A Rare Onset of T-Lymphoid Blast Crisis in Chronic Myeloid Leukemia with Two Distinct Blast Populations.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by bone marrow expansion and the proliferation of one or more myeloid cell lineages, predominantly driven by the expression of the constitutively active fusion product tyrosine kinase BCR:ABL1. Rarely, CML patients directly develop a blast crisis (BC), mostly of myeloid origin. CML at blast crisis with a T-cell phenotype at diagnosis, without any prior history of CML, is extremely rare. Herein, we describe one rare CML case, in a young man showing an unusual and early T-lymphoid blastic crisis at diagnosis, as the first onset of a previously unknown CML. The multidisciplinary collaboration between laboratorians and clinicians for the diagnosis and management of this atypical case was crucial in outlining both a targeted pharmacological treatment and a successful hematopoietic stem cell transplantation.

ß3-adrenergic receptor on tumor-infiltrating lymphocytes sustains IFN-γ-dependent PD-L1 expression and impairs anti-tumor immunity in neuroblastoma.

Neuroblastoma (NB) is a heterogeneous extracranial tumor occurring in childhood. A distinctive feature of NB tumors is their neuroendocrine ability to secrete catecholamines, which in turn, via ß-adrenergic receptors ligation, may affect different signaling pathways in tumor microenvironment (TME). It was previously demonstrated that specific antagonism of ß3-adrenergic receptor (ß3-AR) on NB tumor cells affected tumor growth and progression. Here, in a murine syngeneic model of NB, we aimed to investigate whether the ß3-AR modulation influenced the host immune system response against tumor. Results demonstrated that ß3-AR antagonism lead to an immune response reactivation, partially dependent on the PD-1/PD-L1 signaling axis involvement. Indeed, ß3-AR blockade on tumor-infiltrating lymphocytes (TILs) dampened their ability to secrete IFN-γ, which in turn reduced the PD-L1 expression, caused by TILs infiltration, on NB tumor cells. Further investigations, through a genomic analysis on NB patients, showed that high ADRB3 gene expression correlates with worse clinical outcome compared to the low expression group, and that ADRB3 gene expression affects different immune-related pathways. Overall, results indicate that ß3-AR in NB TME is able to modulate the interaction between tumor and host immune system, and that its antagonism hits multiple pro-tumoral signaling pathways.

Atypical Presentations of IPEX: Expect the Unexpected.

Immune dysregulation, polyendocrinopathy, and enteropathy, X-linked (IPEX) syndrome is a rare disorder that has become a model of monogenic autoimmunity. IPEX is caused by mutations in FOXP3 gene, a master regulator of regulatory T cells (Treg). Cases reported in the last 20 years demonstrate that IPEX clinical spectrum encompasses more than the classical triad of early-onset intractable diarrhea, type 1 diabetes (T1D) and eczema. Atypical cases of IPEX include patients with late-onset of symptoms, single-organ involvement, mild disease phenotypes or rare clinical features (e.g., atrophic gastritis, interstitial lung disease, nephropathy etc.). Several atypical presentations have recently been reported, suggesting that IPEX incidence might be underestimated. Immunosuppression (IS) treatment strategies can control the disease, however at the moment allogeneic hematopoietic stem cell transplantation (HSCT) is the only available definitive cure, therefore it is important to achieve a prompt diagnosis. This review aims to describe unusual clinical phenotypes, beyond classical IPEX. Overall, our analysis contributes to increase awareness and finally improve diagnosis and treatment intervention in IPEX in order to ensure a good quality of life.

Autoimmune Cytopenias and Dysregulated Immunophenotype Act as Warning Signs of Inborn Errors of Immunity: Results From a Prospective Study.

Inborn errors of immunity (IEI) are genetic disorders characterized by a wide spectrum of clinical manifestations, ranging from increased susceptibility to infections to significant immune dysregulation. Among these, primary immune regulatory disorders (PIRDs) are mainly presenting with autoimmune manifestations, and autoimmune cytopenias (AICs) can be the first clinical sign. Significantly, AICs in patients with IEI often fail to respond to first-line therapy. In pediatric patients, autoimmune cytopenias can be red flags for IEI. However, for these cases precise indicators or parameters useful to suspect and screen for a hidden congenital immune defect are lacking. Therefore, we focused on chronic/refractory AIC patients to perform an extensive clinical evaluation and multiparametric flow cytometry analysis to select patients in whom PIRD was strongly suspected as candidates for genetic analysis. Key IEI-associated alterations causative of STAT3 GOF disease, IKAROS haploinsufficiency, activated PI3Kδ syndrome (APDS), Kabuki syndrome and autoimmune lymphoproliferative syndrome (ALPS) were identified. In this scenario, a dysregulated immunophenotype acted as a potential screening tool for an early IEI diagnosis, pivotal for appropriate clinical management and for the identification of new therapeutic targets.

ß3-Adrenoceptors as Putative Regulator of Immune Tolerance in Cancer and Pregnancy.

