Mesenchymal stromal cells from Shwachman-Diamond syndrome patients fail to recreate a bone marrow niche in vivo and exhibit impaired angiogenesis.

Shwachman-Diamond syndrome (SDS) is a rare multi-organ recessive disease mainly characterised by pancreatic insufficiency, skeletal defects, short stature and bone marrow failure (BMF). As in many other BMF syndromes, SDS patients are predisposed to develop a number of haematopoietic malignancies, particularly myelodysplastic syndrome and acute myeloid leukaemia. However, the mechanism of cancer predisposition in SDS patients is only partially understood. In light of the emerging role of mesenchymal stromal cells (MSCs) in the regulation of bone marrow homeostasis, we assessed the ability of MSCs derived from SDS patients (SDS-MSCs) to recreate a functional bone marrow niche, taking advantage of a murine heterotopic MSC transplant model. We show that the ability of semi-cartilaginous pellets (SCPs) derived from SDS-MSCs to generate complete heterotopic ossicles in vivo is severely impaired in comparison with HD-MSC-derived SCPs. Specifically, after in vitro angiogenic stimuli, SDS-MSCs showed a defective ability to form correct networks, capillary tubes and vessels and displayed a marked decrease in VEGFA expression. Altogether, these findings unveil a novel mechanism of SDS-mediated haematopoietic dysfunction based on hampered ability of SDS-MSCs to support angiogenesis. Overall, MSCs could represent a new appealing therapeutic target to treat dysfunctional haematopoiesis in paediatric SDS patients.

Pediatric extraspinal sacrococcygeal ependymoma (ESE): an Italian AIEOP experience of six cases and literature review.

BACKGROUND: Primary pediatric extraspinal sacrococcygeal ependymoma (ESE) is a very rare disease, poorly described in literature, whose diagnostic, therapeutic, and follow-up approach is still controversial. METHODS: We describe six cases of pediatric ESE treated at Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) centers in Italy since 1983, with a review of the literature. RESULTS: All six patients had primary sacrococcygeal disease (two presacral and four subcutaneous) with median age of 10 years. Three patients were males, and two of them are metastatic at diagnosis; 3/6 had myxopapillary ependymoma grade I and 3/6 had classic ependymoma grade II. Five patients underwent surgical resection with complete removal only in one case with coccygectomy. Adjuvant chemoradiotherapy was administered to one metastatic patient obtaining a complete remission. Two patients relapsed at 3 and 8 years from diagnosis: they were treated with salvage chemotherapy (high-dose sequential chemotherapy with myeloablative regimen in one case), surgery, and radiotherapy achieving complete remission (CR). All six patients are in complete continuous remission (CCR) at a median follow-up of 12.8 years. CONCLUSIONS: Pediatric patients with this peculiar disease need to be referred to specialized pediatric cancer centers that can provide multidisciplinary treatment after a centralized pathology review. Our experience highlights the role of chemotherapy and radiotherapy in adjuvant and relapse setting. The final prognosis is relatively optimistic, but with a careful follow-up due to the high risk of recurrence.

Detection of prognostic factors in children and adolescents with Burkitt and Diffuse Large B-Cell Lymphoma treated with the AIEOP LNH-97 protocol.

Burkitt lymphoma (BL) and Diffuse Large B-Cell Lymphoma (DLBCL) account for most cases of non-Hodgkin lymphoma (NHL) in childhood. We report the clinical characteristics, outcome and prognostic factors in children with BL or DLBCL treated according to the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) LNH-97 protocol. Patients aged up to 18 years that were newly diagnosed with BL/DLBCL were included in the study. Therapy consisted of pre-phase followed by 2-6 high-dose chemotherapy courses tailored according to lactate dehydrogenase (LDH) value and disease stage. A total of 442 patients (379 BL, 63 DLBCL) were enrolled between 1997 and 2014, of whom 18 failed to achieve remission, 6 experienced treatment-related death, 2 developed second malignancy and 20 relapsed. At a median follow-up time of 5 years, overall survival was 93% (±1%) and event-free survival was 90% (±1%). LDH value above the median value had an independently negative prognostic value (P < 0·0001). However, in the subgroup of 128 patients in which minimal disseminated disease (MDD) was analysed, MDD-positivity became the only unfavourable prognostic factor for progression-free survival. Tailored chemotherapy could be extremely effective with limited toxicity. Identification of MDD as a hallmark of a higher risk of treatment failure may provide a target population for treatment intensification by anti-CD20.

