Diagnosis Of Angioimmunoblastic T-cell Lymphoma Research Articles

Clinicopathological characteristics of angioimmunoblastic T-cell lymphoma with B-cell proliferation or neoplasms

Objective: To investigate the clinical, pathological and immunophenotypic features, and differential diagnosis of angioimmunoblastic T-cell lymphoma (AITL) with B-cell proliferation or neoplasms. Methods: Eight qualified cases were collected from the Department of Pathology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China from January 2019 to July 2023. One case was diagnosed with AITL and diffuse large B-cell lymphoma (DLBCL) and the other seven cases were diagnosed with AITL and B-cell proliferation. Clinical characteristics and pathological morphology were summarized. Immunohistochemical analysis, fluorescence in situ hybridization and gene rearrangement detection were performed. Results: The patients' average age was 58 years. Five of them were male. Biopsies of the enlarged cervical lymph nodes showed structural destruction and exhibited various histologic patterns. Some cases revealed Burkitt-like morphology, a moderate tumor volume and slightly irregular nuclei. Some cases showed prominent nucleoli. High endothelial venules and expanded follicular dendritic cells were detected. Tumor cells derived from T-follicular helper (TFH) cells were positive for two or more TFH biomarkers. Nodular or diffuse patchy proliferation of B cells was noted around the tumor tissue, which was initially considered as B-cell lymphoma. All of the 8 cases showed monoclonal rearrangements of the T-cell receptor genes while 5 of them also showed clonal rearrangements of the Ig genes. Seven of the 8 cases were subject to the detection of C-MYC gene breakage and were all negative. EBV-positive cells were seen in 6 cases. Neoplastic B cells were positive for C-MYC (>40%), while proliferative B cells were negative for C-MYC (<40%). Conclusions: The histological morphology of AITL with B-cell proliferation or lymphoma may be different from AITL. An integrated analysis, incorporating clinical, morphologic, immunophenotypic, and molecular assessment, helps reach an accurate diagnosis. This group of cases demonstrated the clinical and pathological characteristics of AITL accompanied by B-cell proliferation and B-cell lymphoma. The findings suggest that C-MYC maybe a feasible indicator for distinguishing B-cell proliferation from B-cell lymphoma, and provide a simple and feasible immunohistochemical marker for the diagnosis and research of composite lymphoma.

A new mode for the diagnosis of angioimmunoblastic T-cell lymphoma.

In order to explore a new mode for the diagnosis of angioimmunoblastic T-cell lymphoma (AITL), 31 cases of AITL and 28 cases of peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) were used as the study subjects. Identifying T follicular helper (TFH) cells with CD4, CD10, Bcl-6, and PD-1, identifying proliferative B cells with CD20 and EZH2, identifying proliferative follicular dendritic cells (FDCs) with CD21 and CD23, and analyzing the value of TFH/B/FDC proliferation and immunolocalization in the diagnosis of AITL. (1) Outside the inherent lymphoid follicles, simultaneous proliferation of TFH/B/FDC (a new diagnostic mode) were observed in AITL [83.87%; 26/31], with their immunolocalizations in the same site [83.87%; 26/31], while this phenomenon was not observed in 28 cases of PTCL-NOS (P<0.05). (2) The sensitivity and specificity of using this new mode to diagnose AITL were both high (83.87%, 100%), which was superior to CD2 (100%, 0%), CD3 (100%, 0%), CD4 (100%, 32.14%), CD5 (100%, 25%), CD10 (61.9%, 100%), Bcl-6 (42.86%, 100%), PD-1 (83.87%, 96.43%), and its Youden Index (0.84) was the highest. The areas under the curve (AUC) of CD10, Bcl-6, PD-1, and new mode to diagnosis AITL were 0.81, 0.71, 0.90, and 0.92, respectively, while the new mode had the highest AUC. The simultaneous proliferation of TFH/B/FDC cells outside the inherent lymphoid follicles can be used to assist in the diagnosis of AITL, and the simultaneous spatiotemporal proliferation of TFH/B/FDC cells is a specific immunomorphology of AITL.

Spontaneous remission of angioimmunoblastic T-cell lymphoma in a child with ataxia–telangiectasia: a case report

BackgroundAngioimmunoblastic T-cell lymphoma is an uncommon subtype of peripheral T-cell lymphoma in children with fewer than 20 cases reported in literature.Case presentationA 3-year-old Omani boy was diagnosed with ataxia–talengectasia presenting with fever and generalized lymphadenopathy. His biopsy revealed atypical lymphocytic infiltrate consistent with the diagnosis of angioimmunoblastic T-cell lymphoma. Within 3 weeks from the initial presentation and without any neoadjuvant therapy, he showed complete recovery of symptoms with absence of fever and regression of all previously affected lymph nodes. He has remained in remission ever since.ConclusionThis is the first report of spontaneous improvement of angioimmunoblastic T-cell lymphoma in a patient with ataxia–telangiectasia who was 3 years old at presentation. Owing to the paucity of similar cases, this report adds valuable diagnostic, therapeutic, and monitoring data.

