Paediatric onset lymphomatoid papulosis: results of a multicentre retrospective cohort study, on behalf of the EORTC Cutaneous Lymphoma Tumours Group (CLTG).

BACKGROUND: Lymphomatoid Papulosis (LyP) is a rare cutaneous T-cell lymphoproliferative disorder. Comprehensive data on LyP in the paediatric population is scarce. OBJECTIVES: To characterize epidemiological, clinical, histopathological, and prognostic features of paediatric LyP. METHODS: This was a retrospective, multicentre international cohort study including 87 cases of children and adolescents with LyP diagnosed between 1998 and 2022. Patients aged ≤ 18 years old at disease onset were included. Diagnosis was made in each centre based on clinical-pathological correlation. RESULTS: Eighty-seven patients from 12 centres were included. The mean age at onset was 7.0 years (range 3 months-18 years) with a male to female ratio of 2:1. The mean time between onset of first cutaneous lesions and diagnosis was 1.3 years (range 0-14 years). Initial misdiagnosis concerned 26.4% of patients. Initially, LyP was most often misdiagnosed as Pityriasis lichenoides et varioliformis acuta (PLEVA), insect bites, or mollusca contagiosa. Erythematous papules or papulonodules were the most frequent clinical presentation. Pruritus was specifically mentioned for 20.7% of patients. The main histological subtype was type A in 55.1% of the cases. If analysed, monoclonal TCR rearrangement was found in 76.5% of the skin biopsies. The overall survival rate was 100% with follow up at 5 years available for 33 patients and at 15 years for 8 patients. A development of associated haematological malignancy (HM) occurred in 9.6% of the cases (7/73), including four mycosis fungoides (MF) cases, one primary cutaneous anaplastic large cell lymphoma (pc-ALCL), one systemic ALCL and one case of acute myeloid leukaemia. If we compare incidence rates of cancer with the world 0-19 years old population from 2001-2010, we estimate a significantly higher risk of associated malignancy in general, occurring before the age of 19 years old with incidence rate ratio of 87.49 (CI 86.01-88.99). CONCLUSIONS: We report epidemiological data from a large international cohort of children and adolescents with LyP. Overall the prognosis of the disease is good, with excellent survival rates for all patients. Due to increased risk of associated HM, a long-term follow-up should be recommended for LyP patients.

Boost of innate immunity cytokines as biomarkers of response to extracorporeal photopheresis in patients with leukaemic cutaneous T-cell lymphoma.

BACKGROUND: Extracorporeal photopheresis (ECP) has emerged as a systemic first-line immunomodulatory therapy in leukaemic cutaneous T-cell lymphoma (L-CTCL) and is now beginning to be utilized in other T-cell-mediated diseases. Although ECP has been used for nearly 30 years, its mechanisms of action are not sufficiently understood, and biomarkers for response are scarce. OBJECTIVES: We aimed to investigate the immunomodulatory effects of ECP on cytokine secretion patterns in patients with L-CTCL, to help elucidate its mechanism of action. METHODS: A total of 25 patients with L-CTCL and 15 healthy donors (HDs) were enrolled in this retrospective cohort study. Concentrations of 22 cytokines were simultaneously quantified by using multiplex bead-based immunoassays. Neoplastic cells in patients' blood were evaluated by flow cytometry. RESULTS: Firstly, we observed a distinct cytokine profile pattern difference between L-CTCLs and HDs. There was a significant loss of tumour necrosis factor (TNF)-α, and significant increase of interleukins (IL)-9, IL-12 and IL-13 in the sera of patients with L-CTCL compared with HDs. Secondly, patients with L-CTCL who received ECP were classified as treatment responders and nonresponders according to the quantitative reduction of malignant burden in their blood. We evaluated cytokine levels in culture supernatants from patients' peripheral blood mononuclear cells (PBMCs) at baseline and 27 weeks after ECP initiation. Strikingly, PBMCs purified from ECP responders released statistically higher concentrations of innate immune cytokines IL-1α, IL-1ß, granulocyte-macrophage colony-stimulating factor (GM-CSF) and TNF-α in comparison with ECP nonresponders. In parallel, responders showed clearance of erythema, reduction of malignant clonal T cells in the blood, and a potent boost of relevant innate immune cytokines in individual patients with L-CTCL. CONCLUSIONS: Taken together, our results demonstrate that ECP stimulates the innate immune network, and facilitates redirection of the tumour-biased immunosuppressive microenvironment towards proactive antitumour immune responses. The alterations of IL-1α, IL-1ß, GM-CSF and TNF-α can be used as biomarkers of response to ECP in patients with L-CTCL.

What is new about primary cutaneous B cell lymphomas.

Primary cutaneous B-cell lymphomas (CBCL) are a heterogeneous group of B-cell lymphomas without evidence of extracutaneous disease at the time of diagnosis. The 2022 World Health Organization classification of mature lymphoid neoplasms differentiates the indolent primary cutaneous marginal zone lymphoproliferative disorder, primary cutaneous follicle center lymphoma and Epstein-Barr virus-positive mucocutaneous ulcer, from the more aggressive primary cutaneous diffuse large B-cell lymphoma, leg-type and intravascular large B-cell lymphoma. The new updates in the 2022 classification are based on recent scientific advances in the understanding and characterization of these entities. This article aims to review the main clinical, cellular and molecular features of the five CBCL subsets along with their management and treatment. The exponentially growing evidence for new treatment options for systemic B-cell lymphomas raises expectations for the field of CBCL as well. However, specific prospective high quality research on CBCL is still crucial to further define their management and update international guidelines.