Non-Hodgkin lymphoma in children with an associated inherited condition: A retrospective analysis of the Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP).

BACKGROUND: Inherited conditions affecting genetic aberration, viral oncogenesis, reduced immune surveillance, and long-lasting antigen stimulation may build the way to lymphomagenesis in humans. METHODS: We extracted from the database of 4 consecutive trials for pediatric non-Hodgkin lymphoma (NHL) all cases with an associated genetic disease. RESULTS: Among 1,430 patients, 34 (2.4%) had an associated inherited condition and a mature B-lineage (n = 28), anaplastic large cell lymphoma (n = 4), or T-lineage (n = 2) NHL. Their median age at the diagnosis was 9.3 years (range, 2.6-17.8 years). In 14 cases (41%) the underlying condition was considered to be a potential cause for undue toxicity if the expected therapy was applied. Thus, treatment modification had been planned in advance. The overall survival was 89% (standard error [SE] 1%), 73% (SE 10%), and 73% (SE 23%) at 3 years for registered patients with no inherited condition associated, with genetic abnormalities and with underlying condition causing an immune deficiency, respectively (P = 0.003). CONCLUSION: In our cohort, patients with NHL with an underlying constitutional condition represent the 2.4% of the cases. In the subset of patients with primary immune deficiency, which may have contributed to lymphomagenesis, allogeneic hematopoietic stem cell transplantation may be required. In the remaining patients, the association with lymphoma remains apparently unexplained and could be not causative. Detailed reporting of such cases may contribute to disclose even rare and fully unexpected association, which may have implications for research in the field of lymphomagenesis.

Cutaneous melanoma in children and adolescents: the Italian rare tumors in pediatric age project experience.

OBJECTIVE: To describe a series of cutaneous melanoma in children collected by the Italian Rare Tumors in Pediatric Age project. STUDY DESIGN: From 2000 to 2012, 54 patients younger than 18 years of age were prospectively registered and treated at 12 Italian pediatric centers on the basis of the same diagnostic/therapeutic recommendations and with the same forms to record clinical data. RESULTS: Considering the estimated annual incidence in Italy, the registered cases accounted for 30% of those expected in children and 10% of adolescents. Clinically, 47% of the tumors were amelanotic and 81% were raised, 39% of cases had tumor thickness >2 mm, and 36% had lymph node involvement. For the whole series, 5-year event-free survival and overall survival rates were 75.2% and 84.6%, respectively. Patient survival correlated with tumor stage and ulceration. No relapses were recorded for T1-2 (thickness <2 mm), N0, and stage 0-I-II cases. CONCLUSION: We suggest that the variables influencing survival in children with melanoma are the same as for adults, the clinical approach used in adults is feasible in children, and pediatric cases are more likely to have advanced disease at diagnosis but similar survival. New effective drugs are needed for advanced disease, and biological studies and international cooperative schemes are warranted.

Single-day trimethoprim/sulfamethoxazole prophylaxis for Pneumocystis pneumonia in children with cancer.

OBJECTIVE: To determine whether a simplified, 1-day/week regimen of trimethoprim/sulfamethoxazole is sufficient to prevent Pneumocystis (jirovecii [carinii]) pneumonia (PCP). Current recommended regimens for prophylaxis against PCP range from daily administration to 3 consecutive days per week dosing. STUDY DESIGN: A prospective survey of the regimens adopted for the PCP prophylaxis in all patients treated for childhood cancer at pediatric hematology-oncology centers of the Associazione Italiana Ematologia Oncologia Pediatrica. RESULTS: The 20 centers participating in the study reported a total of 2466 patients, including 1093 with solid tumor and 1373 with leukemia/lymphoma (or primary immunodeficiency; n = 2). Of these patients, 1371 (55.6%) received the 3-day/week prophylaxis regimen, 406 (16.5%) received the 2-day/week regimen, and 689 (27.9%), including 439 with leukemia/lymphoma, received the 1-day/week regimen. Overall, only 2 cases of PCP (0.08%) were reported, both in the 2-day/week group. By intention to treat, the cumulative incidence of PCP at 3 years was 0.09% overall (95% CI, 0.00-0.40%) and 0.51% for the 2-day/week group (95% CI, 0.10%-2.00%). Remarkably, both patients who failed had withdrawn from prophylaxis. CONCLUSION: A single-day course of prophylaxis with trimethoprim/sulfamethoxazole may be sufficient to prevent PCP in children with cancer undergoing intensive chemotherapy regimens. This simplified strategy might have implications for the emerging need for PCP prophylaxis in other patients subjected to the increased use of biological and nonbiological agents that induce higher levels of immune suppression, such as those with rheumatic diseases.

