Clonality Assay Research Articles

SLC7A9 suppression increases chemosensitivity by inducing ferroptosis via the inhibition of cystine transport in gastric cancer

SLC7A9 is responsible for the exchange of dibasic amino acids and cystine (influx) for neutral amino acids (efflux). Cystine/cysteine transport is related to ferroptosis. Sanger sequencing detected TP53 status of cancer cells. Transcriptomic sequencing and untargeted metabolome profiling were used to identify differentially expressed genes and metabolites, respectively, upon SLC7A9 overexpression. CCK8, cell clonality, and EdU assays were used to observe cell proliferation. Cystine probes, glutathione (GSH) probes, and lipid ROS probes were used to examine cystine, GSH, and lipid ROS levels. 13C metabolic flow assays were used to monitor cellular cystine and GSH metabolism. Patient-derived organoids (PDO), immunocompetent MFC mice allograft models and patient-derived xenograft (PDX) models were used to evaluate SLC7A9 impact on chemotherapeutic response and to observe therapeutic effect of SLC7A9 knockdown. Elevated SLC7A9 expression levels in gastric cancer cells were attributed to p53 loss. SLC7A9 knockdown suppressed the proliferation and increased the chemotherapy sensitivity of the cells. Chemotherapy was more effective in PDX and immunocompetent mice models upon SLC7A9 knockdown. Differentially expressed genes and metabolites between the SLC7A9 overexpression and control groups were associated with ferroptosis and GSH metabolism. SLC7A9 knockdown reduced cystine transport into cells, hampered intracellular cystine and GSH metabolic flow, decreased GSH synthesis, and increased lipid ROS levels in gastric cancer cells. Erastin was more effective at inducing ferroptosis in PDO and PDX models upon SLC7A9 knockdown. SLC7A9 promotes gastric cancer progression by acting as a suppressor of ferroptosis, independent of SLC7A11, which is negatively regulated by p53. This work was supported by National Natural Science Foundation of China, Innovation Promotion Program of NHC and Shanghai Key Labs SIBPT, and Shanghai Academy of Science & Technology.

Comparison of the accuracy of minimally invasive techniques (cytology, cell block, immunocytochemistry and clonality assay) in the diagnosis of canine multicentric lymphoma

Lymphoma ranks among the most prevalent neoplasms in veterinary oncology, frequently diagnosed in dogs, particularly in its multicentric form. While histopathology plays a crucial role in lymphoma diagnosis, prognosis and prediction of biological behavior, minimally invasive diagnostic methods are increasingly emerging as viable alternatives. This study aims to assess and compare various minimally invasive diagnostic techniques for multicentric lymphomas in dogs. A total of 38 dogs, encompassing various sexes, ages, and breeds, with clinical suspicion of multicentric lymphoma, was included in the study. Fine needle aspiration was employed to collect samples from lymph nodes, which were subsequently used for cytology, cell block preparation, PCR for antigen receptor rearrangement (PARR), and immunocytochemistry. Among the animals evaluated, 31 dogs received a cytological diagnosis of lymphoma, while 7 showed findings suggestive of lymphoma or lymphadenitis. Immunocytochemistry on cytological smears yielded inconclusive results in 50 % of cases, with 44.74 % diagnosed with B-cell lymphoma and 5.26 % with T-cell lymphoma. Cell block analysis identified lymphoma in 30 dogs and suggested lymphoma or a round cell neoplasm in 8 cases. Cell block immunocytochemistry confirmed lymphoma in 35 dogs, comprising 80 % B-cell and 20 % T-cell lymphomas. PARR revealed monoclonal rearrangement/clonality in 33 cases, with 84.85 % of these being B-cell and 15.15 % T-cell lymphomas. This study underscores the precision of minimally invasive techniques in diagnosing and characterizing multicentric lymphoma in dogs, reaffirming their significance in veterinary clinical practice.

Comparison of 2 T-Cell Receptor-γ Clonality Assays on Skin Biopsies Suspicious for Mycosis Fungoides.

