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Langerhans cell histiocytosis (LCH) consists of lesions composed of cells with a dendritic Langerhans cell (LC) phenotype. The clinical course of LCH ranges from spontaneous resolution to a chronic and sometimes lethal disease. We studied 25 patients with various clinical forms of the disease. In bone and chronic lesions, LCH cells had immature phenotype and function. They coexpressed LC antigens CD1a and Langerin together with monocyte antigens CD68 and CD14. Class II antigens were intracellular and LCH cells almost never expressed CD83 or CD86 or dendritic cell (DC)–Lamp, despite their CD40 expression. Consistently, LCH cells sorted from bone lesions (eosinophilic granuloma) poorly stimulated allogeneic T-cell proliferation in vitro. Strikingly, however, in vitro treatment with CD40L induced the expression of membrane class II and CD86 and strongly increased LCH cell allostimulatory activity to a level similar to that of mature DCs. Numerous interleukin-10–positive (IL-10+), Langerin−, and CD68+ macrophages were found within bone and lymph node lesions. In patients with self-healing and/or isolated cutaneous disease, LCH cells had a more mature phenotype. LCH cells were frequently CD14− and CD86+, and macrophages were rare or absent, as were IL-10–expressing cells. We conclude that LCH cells in the bone and/or chronic forms of the disease accumulate within the tissues in an immature state and that most probably result from extrinsic signals and may be induced to differentiate toward mature DCs after CD40 triggering. Drugs that enhance the in vivo maturation of these immature DCs, or that induce their death, may be of therapeutic benefit.

Activation of tyrosine kinase genes is a frequent event in human hematologic malignancies. Because gene activation could be associated with gene dysregulation, we attempted to screen for activating gene mutation based on high-level gene expression. We focused our study on the Janus kinase 2 (JAK2) gene in 90 cases of acute leukemia. This strategy led to the identification of a novel JAK2-acquired mutation in a patient with Down syndrome (DS) with B-cell precursor acute lymphoblastic leukemia (BCP-ALL). This mutation involves a 5–amino acid deletion within the JH2 pseudokinase domain (JAK2ΔIREED). Expression of JAK2ΔIREED in Ba/F3 cells induced constitutive activation of the JAK-STAT pathway and growth factor–independent cell proliferation. These results highlight the JAK2 pseudokinase domain as an oncogenic hot spot and indicate that activation of the JAK-STAT pathway may contribute to lymphoid malignancies and hematologic disorders observed in children with DS.

Inherited deficiency of major histocompatibility complex (MHC) class II molecules impairs antigen presentation to CD4+ T cells and results in combined immunodeficiency (CID). Autosomal-recessive mutations in the RFXANK gene account for two-thirds of all cases of MHC class II deficiency. We describe here the genetic, clinical, and immunologic features of 35 patients from 30 unrelated kindreds from North Africa sharing the same RFXANK founder mutation, a 26-bp deletion called I5E6-25_I5E6 + 1), and date the founder event responsible for this mutation in this population to approximately 2250 years ago (95% confidence interval [CI]: 1750-3025 years). Ten of the 23 patients who underwent hematopoietic stem cell transplantation (HSCT) were cured, with the recovery of almost normal immune functions. Five of the patients from this cohort who did not undergo HSCT had a poor prognosis and eventually died (at ages of 1-17 years). However, 7 patients who did not undergo HSCT (at ages of 6-32 years) are still alive on Ig treatment and antibiotic prophylaxis. RFXANK deficiency is a severe, often fatal CID for which HSCT is the only curative treatment. However, some patients may survive for relatively long periods if multiple prophylactic measures are implemented.