Understanding the mechanisms of immune tolerance is currently one of the most important challenges of scientific research. Pregnancy affects the immune system balance, leading the host to tolerate embryo alloantigens. Previous reports demonstrated that ß-adrenergic receptor (ß-AR) signaling promotes immune tolerance by modulation of NK and Treg, mainly through the activation of ß2-ARs, but recently we have demonstrated that also ß3-ARs induce an immune-tolerant phenotype in mice bearing melanoma. In this report, we demonstrate that ß3-ARs support host immune tolerance in the maternal microenvironment by modulating the same immune cells populations as recently demonstrated in cancer. Considering that ß3-ARs are modulated by oxygen levels, we hypothesize that hypoxia, through the upregulation of ß3-AR, promotes the biological shift toward a tolerant immunophenotype and that this is the same trick that embryo and cancer use to create an aura of immune-tolerance in a competent immune environment. This study confirms the analogies between fetal development and tumor progression and suggests that the expression of ß3-ARs represents one of the strategies to induce fetal and tumor immune tolerance.

Case Report: Signal Transducer and Activator of Transcription 3 Gain-of-Function and Spectrin Deficiency: A Life-Threatening Case of Severe Hemolytic Anemia.

STAT3 gain-of-function (GOF) mutations can be responsible for an incomplete phenotype mainly characterized by hematological autoimmunity, even in the absence of other organ autoimmunity, growth impairment, or severe infections. We hereby report a case with an incomplete form of STAT3 GOF intensified by a concomitant hereditary hematological disease, which misleads the diagnosis. The patient presented with lymphadenopathy, splenomegaly, hypogammaglobulinemia, and severe autoimmune hemolytic anemia (AIHA) with critical complications, including stroke. A Primary Immune Regulatory Disorders (PIRD) was suspected, and molecular analysis revealed a de novo STAT3 gain-of-function mutation. The response to multiple immune suppressive treatments was ineffective, and further investigations revealed a spectrin deficiency. Ultimately, hematopoietic stem cell transplantation from a matched unrelated donor was able to cure the patient. Our case shows an atypical presentation of STAT3 GOF associated with hereditary spherocytosis, and how achievement of a good long-term outcome depends on a strict clinical and laboratory monitoring, as well as on prompt therapeutic intervention.

CD25 deficiency: A new conformational mutation prevents the receptor expression on cell surface.

CD25 deficiency is a very rare autosomal recessive disorder that shows a clinical phenotype highly overlapping IPEX syndrome with an increased susceptibility to viral, bacterial, and fungal infections. It is due to mutations in the IL2Rα gene that codes for the α subunit of the IL2 receptor complex. Here we report the characterization of a novel IL2Rα gene mutation leading to a severe protein conformational alteration that abrogates its cell surface expression in a child presenting with early-onset IPEX-like disorder. Cytofluorimetric analysis revealed the total absence of CD25 cell surface expression and addressed IL2Rα molecular investigation. The early clinical and molecular diagnosis of CD25 deficiency in this patient promptly led to hematopoietic stem cell transplantation (HSCT), allowing complete resolution of the symptoms and definitive cure of the disease.

Novel molecular defects associated with very early-onset inflammatory bowel.

PURPOSE OF REVIEW: Immune dysregulation disorders present with common clinical features of multiorgan autoimmunity. Gastrointestinal involvement is the hallmark of an impaired immune homeostasis. This review will give an overview on the novel phenotypes, highlighting the major points that will help to enable early diagnosis and treatment. RECENT FINDINGS: The rapid progress on DNA sequencing technologies have led to the identification of monogenic defects that adversely impact the control of immune homeostasis. Lymphocytes may be present but dysfunctional, allowing for the development of excessive autoreactivity and resultant autoimmune disease. Regulatory T cells (Tregs) play an essential role in enforcing immune tolerance. Here we illustrate disorders caused by impairment of mechanisms ensuring Tregs function (Tregs related) in which autoimmunity is a hallmark of the clinical disease presentation and other disorders, affecting molecules more broadly involved in immune responses and indirectly causing immune dysregulation (Tregs unrelated). Clinical presentation is sometime mischievous and often symptoms are analogous in different diseases and can mislead diagnosis. SUMMARY: The increasing comprehension of immunological concepts behind immune dysregulation diseases will allow better and in some cases possibly even targeted treatment. A genetic diagnosis therefore becomes important information in this group of patients, especially as some patients might require hematopoietic stem cell transplantation.

Human IL2RA null mutation mediates immunodeficiency with lymphoproliferation and autoimmunity.

Cell-surface CD25 expression is critical for maintaining immune function and homeostasis. As in few reported cases, CD25 deficiency manifests with severe autoimmune enteritis and viral infections. To dissect the underlying immunological mechanisms driving these symptoms, we analyzed the regulatory and effector T cell functions in a CD25 deficient patient harboring a novel IL2RA mutation. Pronounced lymphoproliferation, mainly of the CD8(+) T cells, was detected together with an increase in T cell activation markers and elevated serum cytokines. However, Ag-specific responses were impaired in vivo and in vitro. Activated CD8(+)STAT5(+) T cells with lytic potential infiltrated the skin, even though FOXP3(+) Tregs were present and maintained a higher capacity to respond to IL-2 compared to other T-cell subsets. Thus, the complex pathogenesis of CD25 deficiency provides invaluable insight into the role of IL2/IL-2RA-dependent regulation in autoimmunity and inflammatory diseases.