PCR-based fragment analysis of the T-cell receptor (TCR) gene is used extensively in diagnostic labs to assess clonality in T-cell populations in multiple tissue sites. Of the numerous TCR assays that have been reported, studies assessing use on biopsies suspicious for mycosis fungoides specifically are lacking. We compared clonality findings from a previously run 2-tube/2-fluorochrome dye assay to a redesigned 1-tube/1-fluorochrome dye assay on formalin-fixed skin biopsies. Overall, the accuracy of the 2-tube assay was marginally better (75.7% vs. 71.4%), when using clinical history combined with histologic diagnosis as the gold standard. The 2-tube assay had better sensitivity (73.7% vs. 65.8%), while the 1-tube assay had superior specificity (93.8% vs. 87.5%). Clonality results were easier to interpret with the 1-tube assay. In nearly 19% of cases, a change of assays on the same biopsy resulted in a change of clonality interpretation. For laboratories that change TCR-γ clonality assays, follow-up biopsies for mycosis fungoides assessment may result in a change of diagnosis.

Dual T-cell constant β chain (TRBC)1 and TRBC2 staining for the identification of T-cell neoplasms by flow cytometry

The diagnosis of leukemic T-cell malignancies is often challenging, due to overlapping features with reactive T-cells and limitations of currently available T-cell clonality assays. Recently developed therapeutic antibodies specific for the mutually exclusive T-cell receptor constant β chain (TRBC)1 and TRBC2 isoforms provide a unique opportunity to assess for TRBC-restriction as a surrogate of clonality in the flow cytometric analysis of T-cell neoplasms. To demonstrate the diagnostic utility of this approach, we studied 164 clinical specimens with (60) or without (104) T-cell neoplasia, in addition to 39 blood samples from healthy donors. Dual TRBC1 and TRBC2 expression was studied within a comprehensive T-cell panel, in a fashion similar to the routine evaluation of kappa and lambda immunoglobulin light chains for the detection of clonal B-cells. Polytypic TRBC expression was demonstrated on total, CD4+ and CD8+ T-cells from all healthy donors; and by intracellular staining on benign T-cell precursors. All neoplastic T-cells were TRBC-restricted, except for 8 cases (13%) lacking TRBC expression. T-cell clones of uncertain significance were identified in 17 samples without T-cell malignancy (13%) and accounted for smaller subsets than neoplastic clones (median: 4.7 vs. 69% of lymphocytes, p < 0.0001). Single staining for TRBC1 produced spurious TRBC1-dim subsets in 24 clinical specimens (15%), all of which resolved with dual TRBC1/2 staining. Assessment of TRBC restriction by flow cytometry provides a rapid diagnostic method to detect clonal T-cells, and to accurately determine the targetable TRBC isoform expressed by T-cell malignancies.

Molecular B-cell clonality assay in minor salivary glands as a useful tool for the lymphoma risk assessment in Sjögren's syndrome

ObjectivesNon-Hodgkin's lymphoma (NHL) risk assessment is crucial in Sjögren's syndrome (SS). We studied the prevalence of clonal immunoglobulin gene rearrangements in minor salivary glands (MSG) and their correlations with lymphoma occurrence and with previously established NHL predictors. MethodsMolecular B-cell expansion was studied in fresh-frozen MSG of 207 patients with either suspected SS or with suspected lymphoma during SS, using a standardised multiplex PCR assay combined with heteroduplex analysis by microcapillary electrophoresis. The assignation of clonal cases was based on EuroClonality consortium guidelines. ResultsAmong 207 studied patients, 31 (15%) had MSG monoclonal B-cell infiltration. Monoclonality was significantly more frequent in patients with SS (28/123, 22.8%) compared with patients without SS (3/84, 3.6%, P<0.001). Monoclonal B-cell infiltration in MSG of SS patients correlated significantly with ongoing salivary gland NHL, salivary gland swelling, CD4+ T-cell lymphopenia, rheumatoid factor (RF) activity, low complement levels and type 2 mixed cryoglobulinemia. The accumulation of biological risk factors was associated with a higher rate of MSG B-cell monoclonality given that patients with only positive RF had no probability of MSG B-cell monoclonality, RF-positive patients with 1 or 2 other risk factors had a 25.0% and 85.7% probability of MSG B-cell monoclonality, respectively. ConclusionThe detection of MSG monoclonal B-cell expansion by this easy-to-perform molecular assay is useful, both at the time of diagnosis and during the course of SS. Monoclonal B-cell expansion is associated with a subset of SS patients presenting either ongoing lymphoma or other established lymphoma predictive factors.

Rho GTPase-activating protein 1 promotes hepatocellular carcinoma progression via modulation by CircPIP5K1A/MiR-101-3p.

