Transcriptional heterogeneity of clonal plasma cells and immune evasion in immunoglobulin light chain amyloidosis

Tracheobronchial Amyloidosis: A Rare Airway Disorder With Diagnostic and Therapeutic Challenges-A Case Report and Literature Review

Tracheobronchial amyloidosis (TBA) is a rare, localised form of amyloidosis characterised by the extracellular deposition of abnormal proteins within the tracheal and bronchial tissues. This condition, although uncommon, can significantly impact airway function, leading to symptoms such as persistent cough, dyspnea and airway obstruction. This report highlights the clinical presentation, diagnostic approaches and therapeutic options for TBA, emphasising the need for individualised management strategies and comprehensive patient care. This case describes a 62-year-old male with a history of smoking debuting with progressive hoarseness, dyspnea and dysphagia, who was initially diagnosed with tracheobronchial amyloidosis following biopsy of a subglottic mass. After surgical excision and a 3-year disease-free interval, he experienced multiple recurrences requiring further interventions, including bronchoscopic evaluation. Histopathological confirmation of recurrent amyloidosis led to a decision for strict follow-up, as symptoms remained mild post-biopsy.

Gene Expression Sets and Renal Profiling from the Renal AL Amyloid Involvement and NEOD00 (RAIN) Trial

Introduction

There is an unmet need to understand the mechanisms by which amyloid deposition drives alterations in the kidney. We leveraged renal biopsies from amyloid light-chain (AL) amyloidosis participants of the Renal AL Amyloid Involvement and NEOD00 (RAIN) trial (NCT03168906) to perform transcriptional profiling and to employ a novel histologic scoring tool. Our objective was to utilize a transcriptome-driven approach to identify AL molecular signatures that may be prognostic.

Methods

Clinical data were correlated to histologic and molecular findings. A composite scarring injury and amyloid score (AS) were assigned to each biopsy. Glomerular and tubulointerstitial (TI) compartments were microdissected and sequenced separately. Expression data were compared to healthy living donors and focal segmental glomerulosclerosis (FSGS) profiles. Differentially expressed genes were determined.

Results

Cluster analysis revealed 2 distinct patient clusters (G1 and G2) based on gene expression. The AS was higher in the TI compartment (6.5 vs. 4.5; P = 0.0290) of G2. Glomeruli showed activation of fibrotic pathways and increased canonical signaling of LPS/IL-1. TNF activation was noted in TI. Enriched ingenuity canonical pathways included "coagulation system," "GADD45 signaling," and "Wnt/Ca+ pathway," among others. For AL versus living donors, ingenuity pathway analysis identified enrichment in PI3K/Akt signaling. Gene regulators of cellular proliferation were enriched in the amyloid group.

Conclusion

Despite the small sample size, we identified 2 distinct groups of patients with AL based on molecular signatures. Detailed studies of a larger cohort encompassing omics technologies at a single cell resolution will further help to identify the response of individual kidney cell types to amyloid deposits, potentially leading to the development of novel therapeutic targets.

The Clinical Characteristics of Immunoglobulin Light Chain Amyloidosis in the Chinese Population: A Systematic Scoping Review

Immunoglobulin light chain (AL) amyloidosis is the most common type of systemic amyloidosis in China and is associated with increased morbidity and a poor prognosis. However, the clinical characteristics of Chinese patients with AL amyloidosis have not been systematically investigated. This scoping review aimed to summarize the available literature regarding the clinical characteristics of patients with AL amyloidosis and identify potential knowledge gaps. We searched three electronic databases from inception to 7 February 2021. PICOS (Patient, Intervention, Comparison, Outcome and Study) design structure was used to formulate the data extraction. All statistical calculations and analyses were performed with R (version 3.6.0). Sixty-seven articles with 5022 patients were included. Results suggest Chinese patients were younger (57 years) at the time of diagnosis when compared with other patient populations and were predominantly male (61.2%). The time interval from the onset of symptoms to diagnosis was between 6 and 12 months. It was found that 41.1% of Chinese patients with AL amyloidosis were diagnosed with an advanced stage III disease when diagnosed, and 20.2% had a concurrent disease. The most involved organs were the kidneys (84.3%) and the heart (62.5%). In conclusion, our study shows some similarities and differences with other studies on the clinical characteristics of Chinese patients with AL amyloidosis, including the age at diagnosis, Mayo stage, and organ involvement. However, a nationwide epidemiological investigation is still needed to provide a comprehensive overview of this patient population in China.

T cell landscape and dynamics in immunoglobulin light chain amyloidosis before and after daratumumab-based therapy

Amyloid light-chain (AL) is characterized by the presence of small, poorly proliferating plasma cell clones with the production and deposition of light chains into tissues. T cell changes within the tumour microenvironment in AL are poorly understood. By sequencing at a single-cell level of CD3+ T cells purified from bone marrow (BM) and blood of newly diagnosed AL patients before and after a combination of daratumumab with cyclophosphamide, bortezomib, and dexamethasone (Dara-BCD), we analysed the transcriptomic features of T cells and found an expansion, activation and type I cytokine upregulation in BM and circulating T cells after the treatment. More prominent changes were shown in CD8+ T cells. In particular, we found the presence of CD8+ BM resident memory T cells (TRM ) with high expression of inhibitory molecules in AL patients at diagnosis. After Dara-BCD, these TRM cells were quickly activated with downregulation of suppressive molecules and upregulation of IFNG expression. These data collectively demonstrate that Dara-based therapy in patients with AL amyloidosis promotes anti-tumour T cell responses. The similar transcriptomic features of BM and circulating T cells before and after therapy further provide a less invasive approach for molecular monitoring of T cell response in AL amyloidosis.