From 06/93 to 12/99, 1395 children and adolescents were included in the FRALLE 93 protocol: group A (Very Low Risk): 182, B (Standard risk): 672 and C (High risk including T-ALL): 541. The median FU is 9.5 yr. Inclusion criterias in group B were: age between 1 and 15 yr, WBC< 100,000, BCP phenotype and no poor-prognosis cytogenetic feature (MLL rearrangement or Ph1). Group B pts were randomised in a 2-steps schedule: at inclusion: daunorubicin (DNR: 40 mg/m2 × 2) vs idarubicin (IDA: 8 mg/m2 × 2), and at consolidation: high-dose IV methotrexate (HD-MTX): 4 × 8g/m2 at D1, D15, D29 and D42, vs low-dose po MTX (LD-MTX): 4 × 25 mg/m2; the number of triple IT was the same for both arms (N = 18). Pts with CNS leukemia were not randomized for MTX. During induction, pts were also classified on D21 bone marrow aspiration according to the level of residual blasts: M1 (< 5%): n=555, M2 (6–25%): n=71 and M3 (> 25%): n=41; M2/M3 pts received 1 more antracyclin infusion at D22 and M3 pts were subsequently treated according to the HR group and not randomized for MTX. Both M1 and M2 pts who reached CR were randomized for MTX. The overall group B EFS, DFS and OS were respectively 80±2, 81±2, and 91±1%. Globally there is no statistically significant impact of 1st or 2nd randomization on the outcome of patients. When we look at the outcome according to the D21 status, the EFS are very different: M1: 84±2%, M2: 63±6% and M3: 74±7%. The very poor EFS of M2 pts, who can not actually be classified as SR pts, and the fact that M1 pts represent 90% of pts randomized for MTX led us to analyse separately M1 pts. For M1 pts there is no interaction between 1st and 2nd randomization for survival, EFS and relapse rate (Gail and Simon test, p = 0.51); therefore pts were pooled for 2nd randomization analysis. Among M1 pts, 271 pts were randomized for HD-MTX and 264 for LD-MTX; there is no difference regarding age or leucocytosis between the 2 arms. Results are as follows: 5-yr EFS Relapses CI iBM relapses CI Other relapses CI 5-yr OS (EFS: event-free survival, CI: cumulative incidence, iBM: isolated bone-marrow, OS: overall survival) HD-MTX 87.82±1.99% 0.12±0.04 7.01±0.02 5.17±0.02 95.20±1.30 LD-MTX 79.92±2.47% 0.20±0.06 10.6±0.03 9.10±0.03 88.64±1.95 Test log-rank Gray Gray Gray log-rank p value 0.028 0.037 0.16 0.18 0.07 At the contrary, among M2 pts there is no difference in EFS for pts treated with HD-MTX (61±7%) and LD-MTX (65±9%) Conclusion: HD-MTX seems to benefit to pts with standard-risk BCP-ALL and good early response to chemotherapy, and the benefit is associated with a reduction in the number of relapses. No benefit is demonstrated in M2 pts with SER who have a very poor outcome and do require a more intensive treatment; the better EFS of M3 patients treated with double delayed intensification is in favour of this hypothesis.

