Hematopoietic stem cell transplantation does not increase the risk of infection-related complications for pediatric patients with Hodgkin and non-Hodgkin lymphomas: A multicenter nationwide study.

BACKGROUND: Hodgkin (HL) and non-Hodgkin lymphoma (NHL) represent a spectrum of lymphoid malignancies that are often curable with currently applied treatment regimens; however, 15%-30% of lymphoma patients still suffer from relapsed or refractory (rel/ref) disease. Although hematopoietic stem cell transplantation (HSCT) improves outcomes of second-line therapy for lymphoma in childhood, the complication rates in this group of patients, especially infectious complications (IC), remain unclear. OBJECTIVE: The aim of this population-based cohort study was a retrospective analysis of incidence, epidemiology and profile of bacterial infections (BI), invasive fungal disease (IFD), and viral infections (VI) in primary or rel/ref lymphoma patients, both HL and NHL. PATIENTS AND METHODS: We subdivided lymphoma patients into three groups: patients with primary conventional chemotherapy/radiotherapy regimens (group A), patients with rel/ref lymphoma treated with second-line chemotherapy (group B), and rel/ref lymphoma patients who underwent HSCT (group C). The medical records of the patients were biannually reported by each pediatric oncology center, and the data were analyzed centrally. RESULTS: Within 637 patients with primary lymphoma, at least one IC was diagnosed in 255 (40.0%), among 52 patients with rel/ref lymphoma 24 (46.2%) ICs were observed, and in transplanted group, 28 (57.1%) out of 49 children were diagnosed with IC (P = .151). The distribution of etiology of IC differed between the patient groups (A, B, C), with a predominance of BI in group A (85.6% vs 72.0% and 47.9%, respectively), VI in group C (9% and 16.0% vs 46.6%, respectively), and IFD in group B (5.4% vs 12.0% vs 5.5%, respectively). Overall, 500 (68.0%) episodes of bacterial IC were diagnosed in the entire group. Apart from HL patients treated with chemotherapy, in all the other subgroups of patients Gram-positives were predominant. The rate of multidrug-resistant bacteria was high, especially for Gram-negatives (41.1% in group A, 62.5% in group B, and 84.6% in group C). The infection-related mortality was comparable for each group. CONCLUSIONS: The incidence of IC was comparable during first- and second-line chemotherapy and after HSCT, but their profile was different for primary or re/ref lymphoma and depended on the type of therapy.

Adenovirus infection among pediatric patients with cancer and in pediatric recipients of hematopoietic stem cell: A multicenter nationwide study.

The aim was to evaluate the incidence, clinical course, and outcome of adenoviral infection (AdVI) in pediatric patients diagnosed and treated due to cancer and in pediatric recipients of hematopoietic stem cell. Over a 72-month period, all-in 5599 children with cancer: 2441 patients with hematological malignancy (HM) and 3158 with solid tumors (ST), and 971 patients after transplantation: 741 after allogeneic (allo-HSCT) and 230 after autologous (auto-HSCT) were enrolled into the study. Among cancer patients, 67 episodes of AdVI appeared in 63 (1.1%) children, including 45 (1.8%) with HM and 18 (0.6%; P < .001) with ST. Within transplanted patients, AdVIs were responsible for 88 episodes in 81 (8.3%) children (P < .001), including 78 (10.5%) patients after allo-HSCT and 3 (1.3%) after auto-HSCT. Time to develop AdVI was short, especially after allo-HSCT. The most common clinical manifestation in cancer patients was enteritis diagnosed in 63 (94.0%) cases, while among HSCT recipient asymptomatic adenoviremia was found in 36 (40.9%) cases and the most common clinical manifestation was urinary tract infection. Cancer patients with disseminated disease, as well as HSCT recipients with either asymptomatic viremia or disseminated disease, received antiviral treatment. The most commonly used first-line therapy was cidofovir. None of the cancer patients died due to AdVI, while within HSCT recipients three patients developed disseminated adenoviral disease and died despite antiviral treatment. In cancer patients, AdVIs are rare and associated with very good prognosis even without specific treatment. However, in allo-HSCT recipients, disseminated disease with fatal outcome is more likely to occur.

Multidrug-resistant bacterial infections in children undergoing haematopoietic stem cell transplantation over a 6-year period: analysis of the Polish Pediatric Group for Hematopoietic Stem Cell Transplantation.