Genetic abnormalities assist in pathological diagnosis and EBV-positive cell density impact survival in Chinese angioimmunoblastic T-cell lymphoma patients.

To explore the application of genetic abnormalities in the diagnosis of angioimmunoblastic T-cell lymphoma (AITL) and the reliable pathological prognostic factors. This study included 53 AITL cases, which were reviewed for morphological patterns, immunophenotypes, presence of Hodgkin and Reed-Sternberg (HRS)-like cells, and co-occurrence of B cell proliferation. The Epstein-Barr virus (EBV)-positive cells in tissues were counted, and cases were classified into "EBV encoded RNA (EBER) high-density" group if >50/HPF. Targeted exome sequencing was performed. Mutation data can assist AITL diagnosis: 1) with considerable HRS-like cells (20 cases): RHOA mutated in 14 cases (IDH2 co-mutated in 3 cases, 4 cases with rare RHOA mutation), TET2 was mutated in 5 cases (1 case co-mutated with DNMT3A), and DNMT3A mutated in 1 case; 2) accompanied with B cell lymphoma (7 cases): RHOA mutated in 4 cases (1 case had IDH2 mutation), TET2 mutated in 2 cases and DNMT3A mutated in 1 case; 3) mimic peripheral T cell lymphoma, not otherwise specified (5 cases): RHOA mutated in 2 cases (IDH2 co-mutated in 1 case), TET2 mutated in 3 cases, and DNMT3A mutated in 1 case; 4) pattern 1 (1 case), RHOA and TET2 co-mutated. Besides RHOAG17V (30/35), rare variant included RHOAK18N, RHOAR68H, RHOAC83Y, RHOAD120G and RHOAG17del, IDH2R172 co-mutated with IDH2M397V in one case. There were recurrent mutations of FAT3, PCLO and PIEZO1 and genes of epigenetic remodeling, T-cell activation, APC and PI3K/AKT pathway. EBER high-density independently indicated adverse overall survival and progression-free survival (P=0.046 and P=0.008, Kaplan-Meier/log-rank). Over half AITL cases might be confused in diagnosis for certain conditions without mutation data. Targeted exome sequencing with a comprehensive panel is crucial to detect both hot-spot and rare mutation variants for RHOA and IDH2 and other recurrent mutated genes in addition to TET2 and DNMT3A. EBER high-density independently indicated adverse survival.

Oral Azacytidine in Patients with Relapsed/Refractory Angioimmunoblastic T-Cell Lymphoma: Final Analysis of the Oracle Phase III Study

Background: Angioimmunoblastic T-cell Lymphoma (AITL) and nodal lymphomas of follicular helper T-cell origin have in common frequent mutations affecting genes regulating DNA methylation and hydroxymethylation such as TET2, DNMT3A and IDH2. Preliminary studies suggested efficacy of the hypomethylating agent 5-azacytidine (Blood. 2018; 132(21):2305-09) in relapsed/refractory AITL patients. We present here the final results of the ORACLE study (NCT03593018), a phase III trial comparing CC-486, an oral form of 5-azacytidine, to single agent treatment chosen by the investigator. Patients & methods: Eighty-six patients with relapsed/refractory AITL or nodal follicular helper T-cell lymphoma were randomized between CC-486 (n=42) and investigator's choice (gemcitabine, n=24, bendamustine n=16, romidepsin n=4) between November 2018 and February 2021. CC-486 was given at a daily dose of 300 mg/day (200 mg/day in Asian patients, based on previous phase I pharmacokinetics results) every day for 14 days out of 28 day-cycles, until progression or unacceptable toxicity. Gemcitabine and bendamustine were both administered for 6 cycles, while romidepsin was administered until progression. Patients were evaluated for response using 2014 international working group CT-based criteria. The primary endpoint was progression-free survival (PFS) based on local assessment of progressive disease, and overall survival was a key secondary endpoint in this study. Main secondary endpoints were PFS based on central review, overall response rate (ORR), complete response (CR) rate and safety. Statistical hypotheses were built on a PFS of 12 months in the experimental arm vs 5 months in the standard arm (HR=0.417), with a one-sided alpha risk of 0.025 and 90% power. Results: Median age was 69 years (IQR 62-76), and the male/female ratio was 1.4. Patients had received a median of 2 (IQR 1-2) previous lines of treatment, 90.6% of them had advanced stage (III-IV), 57% had elevated LDH, 23.3% had an ECOG performance status >1, 31.4% had an IPI score 4-5 and 35.8% had a bone marrow involvement. Patients received a median number of 5.5 (IQR 2;14) cycles of CC486, and respectively 2 (1-4), 3.5 (2-6) and 13.5 (5-25) cycles of gemcitabine, bendamustine and romidepsin. The primary endpoint was analysed after a follow-up of 14.4 months. Median PFS in the CC-486 arm was 5.6 (95%CI, 2.66-8.11) months vs 2.8 (95%CI, 1.87-4.83) months in the standard arm (stratified log-rank test p=0.0421), with a hazard ratio of 0.634 (95%CI, 0.38; 1.07), which did not reach the required significance of p<0.025. Median overall survival was 18.4 months (95%CI, 12.9-31.5) in the CC-486 arm vs 10.3 (95%CI, 4.2-13.5) in the standard arm, with a hazard ratio of 0.557 (95%CI, 0.323-0.961). Best overall response and complete response rates at 3 months in the CC-486 arm were 33.3% (95%CI, 19.6%-49.5%) and 11.9% (95%CI, 4%-25.6%) respectively, vs 43.2% (95%CI, 28.3%-59.0%) and 22.7% (95%CI, 11.5%-37.8%) in the standard arm. The most frequent (>40%) treatment emergent adverse events (TEAEs) for the CC-486 versus (vs) standard arm respectively were: blood and lymphatic system disorders (76.2% vs 93%) [neutropenia (42.9% vs 58.1%) and thrombocytopenia (23.8% vs 48.8%)], infections (35.7% vs 67.4%), gastrointestinal disorders (71.4% vs 55.8%). At least one grade 3/4 TEAE occurred in 76.2% patients in CC-486 arm vs 97.7% in the standard arm, and at least one serious TEAE occurred in 26.2% patients in CC-486 arm vs 44.2% patients in the standard arm. Central pathological review confirmed the diagnosis of AITL and TFH PTCL in 69 and 9 cases. We detected TET2, RHOA, DNMT3A and IDH2 mutations in 68/77 (88%), 51/75 (68%), 24/75 (32%) and 25/75 (33%) samples. None of these mutations were associated with PFS or OS of the whole population or the 5-azacytidine treated patients. Conclusion: The trial did not meet its primary endpoint, most likely due to an optimistic hypothesis of PFS improvement, resulting in a study including 86 patients which could be underpowered to detect a clinically meaningful difference. 5-azacytidine had a favourable safety profile compared to standard of care and was associated with prolonged overall survival, suggesting that this drug might have a role in the treatment of TFH PTCL and could be investigated in combination with other agents. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

