Follicular Helper T Cells Research Articles

Pre-treatment 18f-FDG PET/CT for Assessing and Predicting Bone Marrow Involvement in Patients with Newly Diagnosed Peripheral T-Cell Lymphoma

Objective: To explore the value of 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in assessing and predicting bone marrow involvement (BMI) in patients with newly diagnosed peripheral T-cell lymphoma (PTCL) prior to treatment. Methods: This retrospective study included 201 eligible patients of PTCL who received bone marrow biopsy (BMB) and PET/CT between January 2017 and December 2022. Extra subgroup analysis was designed considering the variation of avidity of FDG in different distinct entities. The status of bone marrow (BM) by PET was assessed using a visual examination and a quantitative index (the highest SUV of BM divided by the mean SUV of the liver [M/L]). Prognostic value of BM findings was also evaluated regarding progression free survival (PFS) and overall survival (OS). Results: The sensitivity and specificity of PET/CT for patients with confirmed PTCL by BMB were 43.2% and 90.2%, respectively. As for subgroup analysis, the kappa value reflecting the agreement between BMB and visual analysis in angioimmunoblastic T-cell lymphoma (AITL), peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), anaplastic large cell lymphoma (ALCL) as well as nodal T-follicular helper (TFH) cell lymphoma (PTCL-TFH) was 0.315, 0.307, 0.426 and 0.581, respectively. (Give the number of cases in each lymphoma group) PET score was an independent factor for PFS (P =0.011) but not for OS (P =0.840). In addition, 25 patients with stage I to II disease had no evidence of BMI by either PET/CT or BMB. Image-guided biopsy was also recommended when PET/CT showed a focal FDG uptake outside the iliac crest. Quantitative analysis revealed the differences in the two-level of M/L; however, they were not statistically significant for both PFS and OS (P =0.246 and P =0.227). Conclusion: PET/CT has a complementary role in assessing BMI and prognosis in PTCL patients.

Prognostic Significance of CD30 Expression and Response to Brentuximab Vedotin in Patients with Angioimmunoblastic T Cell Lymphoma

Background Angioimmunoblastic T-cell lymphoma (AITL) is a subtype of peripheral T-cell lymphoma (PTCL) characterized by a follicular helper T-cell phenotype. The standard frontline treatment for AITL typically involves CHOP or CHOP-like regimens, with consideration for autologous stem cell transplant. A promising treatment option for CD30-positive (CD30+) PTCLs, including AITL, is the anti-CD30 antibody drug conjugate, brentuximab vedotin (BV). The ECHELON-2 study demonstrated equivocal outcomes in CD30+ PTCL patients (pts) who received BV-CHP instead of CHOP. However, response of BV in CD30+ AITL pts is still uncertain. This study aims to evaluate the relationship between CD30 expression and the clinical response to BV in pts diagnosed with AITL. Methods This retrospective IRB approved study conducted at MD Anderson Cancer Center, where we analyzed pts with AITL diagnosed between 1997- 2023. Patient demographics, laboratory data at diagnosis, pathology review, treatment, and treatment response were collected and analyzed. Expression of CD30 expression in neoplastic cells was evaluated by immunohistochemistry and scored in 5% increments. Kaplan- Meier method was used to assess overall survival (OS) and log-rank used to compare different groups. Results This study included a cohort of 339 pts with AITL. Among them, 55 (23%, n=237) had no detectable CD30 expression (CD30=0%),182 (77%, n=237) patients had detectable CD30 expression (CD30>1%), and 102 pts had unknown CD30 expression. Table 1 shows patient characteristics by CD30 expression and response to first-, second-, and third- line BV treatment. There were 113 (48%, n=237) females and 124 (52%, n=237) males with a median age of 66 years. Most patients were Whites (88%, n=196) followed by Black (4%, n=196), and Asian (5%, n=196). Fifty-two (n=122) of pts who were CD30+ had stage III, 43% (n=122) had stage IV (p-value= <0.001), and 38% had BM involvement (p- value= 0.3). For pts with disease showing no CD30 expression (CD30neg) 16% (n=43) of pts had stage III, 70% (n=43) had stage IV, and 48% (n=42) had BM involvement. Auto-Stem cell transplant (ASCT) was performed in 48% of those with CD30+ and 43% of CD30neg. The most common first-line treatment was chemotherapy combination of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) followed by other CHOP like regimens. In total, 35 pts received BV treatment as first-line, 32 patients received BV in combination with chemotherapy and 3 received BV only. For second-line treatment, 11 received BV treatment and for third- line only 6 received BV. First- line treatment with BV showed better clinical response rates, with 82% achieving complete response (CR, n= 34), followed by second line CR with 56% (n= 9) and third- line with 0% (n= 6). The median OS were similar between those with CD30+ who did or did not receive first line BV (20 months vs. 19 months, p>0.05). The median OS for CD30neg pts who did not receive BV was 25 months (p=0.42). Furthermore, there was no statistically significant difference in OS between pts who underwent a ASCT (CD30+ 24.5 months and CD30neg 32.5 months, respectively) and those who did not (CD30+ 18.5 months and CD30neg 24.5 months, respectively, p- value = 0.29). Conclusion While this study did not find CD30 expression to be a predictor of response to BV treatment or ASCT in AITL pts, it provides valuable insights into the prevalence of CD30 expression and BV response as first- line treatment. Notably, 77% of pts had CD30 expression and pts who received BV as first- line had a higher proportion of CRs compared to pts who received BV as second- and third- line treatments. Further investigations with larger patient cohorts are necessary to determine the prognostic and predictive role of CD30 in AITL. Additional studies analyzing CD30 expression levels in malignant cells, immunoblasts, and macrophages are planned for presentation at the upcoming annual meeting.