There has been an increased focus on regulating cell function with Rho family GTPases, including proliferation, migration/invasion, polarity, and adhesion. Due to the challenges involved in targeting Rho family GTPases directly, it may be more effective to target their regulators, such as Rho GTPase-activating protein 1 (ARHGAP1). This present research was performed to define the clinical significance of ARHGAP1 expression, as well as its regulatory mechanisms in hepatocellular carcinoma. ARHGAP1 and miR-101-3p expression of liver cancer patients, and their relevance with clinicopathological characteristics and prognosis were analyzed by the Cancer Genome Atlas sequencing data, and verified using samples of hepatocellular carcinoma patients. The interactions between miR-101-3p and ARHGAP1 or circPIP5K1A were validated by bioinformatic analyses, as well as confirmed by quantitative reverse transcription polymerase chain reaction, western blotting, and dual-luciferase reporter analysis. Plate clonality assays, cell adhesion and migration experiments, and proliferation experiments were used for assessing the participation of the circPIP5K1A/miR-101-3p/ARHGAP1 pathway in cell proliferation and motility. Elevated ARHGAP1 and reduced miR-101-3p expression are related to poorer survival. MiR-101-3p targets ARHGAP1 to suppress hepatocellular carcinoma cell colony formation and invasion, whereas miR-101-3p inhibitor reverses liver cancer proliferation and metastasis suppression caused by ARHGAP1 knockdown. In addition, circPIP5K1A, which is mainly distributed in the cytosol, showedcarcinogenic effects by sponging miR-101-3p, thus regulating ARHGAP1 expression. ARHGAP1 serves as an oncogenic gene in liver cancer, and the expression thereof is regulated by circPIP5K1A through sponging miR-101-3p.

Determination of T-cell clonality and expression profiles of Toll-like receptors signaling pathway genes and related miRNAs in patients with mycosis fungoides

Cutaneous T-cell lymphomas (CTCL) encompass a group of diseases characterized by the presence of malignant clonal CD4+ T lymphocytes in the skin. Mycosis fungoides (MF) is the most prevalent form of CTCL, accounting for approximately 60 % of cutaneous T-cell lymphomas and 50 % of all primary cutaneous lymphomas. Despite ongoing research, the precise pathogenesis of MF remains incompletely understood. Toll-like receptors (TLRs) have the ability to specifically recognize ligands, subsequently induce the expression of diverse genes and activate innate immunity within the cell. Furthermore, miRNAs play a crucial role in regulating various aspects of immune cell function. The aim of our study was to explore the potential roles of TLRs and the genes implicated in their signal transduction, along with the expression status of miRNAs in the mechanisms underlying MF. Additionally, we assessed the clonal status and compared it with clinicopathological data using a T-cell clonality assay. To determine the expression status of TLR pathway genes and miRNAs, we conducted RT-PCR analysis on 52 MF samples and 50 control paraffin block materials. Pathway analysis were conducted using the KEGG database. T-cell receptor (TCR) gamma clonality changes were evaluated. Results from the study revealed increased expressions of TLR-1, -4, -8, IRF7, TRAF3, MEK1, MEK2, Elk1, NFkB, hsa-miR-21-5p, and hsa-miR-155-5p, as well as decreased expressions of hsa-miR-130a-3p, hsa-miR-210-3p, and hsa-let-7e-5p in the MF group. TCR gamma clonal change analysis demonstrated that 55.5 % of the analysed DNAs exhibited monoclonal and biallelic patterns, while 45.5 % displayed polyclonality. These findings collectively suggest the potential influence and therapeutic possibilities of the TLR signalling pathway in the molecular pathogenesis of MF.

Single-Step IGHV Next-Generation Sequencing Detects Clonality and Somatic Hypermutation in Lymphoid Malignancies: A Phase III Diagnostic Accuracy Study.