The clinicopathological characteristics of C-MYC protein in angioimmunoblastic T-cell lymphoma.

To investigate the relationship between expression of C-MYC protein and clinicopathologic characteristics in angioimmunoblastic T-cell lymphoma (AITL), then discuss the prognosis. Patient samples were collected and made into tissue microarray for the same experimental condition. Pathomorphological features and immunohistochemistry of specific markers were used to determine the diagnosis of AITL. Epstein-Barr virus (EBV) infection was detected by EBV-encoded small RNA by in situ molecular hybridizations. B cells atypical hyperplasia was explored by the immunohistochemistry and gene rearrangement, C-MYC protein was expressed by the immunohistochemical staining and C-MYC gene abnormalities were detected by fluorescence in situ hybridization (FISH). 44 AITL patients were divided into two groups and the relation among C-MYC protein, EBV infection and B cells hyperplasia was observed. We followed up the overall survival rate (OS) and progression-free survival (PFS), and analyzed C-MYC protein, and the relationship between the prognosis of survival. Among 44 AITL patients, 29 cases (65.9%) were C-MYC protein-positive, and 32 (32/44, 72.3%) were EBV-positive. The expression rate of C-MYC protein in the high-risk group ranked by international prognostic index (IPI) and stage III-IV were higher than that in the low-risk group and stage I-II (P<0.05). The expression rate of C-MYC protein was higher in B cells excessive proliferation group, including simple hyperplasia, atypical hyperplasia, monoclonal B cells hyperplasia, and the diffuse large B lymphoma than in the low-proliferation group (P<0.05). The expression rate of C-MYC protein in EBV-positive patients was indifferent compared with the negative group (P>0.05). C-MYC gene rearrangement was not found in any samples, while the multi-copies of the C-MYC gene were found in only one case. As followed, 5-year OS was significantly low, and there was no significant difference in OS between the C-MYC protein-positive and negative groups. PFS in the positive group was significantly lower than that of the negative group. The difference in response to treatment between the two groups was statistically significant (P<0.05). We discussed the clinicopathologic characteristics and significance in AITLs, which predominantly express MYC-protein in <50% of cells, lacking C-MYC gene rearrangement. C-MYC protein-positive or negative expression was closely related to B cells excessive proliferation. C-MYC protein may be used as an indicator to judge the malignancy and to predict the prognosis of AITL.

A Case of Angioimmunoblastic T-cell Lymphoma Hidden in Plain Sight: A Delay in Diagnosis and Management

Angioimmunoblastic T-cell lymphoma (AITL) is an uncommon type of cluster of differentiation (CD)4 T-cell peripheral lymphoma. The varied clinical presentations of AITL present a challenge for accurate diagnosis. We present a case of a 57-year-old female with a history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in May 2020, who presented to the hospital in the summer of 2021 with shortness of breath for 3 months. She underwent an extensive workup for lymphadenopathy while in Canada involving multiple core lymph node biopsies, which were inconclusive. Here in our institution, several tests for infectious diseases were unremarkable. Imaging tests revealed bilateral pleural effusion, lymphadenopathies, and rectal thickening. Results from rectal biopsy and excisional cervical lymph node biopsy revealed findings typical of AITL. Due to worsening hypoxia with pleural fluid accumulation, bilateral chest tubes (PleurX catheter) were placed. Steroids and chemotherapy were started. She was discharged in stable condition to follow-up care. An integrated and persistent approach comprising clinical, morphologic, excisional biopsy, immunophenotyping, and molecular tests is essential in reaching a correct diagnosis of AITL. Through our consistent effort to obtain further imaging and tissue biopsies, we came to the diagnosis which allowed her to begin appropriate life-saving treatments.

