Long-term follow-up of IPEX syndrome patients after different therapeutic strategies: An international multicenter retrospective study

Background

Immunodysregulation polyendocrinopathy enteropathy x-linked(IPEX) syndromeis a monogenic autoimmune disease caused by FOXP3 mutations. Because it is a rare disease, the natural history and response to treatments, including allogeneic hematopoietic stem cell transplantation (HSCT) and immunosuppression (IS), have not been thoroughly examined.

Objective

This analysis sought to evaluate disease onset, progression, and long-term outcome of the 2 main treatments in long-term IPEX survivors.

Methods

Clinical histories of 96 patients with a genetically proven IPEX syndrome were collected from 38 institutions worldwide and retrospectively analyzed. To investigate possible factors suitable to predict the outcome, an organ involvement (OI) scoring system was developed.

Results

We confirm neonatal onset with enteropathy, type 1 diabetes, and eczema. In addition, we found less common manifestations in delayed onset patients or during disease evolution. There is no correlation between the site of mutation and the disease course or outcome, and the same genotype can present with variable phenotypes. HSCT patients (n = 58) had a median follow-up of 2.7 years (range, 1 week-15 years). Patients receiving chronic IS (n = 34) had a median follow-up of 4 years (range, 2 months-25 years). The overall survival after HSCT was 73.2% (95% CI, 59.4-83.0) and after IS was 65.1% (95% CI, 62.8-95.8). The pretreatment OI score was the only significant predictor of overall survival after transplant (P = .035) but not under IS.

Conclusions

Patients receiving chronic IS were hampered by disease recurrence or complications, impacting long-term disease-free survival. When performed in patients with a low OI score, HSCT resulted in disease resolution with better quality of life, independent of age, donor source, or conditioning regimen.

Hemophagocytic syndrome in children with acute monoblastic leukemia-another cause of fever of unknown origin

PURPOSE

Intensification of antileukemic treatment and progress in supportive management have improved the survival rates of children with acute myeloid leukemia (AML). However, morbidity and early mortality in these patients are still very high, especially in children with acute monoblastic leukemia (AML FAB M5). Inflammatory syndromes complicating the management of these children after application of cytosine arabinoside and due to hyperleukocytosis at initial presentation have been reported. Hemophagocytic lymphohistiocytosis (HLH) has been described as a serious and life-threatening acute complication during treatment of different oncologic entities; however, data on HLH in children with AML FAB M5 are extremely rare.

METHODS

A retrospective study of all children with AML FAB M5 treated at our institution between 1993 and 2013 was performed to describe the clinical characteristics of patients who developed an inflammatory syndrome with HLH during oncologic treatment.

RESULTS

Three of 10 children developed an inflammatory syndrome with fever, elevation of C-reactive protein, hyperferritinemia, elevation of soluble interleukin-2, and hemophagocytosis during prolonged aplasia following the first cycle of chemotherapy not responding to broad-spectrum antibiotics. No infectious agents could be identified; the initial symptoms occurred 17, 18, and 28 days after diagnosis of AML, respectively. The children immediately responded to dexamethasone; however, the same syndrome was observed again after the second cycle of chemotherapy and, in one patient, also after the third cycle.

CONCLUSIONS

Treating physicians should be aware of an inflammatory syndrome resembling HLH in children with monoblastic leukemia since this problem might extremely complicate management and supportive care of these children. The co-incidence of monoblastic leukemia with HLH might be explained by cytokines released from the monoblastic leukemic cells themselves.

Concurrent FOXP3- and CTLA4-associated genetic predisposition and skewed X chromosome inactivation in an autoimmune disease-prone family

CLTA4 is relevant for FOXP3(+)Treg cells, and the link between skewed X chromosome inactivation (XCI) and autoimmunity is recognized. The observation of immune dysregulation polyendocrinopathy enteropathy X-linked syndrome and multiorgan endocrine autoimmune phenomena in various members of one family, associated with a CTLA4 polymorphism and skewed XCI, provides an in vivo model of how mechanisms of immune dysregulation may cooperate.

Clinical and immunological overlap between autoimmune lymphoproliferative syndrome and common variable immunodeficiency

Autoimmune lymphoproliferative syndrome (ALPS) is mainly caused by defects in the CD95 pathway. Raised CD3+TCRαβ+CD4-CD8- double negative T cells and impaired T cell apoptosis are hallmarks of the disease. In contrast, the B cell compartment has been less well studied. We found an altered distribution of B cell subsets with raised transitional B cells and reduced marginal zone B cells, switched memory B cells and plasma blasts in most of 22 analyzed ALPS patients. Moreover, 5 out of 66 ALPS patients presented with low IgG and susceptibility to infection revealing a significant overlap between ALPS and common variable immunodeficiency (CVID). In patients presenting with lymphoproliferation, cytopenia, hypogammaglobulinemia and impaired B cell differentiation, serum biomarkers were helpful in addition to apoptosis tests for the identification of ALPS patients. Our observations may indicate a role for apoptosis defects in some diseases currently classified as CVID.

Indoleamine 2,3-dioxygenase in hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) is complicated by unwelcome side-effects that arise on the basis of an altered immune system. Infectious complications and alloreactive T-cell responses trigger a process of ongoing immune activation and inflammation. Negative-feedback mechanisms to counteract inflammation involve the induction of the immunoregulatory enzyme indoleamine 2,3-dioxygenase (IDO), which mediates anti-inflammatory activities and T-cell inhibition via tryptophan catabolism. However, persistent immune activation and generalized release of pro-inflammatory cytokines deviate immune regulation towards chronic suppression incapable to abrogate the inflammatory response. This review focuses on the unique role of tryptophan catabolism in modulating inflammatory processes and T-cell responses after HSCT.