Multiplex PCR based on consensus primers followed by capillary electrophoresis and Sanger sequencing are considered as the gold standard method for the evaluation of clonality and somatic hypermutation in lymphoid malignancies. As an alternative, the next-generation sequencing (NGS) of immune receptor genes has recently been proposed as a solution, due to being highly effective and sensitive. Here, we designed a phase III diagnostic accuracy study intended to compare the current gold standard methods versus the first commercially available NGS approaches for testing immunoglobulin heavy chain gene rearrangements. We assessed IGH rearrangements in 68 samples by means of both the NGS approach (LymphoTrack® IGH assay, and LymphoTrack® IGH somatic hypermutation assay, run on Illumina MiSeq) and capillary electrophoresis/Sanger sequencing to assess clonality and somatic hypermutations (SHM). In comparison to the routine capillary-based analysis, the NGS clonality assay had an overall diagnostic accuracy of 96% (63/66 cases). Other studied criteria included sensitivity (95%), specificity (100%), positive predictive value (100%) and negative predictive value (75%). In discrepant cases, the NGS results were confirmed by a different set of primers that provided coverage of the IGH leader sequence. Furthermore, there was excellent agreement of the SHM determination with both the LymphoTrack® FR1 and leader assays when compared to the Sanger sequencing analysis (84%), with NGS able to assess the SHM rate even in cases where the conventional approach failed. Overall, conventional Sanger sequencing and next-generation-sequencing-based clonality and somatic hypermutation analyses gave comparable results. For future use in a routine diagnostic workflow, NGS-based approaches should be evaluated prospectively and an analysis of cost-effectiveness should be performed.

Clonal T-cell proliferations occasionally occur in Kikuchi–Fujimoto disease

Kikuchi-Fujimoto disease (KFD) is a benign self-limiting disorder that frequently leads to swelling of cervical lymph nodes in young women. It has a characteristic histologic appearance with sharply demarcated foci containing apoptotic debris, histiocytes, and proliferating large T-cells. Since in the past years, core needle biopsies have been increasingly used for diagnostic work-up, a small biopsy of the pathognomonic proliferating T-cell foci may lead to misinterpretation as a large T-cell neoplasia. The aim of the present study therefore was to analyze how frequently clonal T-cell receptor (TCR) amplificates may be obtained in KFD using a commonly used TCR gamma rearrangement clonality assay. In 88 KFD cases, TCR gamma clonality assays could be successfully applied. Clonal peaks of TCR gamma in front of a polyclonal background were observed in 15 cases (18%). The investigated clinical parameters (age, gender, extent of infiltration of the lymph node, percentage of proliferative compartment) did not differ between patients with detectable TCR gamma clones from those patients who had polyclonal TCR gamma results. Our study therefore demonstrates that clonal TCR gamma amplificates may be obtained in any type of KFD and that an over-interpretation of clonal T-cell proliferates in diagnostically equivocal material should be avoided.

Clinical validation of next-generation sequencing-based clonality assays for minimal residual disease tracking in multiple myeloma.

e20037 Background: The prognosis of multiple myeloma (MM) patients is dependent on minimal residual disease (MRD) status after treatment. Multicolor flow cytometry (MFC) as a clinical MRD evaluation method has certain limitations regarding sample requirement, sensitivity and specificity. Next-generation sequencing (NGS)-based B cell receptor (BCR) clonality assessment has an edge in lymphoid clone MRD detection, with easier sample preparation and higher sensitivity. NGS-based BCR clonality assays were performed to evaluate curative effect and track MRD of MM patients, and its performance in testing samples with limited DNA contents was explored. Methods: In this retrospective study, newly diagnosed or relapsed MM patients with paired sample collected before and after initial treatment were included, and OriMIRACLE L NGS assay were used for BCR clonality detection in genomic DNA (gDNA) extracted from clinical residual marrow smear samples. The quantitative accuracy of NGS was compared to MFC. The concordance of MRD between MFC, NGS and clinical response assessment were analyzed. Results: From December 2016 to April 2022, 29 patients were included with a median age of 65 years old. The gDNA input of the sample collected before treatment was 100.0 ng, and the median DNA content of the sample collected after treatment was 1673.4 ±594.8 ng. The quantitative results of NGS and MFC were consistent in samples with a frequency of cancer cells of above 1x10-4 among all nucleated cells. BCR clonality detection in 23 newly diagnosed and 6 relapsed cases showed a 100% sensitivity at diagnosis. For post-treatment monitoring, patients with positive MRD by both MFC and NGS (n = 18), the MRD results were consistent with clinical response assessment. One of the patients achieved complete response (CR), while the remaining patients were unable to achieved CR. The CR patient was relapsed after 134 days. The clinical responses of 11 cases with negative MRD by MFC and positive MRD by NGS were reviewed. There were 7 cases with CR, 3 cases with very good partial response or partial response, and one case with stable disease. Among those CR patients, except for one patient who was lost to follow-up, 4 patients who underwent continuous treatment were still CR and 2 patients who had treatment discontinued recurred at 67 and 134 days. Conclusions: OriMIRACLE L NGS assay showed the higher sensitivity and specificity of MRD evaluation than MFC. For patients with negative MRD by MFS and positive MRD by NGS, recurrence might occur in case of treatment discontinuation. It is recommended to consider carefully that whether maintenance treatment is required in such cases.