TP53 and CDKN2A alterations Define a Poor Prognostic Subgroup in Patients with Nodal T-Follicular Helper Cell Lymphoma

Nodal T-follicular helper cell lymphoma (nTFHL) is a subset of peripheral T-cell lymphoma (PTCL) characterized by a distinct immunophenotype (such as CD10, BCL6, CXCL13, PD1, and ICOS) and mutations (including TET2, RHOA G17V, and IDH2 R172). However, the impact of molecular classification based on genetic profiling on prognosis in nTFHL remains largely unknown. Here we performed targeted-capture sequencing (targeted-seq) covering 235 T/NK-cell lymphoma-related genes with a mean depth of 526×. Then, we analyzed 49 genes which were reported as drivers in the previous PTCL studies to reveal the associations between clinical phenotypes and somatic alterations in a cohort of 153 patients whose clinical information was available and who were pathologically diagnosed with nTFHL according to the WHO-HAEM5. When mutation and copy number alteration (CNA) data were combined, we identified recurrent alterations in 40 among 49 driver genes. TET2 was most frequent (68%), followed by RHOA (51%), IDH2 (27%), DNMT3A (20%), PLCG1 (9%), TP53 (7%), KMT2C (6%), VAV1 (6%), CD28 (6%), KMT2D (6%), NOTCH1 (5%), and CDKN2A (5%). To create a molecular classification based on genetic alterations in nTFHL, we conducted hierarchical clustering using driver alterations and arm-level CNAs. This analysis identified four molecular subgroups named after their characteristic genetic alterations ( Fig. 1A). TR-ID (+) ( n = 52) and TR-ID (-) ( n = 60) were defined by TFH-related mutations ( TET2 and RHOA). Among them, TR-ID (+) harbored IDH2 and/or DNMT3A mutations. A53 ( n = 8) was notable for biallelic inactivation of TP53 and/or CDKN2A and associated with marked aneuploidy. NSD ( n = 33) had no subgroup-defining alterations with the fewest number of mutations. Clinically, TR-ID (+) tumors were mostly nTFHL-angioimmunoblastic-type (AI), which is consistent with the enrichment of IDH2 and/or DNMT3A mutations. On the other hand, TR-ID (-) tumors exhibited a higher proportion of nTFHL-NOS. NSD exhibited lower LDH levels and was significantly associated with younger age and localized stage than other subgroups. A53 showed the worst prognosis with a median overall survival (OS) of 15.1 months (mos) ( Fig. 1B). By contrast, the OS of NSD was significantly superior to the others (median OS not reached). The OS of TR-ID (+) and TR-ID (-) was comparable with a median OS of 40.6 and 46.4 mos, respectively. Notably, A53 remained significant in multivariate analyses adjusted for IPI or PIT score. Thus, genetic profiling enables to classify nTFHL patients into genetically and clinically distinct subgroups, including the unfavorable prognostic subgroup (A53). Next, to identify potential genes linked to the poor prognosis of the A53 subtype, we examined the prognostic impact of individual alterations. Among the genes examined, TP53 and CDKN2A, hallmarks of A53, were significantly associated with shorter OS in univariate analysis. Consequently, cases with TP53 and/or CDKN2A alterations showed a poor prognosis (median OS 11.4 vs 181.2 mos, P = 8.2×10 -7), thereby reinforcing the negative prognostic impact of A53. Then, we investigated other prognostic factors within each molecular subgroup. First, in TR-ID (+) and (-) cases, we examined the EBV status, which was known to be associated with worse prognosis in nTFHL-AI. Among them, 22 (16%) cases were EBV-positive. Despite no observed differences in genetic and clinical factors, EBV-positive cases exhibited a worse prognosis (median OS 66.5 vs 14.9 mos, P = 0.0018). Next, we assessed the influence of TCR clonality on prognosis in NSD cases. The clonal T-cell fraction assessed by targeted-seq was highest in A53 (median, 75%) but lowest in NSD (median, 16%). OS of NSD cases was further stratified by T-cell clonality (median OS not reached vs 67.7 mos for low and high clonal T-cell fraction; P = 0.042), while the presence of driver alterations failed to predict the prognosis. These findings suggest that assessment of T-cell clonality helps to identify the favorable prognostic subgroup characterized by low tumor content. In summary, we defined four molecular subgroups with different clinical features and also clarified subgroup-specific prognostic factors in nTFHL. Particularly, we identified the molecular subgroup with unfavorable prognosis (A53) for which different clinical approach should be warranted. This classification will refine the patient prognostication and stratification in nTFHL.

