Comprehensive analysis of peripheral T-cell and natural killer/T-cell lymphoma in Asian patients: A multinational, multicenter, prospective registry study in Asia

Increased coexpression of PD-L1 and IDO1 is associated with poor overall survival in patients with NK/T-cell lymphoma

Immunotherapy with programmed cell death 1 ligand 1 (PD-L1) blockade was effective in patients with NK/T-cell lymphoma. In addition to PD-L1, indoleamine 2,3-dioxygenase-1 (IDO1) is one of the most promising immunotherapeutic targets. High proportions of PD-L1 and IDO1 proteins were observed by immunohistochemistry (IHC) from 230 newly diagnosed patients with NK/T lymphoma with tissue samples from three cancer centers and were associated with poor overall survival (OS) in patients with NK/T lymphoma. Importantly, the coexpression of PD-L1 and IDO1 was related to poor OS and short restricted mean survival time in patients with NK/T lymphoma and was an independent prognostic factor in the training cohorts, and which was also validated in 58 NK/T lymphoma patients (GSE90597). Moreover, a nomogram model constructed with PD-L1 and IDO1 expression together with age could provide concise and precise predictions of OS rates and median survival time. The high-risk group in the nomogram model had a positive correlation with CD4 + T-cell infiltration in the validation cohort, as did the immunosuppressive factor level. Therefore, high PD-L1 and IDO1 expression was associated with poor OS in patients with NK/T lymphoma. PD-L1 and IDO1 might be potential targets for future immune checkpoint blockade (ICB) therapy for NK/T lymphoma.

Novel clinical risk stratification and treatment strategies in relapsed/refractory peripheral T-cell lymphoma

Peripheral T cell lymphoma (PTCL) represents a group of heterogeneous hematological malignancies, which are notoriously challenging to treat and outcomes are typically poor. Over the past two decades, clinical prognostic indices for patient risk stratification have evolved, while several targeted agents are now available to complement combination chemotherapy in the frontline setting or as a salvage strategy. With further understanding of the molecular pathobiology of PTCL, several innovative approaches incorporating immunomodulatory agents, epigenetic therapies, oncogenic kinase inhibitors and immunotherapeutics have come to the forefront. In this review, we provide a comprehensive overview of the progress in developing clinical prognostic indices for PTCL and describe the broad therapeutic landscape, emphasizing novel targetable pathways that have entered early phase clinical studies.

Update on T-Cell Lymphoma Epidemiology

PURPOSE OF REVIEW

T-cell lymphomas (TCLs) are a group of rare subtypes of non-Hodgkin lymphoma derived from mature T-lymphocytes. Recent updates in lymphoma classification based on the cell-of-origin pathogenesis have shed new light on TCL epidemiology and outcomes. Contemporary regional consortia and international studies, including those conducted recently in Asia and South America, have provided an updated delineation of the major subtypes across various global regions.

RECENT FINDINGS

Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), remains the most common subtype globally except in Asia, where extra-nodal NK-T cell lymphoma (ENKTL) has emerged as the most prevalent. Angioimmunoblastic T-cell lymphoma (AITL) is the second most common subtype globally except in South America where its incidence falls behind adult T-cell leukemia/lymphoma (ATLL) and ENKTL. ALK-negative anaplastic large cell lymphoma (ALCL) has been recognized as the second most common subtype in some parts of South America. Studies on the newly classified breast implant-associated ALCL (BIA-ALCL) are beginning to reveal its distribution and risk factors. Deciphering the epidemiology of TCLs is a challenging endeavor due to the rarity of these entities and ongoing refinement in classification. Collaborative efforts on prospective registries based on the most current WHO classifications will help capture the true epidemiology of TCL subtypes to better focus resources for diagnostic, prognostic, and therapeutic efforts.

Role of upfront autologous transplant for peripheral T-cell lymphoma patients achieving a complete remission with first-line therapy: a systematic review and meta-analysis

There is currently no consensus on the role of upfront autologous transplantation (ASCT) for patients with peripheral T-cell lymphomas (PTCL), especially in patients achieving first complete remission (CR1) following chemotherapy, and data in the literature is conflicting. A systematic review and meta-analysis was performed to address this question. We searched key databases from January 2000 to February 2022. Six prospective and eleven retrospective studies were included among 2959 unique records. Median follow up in these studies ranged from 22 to 94 months. There was a trend towards benefit in PFS (HR = 0.80, 95% CI 0.62-1.05, p = 0.11) and OS (HR = 0.79, 95% CI 0.57-1.09, p = 0.15) in the ASCT compared to chemotherapy only group. Importantly, in transplant eligible patients in CR1, a significant benefit was demonstrated in both OS (HR = 0.59, 95% CI 0.36-0.95, p = 0.03) and PFS (HR = 0.61, 95% CI 0.47-0.81, p = 0.0004) in the ASCT group. Amongst the nodal PTCL subgroups, ASCT showed a significant PFS benefit for the AITL subgroup (HR = 0.43, 95% CI 0.20-0.94, p < 0.03) but not PTCL-NOS or ALK-ve ALCL subgroups. Our findings support upfront ASCT for transplant eligible PTCL patients achieving CR1 post chemotherapy. In particular, patients with AITL exhibited a significantly better PFS after upfront ASCT.