E2A-HLF usurps control of evolutionarily conserved survival pathways

E2A-HLF, the chimeric fusion protein resulting from the leukemogenic translocation t(17;19), appears to employ evolutionarily conserved signaling cascades for its transforming and antiapoptotic functions. These arise from both impairment of normal E2A function and activation of a survival pathway triggered through the HLF bZip DNA binding and dimerization domain. Recent reports identify wild-type E2A as a tumor suppressor in T lymphocytes. Moreover, E2A-HLF has been shown to activate SLUG, a mammalian homologue of the cell death specification protein CES-1 in Caenorhabditis elegans, which appears to regulate an evolutionarily conserved cell survival program. Recently, several key mouse models have been generated, enabling further elucidation of these pathways on a molecular genetic level in vivo. In this review, we discuss the characteristics of both components of the fusion protein with regard to their contribution to the regulation of cell fate and the oncogenic potential of E2A-HLF.

Activation of mitogen-activated protein kinase by the A(2A)-adenosine receptor via a rap1-dependent and via a p21(ras)-dependent pathway

The A(2A)-adenosine receptor, a prototypical G(s)-coupled receptor, activates mitogen-activated protein (MAP) kinase in a manner independent of cAMP in primary human endothelial cells. In order to delineate signaling pathways that link the receptor to the regulation of MAP kinase, the human A(2A) receptor was heterologously expressed in Chinese hamster ovary (CHO) and HEK293 cells. In both cell lines, A(2A) agonist-mediated cAMP accumulation was accompanied by activation of the small G protein rap1. However, rap1 mediates A(2A) receptor-dependent activation of MAP kinase only in CHO cells, the signaling cascade being composed of G(s), adenylyl cyclase, rap1, and the p68 isoform of B-raf. This isoform was absent in HEK293 cells. Contrary to CHO cells, in HEK293 cells activation of MAP kinase by A(2A) agonists was not mimicked by 8-bromo-cAMP, was independent of Galpha(s), and was associated with activation of p21(ras). Accordingly, overexpression of the inactive S17N mutant of p21(ras) and of a dominant negative version of mSos (the exchange factor of p21(ras)) blocked MAP kinase stimulation by the A(2A) receptor in HEK 293 but not in CHO cells. In spite of the close homology between p21(ras) and rap1, the S17N mutant of rap1 was not dominant negative because (i) overexpression of rap1(S17N) failed to inhibit A(2A) receptor-dependent MAP kinase activation, (ii) rap1(S17N) was recovered in the active form with a GST fusion protein comprising the rap1-binding domain of ralGDS after A(2A) receptor activation, and (iii) A(2A) agonists promoted the association of rap1(S17N) with the 68-kDa isoform of B-raf in CHO cells. We conclude that the A(2A) receptor has the capacity two activate MAP kinase via at least two signaling pathways, which depend on two distinct small G proteins, namely p21(ras) and rap1. Our observations also show that the S17N version of rap1 cannot be assumed a priori to act as a dominant negative interfering mutant.

Stimulation of natural killer activity in peripheral blood lymphocytes of healthy donors and melanoma patients in vitro: synergism between interleukin (IL)-12 and IL-15 or IL-12 and IL-2

Interleukin-2 (IL-2) and IL-12 modify the functional status of T- and natural killer (NK) cells by regulating proliferation, cytolytic activity, cytokine induction, and T-cell subset differentiation. These effects are exploited in immunotherapy of cancer patients with IL-2 or IL-12, which, however, is limited by potentially life-threatening side effects. IL-15 shares many of the biological activities of IL-2 and may therefore represent a therapeutic alternative. Here we have compared the ability of these interleukins to stimulate NK activity in peripheral blood lymphocytes (PBLs) isolated from healthy donors (n = 12) as well as from patients (n = 12) suffering from metastatic disease (melanoma). Target (K562) cell lysis was assessed by determining the release of 51Cr and lactate dehydrogenase (LDH) which gave equivalent results. The NK-resistant DAUDI cell line served as control target. Unstimulated NK activity was significantly lower in PBLs purified from melanoma patients. However, cytolytic activity was readily stimulated by preincubation of PBLs (18 h) with cytokines such that the maximum target cell lysis was comparable to that seen in PBL of healthy donors. Similarly, the potency of IL-2 (EC50 = 20.2+/-1.3 and 22.0+/-1.3 u/ml in healthy donors and patients, respectively), IL-12 (EC50 = 11.0+/-1.1 and 4.3+/-1.6 u/ml) and IL-15 (EC50 = 0.3+/-0.1 and 0.2+/-0.1 u/ml) was comparable. Importantly, if the preincubation was carried out with cytokine concentrations in the EC50 range, the effects of two cytokines (tested in all combinations) were additive. A synergism was evident in PBLs obtained both from healthy donors and melanoma patients if concentration-response curves for IL-12 were determined in the presence of increasing concentrations of IL-2 (enhanced efficacy) or IL-15 (enhanced efficacy and potency). Our observations suggest possible alternatives to the monotherapy with IL-2 (or IL-12) in cancer treatment. Provided that the present findings can be extrapolated to the situation in vivo, the combined administration of IL-12 and IL-15 may be as efficacious as the immunotherapy with IL-2; this approach ought to allow for a marked reduction in cytokine dose and thereby improve the therapeutic index.