Cytopathological characteristics of angioimmunoblastic T-cell lymphoma diagnosed by fine needle aspiration.

To analyse the cytopathological features of fine needle aspiration (FNA) in angioimmunoblastic T-cell lymphoma (AITL) diagnostics. Fine needle aspiration lymph node biopsy samples from 12 patients with AITL were collected at a single centre between January 2014 and December 2020. The clinical, cytological and histopathological characteristics were retrospectively analysed. Three male and six female patients with AITL who had a median onset age of 65years (range 51-74years) and a mean follow-up period of 29months (range 12-47 months) were included. The FNA cytological and morphological analysis of the reactive lymph node background revealed diffusely distributed non-homogeneous mixed lymphocytes, including mature small lymphocytes, medium-sized lymphoid cells, immune cells, and plasma cells; some mixed eosinophils, macrophages, and an occasional mixture of visible and medium-sized lymphocytes and epithelioid cells were observed. Mitotically active lymphocytes and sporadic pigmented bodies were observed occasionally. An abnormal proliferation of follicular dendritic cells observed under the microscope is important for AITL diagnosis, and these cells are often distributed in a scattered pattern of small clusters with many nuclear morphologies. Branched capillaries are another important diagnostic clue. Two patients with AITL who achieved clinical remission after treatment experienced recurrence and were diagnosed using FNA and cell block immunohistochemistry. Fine needle aspiration provides clues for the diagnosis of AITL in special clinical situations, and cell block immunohistochemistry is worthy of further exploration.

Human Germinal Center-associated Lymphoma (HGAL) Is a Reliable Marker of Normal and Neoplastic Follicular Helper T Cells Including Angioimmunoblastic T-Cell Lymphoma.

The diagnosis of angioimmunoblastic T-cell lymphoma (AITL) is complex and requires the demonstration of a T-follicular helper (TFH) phenotype. Immunophenotypic markers that detect the TFH phenotype are highly variable, thereby necessitating the use of 3 to 5 TFH markers to substantiate a TFH phenotype. We tested the utility of germinal center markers human germinal center-associated lymphoma (HGAL) and LIM-domain only 2 (LMO2) in detecting a TFH phenotype. We compared their staining to that of 6 TFH markers in current use, PD-1, ICOS, CXCL13, SAP, CD10, and BCL6, in a cohort of 23 AITL. Our results show that although both markers can detect a TFH phenotype, HGAL was superior to LMO2 in the percent of cells stained and the intensity of staining, 2 variables used to generate H-scores. Using H-scores as the metric, HGAL was most comparable to BCL6 among the currently used TFH markers and was more sensitive than CXCL13, SAP, CD10, and LMO2. PD-1 and ICOS emerged as the most robust of the 8 markers tested in this study in detecting a TFH phenotype. We conclude that HGAL is a reliable marker of TFH cells and can aid in the diagnosis of lymphomas of TFH derivation, particularly in the recognition of early patterns of AITL.

Fever, rash, and eosinophilia – early signs of angioimmunoblastic T-cell lymphoma

Angioimmunoblastic T-cell lymphoma (AITL) is an uncommon lymphoma of elderly adults with a poor prognosis. AITL patients show systemic symptoms, lymphadenopathy, and not infrequently, skin rash with various dysimmune phenomena rashes. The case is presented of a 68-year-old male with skin rash, lymphadenopathy and hypereosinophilia who, after investigations, was diagnosed with AITL. Despite the treatment used, the patient's condition gradually deteriorated and died due to heart and kidney failure. The diagnosis of AITL is often established only after several weeks or months because of transient physical findings, non-specific symptoms, and a broad range of serologic or radiologic abnormalities. Some patients with AITL experience non-specific dermatitis and eosinophilia. The presented case should raise awareness of the presentations of AITL which is important for physicians to reach an accurate diagnosis.

Angioimmunoblastic T‐cell lymphoma diagnosed from pleural fluid by integration of morphologic, immunophenotypic, and molecular findings

An 88-year-old man with end-stage renal disease on hemodialysis presented with shortness of breath and was found to have lower extremity edema and bilateral pleural effusions on a chest X-ray. A therapeutic and diagnostic thoracentesis was performed, and cytologic examination revealed atypical mononuclear cells. Based on this, flow cytometry was performed on the pleural fluid, along with immunostains on the cellblock and a next-generation sequencing (NGS) panel. A definitive diagnosis of angioimmunoblastic T-cell lymphoma (AITL) was made based on demonstrating an atypical T follicular helper cell population expressing CD10, BCL6, CXCL13, CD200, CD57, and PD1, and detection of pathogenic variants in RHOA, IDH2, and TET2. This case represents the first reported case where a primary diagnosis of AITL was made on a body fluid specimen and highlights how immunophenotyping and NGS can provide a definitive diagnosis of AITL on a cytologic specimen.