Characterization of primary small intestinal lymphoma: a retrospective study based on double balloon endoscopy

BACKGROUND

The diagnosis of primary small intestinal lymphoma (PSIL) is difficult. This study aimed to evaluate the clinical, radiological and endoscopic characteristics of PSIL and provide clue for diagnosis.

METHODS

A total of 30 patients diagnosed with PSIL who underwent double balloon endoscopy (DBE) in the First Affiliated Hospital of Zhejiang University were retrospectively analyzed. Clinical, radiological and endoscopic data were collected. Univariate analysis was used to determine significant indicators for differentiating three main subtypes of PSIL. Cox regression analysis was performed to assess the risk factors for survival.

RESULTS

In this study, 10 patients were pathologically diagnosed as diffuse large B-cell lymphoma (DLBCL), 11 were indolent B-cell lymphoma (BCL) and 9 were T-cell lymphoma (TCL). Compared with DLBCL patients, the body mass index (BMI) of TCL patients was significantly lower (p = 0.004). Meanwhile, compared with patients with DLBCL, the patients with indolent BCL had lower levels of C-reactive protein, lactate dehydrogenase (LDH), fibrinogen and D-Dimer (p = 0.004, p = 0.004, p = 0.006, and p = 0.002, respectively), and lower proportion of thicker intestinal wall and aneurysmal dilation in CT scan (p = 0.003 and p = 0.020, respectively). In terms of ulcer morphology, patients with DLBCL had significantly higher proportion of deep ulcers than patients with indolent BCL (p = 0.020, respectively). Cox regression analysis showed that drink (p = 0.034), concomitant colonic ulcers (p = 0.034) and elevated LDH (p = 0.043) are risk factors for mortality in patients with PSIL.

CONCLUSIONS

This study provides clinical characteristics of patients with PSIL. Thicker intestinal wall and aneurismal dilation detected on CT scan and deeper ulcer on DBE examination helps to establish a diagnosis of DLBCL.

Liquid biopsy in T-cell lymphoma: biomarker detection techniques and clinical application

T-cell lymphoma is a highly invasive tumor with significant heterogeneity. Invasive tissue biopsy is the gold standard for acquiring molecular data and categorizing lymphoma patients into genetic subtypes. However, surgical intervention is unfeasible for patients who are critically ill, have unresectable tumors, or demonstrate low compliance, making tissue biopsies inaccessible to these patients. A critical need for a minimally invasive approach in T-cell lymphoma is evident, particularly in the areas of early diagnosis, prognostic monitoring, treatment response, and drug resistance. Therefore, the clinical application of liquid biopsy techniques has gained significant attention in T-cell lymphoma. Moreover, liquid biopsy requires fewer samples, exhibits good reproducibility, and enables real-time monitoring at molecular levels, thereby facilitating personalized health care. In this review, we provide a comprehensive overview of the current liquid biopsy biomarkers used for T-cell lymphoma, focusing on circulating cell-free DNA (cfDNA), circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), Epstein-Barr virus (EBV) DNA, antibodies, and cytokines. Additionally, we discuss their clinical application, detection methodologies, ongoing clinical trials, and the challenges faced in the field of liquid biopsy.

Pathobiology of nodal peripheral T-cell lymphomas: current understanding and future directions

Predominantly nodal is the most common clinical presentation of peripheral T- (and NK-) cell lymphomas (PTCL), which comprise three main groups of diseases: (i) systemic anaplastic large cell lymphomas (ALCL), whether positive or negative for anaplastic lymphoma kinase (ALK); (ii) follicular helper T-cell lymphomas (TFHL); and (iii) PTCL, not otherwise specified (NOS). Recent advances in the genomic and molecular characterization of PTCL, with enhanced understanding of pathobiology, have translated into significant updates in the latest 2022 classifications of lymphomas. ALK-negative ALCL is now recognized to be genetically heterogeneous, with identification of DUSP22 rearrangements in approximately 20-30% of cases, correlated with distinctive pathological and biological features. The notion of cell-of-origin as an important determinant of the classification of nodal PTCL is best exemplified by TFHL, considered as one disease or a group of related entities, sharing oncogenic pathways with frequent recurrent epigenetic mutations as well as a relationship to clonal hematopoiesis. Data are emerging to support that a similar cell-of-origin concept might be relevant to characterize meaningful subgroups within PTCL, NOS, based on cytotoxic and/or Th1 versus Th2 signatures. The small group of primary nodal Epstein-Barr virus-positive lymphomas of T- or NK-cell derivation, formerly considered PTCL, NOS, is now classified separately, due to distinctive features, and notably an aggressive course. This review summarizes current knowledge of the pathology and biology of nodal-based PTCL entities, with an emphasis on recent findings and underlying oncogenic mechanisms.

Outcomes and prognostic factors of patients with Extranodal NK T cell lymphoma (ENKTL)

The staging, prognostication, and treatment of ENKTL has evolved over the years with better understanding of the disease biology. There is significant heterogeneity in the treatment followed across the world. Literature from India have been few with small number of patients. We studied the outcomes and prognostic factors of patients with ENKTL treated between May 2010 and December 2021 at our center. A total of 78 patients diagnosed with ENKTL were treated at our center. L-asparaginase based chemotherapy was administered in 84% of the patients. Close to 2/3rd patients received SMILE chemotherapy. After a median follow-up of 30 months (18.5-41.4 months), the median relapse free survival and overall survival for the overall population was 45 months (12-118 months) and 45 months (14-118 months) respectively. By multivariate analysis, PINK score of 2-4, non-receipt of RT and non-achievement of CR were associated with poor survival.