INTEGRATION OF T‐CELL CLONALITY SCREENING USING TRBC‐1 IN LYMPHOMA SUSPECT SAMPLES BY FLOW CYTOMETRY

Background: The diagnosis of T-cell non-Hodgkin lymphomas (NHL) is challenging. Many cases of T-NHL have normal immunophenotypes, and currently available T-cell clonality assays have limitations, including suboptimal sensitivity. The development of a monoclonal antibody (mAb) specific for T-cell receptor β constant region 1 (TRBC1) provides an alternative to discriminate clonal T cells. The aim of this study was to evaluate the diagnostic potential of an anti-TRBC1 mAb for the identification of T-NHL. Materials and Methods: We performed a cross-sectional diagnostic analytic study of samples tested for lymphoma. All samples sent for lymphoma screening were first evaluated using the standard Euroflow Lymphoma Screening Tube (LST), to which a second additional custom-designed T-cell clonality assessment tube was added. LST tube included CD45/CD3/CD4/CD5/CD8/CD19/ CD20/CD38/TRCγδ/CD56 and the second CD45/TRBC1/CD2/CD7/CD4/TRCγδ/CD3. The results of TRBC1 expression in patient samples were compared to the normal expression of TRBC1 in 10 normal samples of peripheral blood (PB). Flow cytometry reports were compared with morphological and molecular tests. Clinical data were obtained from the electronic database. This study was approved by the institutional IRB and Clinical Ethics Committee. Results: 69 samples were evaluated. 10 healthy controls, and 59 patient samples. Overall, individuals had a median of 52 years (interquartile range [IRQ], 35–70 years) and 53.6% were female. Normal TRBC1 expression was assessed in 10 normal PB samples. Within the T-cell population (CD45+/CD3+), CD4+ cells expressed (±SD) TRBC1 in 42% (4.2), while CD8+ cells in 38% (4.7). This resulted in a TRBC1+/- ratio of 0.72 ± 0.13 for CD4+ and 0.61 ± 0.13 for CD8+ T cells. Cut-off percentages in the CD4+ cells were from 29.4% to 54.6%, and from 23.9 to 52.1% in CD8+ T-cells. Cut-off ratios in CD4+ T cells were from 0.33 to 1.1, and in CD8+ T cells between 0.22 and 1.0. Using predefined normal cut-off values, 18 of 59 (30.5%) samples showed a restricted (monotypic) expression of TRBC1. 6/18 were monotypic positive (33.3%) and 12/18 were monotypic negative (66.6%). A final diagnosis of a T-NHL was confirmed by IHC in 15 of the 18 cases (83.3%). A molecular TCR gene rearrangement assay was available in 3/15 cases, which confirmed clonality. The 3 discordant cases were 2 samples from an EBV+ primary effusion lymphoma (PEL) and 1 of lung adenocarcinoma. There were no cases of a diagnosis of a T-NHL by morphology / IHC with normal TRBC1 expression. Non-neoplastic patient samples behaved between predefined TRBC1 cut-off values. Conclusions: Expression of TRBC1 provides a robust method for T- cell clonality assessment, with very high sensitivity and good correlation with complementary methods. TRBC1 can be integrated into routine lymphoma screening strategies via flow cytometry to improve T-NHL diagnosis capacities. The research was funded by: Fondecyt 11200805 Clínica Alemana de Santiago ID1025 Keyword: diagnostic and prognostic biomarkers No conflicts of interests pertinent to the abstract.

Development and implementation of an automated and highly accurate reporting process for NGS-based clonality testing.

B and T cells undergo random recombination of the VH/DH/JH portions of the immunoglobulin loci (B cell) and T-cell receptors before becoming functional cells. When one V-J rearrangement is over-represented in a population of B or T cells indicating an origin from a single cell, this indicates a clonal process. Clonality aids in the diagnosis and monitoring of lymphoproliferative disorders and evaluation of disease recurrence. This study aimed to develop objective criteria, which can be automated, to classify B and T cell clonality results as positive (clonal), No evidence of clonality, or invalid (failed). Using clinical samples with "gold standard" clonality data obtained using PCR/CE testing, we ran NGS-based amplicon clonality assays and developed our own model for clonality reporting. To assess the performance of our model, we analyzed the NGS results across other published models. Our model for clonality calling using NGS-based technology increases the assay's sensitivity, more accurately detecting clonality. In addition, we have built a computational pipeline to use our model to objectively call clonality in an automated fashion. Collectively the results outlined below will have a direct clinical impact by expediting the review and sign-out process for concise clonality reporting.