AIMS: Multidrug-resistant (MDR) bacteria are an emerging cause of morbidity and mortality after haematopoietic stem cell transplantation (HSCT). The aim of the study was to analyse the incidence, clinical characteristics and survival from bacterial infections (BI) caused by MDR pathogens in paediatric HSCT recipients. METHODS AND RESULTS: Among 971 transplanted patients, BI were found in 416 children between the years 2012 and 2017. Overall, there were 883 bacterial episodes, which includes 85·8% after allo-HSCT and 14·2% after auto-HSCT. MDR strains were responsible for half of the total number of bacterial episodes. Over 50% of MDR pathogens were Enterobacteriaceae causing mainly gut infections or urinary tract infections. CONCLUSIONS: Regarding HSCT type, we did not find differences in the profile of MDR BI between allo- and auto-HSCT recipients. However, survival in MDR and non-MDR infections was comparable. SIGNIFICANCE AND IMPACT OF THE STUDY: The large sample size enables unique analysis and makes our data more applicable to other paediatric HSCT centres. In the absence of local epidemiological data, presented clinical characteristics of MDR-caused infections may be used to optimize the prophylactic strategies, early identification of infectious complications of MDR aetiology and thus promptly initiate adequate antibiotic therapy and further improve patients' outcome.

Incidence, course, and outcome of Clostridium difficile infection in children with hematological malignancies or undergoing hematopoietic stem cell transplantation.

Clostridium difficile infection (CDI) is one of the most common causes of nosocomial infectious diarrhea in children during anticancer therapy or undergoing hematopoietic stem cell transplantation (HSCT) in Europe. Immunosuppression in these patients is a risk factor for CDI. Malignant diseases, age, acute graft-versus-host disease (aGVHD), HLA mismatch, or use of total body irradiation may play an important role in CDI course. The aim of this study was to evaluate the incidence, course, and outcome of CDI in children treated for malignancy or undergoing HSCT. Between 2012 and 2015, a total number of 1846 patients were treated for malignancy in Polish pediatric oncological centers (PHO group) and 342 underwent transplantation (HSCT group). In PHO group, episodes of CDI occurred in 210 patients (14%). The incidence of CDI was higher in patients with hematological malignancies in comparison to that with solid tumors. Patients with acute myeloblastic leukemia had shorter time to episode of CDI than those with acute lymphoblastic leukemia. Patients over 5 years and treated for acute leukemia had more severe clinical course of disease in PHO group. In HSCT group, CDI occurred in 29 (8%) patients. The incidence of CDI was higher in patients transplanted for acute leukemia. The recurrence rate was 14.7% in PHO and 20.7% in HSCT patients. CDI incidence was highest in patients with hematological malignancies. Most of patients experienced mild CDI. Age < 5 years and diagnosis other than acute leukemia were the positive prognostic factors influencing clinical CDI course.

Incidence of Infectious Complications in Children With Acute Lymphoblastic Leukemia Treated With Hematopoietic Stem Cell Transplantation.

OBJECTIVE: We analyzed incidence and profile of infections in children with acute lymphoblastic leukemia (ALL) treated with hematopoietic stem cell transplantation (HSCT) in Polish pediatric HSCT departments, over a 2-year period. PATIENTS AND METHODS: Hospital records of 67 patients, who underwent allogeneic HSCT for ALL, were analyzed retrospectively for microbiologically documented infection: bacterial infection (BI), viral infection (VI), and fungal infection (FI). The majority of patients (40/67; 59.7%) underwent HSCT from matched unrelated donors (MUD). RESULTS: In total, 84 BI in 31 patients, 93 VI in 50 patients, and 27 FI in 22 patients were diagnosed. No differences were found in the frequency of occurrence of BI according to the type of transplant (P = .16); the occurrence of VI was statistically more frequent in MUD transplant recipients as compared with matched sibling donors (MSD) and mismatched related donors (MMFD; P = .001) and there was a trend in MUD patients for the higher occurrence of FI in comparison with MSD and MMFD transplants (P = .08). Regarding disease status, the occurrence of BI, VI, and FI was statistically more frequent in children who underwent transplantation in their first complete remission (CR1), rather than those who underwent transplantation in ≥CR2 (P < .05). In conclusion, infectious complications are an important cause of morbidity in children with ALL treated with allogeneic HSCT and the incidence of infections is high in this group of patients.