Influence of treatment intensity and medical comorbidities in older adults with peripheral T cell lymphoma

We conducted a population-based study of patients >65 years, diagnosed 2008-2017, with peripheral T-cell lymphoma (PTCL) using SEER-Medicare. Associations between PTCL subtype, treatment regimen, comorbidity, and mortality were assessed using the Kaplan-Meier method and multivariable Cox regression. Amongst the 2,546 patients, the median age was 77 years (interquartile range, 71-83). 5-year overall survival (OS) ranged from 22.2% to 37.3% depending on PTCL subtype. The most common frontline regimen was cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP). 5-year OS rate was 47.0% for patients treated with etoposide + CHOP (N = 67; CHOEP), 33.7% for those treated with CHOP (N = 732), and 23.8% for patients treated with non-anthracycline-containing regimens (N = 105; p < 0.001). In patients without comorbidities, CHOEP remained independently associated with improved OS (HR 0.52, 95% CI,0.30-0.91). Median OS was 1.2 years from initiation of second-line therapy (N = 228) independent of treatment regimen. Frontline but not second-line treatment regimen is associated with OS in older patients with PTCL.

Intensive therapy can improve long-term survival in newly diagnosed, advanced-stage extranodal NK/T-cell lymphoma: A multi-institutional, real-world study

The study investigated the treatment and prognosis of advanced-stage extranodal natural killer/T-cell lymphoma (ENKTL). With a median follow-up of 75.03 months, the median overall survival (mOS) for the 195 newly diagnosed stage III/IV ENKTL patients was 19.43 months, and estimated 1-, 2-, 3- and 5-year OS were 59.5%, 46.3%, 41.8% and 35.1%, respectively. Chemotherapy (CT) + radiotherapy (RT) compared to CT alone (P = .007), and hematopoietic stem cell transplantation (HSCT) compared to non-HSCT (P < .001), both improved OS. For patients ≤60 years and ineligible for HSCT, other therapies with complete remission led to comparable OS (P = .141). Nine patients ever treated with chidamide achieved a median progression-free survival (mPFS) and mOS of 53.63 (range, 3.47-92.33) and 54.80 (range, 5.50-95.70) months, and four with chidamide maintenance therapy (MT) achieved a mPFS and mOS of 55.83 (range, 53.27-92.33) and 60.65 (range, 53.70-95.70) months, possibly providing an alternative option for non-HSCT patients. Non-anthracycline (ANT)- compared to ANT-, asparaginase (Aspa)- compared to non-Aspa- and gemcitabine (Gem)- compared to non-Gem-based regimens, prolonged PFS (P = .031; P = .005; P = .009) and OS (P = .010; P = .086; P = .003), respectively. Multivariate analysis demonstrated that Gem-based regimens improved PFS (HR = 0.691, P = .061) and OS (HR = 0.624, P = .037). Gem + Aspa combinations slightly improved PFS and OS compared to regimens containing Gem or Aspa alone (P > 0.05). First-line "intensive therapy," including CT (particularly Gem + Aspa regimens), RT, HSCT and alternative chidamide MT, was proposed and could improve long-term survival for advanced-stage ENKTLs. Ongoing prospective clinical studies may shed further light on the value of chidamide MT.

The clinical features, treatment, and prognostic factors for peripheral T-cell lymphomas: A single-institution analysis of 240 Chinese patients

AIM

This study aimed to analyze the clinical features, treatment, survival, and prognostic factors of Chinese patients with peripheral T-cell lymphoma (PTCL) excluding natural killer/T-cell lymphoma (NKTCL).

METHODS

Data on patients with newly diagnosed PTCLs between January 1, 2006 and December 31, 2017 at our hospital were retrospectively reviewed. Patients with NKTCL were excluded.

RESULTS

A total of 240 patients were included. PTCL, not otherwise specified (PTCL-NOS), was the most frequent subtype (42.5%), followed by angioimmunoblastic T-cell lymphoma (AITL) (21.3%), anaplastic lymphoma kinase (ALK)-negative anaplastic large-cell lymphoma (ALK-ALCL) (16.7%), ALK-positive ALCL (ALK+ALCL) (10.8%) and others (8.8%). With a median follow-up of 81.1 months, the 5-year progression-free survival (PFS) and overall survival (OS) rates for all patients were 30.4% (95% CI 25.0%-37.0%) and 48.8% (95% CI 42.6%-55.7%), respectively. On multivariate analysis, no consolidative autologous stem cell transplantation (ASCT) and not achieving complete response after first-line chemotherapy retained independently prognostic value for inferior PFS and OS. Besides, bone marrow involvement and serum albumin level were independent factors for PFS, and Eastern Cooperative Oncology Group performance status ≥2 was significantly predictive of inferior OS. Compared with PTCL-NOS, significantly superior PFS and OS were observed for ALK+ALCL and ALK-ALCL.