Measurement of PD-1 Expression on Lymphoma Cells By Flow Cytometry Is a Useful Tool in Diagnosing and Monitoring Minimal Residual Disease in Angioimmunoblastic T-Cell Lymphoma

Introduction: Angioimmunoblastic T-cell Lymphoma (AITL) is one of the most common types of peripheral T-cell lymphoma (PTCL), representing about 15-20% of cases of PTCL. Diagnosis of AITL is often challenging and a definitive diagnosis requires a use of ancillary testing including broad panels of immunohistochemistry and molecular studies. We evaluated the utility of evaluation of Programmed-Death-1 (PD-1) expression on lymphoma cells by flow cytometry as a diagnostic tool as well as monitoring minimal residual disease (MRD) of AITL.Methods: The study group was composed of 81 patients who were diagnosed with PTCL at Memorial Sloan Kettering Cancer Center between May 2015 and July 2017. This includes 36 patients with AITL, 6 with ALK-negative anaplastic large cell lymphoma (ALCL, ALK-), 2 with ALK-positive anaplastic large cell lymphoma (ALCL, ALK+), 9 with adult T-cell leukemia/lymphoma (ATLL), 11 with peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), 6 with nodal involvement by mycosis fungoides (MF), 5 with T-cell large granular lymphocytic leukemia (T-LGL), and 6 with T-cell prolymphocytic leukemia (T-PLL). The expression of PD-1 (CD279) on lymphoma cells was evaluated by 10-color flow cytometry using BV605-conjugated anti-CD279 antibody, and mean fluorescence intensity (MFI) was evaluated. Immunohistochemistry for PD-1, CD10, BCL6, and CXCR13 were also performed on tissue samples of AITL. Flow cytometry for variable regions of T-cell receptor beta chain (Vbeta) and genetic analysis for T-cell receptor gene rearrangement were performed on sorted abnormal T-cell population by flow cytometry in selected cases for the evaluation of clonality. Peripheral blood sample was used for the monitoring of MRD.Results: All AITL cases with tissue biopsy showed PD-1 immunoreactivity by immunohistochemistry (IHC), and PD-1 expression by flow cytometry showed excellent correlation with IHC. The abnormal CD4-positive PD-1 bright T-cell population detected by flow cytometry in AITL cases was confirmed to be clonal by restricted Vbeta fragment expression and molecular genetic analysis (Fig 1). On tissue samples, expression of other T-follicular helper cell markers was not observed by IHC in 7 cases (25%), and additional 3 cases (11%) presented with concomitant lymphoid neoplasm, which obscured morphologic and immunohistochemical evaluation for AITL. The latter 3 cases would be misdiagnosed by morphologic assessment alone. However, flow cytometry reliably detected AITL in all 10 challenging cases. Overall flow cytometry including PD-1 expression had 100% sensitivity in detection of AITL. The expression of PD-1 was significantly higher in AITL than that of other PTCL (CD279-BV605 MFI; Mean ± SEM; 6990.0 ± 934.9 vs. 547.3 ± 155.5; p<0.0001) (Fig 2A). PD-1 MFI differentiated AITL from other PTCL with high sensitivity and specificity (AUC 0.978; Fig 2B). The significant increase in PD-1 expression in AITL was a consistent finding with peripheral blood specimen. In 54 patients who had circulating lymphoma cells in peripheral blood, PD-1 expression was significantly higher in AITL than that of other PTCL (CD279-BV605 MFI; Mean ± SEM; 3079.0 ± 508.8 vs. 341.8 ± 54.17; p<0.0001: AUC 0.986) (Fig 2C, 2D). In 12 AITL patients who had tissue sample with concomitant bone marrow and peripheral blood specimens, flow cytometry detected lymphoma cells in bone marrow and peripheral blood in all patients. Among them, 9 patients were followed for monitoring of MRD. MRD in peripheral blood was not detected in 4 patients after therapy (Median 4.5 months; Range; 2-6 months); 2 patients received stem cell transplant, and 2 patients received chemotherapy only, and all 4 patients were free of disease at the time of last follow up (Median 18.5 months; Range 17-26 months). 5 patients kept having MRD after therapy (Median 13 months; Range: 3-21 months), and one of 5 patients presented with new lesion of AITL 12 months after the initial diagnosis.Conclusions: Flow cytometric immunophenotyping with anti-PD-1 antibody reliably detects neoplastic population in AITL cases, and PD-1 MFI differentiates AITL from other PTCL with high sensitivity and specificity. Bright PD-1 expression alone is a reliable indicator of TFH immunophenotype by flow cytometry. Measurement of PD-1 expression by flow cytometry is a useful tool both in diagnosing and monitoring MRD of AITL. [Display omitted] DisclosuresMoskowitz:ADC Therapeutics: Research Funding; Seattle Genetics: Honoraria, Research Funding; Bristol Myers-Squibb: Consultancy, Research Funding; Takeda: Honoraria; Incyte: Research Funding. Horwitz:Seattle Genetics: Consultancy, Research Funding; Millenium/Takeda: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; ADCT Therapeutics: Research Funding; Kyowa-Hakka-Kirin: Consultancy, Research Funding; Forty-Seven: Consultancy, Research Funding; Infinity/Verastem: Consultancy, Research Funding; HUYA: Consultancy; BMS: Consultancy; Mundipharma: Consultancy; Aileron Therapeutics: Research Funding. Dogan:Celgene: Consultancy; Roche Pharmaceuticals: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Peer Review Institute: Consultancy.