Bacterial infections in pediatric hematopoietic stem cell transplantation recipients: incidence, epidemiology, and spectrum of pathogens: report of the Polish Pediatric Group for Hematopoietic Stem Cell Transplantation.

BACKGROUND: Infectious complications are a significant cause of hematopoietic stem cell transplantation (HSCT) failure, especially allogeneic HSCT (allo-HSCT) because of delayed immune reconstitution and graft-versus-host disease (GVHD) occurrence. Identifying the factors responsible for bacterial infections (BI) in patients undergoing HSCT will provide much more effective empirical antimicrobial treatment in this group of patients. OBJECTIVE: The aim of this study was to evaluate the epidemiology and profile of BI in patients after HSCT in 5 centers of the Polish Pediatric Group for Hematopoietic Stem Cell Transplantation in 2012-2013. PATIENTS AND METHODS: In 308 HSCT recipients, we retrospectively analyzed 273 episodes of BI in 113 (36.7%) children aged 0.02-22 years (median age: 7 years), 92 after allo-HSCT and 22 after autologous HSCT (auto-HSCT). We assessed incidence of BI in different HSCT types by calculating the Index of Bacterial Infection (IBI) as a ratio of patients with at least 1 BI to all patients who underwent this type of HSCT in the analyzed period. We assessed the profile of BI with particular emphasis on multidrug-resistant organisms, and impact of underlying disease and of graft-versus-host disease on BI episodes. RESULTS: In the studied group, 273 episodes of BI were diagnosed, including 237 episodes after allo-HSCT and 36 after auto-HSCT. Among allo-HSCT recipients diagnosed with at least 1 BI, the IBI was 0.4 (matched sibling donor-HSCT 0.3; matched donor-HSCT 0.4; mismatched unrelated donor [MMUD]-HSCT 0.8; P = 0.027) and after auto-HSCT 0.3 per 1 transplanted patient. In patient after allo-HSCT because of myelo- or lymphoproliferative diseases and bone marrow failures, the major cause of infections was Enterobacteriaceae, while gram-positive bacteria predominated in the group with primary immunodeficiencies. In all patients after auto-HSCT, the dominant pathogen of BI were Enterobacteriaceae (P = 0.011). Time from each type of HSCT to infection caused by different pathogens did not differ significantly. CONCLUSIONS: The risk of BI does not depend on the underlying disease, but only on HSCT donor type and is the highest after MMUD-HSCT procedure. The profile of BI depends on the underlying disease and HSCT donor type, but does not depend on the occurrence of acute GVHD. Gram-negative bacteria predominated in patients with myelo- and lymphoproliferative diseases, while in patients with primary immunodeficiencies gram-positive strains were predominant.

Adoptive therapy with donor lymphocyte infusion after allogenic hematopoietic SCT in pediatric patients.

The aim of this study was to analyse the experience of Polish Pediatric Group for Hematopoietic Stem Cell Transplantation in respect to donor lymphocyte infusion procedure. The study included 51 pediatric patients with malignant (45) and non-malignant (6) diseases treated with DLI in the period 1993-2012. The indications for DLI were as follows: (1) increasing recipient chimerism after non-ablative hematopoietic SCT (18 patients); (2) immunomodulation after a reduced intensity conditioning regimen (2 patients); (3) increase in minimal residual disease detection (3 patients); and (4) relapse (28 patients). DLI was carried out at a median of 6 (0.5-79) months after SCT. DLI was administered as either a single-dose (in 19 cases) or in escalating-dose regimens (in 32 cases). The median total dose of CD3-positive T cells was 28.0 (0.1-730.0) × 10(6)/kg body weight. The time for assessment of DLI efficacy ranged from 0 to 70 (median 3) months. At evaluation, 18 patients experienced CR, 3 achieved PR, 19 showed relapse and 11 rejected the graft. DLI was found to be effective in 39% of cases. Complications of the procedure occurred in 18 patients; of these, 2 died. To sum up DLI shows efficacy in a significant percentage of children. Mortality related to the therapy adverse effects is low. However, this method requires standardization.