CONCLUSION

The survival outcomes with current treatment for most PTCL subtypes are still unsatisfactory. Prospective randomized studies are needed to establish the value of consolidative ASCT in PTCL, and novel therapeutic approaches should be explored.

Darinaparsin in patients with relapsed or refractory peripheral T-cell lymphoma: results of an Asian phase 2 study

Darinaparsin is a novel organic arsenical compound of dimethylated arsenic conjugated to glutathione, with antitumor activity and a mechanism of action markedly different from other available agents. This phase 2, nonrandomized, single-arm, open-label study evaluated the efficacy and safety of intravenous darinaparsin (300 mg/m2 over 1 hour, once daily for 5 consecutive days, per 21-day cycle) and its pharmacokinetics at multiple doses in 65 Asian patients with relapsed or refractory peripheral T-cell lymphoma (PTCL). The primary end point was the overall response rate (ORR). The ORR based on central assessment was 19.3% (90% confidence interval, 11.2-29.9), which was significantly higher than the predefined threshold of 10% (P = .024). The ORR was 16.2% in patients with PTCL-not otherwise specified and 29.4% in patients with angioimmunoblastic T-cell lymphoma. Tumor size decreased in 62.3% of patients. Treatment-emergent adverse events (TEAEs) were observed in 98.5% of patients. Grade ≥3 TEAEs with an incidence rate of ≥5% included anemia (15.4%), thrombocytopenia (13.8%), neutropenia (12.3%), leukopenia (9.2%), lymphopenia (9.2%), and hypertension (6.2%). Darinaparsin is effective and well tolerated, with TEAEs that were clinically acceptable and manageable with symptomatic treatment and dose reductions. This trial was registered at www.clinicaltrials.gov as #NCT02653976.

Follicular helper T-cell lymphomas: disease spectrum, relationship with clonal hematopoiesis, and mimics. A report of the 2022 EA4HP/SH lymphoma workshop

Follicular helper T-cell lymphomas (TFH lymphomas) were discussed in session V of the lymphoma workshop of the European Association for Haematopathology (EA4HP)/Society for Hematopathology (SH) 2022 meeting in Florence, Italy. The session focused on the morphologic spectrum of TFH lymphoma, including its three subtypes: angioimmunoblastic-type (AITL), follicular-type, and not otherwise specified (NOS). The submitted cases encompassed classic examples of TFH lymphoma and unusual cases such as those with early or indolent presentations, associated B-cell proliferations, or Hodgkin/Reed-Sternberg-like cells. The relationship between TFH lymphoma and clonal hematopoiesis was highlighted by several cases documenting divergent evolution of myeloid neoplasm and AITL from shared clonal mutations. The distinction between TFH lymphoma and peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS), was stressed, and many challenging examples were presented. Various cases highlighted the difficulties of differentiating TFH lymphoma from other established types of lymphoma and reactive conditions. Cutaneous T-cell lymphoma expressing TFH markers, particularly when resulting in lymph node involvement, should be distinguished from TFH lymphomas. Additional immunophenotyping and next-generation sequencing studies were performed on various cases in this session, highlighting the importance of these technologies to our current understanding and classification of TFH lymphomas.

Comparison of first-line treatment with CHOP versus ICED in patients with peripheral T-cell lymphoma eligible for upfront autologous stem cell transplantation

Introduction

Upfront autologous stem cell transplantation (ASCT) has been recommended for patients who are newly diagnosed with peripheral T-cell lymphoma (PTCL), and CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone), an anthracycline-based chemotherapy has been the frontline chemotherapy for PTCL. However, it is not clear whether anthracycline-based chemotherapies such as CHOP could be standard induction therapy for PTCL.

Methods

We conducted a randomized phase II study to compare CHOP with fractionated ifosfamide, carboplatin, etoposide, and dexamethasone (ICED) for patients eligible for ASCT. The primary endpoint was progression-free survival (PFS) and secondary endpoints included objective response rate, overall survival (OS), and safety profiles.

Results

Patients were randomized into either CHOP (n = 69) or ICED (n = 66), and the characteristics of both arms were not different. PTCL-not otherwise specified (NOS, n = 60) and angioimmunoblastic T-cell lymphoma (AITL, n = 53) were dominant. The objective response rate was not different between CHOP (59.4%) and ICED (56.1%), and the 3-year PFS was not different between CHOP (36.7%) and ICED (33.1%). In AITL patients, CHOP was favored over ICED whereas ICED was associated with more cytopenia and reduced dose intensity. Patients who received upfront ASCT after achieving complete response to CHOP or ICED showed 80% of 3-year OS.

Discussion

In summary, our study showed no therapeutic difference between CHOP and ICED in terms of response and PFS. Thus, CHOP might remain the reference regimen especially for AITL based on its better outcome in AITL, and upfront ASCT could be recommended as a consolidation of complete response in patients with PTCL.