An immune infiltration-related prognostic model of kidney renal clear cell carcinoma with two valuable markers: CAPN12 and MSC.

Since its discovery, clear cell renal cell carcinoma (ccRCC) has been the most prevalent and lethal kidney malignancy. Our research aims to identify possible prognostic genes of ccRCC and to develop efficient prognostic models for ccRCC patients based on multi-omics investigations to shed light on the treatment and prognosis of ccRCC. To determine a risk score for each patient, we screened out differentially expressed genes using data from tumor samples, and control samples mined from The Cancer Genome Atlas (TCGA) and GTEx datasets. Somatic mutation and copy number variation profiles were analyzed to look for specific genomic changes connected to risk scores. To investigate potential functional relationships of prognostic genes, gene set variation analysis (GSVA) and gene set enrichment analysis (GSEA) were carried out. We created a prognostic model by fusing risk ratings with other clinical variables. For validation, the 786-O cell line was used to carry out the dual-gRNA approach to knock down CAPN12 and MSC. This was followed by qRT-PCR to verify the knockdown of CAPN12 and MSC. For ccRCC, seven predictive genes were discovered: PVT1, MSC, ALDH6A1, TRIB3, QRFPR, CYS1, and CAPN12. The most enriched pathways in the GSVA study and GSEA analysis promote tumorigenesis and immune system modulation. The risk score derived from prognostic genes corresponds with immune infiltration cells and helps predict how well a medicine will work. The mutation of numerous oncogenes was also linked to a high-risk score. A prognostic model with a high ROC value was created for the risk score. An in vitro study demonstrates that the suppression of CAPN12 and MSC dramatically reduced the ability of 786-O cells to proliferate in the CCK-8 proliferation assay and plate clonality assays. A thorough prognostic model with good performance has been developed for ccRCC patients using seven prognostic genes that were discovered to be related to ccRCC prognosis. In ccRCC, CAPN12 and MSC were significant indicators and would make good therapeutic targets.

Read the clonotype: Next-generation sequencing-based lymphocyte clonality analysis and perspectives for application in pathology.

Clonality assessment using the unique rearrangements of immunoglobulin (IG) and T-cell receptor (TR) genes in lymphocytes is a widely applied supplementary test for the diagnosis of B-cell and T-cell lymphoma. To enable a more sensitive detection and a more precise comparison of clones compared with conventional clonality analysis based on fragment analysis, the EuroClonality NGS Working Group developed and validated a next-generation sequencing (NGS)-based clonality assay for detection of the IG heavy and kappa light chain and TR gene rearrangements for formalin-fixed and paraffin-embedded tissues. We outline the features and advantages of NGS-based clonality detection and discuss potential applications for NGS-based clonality testing in pathology, including site specific lymphoproliferations, immunodeficiency and autoimmune disease and primary and relapsed lymphomas. Also, we briefly discuss the role of T-cell repertoire of reactive lymphocytic infiltrations in solid tumors and B-lymphoma.

Enhancing diagnosis of T-cell lymphoma using non-recombined T-cell receptor sequences.

Clonality assessment, which can detect neoplastic T cells by identifying the uniquely recombined T-cell receptor (TCR) genes, provides important support in the diagnosis of T-cell lymphoma (TCL). BIOMED-2 is the gold standard clonality assay and has proven to be effective in European TCL patients. However, we failed to prove its sensitivity in Taiwanese TCL patients, especially based on the TCRβ gene. To explore potential impact of genetic background in the BIOMED-2 test, we analyzed TCRβ sequences of 21 healthy individuals and two TCL patients. This analysis suggests that genetic variations in the BIOMED-2 primer sites could not explain the difference in sensitivity. The BIOMED-2 test results of the two TCL patients were positive and negative, respectively. Interestingly, a higher percentage (>81%) of non-recombined TCRβ sequences was observed in the test-negative patient than those of the test-positive patient and all healthy individuals (13~66%). The result suggests a new TCR target for enhancing TCL diagnosis. To further explore the hypothesis, we proposed a cost-effective digital PCR assay that quantifies the relative abundance of non-recombined TCRβ sequences containing a J2-2P~J2-3 segment. With the digital PCR assay, bone marrow specimens from TCL patients (n=9) showed a positive outcome (i.e., the relative abundance of the J2-2P~J2-3 sequences ≧5%), whereas non-TCL patients (n=6) gave a negative result. As five of nine TCL patients had a negative BIOMED-2 test result, the J2-2P~J2-3 sequences may improve TCL detection. This is the first report showing the capability of characterizing non-recombined TCR sequences as a supplementary strategy for the BIOMED-2 clonality test.