Steroid-sparing effect of extracorporeal photopheresis in the therapy of graft-versus-host disease after allogeneic hematopoietic stem cell transplantation.

INTRODUCTION: Steroid-refractory graft-versus-host disease (GVHD) remains a challenging therapeutic problem after allogeneic hematopoietic stem cell transplantation (HSCT). The aim of this study was to evaluate the clinical effect of extracorporeal photopheresis (ECP), and its impact on intensivity of immunosuppresive therapy in allogeneic HSCT patients. PATIENTS AND METHODS: In this study 443 Therakos ECP procedures were performed in 21 patients after allogeneic HSCT with acute (aGVHD, 8 patients) or chronic (cGVHD, 13 patients) therapy-refractory GVHD. The median age at ECP onset was 20.5 years (range, 10-55). Venous access was provided by a nontunelized central venous catheter (12 patients) or 9.6-French portacath (9 patients). RESULTS: In the cGVHD group 9/13 patients were improved with a 4-year overall survival rate of 67.7%. ECP led to steroid discontinuation in 6 and substantial dose reduction in 5 patients. The prednisone dose equivalent per kilogram body weight decreased from 0.32 mg to 0.07 mg after therapy. Therapy of aGVHD led to complete or partial symptom remission in 3/9 subjects. The change in steroid dose in the aGVHD group was not significant, there were no long-term survivors. Portacath access was well tolerated and provided adequate blood flow rates. CONCLUSIONS: The ECP therapy significantly reduced the rates of remissions with steroid discontinuation among cGVHD but not aGVHD patients. Rare ECP-related complications were either catheter related or anticoagulation induced during ECP procedures. Photopheresis was a safe, effective method to treat steroid-resistant cGVHD.

The role of inflammation in the progression of ocular surface damage in children following allogeneic haematopoietic cell transplantation.

The aim of the study was to evaluate HLA-DR expression and cellular morphology of the conjunctival epithelium cells in children who underwent haematopoietic cell transplantation, and to assess the relation between HLA-DR expression and cellular morphology. Impression cytology with staining was used to visualize epithelium cells, whereas immunohistochemistry was applied to assess HLA-DR expression. Elevated HLA-DR expression and increased cytological abnormalities were observed in the study group when compared to the controls. An increase in HLA-DR expression was accompanied by a decrease in the number of eyes with normal epithelium morphology together with the increase in squamous metaplasia features. We can conclude that inflammation of conjunctiva can follow stem cell allotransplantation. Ocular surface inflammation may lead to squamous metaplasia of the conjunctiva.

Consolidation of first-line therapy with busulphan and melphalan, and autologous stem cell rescue in children with Ewing's sarcoma.

According to the published report on current practice of hematopoietic SCT in Europe, high-dose therapy (HDT) with autologous stem cell support is a standard of care in paediatric patients with high risk (HR) or relapsed Ewing's sarcoma (ES). Randomized trials, however, have not confirmed the value of this procedure yet. In this retrospective analysis we intended to evaluate the role of HDT as a consolidation therapy in first remission of ES. A total of 102 patients were included in the analysis and divided according to the following risk factors: metastatic disease at presentation, feasibility of surgery and histological response after induction. Forty-one patients were classified as standard risk (SR) patients, while the remaining 61 children, with at least one risk factor, were classified as HR patients. HR group patients were non-randomized and qualified according to the decision of the local clinician to give a conventional consolidation (CC) or to perform high-dose chemotherapy and radiotherapy in selected patients. Twenty-six children were given CC while 35 patients were treated with HDT. The HDT consisted of oral BU 4 mg/kg p.o. in divided doses daily for 4 days (total dose 16 mg/kg) followed by melphalan 140 mg/m(2) i.v. on day -2. Probability of relapse-free survival (RFS) in median observation time was significantly worse in HR patients who were given CC therapy as compared with children with HR features receiving high-dose chemotherapy (0.27 vs 0.66 (P = 0.008); OS 0.31 vs 0.71 (P = 0.007), respectively). Patients from the SR group had a probability of RFS of 0.72 and OS of 0.75, and the difference between SR and HR patients after HDT was NS (P = 0.37). Our observation confirms that the consolidation of the first-line treatment with BU and melphalan improves the outcome in ES patients with HR features.