Markers of Follicular Helper T Cells Are Occasionally Expressed in T-Cell or Histiocyte-Rich Large B-Cell Lymphoma, Classic Hodgkin Lymphoma, and Atypical Paracortical HyperplasiaA Diagnostic Pitfall For T-Cell Lymphomas of T Follicular Helper Origin.

Follicular helper T cell (TFH) markers are expressed in angioimmunoblastic T-cell lymphoma (AITL) and peripheral T-cell lymphoma of the TFH phenotype (PTCL-TFH). However, differential expression and coexpression of these markers in benign and other malignant lymphoid proliferations have not been well studied. We performed programmed death-1 (PD-1), C-X-C motif chemokine ligand 13 (CXCL13), inducible costimulator (ICOS), CD10, and B-cell lymphoma 6 protein (BCL-6) immunohistochemistry on AITL, PTCL not otherwise specified (PTCL-NOS), PTCL-TFH, T-cell or histiocyte-rich large B-cell lymphoma (THRLBCL), classic Hodgkin lymphoma (CHL), atypical paracortical hyperplasia (PCH), progressive transformation of germinal centers (PTGC), and reactive follicular hyperplasia (RFH). CXCL13 and ICOS were more sensitive but less specific for AITL than PD-1, CD10, and BCL-6. Moreover, 74% of AITL (none of PTCL-NOS or PTCL-TFH) coexpressed more than 2 TFH markers. In background T cells of THRLBCL, 70% of cases coexpressed more than 1 marker. The background T cells of CHL expressed all TFH markers except CD10 in all cases. In addition, 13% of PCH cases coexpressed more than 1 marker. In RFH and PTGC, all markers were expressed mainly in germinal centers with rare extrafollicular staining. AITL, PTCL-NOS, and PTCL-TFH show differential expression of TFH markers. AITL frequently coexpresses more than 2 TFH markers. TFH markers can be expressed in PCH and in background T cells of THRLBCL and CHL. Consequently, caution should be used before a diagnosis of AITL is established, particularly with limited samples.

Combination of multicolor flow cytometry for circulating lymphoma cells and tests for the RHOAG17V and IDH2R172 hot-spot mutations in plasma cell-free DNA as liquid biopsy for the diagnosis of angioimmunoblastic T-cell lymphoma

We applied two-step multicolor flow cytometry (FCM) for circulating lymphoma cells in the blood of 20 patients with angioimmunoblastic T-cell lymphoma (AITL) and confirmed neoplastic T-cells in all. Eleven exhibited dim expression of CD3 and 7 lost its expression. The proportion of CD10+ lymphoma cells ranged widely from 0 to 100%, with a median of 15.7%. Ten patients demonstrated expansion of a single T-cell receptor β-chain repertoire. Lymphoma cells comprised 0.01 to 18.22% (median, 0.26%) of white cells and the absolute numbers ranged from 0.5 to 1491.6 cells (median, 29.3 cells) per microliter of blood. We next found that 14 (70%) and 3 (15%) patients carried RHOAG17V and IDH2R172 mutations, respectively, in cell-free DNA (cfDNA) in the plasma. The combination of multicolor FCM of the blood, and tests for RHOAG17V and IDH2R172 hot-spot mutations in plasma cfDNA provides a blood-based ‘liquid biopsy’ for the diagnosis of AITL.