ORAL GLUTAMINE SUPPLEMENTATION FOR REFRACTORY ECZEMA AND ERYTHRODERMA WITH A HYPER-IGE PHENOTYPE

<h3>Introduction</h3> Severe eczema is managed with ceramide-containing emollients, topical glucocorticoids, dupilumab and/or JAK inhibitors. However, targeted treatments may not be readily available. Glutamine is a safe, inexpensive, over-the-counter oral amino acid that could aid eczema control. <h3>Case Description</h3> A 5-year-old, previously healthy female presented with diffuse erythroderma (Figure 1). Rashes appeared 4 months prior, associated with pruritus. She had inadequate relief despite moisturization, topical and oral glucocorticoids. On exam, she had diffuse erythroderma (40% BSA) and bilateral supraclavicular and axillary lymphadenopathy. Serum IgE was significantly elevated - 45,850 IU/mL (ref. ≤ 90 IU/mL), she had increased eosinophils (1.69k/uL [0-0.8k/uL) and total CD4+ and memory (CD4+CD45RO+) T cells (1153 cells/uL [100-510cells/uL). Due to lymphadenopathy and family history of childhood leukemia in maternal aunt, she had a T-cell clonality assay by PCR which was unremarkable. Targeted primary immunodeficiency genetics panel (obtained for her hyper-IgE phenotype) was negative for pathogenic variants. Skin biopsy showed spongiotic dermatitis with staphylococcal impetiginization. She was treated with 10 days of oral cephalexin without significant improvement. She started oral glutamine 5g daily with continued skin moisturization. Two months later, she had only mild erythema of the shins, with decreased IgE 30,982 IU/mL and resolution of adenopathy. <h3>Discussion</h3> The patient had a hyper-IgE phenotype, raising concern for a primary atopic disorder. She achieved sustained improvement with glutamine supplementation. Previous studies reported improvement with glutamine among patients with eczema and heterozygous dominant-negative CARD11 mutations and decreased eczema risk in infants receiving early glutamine.

Diagnostic Accuracy of Vitreous Cytology in Patients with Vitreoretinal Lymphoma.

(1) Background: To determine the diagnostic value of vitreous cytology in patients with vitreoretinal lymphoma (VRL) and evaluate its diagnostic accuracy relative to that of other diagnostic tests. (2) Methods: In total, 38 eyes from 38 patients with VRL who underwent diagnostic vitrectomy and were followed up for at least 6 months were analyzed. The clinical manifestations and VRL diagnostic rates for all diagnostic tests were determined. (3) Results: The presence of vitreous cells/opacity was the most common ophthalmic finding (97.4%), followed by sub-retinal pigment epithelial infiltration (65.8%) and retinal hemorrhage (21.1%). The VRL diagnostic rates were 89.3% for interleukin (IL)-10 levels &gt; 50 pg/mL; 82.1% for IL-10/IL-6 ratios &gt; 1; 60.0% and 63.3% for immunoglobulin heavy chain and kappa light chain clonality assays, respectively; and 44.4% for vitreous cytology. The VRL diagnostic rate for vitreous cytology was significantly lower in the steroid pretreatment group than in the non-steroid pretreatment group (p = 0.007). (4) Conclusions: The VRL detection rate for vitreous cytology was lower than that for the other tests, especially in patients who received steroid pretreatment. These findings suggest that even if vitreous cytology findings are negative, other tests and characteristic fundus findings should be evaluated to confirm VRL diagnosis.