HaCaT cells as a model system to study primary cilia in keratinocytes.

Primary cilium (PC) is a microtubule-based organelle found on the apical surface of most mammalian cell types, playing a role in development and tissue homeostasis. Ciliopathies are a rapidly growing group of human diseases characterized by disordered cilium. PC plays an important role in pathogenesis of basal cell cancer, the most common human malignancy. A significant increase in ciliation has been observed in the epidermis of atopic dermatitis and psoriasis patients. Spontaneously immortalized human keratinocytes, HaCaT are a model to study the epidermal homeostasis and pathophysiology. In contrast to what has been previously described, here, we show that HaCaT can be efficiently ciliated. In HaCaT cells, differentiation significantly increased the number of ciliated cells and we were able to analyse in detail the ciliary length progression with duration of differentiation. As the number of recognized ciliopathies continues to increase, the importance of ciliary models also rises. Even though keratinocytes do not become as highly and rapidly ciliated as cell lines frequently used in ciliary studies, they are a better model for the study of skin ciliopathies. Detailed progression of ciliation in HaCaT could serve as the basis for ciliary studies in this cell line.

[Mycosis fungoides and Sézary syndrome : a systematic review]. / Mycosis fongoïde et syndrome de Sézary : revue systématique.

The two main subtypes of primary cutaneous T-cell lymphomas include the most frequent, mycosis fungoides (MF), and the rare leukemic variant, Sézary syndrome (SS). MF presents as cutaneous patches and can progress to plaques, tumors and erythroderma. SS is characterized by the presence of erythroderma, generalized lymphadenopathy and clonal T cells in the peripheral blood, consistent with a poorer prognosis. Histologically, early CTCL lesions are sometimes indistinguishable from more common inflammatory skin diseases and a clinico-pathological correlation is essential for an accurate diagnosis. Except for allogenic stem-cell transplantation, therapy is generally palliative and aims to improve patient quality of life.

Les deux principaux sous-types de lymphomes cutanés primaires à cellules T (LCCT) sont le mycosis fongoïde (MF) et le syndrome de Sézary (SS). Le MF se présente sous forme de patchs, pouvant évoluer en plaques, en tumeurs ou en érythrodermie. Le SS, bien plus rare et de mauvais pronostic, est caractérisé par la présence d'une érythrodermie, d'adénopathies généralisées et de cellules T clonales dans le sang périphérique. Histologiquement, les lésions précoces de LCCT sont parfois impossibles à distinguer des maladies inflammatoires et une corrélation clinico-pathologique est essentielle pour un diagnostic précis. Excepté la transplantation allogénique de cellules souches hématopoïétiques, le traitement du MF/SS est généralement palliatif et vise à contrôler au mieux la maladie pour améliorer la qualité de vie du patient.

ARP-T1-associated Bazex-Dupré-Christol syndrome is an inherited basal cell cancer with ciliary defects characteristic of ciliopathies.

Actin-Related Protein-Testis1 (ARP-T1)/ACTRT1 gene mutations cause the Bazex-Dupré-Christol Syndrome (BDCS) characterized by follicular atrophoderma, hypotrichosis, and basal cell cancer. Here, we report an ARP-T1 interactome (PXD016557) that includes proteins involved in ciliogenesis, endosomal recycling, and septin ring formation. In agreement, ARP-T1 localizes to the midbody during cytokinesis and the basal body of primary cilia in interphase. Tissue samples from ARP-T1-associated BDCS patients have reduced ciliary length. The severity of the shortened cilia significantly correlates with the ARP-T1 levels, which was further validated by ACTRT1 knockdown in culture cells. Thus, we propose that ARP-T1 participates in the regulation of cilia length and that ARP-T1-associated BDCS is a case of skin cancer with ciliopathy characteristics.

Encefalitis equina venezolana: perfil clínico epidemiológico de la epidemia ocurrida en 1995 / Equine encephalitis in Venezuela: a clinical epidemiological profile of the 1995 epidemic

La encefalitis equina venezolana ha venido presentándose en brotes episódicos en la Guajira Venezolana desde aprox. 1936. En 1938 se aisló el agente causal por vez primera de un caballo enfermo en Venezuela. El síndrome predominante es el de una enfermedad autolimitada semejante a la gripe, y apenas 4 por ciento de las personas infectadas, principalmente niños menores de 15 años, sufre encefalitis. La mortlidad de niños menores de cinco años con encefalitis es de 35 por ciento. Se describe y analiza el perfil clínico epidemiológico de la epidemia de Encefalitis Equina Venezolana en cinco Municipios (Maracaibo, Mara, Insular, Padilla, Páez, Miranda) del estado Zulia (Venezuela) ocurrida entre el 15 de julio y el 17 de octubre de 1995. Se revisaron los datos obtenidos del departamento de vigilancia epidemiológica del Estado Zulia, teniendo un total de 11.072 casos con diagnóstico clínico-epidemiológico de Encefalitis Equina Venezolana, en una población de 574.769 habitantes comprendida por los cincos municipios ya citados, con tasa de ataque de 1,92 por ciento, no hay diferencia significativa en el sexo, el grupo etario más afectado son los menores de 5 años ocupando más de la mitad de la mortalidad con 8 casos, incluyéndose en este grupo dos muertes en recién nacidos cuyas madres se enfermaron en el último trimestre del embarazo