1505 Relapsed Angioimmunoblastic T-Cell Lymphoma Presenting as Severe Colitis With Bowel Perforation

INTRODUCTION: Angioimmunoblastic T-cell lymphoma (AITL) is a subtype of the uncommon peripheral T-cell lymphomas that usually presents as acute onset of systemic B symptoms and generalized lymphadenopathy. Here, we report a case of a woman with relapsed AITL involving the descending, sigmoid colon, and rectum, presenting as persistent diarrhea and bowel perforation. CASE DESCRIPTION/METHODS: A 78-year-old woman who was diagnosed with AITL in 2002 and had been stable on continuous therapy of romidepsin for the past 2.5 years for relapsed disease, presented with a 6-week history of diarrhea, fatigue, and decreased appetite. The diarrhea was watery, non-bloody, occurred 4-5 times a day, with fecal urgency and incontinence. The patient denied any abdominal pain, nausea, vomiting, or fever. There was no recent change in her medications, and no recent history of travel or contact with children or pets. During the 6-week period, she was hospitalized twice and was initially thought to have infectious colitis, for which she was given ciprofloxacin, metronidazole, and re-hydration therapy. Abdominal CT showed severe left-sided colitis with multiple enlarged perirectal and mesenteric lymph nodes. Upon her third admission, infectious etiologies were ruled-out and sigmoidoscopy showed markedly edematous and erythematous rectum. Biopsies from the rectum and sigmoid colon showed dense atypical T-cell infiltration consistent with involvement of her previous AITL. Her hospital course was further complicated by bowel perforation and polymicrobial positive blood cultures. She refused surgery and was referred to home hospice for palliative care. DISCUSSION: AITL is an aggressive peripheral T-cell lymphoma that is believed to arise from CD4 positive follicular helper T-cells. It accounts for 1-2% of non-Hodgkin lymphoma cases and has a higher incidence among Asian/Pacific Islanders and Hispanic Whites in the United States. Initial presentation commonly includes generalized lymphadenopathy, fever, unintentional weight loss, and night sweats. With progression, it can commonly involve the bone marrow, spleen, skin and soft tissues. However, gastrointestinal involvement is rare. In 1996, Goenka et al. reported AITL presenting as colonic polyps. We are reporting a case of AITL progressing to involve the descending, sigmoid colon, and rectum, whose presentation was initially mistaken for infectious colitis. However, due to high clinical suspicion, sigmoidoscopy was performed and biopsies confirmed the diagnosis of AITL of the colon.

2790 Autoimmune Hemolytic Anemia and a Gastric Mass in a Patient With Acute Epstein-Barr Virus

INTRODUCTION: Angioimmunoblastic T-cell Lymphoma (AITL) is a rare peripheral T-cell lymphoma. This is the first reported case of AITL presenting with a gastric mass. There is an association with Epstein-Barr Virus (EBV), though its role in pathogenesis is unclear. CASE DESCRIPTION/METHODS: A 64-year-old female presented for abdominal pain with a suspicious gastric mass and lymphadenopathy. She developed autoimmune hemolytic anemia during the hospital course with Coombs testing revealing mixed warm and cold agglutinins. Anti-smooth muscle antibody was positive along with serology consistent with an acute EBV infection. Gastric mass biopsy returned inconclusive. Steroids were indicated but held given suspicion for lymphoma and need for accurate tissue samples. A blood transfusion was given and resulted in an appreciable increase in bilirubin level. Following lymph node resection, methylprednisolone was given and the patient’s hemoglobin stabilized. A tissue diagnosis of AITL was made and chemotherapy led to subsequent improvement in her anemia. DISCUSSION: Since AITL was first described in the 1970s, there has been a clear association with auto-immune phenomenon and correlation with EBV. This is the fourth reported case presenting with an acute EBV infection and the first presenting as a gastric mass.1,2 The presence of active EBV infection could potentially steer away from more insidious processes.1 Unfortunately, AITL is aggressive and has a bleak prognosis. Despite advancing treatments, median survival is only 3 years.3,4 The presence of active EBV infection can lead to misdiagnosis as there is some overlap in symptoms and presentation. High suspicion must be maintained for malignancy with this constellation of unusual hematological abnormalities.

Molecular diagnosis angioimmunoblastic T-cell lymphoma

to determine molecular diagnostics routine for different tissue samples in angioimmunoblastic T-cell lymphoma. Molecular studies were performed for 84 primary AITL patients. The median age was 61 year (29-81); the male to female ratio was 48/36. T-cell and B-cell clonality was assessed by GeneScan analysis of rearranged T-cell receptor (TCRG, TCRB) and immunoglobulin heavy chain genes. For the quantitative determination of cells with RHOA G17V mutation real - time polymerase chain reaction (PCR) with allele - specific LNA modified primers was used. In lymph nodes rearrangements of T-cell receptor genes were determined in 76 (90.5%) of 84 patients and were absent in 8 (9.5%) cases. Identification of the same clonal products of the TCRG and TCRB genes in the lymph node and in peripheral blood and/or bone marrow indicated the prevalence of the tumor process and was observed in 64.7% of patients. Clonal products in peripheral blood and/or bone marrow different from those in the lymph node indicated reactive cytotoxic lymphocyte population and were noted in 58.8% of AITL cases. Simultaneous detection of T- and B-cell clonality in the lymph node was observed in 20 (24.7%) of 81 patients. Cells with RHOA G17V mutation were detected in lymph node in 45 (54.9%) of 82 patients. The use of allele - specific PCR with LNA modified primers revealed presence of the tumor cells in peripheral blood in 100% and in bone marrow in 93.9% of patients with G17V RHOA mutation in the lymph nodes. The validity of different molecular assays performed on certain tissue samples for the diagnosis of angioimmunoblastic T-cell lymphoma has been evaluated. Quantitative allele - specific PCR assay for RHOA G17V mutation based on LNA modified primers possesses sufficient sensitivity for tumor process prevalence evaluation and minimal residual disease monitoring.

PB1785 BLOOD COUNTS AND BONE MARROW ASPIRATE MORPHOLOGY IN PRIMARY PATIENTS WITH ANGIOIMMUNOBLASTIC T‐CELL LYMPHOMA.

