by 6 months post transplant. A total of 34 children (59%) developed 39 episodes of infection between neutrophil engraftment and 1 year post transplant. The most common infections included bacteremia, varicella-zoster virus infection and pneumonia, which represented 46, 23 and 9% of infections, respectively. All patients with bacteremia had a central venous catheter in place at the time of infection. Most infections (77%) developed by 6 months post transplant. In this small patient cohort, time to normalization of tests of T- and B-cell function was not significantly different between patients with and without infection. Earlier removal of an indwelling central venous catheter may decrease the risk of bacteremia post transplant. Post-transplant supportive care measures may be discontinued at 6 months post ABMT in most children, as the risk of infection decreases after that time.

Development of common variable immunodeficiency in a patient with Evans syndrome treated by autologous stem cell transplantation

We describe a case report of a patient who developed common variable immunodeficiency (CVID) after autologous haematopoietic stem cell transplantation (SCT) for recurrent Evans syndrome. The disease manifested as attacks of haemolytic anaemia, thrombocytopenia and neutropenia from the age of 12 years. Presence of autoantibodies to blood elements was confirmed together with C4 deficiency. The patient also suffered from dermatitis herpetiformis Duhring without signs of coeliac disease. Autologous T cell-depleted peripheral blood stem cell (PBSC) transplant following conditioning regimen was performed at the age of 20 years. Immunological reconstitution was incomplete and 2 years after SCT he fulfilled laboratory criteria for common variable immunodeficiency (CVID). The patient was found to be a carrier of a risk haplotype for development of CVID DRB1*03/DQB1*0201. We conclude that T cell-depleted SCT here performed for autoimmune manifestations can hasten development of CVID in genetically predisposed patients.

Rapid immune reconstitution following autologous hematopoietic stem cell transplantation in children: a single institution experience

In this retrospective study, we review the immune reconstitution of children undergoing autologous hematopoietic stem cell transplantation. A total of 125 patients underwent autologous transplantation between 1992 and 2000. The report includes data on 58 patients. Data were not available on the remaining patients who either died before testing or data were not obtained. The parameters evaluated include: (a) immunophenotype by flow cytometry to quantify lymphocyte subpopulations (b) mitogen stimulation assays, and (c) quantitative immunoglobulins. The analysis reveals that CD3+ cells did not reach the normal range during the first year post-transplant. The median percentage of CD4+ cells was below normal up to 6 months post-transplant, while the absolute number remain low throughout the first year. The CD8+ percentage and absolute numbers remain normal at all times post-transplant. The CD19+ cells were also normal post-transplantation. The mitogen lymphocyte stimulation was normal in 27 out of 31 patients tested after 6 months post-transplant. Our analysis of immune reconstitution shows a similar pattern to previous studies with a faster recovery of the CD4/CD8 ratio, especially in those patients who did not receive TBI. In conclusion, the observed deficiencies are transient and have very little clinical significance because, historically, the rate of serious infections is low despite prolonged immune suppression. The recovery post-autologous transplant is fast.

Immune reconstitution after haematopoietic cell transplantation in children: immunophenotype analysis with regard to factors affecting the speed of recovery

Immune reconstitution was studied prospectively in 66 children who underwent 77 haematopoietic cell transplantations (HCT): 46 autologous HCTs in 39 patients and 31 allogeneic HCTs in 27 patients. We studied the dynamic analysis of immune recovery with regard to potential factors affecting its speed, including age, type of HCT, diagnosis, graft-versus-host disease (GvHD) and cytomegalovirus (CMV) infection reactivation. Absolute counts of different lymphocyte subsets and immunoglobulin serum levels were determined in peripheral blood of patients on d -7 and +16, and then at various intervals up to 24 months post transplant. Common patterns of immune recovery after both allogeneic and autologous HCT were identified: (i) CD4+CD45RO+ peripheral T-cell expansion on d +16; (ii) inverted CD4+:CD8+ ratio from d +30 onwards; (iii) rapid natural killer (NK) cell (CD16+/-CD56+) count normalization. We observed prolonged T-cell lymphopenia (CD3+, CD3+CD4+, CD4+CD45RA+) until 24 months after autologous HCT, whereas in the allogeneic setting CD3+CD4+ cells, including naive CD45RA+ cells, returned to normal values at 9 months post transplant. Age > 10 years and coexistence of GvHD and CMV reactivation were associated with a substantial delay in T- (CD4+, including CD45RA+) and B-cell recovery after allogeneic HCT. Multidrug GvHD prophylaxis resulted in impaired T- (CD4+, CD4+CD45RA+) and B-cell reconstitution only in the early phase after allogeneic HCT (up to 4 months). Our results demonstrated that T-cell recovery was severely impaired in children after autologous HCT. It should be emphasized that specific approaches to enhance immune reconstitution are necessary to control minimal residual disease and avoid the risk of infectious complications in the autologous setting. Thymic involution after allogeneic HCT seems to be associated with age and coexistence of GvHD and CMV reactivation.

Purified autologous grafting in childhood acute lymphoblastic leukemia in second remission: evidence for long-term clinical and molecular remissions

Autologous transplantation is a treatment option for relapsed childhood acute lymphoblastic leukemia (ALL) in second complete remission (CR2) when a suitable donor is not available. In an attempt to prevent relapses originating from graft leukemic contamination, the experimental protocol of in vitro purification of leukapheretic products with monoclonal antibodies (MoAbs), previously reported for adults, was adopted in 11 of 12 consecutive patients (median age, 9 years) with B cell precursor ALL in CR2 after late relapse (median, 37; range, 31-51 months after the onset) enrolled between July 1997 and July 1999 at a single pediatric center. At a median of 12 days after the mobilizing chemotherapy followed by G-CSF, a median of 13.9 (range, 5.9-18.7) x 10(6) CD34+ cells/kg were collected from each patient and a median of 7.5 (range, 4.1-12.6) x 10(6) CD34+ cells/kg underwent the purification procedure. The first step of immunorosetting allowed a one-log reduction of the total cell count, by eliminating more than 90% of the CD11b+ cells; the second step, performed after incubation with anti-CD19 MoAbs, allowed the depletion of 99% (range, 93-100) of the CD19+ cells, kept within the magnetic field of the immunodepletion column, with a median recovery of 73% (range, 55-87) of the collected CD34+ cells. Molecular analysis assessed the in vitro eradication of detectable leukemic cells. A median reinfusion of 5.2 (range, 3.2-9.1) x 10(6) CD34+ cells/kg for each patient (median viability, 90%), after conditioning with the 'TBI-VP16-CY' regimen, allowed prompt engraftment and immunological reconstitution; no patients experienced severe transplant-related toxicity or major infections. One patient relapsed 7 months after transplantation, while 10 patients are alive in clinical and molecular remission, at a median follow-up of 29 months (range, 15-40) (2-year EFS, 89%, s.e. 9). In conclusion, the procedure proved to be reproducible for pediatric purified autografting, highly efficient concerning stem cell recovery and depletion of leukemia-lineage specific cells, and promising in terms of final outcome.