Retrospective analysis of diagnosis and therapeutic strategies for patients with hepatosplenic T cell lymphoma

Hepatosplenic T cell lymphoma (HSTCL) is a rare and aggressive lymphoma with no standard treatment and poor treatment response. From 2001-2021, 20 from a lymphoma cohort of 7247 patients (0.27%) were diagnosed with HSTCL at Samsung Medical Center. The median age at the time of diagnosis was 37.5 (range, 17-72) years, and 75.0% of patients were male. Most patients had B symptoms, hepatomegaly, and splenomegaly. Lymphadenopathy was found in only 31.6% of patients, and increased PET-CT uptake was found in 21.1% of patients. Thirteen patients (68.4%) expressed T cell receptor (TCR) γδ, and 6 patients (31.6%) expressed TCRαβ. The median progression-free survival (PFS) for the entire cohort was 7.2 months (95% CI, 2.9-12.8), and the median overall survival (OS) was 25.7 months (95% CI, not calculated). In subgroup analysis, the overall response rate (ORR) was 100.0% in the ICE/Dexa group and 53.8% in the anthracycline-based group, and the complete response rate was 83.3% in the ICE/Dexa group and 38.5% in the anthracycline-based group. The ORR was 50.0% in the TCRαβ group and 83.3% in the TCRγδ group. The OS was not reached in the autologous hematopoietic stem cell transplantation (HSCT) group and was 16.0 months (95% CI, 15.1-16.9) in the non-transplant group at the data cutoff time (P value 0.015). In conclusion, HSTCL is rare but has a very poor prognosis. The optimal treatment strategy is not defined. More genetic and biological information is needed.

Expression of Tryptophan Metabolism Enzymes in Patients with Diffuse Large B-cell Lymphoma and NK/T-cell Lymphoma

BACKGROUND

Metabolites of tryptophan (Trp) metabolism in the tumor microenvironment play crucial immunosuppressive roles in various cancers. However, the role of Trp metabolism in diffuse large B-cell lymphoma (DLBCL) or natural killer/T-cell lymphoma (NK/TCL) remains unelucidated.

METHODS

We investigated the potential role of Trp metabolism in a cohort of 43 patients with DLBCL and 23 with NK/TCL. We constructed tissue microarrays and performed in situ staining of Trp-catabolizing enzymes and PD-L1 using immunohistochemistry (IHC).

RESULTS

We observed 14.0% positive staining of IDO1 in DCBCL and 60.9% in NK/TCL; 55.8% of IDO2 in DCBCL and 95.7% in NK/TCL; 79.1% of TDO2 in DCBCL and 43.5% in NK/TCL; 29.7% of IL4I1 in DCBCL and 39.1% in NK/TCL. However, IDO1, IDO2, TDO2, and IL4I1 positivity did not significantly differ between PD-L1+ and PD-L1- biopsy tissue samples of NK/TCL; nonetheless, a positive correlation of IDO1 (r = 0.87, p < 0.001), IDO2 (r = 0.70, p < 0.001), TDO2 (r = 0.63, p < 0.001), and IL4I1 (r = 0.53, p < 0.05) with PD-L1 expression was observed in the TCGA-DLBCL dataset. Finally, immunohistochemical (IHC) analysis revealed the lack of superior prognostic effect with higher expression of Trp enzymes in DLBCL and NK/TCL. Furthermore, IDO1, IDO2, TDO2, and IL4I1 expression, as well as survival rates, did not significantly differ across all groups in the TCGA-DLBCL cohort.

CONCLUSION

Collectively, our findings provide novel insights into the enzymes involved in Trp metabolism in DLBCL and NK/TCL and their association with PD-L1 expression, which offers potential strategies to combine Trp-metabolism enzyme inhibitors with anti-PD-L1 or other immunotherapeutic strategies in clinical DLBCL or NK/TCL treatment.

Diagnostic and prognostic value of pretreatment PET/CT in extranodal natural killer/T-cell lymphoma: a retrospective multicenter study

PURPOSE

The objective of this research was to assess the utility of positron emission tomography combined with computed tomography (PET/CT) to detect bone marrow invasion (BMI) and the predictive value of PET/CT in extranodal natural killer/T-cell lymphoma (ENKTL) patients.

PATIENTS AND METHODS

This multicentre study enrolled ENKTL patients who underwent pretherapy PET/CT and bone marrow biopsy (BMB). The specificity, sensitivity, negative predictive value (NPV), and positive predictive value (PPV) of PET/CT and BMB for BMI were evaluated. Multivariate analysis was used to identify predictive parameters for constructing a nomogram.

RESULTS

Seven hundred and forty-eight patients were identified from four hospitals, with eighty (10.7%) having focal skeletal lesions on PET/CT and fifty (6.7%) having positive BMB. When BMB is considered as the gold standard, the specificity, sensitivity, PPV, and NPV of PET/CT for diagnosing BMI were found to be 93.8%, 74.0%, 46.3%, and 98.1%, respectively. PET/CT-positive individuals showed significantly worse OS than PET/CT-negative patients in the subgroup of BMB-negative cases. The nomogram model created according to the significant risk factors from multivariate analysis performed well in predicting survival probability.

CONCLUSION

PET/CT offers a superior degree of precision for determining BMI in ENKTL. A nomogram model including the parameters of PET/CT can predict survival probability and may help in applying appropriate personalized therapy.

