CD123 a Therapeutic Target for Acute Myeloid Leukemia and Blastic Plasmocytoid Dendritic Neoplasm.

In spite of consistent progress at the level of basic research and of clinical treatment, acute myeloid leukemia (AML) still represents an unmet clinical need for adult and pediatric patients. To improve the outcomes of these patients, it is necessary to identify new therapeutic targets. IL3RA (CD123, alpha subunit of the interleukin 3 receptor) is a cell membrane protein overexpressed in several hematologic malignancies, including AML blastic plasmocytoid dendritic cell neoplasms (BPDCN). Given the higher expression of CD123 on leukemic cells compared to normal hematopoietic cells and its low/absent expression on normal hematopoietic stem cells, it appears as a suitable and attractive target for therapy. Various drugs targeting CD123 have been developed and evaluated at clinical level: interleukin-3 conjugated with diphtheria toxin; naked neutralizing anti-CD123 antibodies; drug-antibody conjugates; bispecific antibodies targeting both CD123 and CD3; and chimeric antigen receptor (CAR) T cells engineered to target CD123. Some of these agents have shown promising results at the clinical level, including tagraxofusp (CD123 conjugated with diphtheria toxin) for the treatment of BPDCN and IMGN632 (anti-CD123 drug-conjugate), and flotetuzumab (bispecific anti-CD123 and anti-CD3 monoclonal antibody) for the treatment of AML. However, the therapeutic efficacy of CD123-targeting treatments is still unsatisfactory and must be improved through new therapeutic strategies and combined treatments with other antileukemic drugs.

[Pathomorphological and clinical characteristics of blastic plasmocytoid dendritic cell neoplasm. Case report].

The paper reveals the 5 cases date about blastic plasmacytoid dendritic cell neoplasm. The presented information demonstrates morphological, immunohistochemical data and clinical manifestations.

Cutaneous presentation preceding acute myeloid leukemia with CD4+/CD56+ expression misdiagnosed as a blastic plasmocytoid dendritic cell neoplasm: A case report.

Acute myeloid leukemia (AML) may initially present as cutaneous lesions corresponding to blasts involving the skin as the first clinical manifestation prior to blood and bone marrow (BM) infiltration. Such presentation is known as myeloid leukemia cutis (LC). Blastic plasmocytoid dendritic cell neoplasm (BPDCN) is an aggressive tumor derived from the precursors of plasmocytoid dendritic cells with cutaneous and BM involvement and leukemic dissemination. Myeloid LC and BPDCN may be difficult to distinguish as they share similar clinical and histopathological features, in particular AML with monocytic differentiation. Nevertheless, the correct diagnosis has to be made to determine adequate and effective therapy. Here, we report the case of a 61-year-old woman who presented with an AML with MLL rearrangement and CD4+/CD56+ expression presenting as LC and that was misdiagnosed as BPDCN. We emphasize that careful and exhaustive analyses should be performed to make the correct diagnosis.

Neoplasia de células dendríticas plasmocitoides blásticas con respuesta inicial a quimioterapia y recaída en sistema nervioso central: caso clínico / Blastic plasmacytoid dendritic cell neoplasm with complete clinical remission with chemotherapy and central nervous system relapse: report of one case

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, clinically aggressive hematologic malignancy that most commonly manifests as cutaneous lesions with or without bone marrow involvement and leukemic dissemination. The demonstration of tumor cells with the characteristic immunophenotype with expression of CD56, generally CD4 and dendritic cell antigens (CD123, cyTCL-1, HLA-DR), in the absence of myeloid or lymphoid lineage markers is required for the diagnosis. Responses to chemotherapy are initially satisfactory, with frequent systemic and central nervous system relapses. We report a 24 year-old male with BPDCN, initially diagnosed and treated as non-Hodgkin CD4+ T-cell lymphoma, with initial complete remission who evolved with early central nervous system relapse. A second attempt of chemotherapy failed and the patient died two months later.

Lenalidomide, celecoxib, and azacitidine therapy for blastic plasmocytoid dendritic cell neoplasm: a case report.