Rapid evaluation of T cell clonality in the diagnostic work-up of mature T cell neoplasms: TRBC1-based flow cytometric assay experience

The identification of mature T cell neoplasms by flow cytometry is often challenging, due to overlapping features with reactive T cells and limitations of currently available T cell clonality assays. The description of an antibody specific for one of two mutually exclusive T cell receptor (TCR) β-chain constant regions (TRBC1) provides an opportunity to facilitate the detection of clonal TCRαβ+ T cells based on TRBC-restriction. Here we prospectively analyzed 14 healthy controls and 63 patients with the flow cytometry protocol currently used for suspected T cell neoplasm implemented with immunostaining targeting TRBC1. Specimens were firstly classified in 3 groups based on clinical records data, laboratory findings and immunophenotypic features. T cell clonality was assessed by TCR Vβ repertoire analysis and the new rapid TRBC1 assay. Results showed that TRBC1 unimodal expression was unequivocally associated with samples presenting with immunophenotypic aberrancies. Moreover, we demonstrated that the use of TRBC1 is useful in solving uncertain cases and confirmed the high sensitivity of the method in identifying small T cell clones of uncertain significance (T-CUS). Finally, we found a high degree of concordance (97%) comparing the currently available clonality assessment methods with the proposed new method. In conclusion, our results provided real-life evidence of the utility of TRBC1 introduction in the flow cytometric clonality evaluation for the routine diagnostic work-up of T cell neoplasms.

A clonality assay in canine B cell tumors targeting the immunoglobulin light chain lambda locus

Clonality assays for antigen receptor rearrangement have been used as adjunct examinations of lymphoproliferative diseases. These assays have been useful for differentiation between inflammation and clonal expansion of lymphocytes. Whereas the immunoglobulin heavy chain (IGH) and immunoglobulin light chain kappa (IGK) loci have been targeted in canine clonality assays previously, the immunoglobulin light chain lambda gene (IGL) locus has not yet been investigated. This study aimed to evaluate the usefulness of clonality assays in dogs using IGL. Canine diffuse large B cell lymphomas (DLBCL), cutaneous plasmacytomas, and pathologically diagnosed lymph nodes without lymphoma, were used in this study. Genomic DNA was extracted from formalin-fixed paraffin embedded sections. Sequences of IGLV and IGLJ were obtained from the ImMunoGeneTics database. Several primers against IGLVs and IGLJs were designed in the regions showing homology, by alignment of the gene segments. Products of polymerase chain reaction were analyzed on a capillary electrophoresis. In total, 20 of 23 cases of DLBCL showed clonality (87.0 %), whereas 8 of 30 cutaneous plasmacytomas were clonal (26.7 %). One of 23 lymph nodes without lymphoma showed clonality, thus the specificity was 95.7 %. These data indicate that the IGL locus could be a target for canine clonality assays and that the sensitivity of IGL-based clonality assays in cutaneous plasmacytomas was lower than that in DLBCL.

Clinical implication of minimal residual disease assessment by next-generation sequencing-based immunoglobulin clonality assay in pediatric B-acute lymphoblastic leukemia.

Measuring minimal residual disease (MRD) during treatment is valuable to identify acute lymphoblastic leukemia (ALL) patients who require intensified treatment to avert relapse. We performed the next-generation sequencing (NGS)-based immunoglobulin gene (Ig) clonality assay and evaluated its clinical implication in pediatric B-ALL patients to assess MRD. Fifty-five patients who were diagnosed and treated with de novo (n = 44) or relapsed/refractory B-ALL (n = 11) were enrolled. MRD assessment was performed using the LymphoTrack® Dx IGH and IGK assay panels. The percentage of the clonal sequences per total read count was calculated as MRD (% of B cells). The data were normalized as the proportion of total nucleated cells (TNC) by LymphoQuant™ Internal control or the B-cell proportion in each sample estimated by flow cytometry or immunohistochemistry. Clonal Ig rearrangement was identified in all patients. The normalized MRD value was significantly lower than the unnormalized MRD value (p < 0.001). When categorizing patients, 27 of 50 patients (54%) achieved normalized MRD <0.01%, while 6 of them did not achieve MRD <0.01% when applying the unnormalized value. The normalized post-induction MRD value of 0.01% proved to be a significant threshold value for both 3-year event-free survival (100% for MRD <0.01% vs. 60.9% ± 10.2% for MRD ≥0.01%, p = 0.007) and 3-year overall survival (100% for MRD <0.01% vs. 78.3% ± 8.6% for MRD ≥0.01%, p = 0.011). However, unnormalized MRD was not a significant factor for outcome in this cohort. Our study demonstrated that MRD assessment by NGS-based Ig clonality assay could be applied in most pediatric B-ALL patients. Normalized post-induction MRD <0.01% was a significant prognostic indicator.