Extended spectrum of human glucose-6-phosphatase catalytic subunit 3 deficiency: novel genotypes and phenotypic variability in severe congenital neutropenia.

OBJECTIVE: To delineate the phenotypic and molecular spectrum of patients with a syndromic variant of severe congenital neutropenia (SCN) due to mutations in the gene encoding glucose-6-phosphatase catalytic subunit 3 (G6PC3). STUDY DESIGN: Patients with syndromic SCN were characterized for associated malformations and referred to us for G6PC3 mutational analysis. RESULTS: In a cohort of 31 patients with syndromic SCN, we identified 16 patients with G6PC3 deficiency including 11 patients with novel biallelic mutations. We show that nonhematologic features of G6PC3 deficiency are good predictive indicators for mutations in G6PC3. Additionally, we demonstrate genetic variability in this disease and define novel features such as growth hormone deficiency, genital malformations, disrupted bone remodeling, and abnormalities of the integument. G6PC3 mutations may be associated with hydronephrosis or facial dysmorphism. The risk of transition to myelodysplastic syndrome/acute myeloid leukemia may be lower than in other genetically defined SCN subgroups. CONCLUSIONS: The phenotypic and molecular spectrum in G6PC3 deficiency is wider than previously appreciated. The risk of transition to myelodysplastic syndrome or acute myeloid leukemia may be lower in G6PC3 deficiency compared with other subgroups of SCN.

Metastatic renal cell carcinoma in children and adolescents: a 30-year unsuccessful story.

BACKGROUND: Because of the rare occurrence of renal cell carcinoma (RCC) among children very little is known about this malignancy in pediatric age. We aimed adding knowledge on the clinical characteristics and outcome of metastatic (m) RCC in children and adolescents. PATIENTS AND METHODS: The series included 14 stage 4 RCC patients with a median age at diagnosis of 155.5 months, observed at the Italian Pediatric Hematology and Oncology Association (AIEOP) centers from January 1973 to November 2010. We were able to reevaluate histopatology of 11 out of the 14 patients and perform immunostaining for TFE3 in 9 out of the 11 patients. RESULTS: Of the 14 patients under study, 5 (3 girls) had a translocation morphology TFE+ RCC, 2 were reassigned as papillary type 1 or 2, respectively, 2 tumor specimens with primary clear cell histology had confirmed the initial histologic diagnosis, and 2-whose biopsy specimen was insufficient-had the diagnosis of RCC not further specified with subtyping. In the remaining 3 cases, the initial diagnosis of clear cell carcinoma was left. Overall, 6 patients received chemotherapy, 9 immunotherapy, and 2 adjuvant antiangiogenic therapy. Overall, 11 patients (78.5%) never achieved complete remission and died from progressive disease 1 to 16 months after diagnosis (median overall survival 5.5 mo). Three patients, 2 of whom received adjuvant antiangiogenic therapy, relapsed to lung at 3, 6, and 8 months after diagnosis, and died 18, 32, and 33 months after diagnosis, respectively. CONCLUSIONS: Despite their possibly different biology, childhood and adult mRCC seems to be sharing comparable outcomes. Because of the very low incidence of mRCC (about 20%) in children and adolescents, an international pediatric cooperation to address biological studies and assess the novel targeted approaches is needed.

A case of syndromic neutropenia and mutation in G6PC3.

BACKGROUND: A previously unrecognized syndrome with congenital neutropenia and various organ abnormalities has been described recently, caused by mutations in the gene encoding glucose-6-phosphatase, catalytic subunit 3 (G6PC3). OBSERVATION: A 10-year-old boy from Ecuador suffering from severe neutropenia and multiple nonhematopoietic abnormalities was admitted to our department. We identified a novel mutation in the G6PC3 gene (c. 765_delAG; p.S255fs). CONCLUSIONS: This is the first case of G6PC3 deficiency in a patient from South America, caused by a novel mutation in the G6PC3 gene. Our results give insights into the molecular and clinical variability of this disease.

Clinical, Immunological, and Molecular Features of Typical and Atypical Severe Combined Immunodeficiency: Report of the Italian Primary Immunodeficiency Network.