Treosulfan-based preparative regimens for allo-HSCT in childhood hematological malignancies: a retrospective study on behalf of the EBMT pediatric diseases working party.

This retrospective analysis evaluated 51 children (0.7-17 years; median eight) with high-risk or advanced hematological malignancies, including 18 (35%) patients undergoing second/third hematopoietic SCT (allo-HSCT), not eligible for standard myeloablative regimens and transplanted from matched sibling (MSD) (n=24) or matched unrelated (MUD) (n=27) donors. Preparative regimens were based on treosulfan (TREO) i.v., a structural analog of BU, given at total dose of 30 g/m(2) (n=21) or 36-42 g/m(2) (n=30) in combination with, fludarabine, cyclophosphamide, melphalan and/or VP-16 according to diagnosis, and risk factors. Deaths due to early regimen-related toxicity (RRT) did not occur. Nonrelapse mortality was 8% at 1 year and 16% after 4 years. Myeloid engraftment was achieved in 94%, complete donor chimerism in 90% of patients. A 4-year incidence of relapse was 24%, and was significantly lower after MUD-HSCT (8%) than after MSD-HSCT (39%), but similar in children undergoing first (28%) or second/third HSCT (17%). A 4-year disease-free survival was 61%, but it was significantly better in myeloid (73%), than in lymphoid malignancies (41%). Thus, children with high-risk and advanced hematological malignancies and high-risk of life-threatening RRT can be transplanted effectively and safely using TREO-based regimens. Particularly favorable results were achieved in myeloid malignancies and in children undergoing second HSCT.

Hematuria due to adenoviral infection in bone marrow transplant recipients.

Late-onset hemorrhagic cystitis (HC) caused by adenovirus (AdV) infection is a common complication in hematopoietic stem cell transplantation (HSCT) recipients. However, limited information exists regarding adenovirus-associated HC. We report a retrospective study of 84 hematopoietic stem cell transplant recipients that evaluated the incidence and risk factors for AdV-induced HC. The development of HC was strongly related to adenoviral infection (P = .004). Among 13 patients who developed late-onset HC, AdVs were identified as a causative agent in 10 cases. AdV preferentially affected younger (P = .013) and male patients. Affected subjects had been transplanted for either malignant (7/10) or nonmalignant disorders (3/10). Most cases of AdV-hematuria were self-limited single or recurrent mild hemorrhagic episodes (P = .000), occurring at a median of 41 days after transplantation and lasting an average of 4 days. Viral load in patients with AdV-induced HC was similar to infected subjects who did not develop HC (2.5 × 10(3) vs 3.4 × 10(3) copies/mL). We HC occurring before 200 days was associated with a greater risk of a fatal outcome (P = .002) but occurrence of AdV infection did not affect a patient's survival. Our study confirmed the suggestion that non-AdV coinfections may worsen the course of AdV-HC.

Haemorrhagic cystitis as a complication after allogenic bone marrow transplantation.

OBJECTIVE: The main objective of the following work is to present our own material and the ways in which we have dealt with haemorrhagic cystitis (HC) following allogenic bone marrow transplantation in children. MATERIALS AND METHOD: From 1994 to 2002, allogenic transplantation of haematopoietic cells was performed in 129 children at the Oncological and Haematological Child Clinic, Wroclaw University of Medicine. The procedure was carried out in patients with neoplastic diseases. In 33 cases, HC symptoms of various intensity were observed. The intensity of the symptoms was evaluated according to Arthur's four-point scale. To confirm the diagnosis USG was carried out in each case. Special attention was given to the ultrasonographic structure of the bladder wall. Cartoni's technique was followed in the examination. RESULTS: Out of 129 children who underwent allogenic transplantation of haematopoietic cells 33 (20.75 %) revealed HC symptoms. The symptoms occurred between the 2nd and the 124th day after transplantation (mean 29 days). The treatment included antiviral medicines, estrogens, reduction of immunosuppression and mechanical urological procedures. The children diagnosed with 2nd grade disease and higher were catheterised and diuresis was forced by the administration of larger amounts of liquids intravenously. Antihaemorrhagic drugs and vitamin K were also given. Blood was substituted if needed as were blood derivatives. Eighteen children with massive haematuria with clots underwent catherisation with a suprapubic catheter so as to continuously rinse the bladder. In 8 cases tamponade of the bladder occurred. The clots were removed from the bladder during cystoscopy under general anaesthesia. Twelve children died from HC. This amounts to 36 % of all the cases identified as HC and 9 % of all the children who underwent allogenic marrow transplantation. CONCLUSIONS: In conclusion it must be emphasised that HC in children after allogenic transplantation of haematopoietic cells is an extremely severe disease, which, if not cured, is terminal. The decision whether to perform embolisation of internal iliac arteries or to remove the bladder when non-radical methods have been exhausted, is worth considering.