Emerging predictive biomarkers for novel therapeutics in peripheral T-cell and natural killer/T-cell lymphoma

Peripheral T-cell lymphoma (PTCL) and natural killer/T-cell lymphoma (NKTCL) are rare subtypes of non-Hodgkin's lymphoma that are typically associated with poor treatment outcomes. Contemporary first-line treatment strategies generally involve the use of combination chemoimmunotherapy, radiation and/or stem cell transplant. Salvage options incorporate a number of novel agents including epigenetic therapies (e.g. HDAC inhibitors, DNMT inhibitors) as well as immune checkpoint inhibitors. However, validated biomarkers to select patients for individualized precision therapy are presently lacking, resulting in high treatment failure rates, unnecessary exposure to drug toxicities, and missed treatment opportunities. Recent advances in research on the tumor and microenvironmental factors of PTCL and NKTCL, including alterations in specific molecular features and immune signatures, have improved our understanding of these diseases, though several issues continue to impede progress in clinical translation. In this Review, we summarize the progress and development of the current predictive biomarker landscape, highlight potential knowledge gaps, and discuss the implications on novel therapeutics development in PTCL and NKTCL.

Treatment of extranodal NK/T-cell lymphoma: From past to future

Extranodal NK/T-cell lymphoma (ENKTCL) is the most common subtype of T/NK-cell lymphoma in Asia and Latin America, but very rare in North American and Europe. Patient survival has improved significantly over the past two decades. However, standard treatment has not yet been established, although dozens of prospective trials have been conducted. To help understand how the treatment of ENKTCL has evolved in the past and what trends lie ahead, we have comprehensively reviewed the treatment of this aggressive malignancy, with a particular focus on neglected or unanswered issues, such as the optimal staging method, the best partner of asparaginase (Asp), the individualized administration of Asp, the preferred sequence of CT and RT and so on. Overall, the 5-year overall survival (OS) of patients with Ann Arbor stage I/II disease increased from < 50% in the early 20th century to > 80% in recent years, and the median OS of patients with Ann Arbor stage III/IV disease increased from < 1 year to more than 3 years. The improvement in patient survival is largely attributable to advances in radiation technology and the introduction of Asp and anti-PD-1/PD-L1 immunotherapy into practice. Radiotherapy is essential for patients with early-stage disease, while Asp-based chemotherapy (CT) and PD-1/PD-L1 inhibitors significantly improved the prognosis of patients with advanced-stage disease. ENKTCL management is trending toward simpler regimens, less toxicity, and higher efficacy. Novel drugs, such as manufactured T cells, monoclonal antibodies, and small molecule inhibitors, are being intensively investigated. Based on the fact that ENKTCL is highly resistant to cytotoxic drugs except Asp, and aggressive CT leads to higher toxicity rather than better outcomes, we recommend it is unnecessary to expend additional resources to compare different combinations of Asp with cytotoxic agents. Instead, more efforts should be made to optimize the use of Asp and immunotherapy to maximize efficacy and minimize toxicity, explore ways to overcome resistance to Asp and immunotherapy, identify novel treatment targets, and define subpopulations who may benefit more from specific treatments.

Extranodal T- and NK-cell lymphomas

Non-cutaneous extranodal NK/T cell lymphoproliferations constitute a heterogenous group of rare neoplasms, occurring primarily in the gastro-intestinal tract, nasal area, spleen, and liver. Their nomenclature refers to their usual clinical presentation and predilection for specific anatomic sites-i.e. extranodal NK/T-cell lymphoma, nasal-type, hepatosplenic T-cell lymphoma, primary intestinal T-cell lymphomas, indolent lymphoproliferative disorders of the gastrointestinal tract, and breast implant-associated anaplastic large cell lymphoma. Extranodal tissues may also be involved by T-cell leukemias, or other entities usually presenting as nodal diseases. Primary extranodal entities range from indolent to highly aggressive diseases. Here, we will review the clinicopathologic features of the pertinent entities including the recent advances in their molecular and genetic characterization, with an emphasis on the changes introduced in the 2022 International Consensus Classification of lymphoid neoplasms, and highlight the diagnostic criteria helpful to sort out the distinction with potential mimickers.

Classification and challenges in the histopathological diagnosis of peripheral T-cell lymphomas, emphasis on the WHO-HAEM5 updates

Mature T-cell lymphomas represent neoplastic expansions of T-cell lymphocytes with a post-thymic derivation. Most of these tumors feature aggressive clinical behavior and challenging histopathological diagnosis and classification. Novel findings in the genomic landscape of T-cell lymphomas are helping to improve the understanding of the biology and the molecular mechanisms that underly its clinical behavior. The most recent WHO-HAEM5 classification of hematolymphoid tumors introduced novel molecular and histopathological findings that will aid in the diagnostic classification of this group of neoplasms. The current review article summarizes the most relevant diagnostic features of peripheral T-cell lymphomas with an emphasis on the updates that are incorporated at the WHO-HAEM5.

Real-World Efficacy of 5-Azacytidine as Salvage Chemotherapy for Angioimmunoblastic T-cell Lymphoma

BACKGROUND

Based on specific epigenetic mutation in AITL such as TET2, DNMT3A, IDH2, and RHOA, hypomethylating agents are emerging as a promising treatment option for AITL.

METHOD

The efficacy and safety of 5-azacytidine as salvage chemotherapy were retrospectively analyzed in 15 patients with RR-AITL from 2019 to 2022.