Severe combined immunodeficiencies (SCIDs) are a group of inborn errors of the immune system, usually associated with severe or life-threatening infections. Due to the variability of clinical phenotypes, the diagnostic complexity and the heterogeneity of the genetic basis, they are often difficult to recognize, leading to a significant diagnostic delay (DD). Aim of this study is to define presenting signs and natural history of SCID in a large cohort of patients, prior to hematopoietic stem cell or gene therapies. To this purpose, we conducted a 30-year retro-prospective multicenter study within the Italian Primary Immunodeficiency Network. One hundred eleven patients, diagnosed as typical or atypical SCID according to the European Society for Immune Deficiencies criteria, were included. Patients were subsequently classified based on the genetic alteration, pathogenic mechanism and immunological classification. A positive relationship between the age at onset and the DD was found. SCID patients with later onset were identified only in the last decade of observation. Syndromic SCIDs represented 28% of the cohort. Eight percent of the subjects were diagnosed in Intensive Care Units. Fifty-three percent had an atypical phenotype and most of them exhibited a discordant genotype-immunophenotype. Pre-treatment mortality was higher in atypical and syndromic patients. Our study broadens the knowledge of clinical and laboratory manifestations and genotype/phenotype correlation in patients with SCID and may facilitate the diagnosis of both typical and atypical forms of the disease in countries where newborn screening programs have not yet been implemented.

Early T-cell precursor acute lymphoblastic leukaemia in children treated in AIEOP centres with AIEOP-BFM protocols: a retrospective analysis.

BACKGROUND: Early T-cell precursor acute lymphoblastic leukaemia was recently recognised as a distinct leukaemia and reported as associated with poor outcomes. We aimed to assess the outcome of early T-cell precursor acute lymphoblastic leukaemia in patients from the Italian Association of Pediatric Hematology Oncology (AIEOP) centres treated with AIEOP-Berlin-Frankfurt-Münster (AIEOP-BFM) protocols. METHODS: In this retrospective analysis, we included all children aged from 1 to less than 18 years with early T-cell precursor acute lymphoblastic leukaemia immunophenotype diagnosed between Jan 1, 2008, and Oct 31, 2014, from AIEOP centres. Early T-cell precursors were defined as being CD1a and CD8 negative, CD5 weak positive or negative, and positive for at least one of the following antigens: CD34, CD117, HLADR, CD13, CD33, CD11b, or CD65. Treatment was based on AIEOP-BFM acute lymphoblastic leukaemia 2000 (NCT00613457) or AIEOP-BFM acute lymphoblastic leukaemia 2009 protocols (European Clinical Trials Database 2007-004270-43). The main differences in treatment and stratification of T-cell acute lymphoblastic leukaemia between the two protocols were that in the 2009 protocol only, pegylated L-asparaginase was substituted for Escherichia coli L-asparaginase, patients with prednisone poor response received an additional dose of cyclophosphamide at day 10 of phase IA, and high minimal residual disease at day 15 assessed by flow cytometry was used as a high-risk criterion. Outcomes were assessed in terms of event-free survival, disease-free survival, and overall survival. FINDINGS: Early T-cell precursor acute lymphoblastic leukaemia was diagnosed in 49 patients. Compared with overall T-cell acute lymphoblastic leukaemia, it was associated with absence of molecular markers for PCR detection of minimal residual disease in 25 (56%) of 45 patients; prednisone poor response in 27 (55%) of 49 patients; high minimal residual disease at day 15 after starting therapy in 25 (64%) of 39 patients (bone marrow blasts ≥ 10%, by flow cytometry); no complete remission after phase IA in 7 (15%) of 46 patients (bone marrow blasts ≥ 5%, morphologically); and high PCR minimal residual disease (≥ 5 × 10(-4)) at day 33 after starting therapy in 17 (85%) of 20 patients with markers available. Overall, 38 (78%) of 49 patients are in continuous complete remission, including 13 of 18 after haemopoietic stem cell transplantation, with three deaths in induction, five deaths after haemopoietic stem cell transplantation, and three relapses. Severe adverse events in the 2009 study were reported in 10 (30%) of 33 patients with early T-cell precursor acute lymphoblastic leukaemia versus 24 (15%) of 164 patients without early T-cell precursor acute lymphoblastic leukaemia and life-threatening events in induction phase IA occurred in 4 (12%) of 33 patients with early T-cell precursor acute lymphoblastic leukaemia versus 7 (4%) of 164 patients without early T-cell precursor acute lymphoblastic leukaemia. No difference was seen in the subsequent consolidation phase IB of protocol I. INTERPRETATION: Early T-cell precursor acute lymphoblastic leukaemia is characterised by poor early response to conventional induction treatment. Consolidation phase IB, based on cyclophosphamide, 6-mercaptopurine, and ara-C at conventional (non-high) doses is effective in reducing minimal residual disease. Although the number of patients and observational time are limited, patients with early T-cell precursor acute lymphoblastic leukaemia treated with current BFM stratification and treatment strategy have a favourable outcome compared with earlier reports. The role of innovative therapies and haemopoietic stem cell therapy in early T-cell precursor acute lymphoblastic leukaemia needs to be assessed. FUNDING: None.