Allogeneic hematopoietic cell transplantation from alternative donors in children with myelodysplastic syndrome: is that an alternative?

Allogeneic hematopoietic cell transplantation (HCT) in children with myelodysplastic syndrome (MDS) remains a challenge due to the toxic conditioning regimens administered to minimize the risk of relapse in the HLA-matched or of graft rejection in the HLA-mismatched settings. In the absence of matched sibling donors, alternative donors such as unrelated and/or partially matched family sources remain risky, yet the only available, options. Herein we report the results of HCT from alternative donors in 14 children with different subtypes of MDS (juvenile myelomonocytic leukemia [JMML] n = 9; myelodysplastic syndrome [MDS] refractory anemia n = 3; MDS refractory anemia with excess of blasts in transformation n = 2) transplanted at our institution. The median time from diagnosis to HCT was 9 months (range 4 to 90 months). The variety of HCT types included: unrelated peripheral blood progenitor cell transplantation (PBPCT) (n = 2), partially matched family donor T-cell-repleted BMT/PBPCT (n = 6), and haploidentical T-cell-depleted PBPCT (n = 6). Five of 14 patients remain alive at 7 to 37 months posttransplant (including two patients after partially matched family donor BMT, two patients after haploidentical T-cell-depleted-PBPCT, and one after unrelated-PBPCT, respectively). The major complications were: primary graft failure in the haploidentical T-cell-depleted-setting or graft-versus-host disease (GvHD) in T-cell-repleted partially matched family or unrelated settings, respectively. Despite the high transplant-related mortality rate in this series, allogeneic HCT from alternative donors remains an interesting solution for children with MDS who lack matched sibling donors. Due to improved immune reconstitution, despite an increased risk of GvHD, T-cell-repleted transplants from single HLA-mismatched family donors remain a valuable option for children without matched donors. Splenectomy prior to HCT may positively affect the posttransplant course in patients with overt splenomegaly for example those afflicted with JMML.

Prompt initiation of immunotherapy in children with an increasing number of autologous cells after allogeneic HCT can induce complete donor-type chimerism: a report of 14 children.

Immunotherapy consisting of withdrawal of immunosuppression and/or donor lymphocyte infusions was initiated in 14 children (10 acute lymphoblastic leukemia, three acute myeloblastic leukemia and one myelodysplastic syndrome) with an increasing amount of autologous DNA (increasing mixed chimerism, inMC) detected after allogeneic hematopoietic cell transplantation (HCT). Two children were in relapse when inMC was detected, 12 remained in CR. Children with overt relapse at the time of cessation of cyclosporine A (CsA) received "debulking" chemotherapy. One of them developed acute grade III graft-versus-host disease, converted to complete donor chimerism (CC) and achieved remission. Another patient did not respond and died due to disease progression. Among 12 children treated in remission, 11 responded with conversion to CC, seven after CsA withdrawal and four after DLI. One patient did not respond, rejected the graft and died due to pulmonary aspergillosis. In one patient, the response was transient, inMC reappeared and frank relapse occurred. One patient developed isolated CNS relapse despite conversion to CC, but achieved CR after conventional treatment. One child died in CC due to infection. No graft-versus-host disease (GvHD)-related death occurred. A total of 10 patients are alive in remission with median follow-up of 338 days. Our results support the hypothesis that chimerism-guided immunotherapy after alloHCT may prevent progression to hematological relapse.

A prospective analysis of immune recovery in children following allogeneic transplantation of t-cell-depleted or non-T-cell-depleted hematopoietic cells from HLA-disparate family donors.

