Novel somatic alterations in unicentric and idiopathic multicentric Castleman disease

Single-cell landscape of idiopathic multicentric Castleman disease in identical twins

ABSTRACT

Idiopathic multicentric Castleman disease (iMCD) is a rare cytokine-driven disorder characterized by systemic inflammation, generalized lymphadenopathy, and organ dysfunction. Here, we present an unusual occurrence of iMCD in identical twins and examined the immune milieu within the affected lymphoid organs and the host circulation using multiomic high-dimensional profiling. Using spatial enhanced resolution omics sequencing (Stereo-seq) transcriptomic profiling, we performed unsupervised spatially constrained clustering to identify different anatomic structures, mapping the follicles and interfollicular regions. After a cell segmentation approach, interleukin 6 (IL-6) pathway genes significantly colocalized with endothelial cells and fibroblastic reticular cells, confirming observations using a single-cell sequencing approach (10× Chromium). Furthermore, single-cell sequencing of peripheral blood mononuclear cells revealed an "inflammatory" peripheral monocytosis enriched for the expression of S100A family genes in both twins. In summary, we provided evidence of the putative cell-of-origin of IL-6 signals in iMCD and described a distinct monocytic host immune response phenotype through a unique identical twin model.

Update: The molecular spectrum of virus-associated high-grade B-cell non-Hodgkin lymphomas

The vast spectrum of aggressive B-cell non-Hodgkin neoplasms (B-NHL) encompasses several infrequent entities occurring in association with viral infections, posing diagnostic challenges for practitioners. In the emerging era of precision oncology, the molecular characterization of malignancies has acquired paramount significance. The pathophysiological comprehension of specific entities and the identification of targeted therapeutic options have seen rapid development. However, owing to their rarity, not all entities have undergone exhaustive molecular characterization. Considerable heterogeneity exists in the extant body of work, both in terms of employed methodologies and the scale of cases studied. Presently, therapeutic strategies are predominantly derived from observations in diffuse large B-cell lymphoma (DLBCL), the most prevalent subset of aggressive B-NHL. Ongoing investigations into the molecular profiles of these uncommon virus-associated entities are progressively facilitating a clearer distinction from DLBCL, ultimately paving the way towards individualized therapeutic approaches. This review consolidates the current molecular insights into aggressive and virus-associated B-NHL, taking into consideration the recently updated 5th edition of the WHO classification of hematolymphoid tumors (WHO-5HAEM) and the International Consensus Classification (ICC). Additionally, potential therapeutically targetable susceptibilities are highlighted, offering a comprehensive overview of the present scientific landscape in the field.

Comprehensive analysis of 65 patients with Castleman disease in a single center in China

This study aimed to investigate the epidemiologic, clinical, pathological characteristics, and treatment of patients with Castleman disease (CD) in a single center in China. We retrospectively analyzed the data of 65 Chinese CD patients, divided into unicentric CD (UCD) and multicentric CD (MCD) groups, and also microscopic subtypes as hypervascular (HV), plasmacytic (PC) and Mixed. Based on whether HHV-8 infection existed, MCD was subdivided into HHV-8-associated MCD and idiopathic Castleman disease (iMCD). Detailed epidemiologic, clinicopathological, and treatment data were analyzed and discussed. Of total 65 patients (UCD 33, MCD 32), HV (81.8%) accounted for the most of UCD and total. More females in UCD (60.6%) and more males in MCD (65.6%) were observed. CD occurred in all age groups, most commonly in 40-49 years. The mean age of onset of total was 38.5 years with PC higher than HV (45.5 vs. 35.1 years, P = 0.0413). The median diagnosis delay of MCD was longer than that of UCD (3.00 vs. 1.25 months, P = 0.0436). Abdomen (39.4%) and neck (30.3%) were the most-seen locations of lymphadenopathy in UCD, with neck (65.6%) being predominant in MCD. Mean major diameter of specimens of UCD was greater than MCD (6.4 vs. 3.1 cm, P < 0.0001). These results provided the featured and detailed profile of Castleman disease in Henan province in China with a considerable number of cases, which presented distinct evidence with other studies.

Castleman disease

Castleman disease (CD), a heterogeneous group of disorders that share morphological features, is divided into unicentric CD and multicentric CD (MCD) according to the clinical presentation and disease course. Unicentric CD involves a solitary enlarged lymph node and mild symptoms and excision surgery is often curative. MCD includes a form associated with Kaposi sarcoma herpesvirus (KSHV) (also known as human herpesvirus 8) and a KSHV-negative idiopathic form (iMCD). iMCD can present in association with severe syndromes such as TAFRO (thrombocytopenia, ascites, fever, reticulin fibrosis and organomegaly) or POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder and skin changes). KSHV-MCD often occurs in the setting of HIV infection or another cause of immune deficiency. The interplay between KSHV and HIV elevates the risk for the development of KSHV-induced disorders, including KSHV-MCD, KSHV-lymphoproliferation, KSHV inflammatory cytokine syndrome, primary effusion lymphoma and Kaposi sarcoma. A CD diagnosis requires a multidimensional approach, including clinical presentation and imaging, pathological features, and molecular virology. B cell-directed monoclonal antibody therapy is the standard of care in KSHV-MCD, and anti-IL-6 therapy is the recommended first-line therapy and only treatment of iMCD approved by the US FDA and EMA.