RESULTS

During the median 6.0 months of follow-up, the overall response rate (ORR) was 40% (n = 6/15) with 2 CRs and 4 PRs. The patients who previously had received ≤2 prior chemotherapies showed higher ORR than subjects with >2 prior chemotherapies (80% vs. 20%). The 10 patients who received 5-azacitidine at the late chemotherapy lines (>2 prior chemotherapy lines) usually received less dose 5-azacitidine. And these patients discontinued treatment due to disease progression (n = 6/10, 60%) or neutropenic fever (n = 4/10, 40%). The patients who received a full dose (75 mg/m² for 7 days) of 5-azacitidine seemed to show better ORR than subjects (100 mg for 7 days) who did not receive an optimal dose (60.0% vs. 30.0%). The median progression-free survival (PFS) was 1.6 months, and the patients who previously had undergone ≤2 chemotherapies had better PFS compared with subjects who previously received >2 chemotherapies (P-value = .04).

CONCLUSION

5-azacitidine shows reasonable efficacy and manageable toxicities for patients with RR-AITL, especially those who previously received ≤2 chemotherapy lines.

[The expressional characteristics and diagnostic values of TRBC1 in mature T-cell lymphoma]

Objective: To investigate the expression characteristics of TRBC1 protein in mature T-cell lymphoma (TCL) , and compare with T-cell receptor (TCR) -Vβ repertoire analysis and TCR gene rearrangement results, to explore the value of TRBC1 in the diagnosis of TCL. Methods: The expression of TRBC1 was detected by multi-parameter flow cytometry in 30 cases of TCL, 40 cases of normal controls and 50 cases of patients without T lymphocyte proliferative diseases (non-TCL) admitted to the Department of Hematology, The First Affiliated Hospital of Nanjing Medical University. The diagnostic value of TCRVβ repertoire analysis, TCR gene rearrangement and TRBC1 restricted expression detection in TCL was evaluated. Results: The positive rates of CD4(+)T and CD8(+)T cell subsets TRBC1 in normal control group were (39.6±6.5) % and (39.3±4.4) %. The positive rates of CD4(+)T and CD8(+)T cell subsets TRBC1 in non-TCL were (39.1±3.8) % and (36.0±8.4) %. All 30 cases of TCL were CD3(+)TCRγδ(-), and the positive rate of TRBC1 was >92.3% or <12.7%. All cases showed restrictive expression pattern (monoclonal expression) , which was significantly different from those of the normal control and the non-TCL cases (P<0.001) . In terms of the diagnostic performance of T cell clonality, the sensitivity of TRBC1 was 100%, the positive detection rate of TCR gene rearrangement was 92.8%, and the sensitivity of TCRVβ detection was 94.1%. Kappa test showed high consistency among the three detective methods. Conclusion: Multi-parameter flow cytometry detection of TRBC1 expression level can quickly and efficiently diagnose mature T-cell lymphoma, which has good clinical application value.

Comprehensive comparison of international prognostic indexes for follicular helper T-cell lymphoma

In 2016, World Health Organization classification of lymphoid neoplasms separated firmly-follicular helper (Tfh) cell origin lymphomas from peripheral T-cell lymphoma-not specified (PTCL-NOS) based on their unique immunogenic characteristics. Generally, Tfh cell origin lymphoma, which has an approximately 25% incidence, is classified into three categories: angioimmunoblastic T-cell lymphoma (AITL), follicular peripheral T-cell lymphoma (F-PTCL), and nodal peripheral T-cell lymphoma with a T-follicular helper phenotype (nodal PTCL with Tfh cell phenotype). Their prognosis has been estimated using four traditional prognostic tools for T-cell lymphoid malignancies: the international prognostic index (IPI), the prognostic index for peripheral T-cell lymphoma unspecified (PIT), the modified PIT (mPIT) and the international T-cell lymphoma project index. In addition, the AITL score that reflects AITL characteristics well has been introduced recently. However, there are no clear guidelines for evaluating the prognosis of Tfh cell lymphoma. Thus, we performed a comparative analysis to determine which of these five indexes is most suitable for Tfh cell lymphoma. We evaluated the accuracy of classification according to risk score and predicted survival rate. Based on review by lymphoma pathology experts, we enrolled 198 patients diagnosed with Tfh cell lymphoma in this retrospective study. AITL was the most common subtype (n = 168), followed by F-PTCL (n = 21) and nodal PTCL with Tfh cell phenotype (n = 9). The median progression-free survival and overall survival with front-line treatment was 0.8 years (95% confidence interval [CI], 0.6-1.1 years) and 2.9 years (95% CI, 1.6-4.2 years), respectively. The AITL score showed better differentiation than other scoring systems in terms of classification according to risk score. However, for predicting PFS (concordance-index [C-index], IPI vs. PIT vs. modified PIT vs. international T-cell lymphoma project index vs. AITL score; 0.617 vs. 0.605 vs. 0.576 vs. 0.591 vs. 0.592) and OS (C-index, IPI vs. PIT vs. modified PIT vs. international T-cell lymphoma project index vs. AITL score; 0.663 vs. 0.651 vs. 0.612 vs. 0.672 vs. 0.583), the IPI, and the international T-cell lymphoma project index showed better performance. In conclusion, there are unmet needs to develop a prognostic index for Tfh cell lymphoma because its characteristics differ from PTCL-NOS. Although the AITL score reflects Tfh cell-origin lymphoma characteristics well and clearly shows their power of classification according to risk score, there are concerns about accurate prediction of survival outcomes. Therefore, it seems too early to settle on a single scoring system in Tfh cell origin lymphoma. In the future, along with classification, a more effective tool for survival prediction needs to be developed that reflects the specific characteristics of T-cell lymphoma.