Renal cell carcinoma in children: a clinicopathologic study.

PURPOSE: To identify the prognostic factors, treatment, and outcome of children affected by renal cell carcinoma (RCC). PATIENTS AND METHODS: The series included 41 patients (18 males and 23 females) with a median age of 124 months observed at the 11 Italian Association for Pediatric Hematology and Oncology centers from January 1973 to January 2001. Clinical data, surgical notes, pathologic findings, and summaries of therapy were taken from the charts. RESULTS: Seven (17%) of the 41 patients had a papillary histology, and 34 (82.4%) had nonpapillary histology. Eighteen patients (43.9%) had stage I, one patient (2.4%) had stage II, two patients (4.8%) had stage IIIA, 10 patients (24.3%) had stage IIIB, and nine patients (21.9%) had stage IV disease. One patient had a bilateral involvement at diagnosis. Seven patients experienced disease recurrence. Lung and liver were the most common distant lesions and usually were fatal. In this study, the major factor influencing the prognosis was the stage. Event-free survival at 20 years was 53.5% for all patients. Overall survival at 20 years was 54.9% for all patients. CONCLUSION: RCC is a rare disease in children and adolescents. This neoplasm has a different clinical presentation in children compared with adults but the same outcome. In our experience, patients with localized disease could be cured by nephrectomy alone. Prospective studies in a larger number of patients are needed to confirm radiation therapy and biologic response modifiers as effective adjunct therapy in RCC stage III. The alternative therapy seems warranted in patients with advanced disease.

Clinical features, long-term follow-up and outcome of a large cohort of patients with Chronic Granulomatous Disease: an Italian multicenter study.

A retrospective clinical and immunological survey was conducted in 60 patients with Chronic Granulomatous Disease. A prospective controlled non-randomized study of the efficacy of long-term IFNgamma treatment was carried out. The mean age at the time of diagnosis was 4.4 years; mean duration of follow-up was 10.4 years. Lung and skin infections were the most frequent manifestations both prior to diagnosis and during follow-up. Aspergillus species was the first cause of infection and of death in our cohort. The mortality rate was 13%. Long term prophylaxis with IFNgamma did not significantly change the rate of total infection per patient-year compared to controls (p=0.07). Our data provide clear evidence that protocols of continuing intensive surveillance and monitoring of compliance with anti-infective regimens may significantly improve the quality of life and long-term survival in patients with CGD. No evidence justifying long-term prophylaxis with IFNgamma was obtained.

Soft-tissue sarcomas in children and adolescents with neurofibromatosis type 1.

BACKGROUND: Patients affected by neurofibromatosis type 1 (NF1) are at higher risk of developing soft-tissue sarcomas (STS) than the general population. The clinical findings and outcome in 43 children and adolescents with NF1 treated for STS in the Italian protocols between 1988 and 2004 are reported. METHODS: The study included 37 patients with neurogenic sarcomas (36 malignant peripheral nerve sheath tumors [MPNST], 1 triton tumor) and 6 cases of rhabdomyosarcoma (RMS). The prevalence of NF1 observed during the study period was 43% in the MPNST population and 1% in the RMS group. RESULTS: Most patients with neurogenic sarcomas had large, invasive tumors. Five-year event-free and overall survival rates were 19% and 28%, respectively. Two of 16 patients with evaluable disease responded to chemotherapy. All 6 RMS patients were

Prognostic role of minimal residual disease in mature B-cell acute lymphoblastic leukemia of childhood.