The most frequent oncogenic activation events characterized in childhood T acute lymphoblastic leukemia (T-ALL) result in the transcriptional activation of genes coding for transcription factors. The main genes are TAL1/SCL, a member of the basic region helix-loop-helix gene family, HOX11L2 a member of the homeobox-containing protein family. Conflicting results have been reported concerning molecular epidemiology and prognostic values of these markers (Cavé Blood2003:103442–445, Ferrando Cancer Cell 2002, Dicciani Blood 2003 abs 67) we therefore analysed retrospectively 200 pts treated in the French protocol FRALLE 93 for T-ALL between 11/93 and 12/99. Pts were stratified according to prednisone response at D8 ( good or poor : GPR or PPR) and bone marrow at D21. Pts with D8 PPR or M3 received an intensified treatment with genoidentical or autologous transplant in CR1. Molecular analysis was possible for 79/200 T-ALL samples. Clinical caracteristics were not significantly different between population with or without molecular analysis male (n=121) (69% vs 70%), median age 8.4y (range1.1–19.5) vs 9.2y, median leucocytosis 140.109 (0.6–736) vs 171.915 109 (100 n=48), mediastinal involvement 72% vs 71% ,CNS+ 4% vs 5%, CD 10 neg 54% vs 52%. Steroid response PPR n=37/73, GPR n=36/73 and D21 bone marrow status (M3 n=10, M2 n=11) were similar. CR was obtained in 72/79 pts (91%) after first induction therapy and 2 deaths occurs during induction treatment. With a median follow-up of 63 months (2–123), 5 y OS , EFS and DFS is 62 %± 9 and 54% ±10. SIL-TAL1/SCL fusion was detected in 20/79 (25%) pts; expression of HOX11L2 was observed in 14/79 (17%) pts. These activations are mutually exclusive and they allow the subclassification of 42 % of the patients. Median leucocytosis was significantly higher in SIL-TAL1/SCL pts (p=0.01) but other significant features ( ie median age, D8 response, D21 status) were not significantly different between each group. OS and EFS for TAL1/SCL , HOX11L2+ and none of these were respectively 81%±10, 43%±13, 62%± 7 and 80%±10 , 42%± 13, 55%± 7. OS and EFS D8 PPR/GPR were 47%± 9 vs 78% ±7 (p=0.009) and 41%±8 vs 71%±7 (p= 0.008); OS and EFS M2M3 vs M1 D21 bone marrow status were 45%± 15 vs 70% ±6 (p=0.05) and 36%±10 vs 66%± 6 (p= 0.018). In multivariate Cox model analysis, D8 steroid response and HOX11L2 expression were significantly associated with adverse event (failure or relapse) Risk Ratio :3 and 2.6 - p=0.008 and 0.03 and a higher risk of death Risk Ratio : 4.1 and 3.4 -p=0.061 and 0.05. Finally HOX11L2 expression and D8 PPR are independently associated with poor outcome in FRALLE 93 protocol analysis which confirms our previous report. Discrepancies among series may be explained by confounding factors such as differences in median leucocytes value(140.109 in our study) and treatment.

Metoclopramide has been shown to be a potential new therapeutic approach for Diamond-Blackfan anemia (DBA) affected individuals and has been hypothetized to stimulate erythropoiesisis through the induction of prolactin release. Among 15 transfusion-dependent patients enrolled in a previous pilot study, 9 completed 16 weeks of treatment, 3 of whom reaching a complete and sustained response (Abkowitz et al, Blood 2002). In order to further assess the drug efficacy we performed a prospective study in patients included in the French DBA registry. Patients over 2 years of age and dependent on regular transfusions were randomized at inclusion either to be treated immediately after a transfusion (Arm B), or 6 weeks later (Arm A), the comparison of these 2 groups aiming to provide a more accurate determination in the delay of response. All patients were prescribed metoclopramide for 16 or 22 weeks: 10 mg x 3/d in adults and 0.2 mg/kg x 3/d in children (weight < 50 kg). Packed Red Blood Cell transfusions were prescribed for hemoglobin values < 80g/L. The definition of response relied on Hb levels, reticulocyte counts, and the intervals between transfusions. Prolactin as well as other hormones levels were assessed. The study was initiated in October 2003. 7 adults and 22 children have been included so far (13F, 16M): 17 in A and 16 in B arms, respectively; 4 additional pts are planned to be included within a month. The treatment had to be prematurely discontinued in 2 pts because of severe side effects: nervous breakdown (8w of treatment) and anaphylaxis (14w of treatment). Other side effects were mild. Most patients complained of asthenia and drowsiness which both decreased after the 1st weeks of treatment; amenorrhoea (2 pts) and bulimia (3 pts) were also observed. No increase in transfusion need occurred. An update of the trial was performed on August 1st: at that time 21 pts had completed at least 16w of treatment. None of them experienced a complete response, as defined by a transfusion independence. In two a partial response, as defined by an increase in the transfusion interval was obtained: In one patient it evolved from 3–4 to 8 w, and in the other from 6–8 to 10–11w. Both are still on treatment. Lastly, it has to be emphasized that the 2 French responder patients previously included in the pilot study are still transfusion independent more than 5 yr after the initiation of metoclopramide treatment. CONCLUSION: metoclopramide may be of interest in some DBA affected individuals, even though we only obtained a low rate of partial responses in the present ongoing trial. We believe that this non toxic, and low cost treatment warrants to be tested in all patients with regular transfusion need or requiring high dose steroids. The duration of response and long term tolerance remain to be determined. Acknowledgments: Maria Daniela Arturi Foundation, DBA foundation and Assistance Publique-Hôpitaux de Paris (DRRC)