Cellular Origins and Pathogenesis of Gastrointestinal NK- and T-Cell Lymphoproliferative Disorders

The intestinal immune system, which must ensure appropriate immune responses to both pathogens and commensal microflora, comprises innate lymphoid cells and various T-cell subsets, including intra-epithelial lymphocytes (IELs). An example of innate lymphoid cells is natural killer cells, which may be classified into tissue-resident, CD56bright NK-cells that serve a regulatory function and more mature, circulating CD56dim NK-cells with effector cytolytic properties. CD56bright NK-cells in the gastrointestinal tract give rise to indolent NK-cell enteropathy and lymphomatoid gastropathy, as well as the aggressive extranodal NK/T cell lymphoma, the latter following activation by EBV infection and neoplastic transformation. Conventional CD4+ TCRαβ+ and CD8αβ+ TCRαβ+ T-cells are located in the lamina propria and the intraepithelial compartment of intestinal mucosa as type 'a' IELs. They are the putative cells of origin for CD4+ and CD8+ indolent T-cell lymphoproliferative disorders of the gastrointestinal tract and intestinal T-cell lymphoma, NOS. In addition to such conventional T-cells, there are non-conventional T-cells in the intra-epithelial compartment that express CD8αα and innate lymphoid cells that lack TCRs. The central feature of type 'b' IELs is the expression of CD8αα homodimers, seen in monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), which primarily arises from both CD8αα+ TCRαβ+ and CD8αα+ TCRγδ+ IELs. EATL is the other epitheliotropic T-cell lymphoma in the GI tract, a subset of which arises from the expansion and reprograming of intracytoplasmic CD3+ innate lymphoid cells, driven by IL15 and mutations of the JAK-STAT pathway.

Immune Checkpoint Inhibitors in Peripheral T-Cell Lymphoma

Peripheral T-cell lymphomas (PTCLs) are highly heterogeneous and present significant treatment challenges. Immune checkpoint therapies, such as PD-1 and CTLA-4 inhibitors, have significantly changed the clinical management paradigm of tumors. The roles of immune checkpoints in PTCL and related agents have been actively explored over recent years. PD-1 and PD-L1 expression is detectable in both PTCL and immune cells within the tumor microenvironment and forms the basis for the exploration of antibodies targeting these proteins. Such antibodies are currently being investigated in clinical trials to guide individualized therapy. PD-1/PD-L1 inhibitors alone and in combination with chemotherapy, radiotherapy, or targeted therapy have shown broad clinical efficacy and improved the survival of cancer patients. Studies of other immune checkpoint proteins, such as CTLA-4, TIM-3, LAG-3, and TIGIT, are likely to provide potential novel targets for immunotherapy. Here, we review the role of and recent advances in immune checkpoint blockade in common subtypes of PTCL, focusing on the anti-tumor immune responses to PD-1/PD-L1 blockers.

Impact of Epstein-Barr Virus on Peripheral T-Cell Lymphoma Not Otherwise Specified and Angioimmunoblastic T-Cell Lymphoma

Purpose

The significance of Epstein-Barr virus (EBV) infections for the prognosis of patients with peripheral T-cell lymphomas (PTCLs), specifically angioimmunoblastic T-cell lymphoma (AITL) and PTCL not otherwise specified (PTCL-NOS), remains unclear. The Epstein-Barr encoding region can be used to detect EBV in tissue sections by in situ hybridization (ISH) and by polymerase chain reaction (PCR) assays of peripheral blood samples from patients with PTCLs. This study compared the outcomes patients with AITL or PTCL-NOS for whom the presence of EBV infection was assessed by these two methods.

Patients and Methods

This was a retrospective study of patients newly diagnosed with AITL or PTCL-NOS. All patients were selected from a single transplantation center. EBV-positive lymphomas were detected at the time of diagnosis in tissue sections by ISH or in the blood by PCR.

Results

Out of a cohort of 140 patients with histologically confirmed AITL or PTCL-NOS, 105 were EBV-positive. The 3-year overall survival of patients with EBV-positive TCL was 43.3% compared to 68.6% in patients with EBV-negative TCL (p = .01). Patients who were treated with autologous or allogeneic hematopoietic stem cell transplantation (n = 28 and n = 11, respectively) or chemotherapy alone (n = 66) had 3-year survival rates of 67.0%, 62.3%, and 30.2%, respectively (p <.02). Patients with EBV-positive TCL had a better prognosis after treatment with hematopoietic stem cell transplantation compared to chemotherapy alone, but no difference was seen among patients with EBV-negative TCL.

Conclusions

EBV infection was shown to negatively affect the clinical outcomes of patients with TCL. Stem cell transplantation has been found to be an effective treatment for EBV-associated lymphomas. Further investigations are warranted to determine the optimal treatment for these patients.