PURPOSE: To study the prevalence of t(8;14) at diagnosis and the response kinetics to treatment of minimal residual disease (MRD) in B-cell acute lymphoblastic leukemia (B-ALL) patients and determine its impact on prognosis. PATIENTS AND METHODS: A total of 68 children affected by de novo B-ALL enrolled onto the Berlin-Frankfurt-Muenster-based Italian Association of Pediatric Hematology and Oncology LNH-97 clinical protocol were studied. Bone marrow aspirate from each patient was analyzed for the presence of t(8;14)(q24;q32) by long-distance polymerase chain reaction at diagnosis, after the first chemotherapy cycle, and after subsequent cycles until negative for MRD. Morphologic and immunophenotypic analyses were reviewed centrally. RESULTS: A total of 47 patients (69%) were positive for t(8;14)(q24;q32). MRD response kinetics was determined in 39 patients. All of them reached clinical complete remission and most (31 of 39) became MRD negative after the first chemotherapy cycle. The 3-year relapse-free survival (RFS) was 38% (SE = 17%) in patients MRD positive after the first chemotherapy cycle compared with 84% (SE = 7%) in MRD-negative patients (P = .0005), whereas there was no difference in RFS for children who reached a clinical complete remission after the first chemotherapy cycle versus those who did not (RFS = 72% and SE = 9%; RFS = 79% and SE = 11%, respectively; P = .8). In multivariate analysis, MRD was shown to be predictive of higher risk of failure. CONCLUSION: Our study demonstrated that MRD carries a negative prognostic impact in B-ALL patients and suggests that a better risk-adapted therapy, possibly including the use of anti-CD20 monoclonal antibody, should be considered in selected patients.

Conservative management of hyperplastic and multicentric nephroblastomatosis.

PURPOSE: The treatment of hyperplastic nephroblastomatosis remains controversial. We report the advantages of conservative management of hyperplastic and multicentric nephroblastomatosis associated with unilateral Wilms tumor (WT). MATERIALS AND METHODS: During the last 10 years 48 children with unilateral WT were consecutively treated at our 2 institutions. Children with multiple solid renal masses on imaging were treated with 2-drug chemotherapy until disappearance of the lesions. Stabilization or progression of the lesions despite chemotherapy, as well as heterogeneity of the lesions on imaging, prompted nephron sparing surgery (NSS). RESULTS: Three female infants (12, 13 and 20 months old, respectively) presented with multiple solid renal tumors at imaging. Despite chemotherapy, small and unilateral WT developed in 2 cases of hyperplastic nephroblastomatosis, which was excised. One of these infants subsequently presented with a small contralateral metachronous WT, which was excised. Both infants are disease-free with 2 normal kidneys at followup of 6 and 2 years, respectively. The third infant, who presented with unilateral multicentric WT and unilateral hyperplastic nephroblastomatosis nodules, was successfully treated with preoperative chemotherapy and enucleation of 5 tumors. Subsequently, nephrectomy was performed at another institution because the abnormal kidney outline due to NSS was misinterpreted as a recurrence of WT. She was lost to followup. CONCLUSIONS: Hyperplastic and multicentric nephroblastomatosis is not a rare lesion and is most often associated, either initially or subsequently, with WT. In some infants with multiple solid renal masses on imaging chemotherapy and for developing WT NSS may safely allow maximum sparing of the parenchyma of both kidneys.

Rituximab for the treatment of refractory autoimmune hemolytic anemia in children.

Autoimmune hemolytic anemia (AIHA) in children is sometimes characterized by a severe course, requiring prolonged administration of immunosuppressive therapy. Rituximab is able to cause selective in vivo destruction of B lymphocytes, with abrogation of antibody production. In a prospective study, we have evaluated the use of rituximab for the treatment of AIHA resistant to conventional treatment. Fifteen children with AIHA were given rituximab, 375 mg/m(2)/dose for a median of 3 weekly doses. All patients had previously received 2 or more courses of immunosuppressive therapy; 2 patients had undergone splenectomy. After completing treatment, all children received intravenous immunoglobulin for 6 months. Treatment was well tolerated. With a median follow-up of 13 months, 13 patients (87%) responded, whereas 2 patients did not show any improvement. Median hemoglobin levels increased from 7.7 g/dL to a 2-month posttreatment level of 11.8 g/dL (P <.001). Median absolute reticulocyte counts decreased from 236 to 109 x 10(9)/L (P <.01). An increase in platelet count was observed in patients with concomitant thrombocytopenia (Evans syndrome). Three responder patients had relapse, 7, 8, and 10 months after rituximab infusion, respectively. All 3 children received a second course of rituximab, again achieving disease remission. Our data indicate that rituximab is both safe and effective in reducing or even abolishing hemolysis in children with AIHA and that a sustained response can be achieved in the majority of cases. Disease may recur, but a second treatment course may be successful in controlling the disease.