Background:Angioimmunoblastic T‐cell lymphoma (AITL) is a rare T‐cell lymphoma characterized by a pronounced reactive microenvironment, represented by B and T lymphocytes, eosinophils and histiocytes. In most cases, infection of B‐immunoblasts with Epstein‐Barr virus (EBV) is noted. Anemia, leukopenia, thrombocytopenia and gammopathy could develop through the disease course. Futhermore tumor cells could appear in peripheral blood and bone marrow. Therefore examination of blood smears and bone marrow aspirates is an crucial step in the initial diagnosis and staging in AITL.Aims:To correlate cell composition of peripheral blood (PB) and bone marrow (BM) samples with the the presence of RHOA gene (G17 V) mutation in tumor cells, small non‐coding EBV RNA in the lymph node biopsy specimen and bone marrow involvement in primary patients with AITL.Methods:The study includes 53 primary patients with AITL, admitted to the National Research Center for Hematology between 2002 and 2018. The diagnosis of AITL was based on the morphological study of the lymph node biopsy according to the criteria of the WHO classification 2017. A morphological study of BM biopsy was performed in 52 patients. RHOA gene (G17 V) point mutation was tested in 51 patients using quantitative allele‐specific real‐time PCR. The expression of small non‐coding EBV (EBER) RNA in lymph node biopsy specimens was determined in 43 patients by in situ hybridization. A complete blood count was performed on a Sysmex‐XT 4000i automated analyzer, the leukocyte counts were calculated using a PB smear. For BM counts were used 2 smears of BM aspirate (Pappenheim stain).Results:Anemia (52.8%), an increase in relative counts of granulocytes and lymphocytes for more than 4 times (51.9%), thrombocytopenia (43.4 %) were most frequently observed in PB. Absolute and relative lymphopenia was detected in 44.2% and 51.9% of patients, respectively. Plasma cells in PB were found in 11.5% of cases. The prevalence of the relative number of granulocytes over lymphocytes more than 4 times (82.2%) and abnormal leuco‐erythroblastic ratio (66.7%) were most often detected in BM. A decrease of erythroid lineage was observed in 48.9% of patients, that was combined with anemia of varying severity in 26.7% of cases. In patients with morphological involvement of the BM, anemia and thrombocytopenia were significantly more frequent (p = 0.0001, p = 0.002, respectively). Plasma cells in PB were found only in cases with morphological involvement of the BM (p = 0.01). Also, in this group of patients, a decrease in granulocyte lineage in the BM was significantl(p = 0.04). In patients with RHOA gene (G17 V) mutation, the average hemoglobin level was significantly lower than in patients without mutation (p = 0.01). Anemia was significantly more frequent (p = 0.04) in PB of EBER‐positive patients. On the other hand in EBER‐negative group of patients leukopenia and neutropenia where more frequent (p = 0.01 and p = 0.02, respectively).Summary/Conclusion:Appearance of plasma cells in the PB is associated with the morphological involvement of the BM in AITL. This finding could be possibly used as a new non‐invasive marker of BM involvement in AITL. Furthermore differences in PB and BM counts were associated with small non‐coding EBV RNA, the G17 V mutation of the RHOA and BM morphology.

A Rare Entity of Angioimmunoblastic T-Cell Lymphoma

Introduction: Angioimmunoblastic T Cell Lymphoma (AITL) is a well-recognized subtype of peripheral T cell lymphoma. It occurs predominantly in the lymph nodes with presence of systemic symptoms and carries a dismal prognosis. AITL accounts for about 1% - 2% of all cases of non-Hodgkin lymphoma. Case presentation: A 59-year-old gentleman of Chinese ethnicity with no prior medical illness presented to Tengku Ampuan Afzan Hospital with a two-month history of fever, anorexia, unintentional weight loss and generalized lymphadenopathies. Physical examination revealed diffuse lymphadenopathies involving the cervical, axillary and inguinal regions bilaterally. He had hepatosplenomegaly. An excisional biopsy of the cervical and inguinal lymph nodes was compatible with AITL. The bone marrow biopsy demonstrated disease infiltration. He was treated with 6 cycles of Etoposide-CHOP (cyclophosphamide, doxorubicin, vincristine, prednisolone) induction chemotherapy followed by consolidation high dose therapy-autologous stem cell transplant (HDT-ASCT). He achieved complete remission on 18-Fluoro- deoxyglucose Positron Emission Tomography (18-FDG-PET) imaging. His bone marrow biopsy showed disease clearance. Conclusion: The diagnosis of AITL remains challenging and often poses a dilemma to clinicians and lymphoma pathologists. The natural history of AITL remains very variable with many of them relapsing subsequently despite achieving prior complete remission.

Lenalidomide in Combination with CHOP in Patients with Angioimmunoblastic T-Cell Lymphoma (AITL): Final Analysis of Clinical and Molecular Data of a Phase 2 Lysa Study

Lenalidomide in Combination with CHOP in Patients with Angioimmunoblastic T-Cell Lymphoma (AITL): Final Analysis of Clinical and Molecular Data of a Phase 2 Lysa Study