Blastic plasmocytoid dendritic cell neoplasm is characterized by aggressive behavior with a tendency for systemic dissemination and a predilection for skin, lymph nodes, soft tissues, peripheral blood, or bone marrow. It usually occurs in elderly patients with a mean age between 60 and 70 years. Despite initial response to chemotherapy, the disease regularly relapses with a short median overall survival. Better outcomes have been reported with high-dose acute leukemia-like induction chemotherapy followed by consolidation with allogeneic hematopoietic stem cell transplantation. However, elderly patients are not candidates for intensive therapy or allogeneic stem cell transplantation. So, new active and tolerable drugs are needed. Our case illustrates that one cycle of lenalidomide and celecoxib provides at least a partial cutaneous and hematologic response, but this regimen was discontinued due to toxicity and followed by a consolidation/maintenance phase with azacitidine, thus achieving a final complete response with a much higher than expected progression-free and overall survival in an elderly patient with comorbidities. This information may be useful in the design of treatment approaches for elderly patients with blastic plasmocytoid dendritic cell neoplasm. However, it should be confirmed in clinical trials as well as by optimizing the induction and extending the consolidation/maintenance period to avoid early relapses after discontinuation and improve progression-free survival.

[Blastic plasmacytoid dendritic cell neoplasm: two case reports]. / Leucémie dérivée des cellules dendritiques plasmocytoïdes : à propos de deux cas.

Blastic plasmacytoid dendritic cell neoplasm (LPDC) is a rare and aggressive leukemia entity with cutaneous and extracutaneous involvement, reaching most often lymph, blood and bone marrow. Two cases of LPDC diagnosed in Hospital Center of Le Mans are reported, a 78 year old woman (case 1) and a 82 year old man (case 2), and have been clinically, biologically and histologically documented. The clinical presentation, diagnostic difficulties are reminded, as well as the pathogenesis and therapeutic aspect.

Plasmocytoid dendritic cell deficit of early response to toll-like receptor 7 agonist stimulation in multiple sclerosis patients.

Plasmacytoid dendritic cells (pDCs), an important immunoregulatory population, are characterized by vigorous secretion of type I interferons (IFNs) in response to toll-like receptor (TLR) 7 and 9 stimulation. We studied the function of pDCs in multiple sclerosis (MS) patients by analysis of TLR7 responses. We assessed a pDC secretion pattern of cytokines in the short term PBMC cultures stimulated with TLR7 agonist. pDCs sorted from PBMCs of both MS patients and controls were used to assess TLR7 expression profile. TLR7 induced signaling in pDCs has been analyzed with intracellular flow cytometry. We have identified a clinically correlated significant decrease of the TLR7-induced IFN-alfa (IFNa) secretion by pDCs from MS patients. This deficit has been accompanied by insufficient intracellular phosphorylation of protein kinase Akt and a decrease of the TLR7 gene expression in MS pDCs. Our results demonstrated a selective pDC deficit in MS supporting a relationship between pDCs and mechanisms of MS.

Enfermedad de Kikuchi-Fujimoto (linfadenitis histiocítica necrosante): Estudio clinicopatológico e inmunohistoquímico de 14 casos y su diagnóstico diferencial con otras linfadenitis necrosantes reactivas y neoplásicas / Kikuchi-Fujimoto disease (histiocytic necrotizing lymphadenopathy) clinicopathologic and immunohistochemical study of 14 cases and its differential diagnosis with other reactive and neoplastic necrotizing lymphadenopathies

Kikuchi-Fujimoto disease also known as histiocytic necrotizing lymphadenopaty (HNL) is a rare entity, originally described in Japanese population, although currently it has been described all over the world. It is more frequent in young women and it is usually located in cervical lymph nodes. We report 14 cases of HNL in Mexican population, their clinicopathological and immunohistochemical study as well as a comparative study with other necrotizing lymphadenopaties due to B or T-cell lymphomas, tuberculosis, Epstein Barr virus infection, and non-specific necrosis. In our study we found that there was more expression of the immunomarkers CD68, MPO, CD123 and antikerat in OSCAR in the cases of HNL in contrast with the lesser or even null expression of the same markers in the necrotized lymph nodes of the comparative study group.

La enfermedad de Kikuchi-Fujimoto o linfadenitis histiocítica necrosante (LHN) es una entidad poco frecuente, inicialmente descrita en población japonesa. Sin embargo, actualmente se ha descrito alrededor de todo el mundo. Es más frecuente en mujeres jóvenes y su localización habitual es en ganglios linfáticos cervicales. Presentamos estudio clinicopatológico de 14 casos de LHN en pacientes mexicanos, y los comparamos con linfadenitis necrosantes secundarias a linfomas B y T, tuberculosis, virus de Epstein Barr y necrosis inespecífica. Encontramos mayor expresión de los anticuerpos CD68, MPO, CD 123 y antiqueratina OSCAR en los casos de LHN comparados con la expresión baja o nula de los mismos anticuerpos en las necrosis ganglionares del grupo comparativo.