Bone metabolism in Langerhans cell histiocytosis

Gaucher-like Cells in Thalassemia Intermedia: Is It a Challenge?

We describe two cases of thalassemia intermedia (TI) patients with the presence of Gaucher-like cells in hematopoietic tissue biopsies, raising diagnostic dilemmas. The first is a 56-year-old female with bone lesions, splenomegaly, hypochromic microcytic anemia and Gaucher-like cells in the bone marrow, with a final diagnosis of TI, and the second is a 69-year-old male with TI, monoclonal gammopathy of undetermined significance (MGUS) that accelerated to multiple myeloma (MM) requiring treatment, bone disease and Gaucher-like cells in the bone marrow and the spleen, and heterozygoty of Gaucher disease (GD). Gaucher-like cells are difficult to differentiate from true Gaucher cells, that are the hallmark of GD suspicion. These cells are usually reported in the lymphohematopoietic system. They have been described in myeloproliferative disorders, hematological malignancies, infectious diseases, hemoglobinopathies and other hemolytic anemias. The presence of Gaucher-like cells in patients with thalassemia major has been well documented, whereas there are limited references regarding cases with thalassemia intermedia. The identification of these cells in thalassemia probably reflects the high cell turnover. The bony complications in GD and TIare not yet fully explained in the literature, and this raises the question of whether Gaucher-like cells could play a pathogenetic role in the bone disease of thalassemia, as Gaucher cells are considered to play a similar role in bone complications of GD. Moreover, given the rarity and similarity of Gaucher and Gaucher-like cells, we would like to highlight that the presence of Gaucher-like cells in the bone marrow should not be overlooked, as they might be obscuring an underlying pathology, in order to ensure that hematologists, internists and hematopathologists will be promptly and accurately diagnosed.

Adult Langerhans Cell Histiocytosis and the Skeleton

Langerhans cell histiocytosis (LCH) is a rare inflammatory neoplasia in which somatic mutations in components of the MAPK/ERK pathway have been identified. Osseous involvement is evident in approximately 80% of all patients and may present as a single osteolytic lesion, as a multi-ostotic single system disease or as part of multisystem disease. Both exogenous, such as treatment with glucocorticoids, and endogenous parameters, such as anterior pituitary hormone deficiencies and inflammatory cytokines, may severely affect bone metabolism in LCH. Computed tomography (CT) or magnetic resonance imaging (MRI) are usually required to precisely assess the degree of bone involvement; 18F-fluorodeoxyglucose (FDG) positron emission tomography-CT can both detect otherwise undetectable LCH lesions and differentiate metabolically active from inactive or resolved disease, while concomitantly being useful in the assessment of treatment response. Treatment of skeletal involvement may vary depending on location, extent, size, and symptoms of the disease from close observation and follow-up in unifocal single-system disease to chemotherapy and gene-targeted treatment in cases with multisystem involvement. In any case of osseous involvement, bisphosphonates might be considered as a treatment option especially if pain relief is urgently needed. Finally, a patient-specific approach is suggested to avoid unnecessary extensive surgical interventions and/or medical overtreatment.

Neutralizing Anti-IL-17A Antibody Demonstrates Preclinical Activity Enhanced by Vinblastine in Langerhans Cell Histiocytosis

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasm characterised by the accumulation into granulomas of apoptosis-resistant pathological dendritic cells (LCH-DCs). LCH outcome ranges from self-resolving to fatal. Having previously shown that, (i) monocyte-derived DCs (Mo-DCs) from LCH patients differentiate into abnormal and pro-inflammatory IL-17A-producing DCs, and (ii) recombinant IL-17A induces survival and chemoresistance of healthy Mo-DCs, we investigated the link between IL-17A and resistance to apoptosis of LCH-DCs. In LCH granulomas, we uncovered the strong expression of BCL2A1 (alias BFL1), an anti-apoptotic BCL2 family member. In vitro, intracellular IL-17A expression was correlated with BCL2A1 expression and survival of Mo-DCs from LCH patients. Based on the chemotherapeutic drugs routinely used as first or second line LCH therapy, we treated these cells with vinblastine, or cytarabine and cladribine. Our preclinical results indicate that high doses of these drugs decreased the expression of Mcl-1, the main anti-apoptotic BCL2 family member for myeloid cells, and killed Mo-DCs from LCH patients ex vivo, without affecting BCL2A1 expression. Conversely, neutralizing anti-IL-17A antibodies decreased BCL2A1 expression, the downregulation of which lowered the survival rate of Mo-DCs from LCH patients. Interestingly, the in vitro combination of low-dose vinblastine with neutralizing anti-IL-17A antibodies killed Mo-DCs from LCH patients. In conclusion, we show that BCL2A1 expression induced by IL-17A links the inflammatory environment to the unusual pro-survival gene activation in LCH-DCs. Finally, these preclinical data support that targeting both Mcl-1 and BCL2A1 with low-dose vinblastine and anti-IL-17A biotherapy may represent a synergistic combination for managing recurrent or severe forms of LCH.