Transplantation of HLA-disparate hematopoietic stem cells from related donors is an alternative for the treatment of patients lacking an HLA-matched family or unrelated donor. In the cases of a single HLA antigen disparity, extensive T-cell depletion (TCD) is not required, yet antithymocyte globulin (ATG) must be administered to prevent GvHD or graft rejection. The major concern after HLA-mismatched transplants remains immune reconstitution. Therefore, we prospectively studied the recovery of lymphocyte subsets among 22 children transplanted from partially HLA-matched family donors. We compared two groups of patients: (1) the TCD group included children (n = 1.3) who received grafts after TCD (MACS) due to an HLA disparity for more than one antigen; (2) The non-TCD group included children with either one HLA-mismatched antigen, n = 7; or more than one disparate antigen (n = 2) who received T-cell-repleted grafts and ATG. The study demonstrated rapid NK cell reconstitution among the TCD group. TCD compromised T-cell reconstitution, thus preventing GvHD, but resulting in a higher incidence of severe infectious complications, graft rejection, and disease relapse. Increasing mixed chimerism required the application of donor T-cell addbacks, thus potentiating the risk of GvHD. Primary graft rejection occurred in eight children, who required further transplants. In the non-TCD group faster T-cell reconstitution (predominantly CD3+CD8+ cells) resulted in a lower rate of relapse and infection, yet a higher rate of GvHD, including two fatal cases. Due to improved immune reconstitution, in spite of an increased risk of GvHD, non-TCD transplants from single HLA-mismatched family donors remain a valuable option for children without matched donors.

Clinical value of the flow cytometric method for measuring lymphocyte subset activation: spontaneous activation of T-cell subpopulations is associated with acute GvHD.

Thymidine ((3)H-TdR) incorporation remains the most commonly used method to quantifying T-cell proliferation. This method, however, does not provide information about specific lymphocyte subpopulations responding to different stimuli. In our study, we modified previously described nonradioactive flow-cytometric T-cell activation assay measuring the expression of a CD69+ antigen on T-cell subsets and applied it to analysis of lymphocyte subsets activation/proliferation in children after allogeneic hematopoietic cell transplantation (HCT). We compared the percentage of spontaneously activated lymphocyte subpopulations (background) and the percentage of PHA-P, PWM, and SEB-stimulated cell subsets from two groups of patients: group 1, children with Graft versus Host Disease (GvHD) and group 2, children without any signs of GvHD at the time of analysis. High rate of spontaneous T-cell subset activation was found in group 1 with CD3+CD8+Ts cells being the most affected cell population. High background activation of Th and B cells correlated with the occurrence of autoimmune phenomena posttransplant. Rapid quantification of CD69+ expression on unstimulated and stimulated T-cell subsets proved to be a valuable method for monitoring children after allogeneic HCT. High proportion of activated, unstimulated Ts cells observed in the GvHD group may underline the critical role of CD3+CD8+ cells in the pathogenesis of GvHD. Thus in future immunosuppressive therapy may be adjusted according to the proportion of activated Ts cells.

Metabolic functions of the liver during chemotherapy in children with acute lymphoblastic leukemia.

OBJECTIVE: The purpose of the present work was estimation of liver function using the phenazone test and commonly used biochemical tests in children with acute lymphoblastic leukemia (ALL) during anticancer treatment. METHODS: Observations were carried out in the same 21 patients with ALL before the beginning of chemotherapy, after Protocol I and after Protocol M of the antileukemic treatment carried out according to the program BFM 86. RESULTS: The applied chemotherapy inhibited phenazone elimination. Both phenazone half-life and metabolic clearance rate were significantly different in patients after treatment with anticancer drugs, especially with high-dose of methotrexate (MTX), from those in patients before the beginning of chemotherapy (p < 0.001). Moreover, after MTX administration transaminases activity and serum bilirubin concentration were significantly higher than before treatment (p < 0.05). CONCLUSION: Our results showed that in children with acute lymphoblastic leukemia, anticancer chemotherapy decreased liver metabolic capacity. Particularly, high-dose methotrexate treatment altered the elimination of phenazone by inhibiting the activity of hepatic mixed function oxidase system. This change may lead to an increase in toxicity of active drugs which are metabolized by this enzyme system. In addition, altered activity of liver metabolic function can impair transformation of prodrugs to active forms. It should be considered in selection of individual drug dosages. The objective estimation of the type and degree of liver dysfunction can only be achieved by the combination of a quantitative phenazone dynamic test and static biochemical tests.