[Infantile hepatic cholestatis: An unusual case of Langerhans cells histiocytosis associated with advanced fibrosis]

Neonatal cholestasis is a clinical metabolic alteration requiring investigation of its eitiology. It is characterized by elevation of liver enzymes with cholestasis pattern and, in some cases, with acute liver failure. Its etiology is variable although the most frequent cause is atresia of extrahepatic bile ducts. We present a case of a 23-month-old boy who presented with cholestasis and was finally diagnosed with systemic Langerhans cell histiocytosis.

Comparison of three different ELISAs for the detection of recombinant, native and plasma IL-17A

Plasma IL-17A detection in Langerhans Cell Histiocytosis (LCH) is currently a source of debate. Indeed, 500-P07G (PeproTech) and 41802 (R&D Systems) anti-IL-17A antibodies have been suspected to recognize nonspecific proteins. To resolve this discrepancy, we set up two new ELISAs by using 41802 or neutralizing eBio64CAP17 (eBioscience) capture monoclonal antibodies that we compared to the commercial PeproTech ELISA kit. The three ELISAs, called E_500-P07G, E_41802 and E_eBio64CAP17, differ in their anti-IL-17A capture antibodies: either polyclonal, monoclonal or neutralizing monoclonal antibodies, respectively. Here, we show that these ELISAs had a similar capacity to specifically detect recombinant or native human IL-17A. However, a significantly lower plasma IL-17A detection was obtained with E_41802 compared to the two other ELISAs. Both E_500-P07G and E_eBio64CAP17 showed similar results. Consequently, we propose that the use of E_500-P07G and E_eBio64CAP17 may ensure more accurate and reliable results in the context of LCH studies. The highest plasma IL-17A levels in LCH patients compared to controls detected by both E_500-P07G and E_eBio64CAP17 ELISAs led us to propose these latter as reference techniques to investigate IL-17A as a potential new biomarker in LCH.•

The customization of a new E_eBio64CAP17 ELISA is suitable to detect human IL-17A.

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E_eBio64CAP17 ELISA protocol differs only in the anti-IL-17A capture antibody compared to the commercial E_500-P07G PeproTech kit.

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Data generated using the E_eBio64CAP17 ELISA are consistent with the PeproTech kit.

[Langerhans cell histiocytosis involving the oral and maxillofacial region: an analysis of 12 cases]

OBJECTIVE

To study the clinical features of Langerhans cell histiocytosis (LCH) involving the oral and maxillofacial region in children.

METHODS

A retrospective analysis was performed for the clinical data of 12 children with LCH involving the oral and maxillofacial region who were hospitalized and treated from September 2012 to September 2017, including clinical manifestations, pathological features, treatment and prognosis.

RESULTS

Of the 12 children, 8 (67%) had multiple system involvement and 7 (58%) had the involvement of organs at risk. Bone was the most common affected site (11 children, 92%), among whom 7 children had the involvement of the mandible. Oral soft tissue involvement manifested as gingival ulcer or hyperplasia in 4 children, loose teeth in 5 children, oral mucosal lesions in 2 children, and nodular lesions in 1 child. Pathological examination showed positive CDla in 11 children and positive CD207, CD68, S-100, and LCA in 12 children. Surgery combined with chemotherapy was the major treatment method, and surgical resection alone was performed for focal lesions. After treatment, 11 children were cured or improved and 1 gave up treatment and was lost to follow-up. No recurrence was observed.

CONCLUSIONS

LCH children with oral and maxillofacial involvement often have the involvement of multiple systems and organs at risk, with the mandible as the most common affected site. These children may also have the involvement of gingiva, oral mucosa and teeth. Surgery combined with chemotherapy is the major treatment method, and the patients generally have a good prognosis without recurrence.