Angioimmunoblastic T-cell lymphoma and Kaposi sarcoma: A fortuitous collision?

Follicular helper T-cell (TFH) lymphoma of the angioimmunoblastic-type (AITL), one of the most prevalent T-cell lymphomas, typically encompasses proliferation of high endothelial venules and Epstein-Barr virus-positive immunoblasts, but neither infection with HHV8 nor association with Kaposi's sarcoma (KS) have been described. The aims of this study are to characterise the association between AITL and HHV8 infection or KS. Three male patients aged 49-76 years, HIV-negative, with concurrent nodal involvement by AITL and KS, were identified from our files and carefully studied. Two patients originated from countries where endemic KS occurs, including one with cutaneous KS. The lymphomas featured abundant vessels, expanded follicular dendritic cells and neoplastic TFH cells [PD1+ (three of three), ICOS+ (three of three), CXCL13+ (three of three), CD10+ (two of three), BCL6 (two of three)] but lacked EBV+ immunoblasts. The foci of KS consisted of subcapsular proliferations of ERG+, CD31+ and/or CD34+ , HHV8+ spindle cells. High-throughput sequencing showed AITL-associated mutations in TET2 (three of three), RHOA (G17V) (three of three) and IDH2 (R172) (two of three), which were absent in the microdissected KS component in two cases. Relapses in two patients consisted of AITL, without evidence of KS. No evidence of HHV8 infection was found in a control group of 23 AITL cases. Concurrent nodal involvement by AITL and KS is rare and identification of both neoplastic components may pose diagnostic challenges. The question of whether the association between AITL and KS may be fortuitous or could reflect the underlying immune dysfunction in AITL remains open.

Past, present and future therapeutic approaches in nodal peripheral T-cell lymphomas.

Peripheral T-cell lymphomas (PTCL) encompass over 30 different entities and although they share post-thymic T- or NK-cell derivation, the disease biology and genomic landscape are very diverse across subtypes. In Western populations, nodal PTCL are the most frequently encountered entities in clinical practice and although important achievements have been made in deciphering the underlying biology and in therapeutic advances, there are still large gaps in disease understanding and clinical scenarios in which controversy over best practice continues. CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone)- based chemotherapy continues to be the 'standard' treatment, with the addition of brentuximab vedotin (BV) in the combination CHP (cyclosphosphamide, doxorubicin, prednisone)-BV representing a new treatment paradigm in CD30+ PTCL although its benefit is less certain in the non-anaplastic large cell lymphoma subtypes. Given the high risk of relapse, consolidative autologous stem cell transplant is considered in nodal PTCL, outside of ALK-positive anaplastic large cell lymphoma; however, in the absence of a randomized controlled trials, practices vary. Beyond CHP-BV, most study activity has focused on adding a novel agent to CHOP (i.e., CHOP + drug X). However, with high complete remission rates observed with some novel therapy combinations, these regimens are being tested in the front-line setting, with a particular rationale in follicular helper T-cell lymphomas which have a clear sensitivity to epigenetic modifying therapies. This is well exemplified in the relapsed/refractory setting in which rational combination therapies are being developed for specific subtypes or guided by underlying biology. Taken together, we have finally moved into an era of a more personalized approach to the management of nodal PTCL.

Increased development of T-bet+CD11c+ B cells predisposes to lupus in females: Analysis in BXD2 mouse and genetic crosses

Cardinal features of lupus include elevated B cell activation and autoantibody production with a female sex preponderance. We quantified interactions of sex and genetic variation on the development of autoimmune B-cell phenotypes and autoantibodies in the BXD2 murine model of lupus using a cohort of backcrossed progeny (BXD2 x C57BL/6J) x BXD2. Sex was the key factor leading to increased total IgG, IgG2b, and autoantibodies. The percentage of T-bet+CD11c+ IgD+ activated naive B cells (aNAV) was higher in females and was associated with increased T-bet+CD11c+ IgD− age-related B cells, Fas+GL7+ germinal center B cells, Cxcr5−Icos+ peripheral T-helper cells, and Cxcr5+Icos+ follicular T-helper cells. IFN-β was elevated in females. Variation in aNAV cells was mapped to Chr 7 in a locus that shows significant interactions between the female sex and heterozygous B/D variant. Our results suggest that activation of naive B cells forms the basis for the female-predominant development of autoantibodies in lupus-susceptible BXD2 mice.

IL6 suppresses vaccine responses in neonates by enhancing IL2 activity on T follicular helper cells

The inability of neonates to develop CD4+FoxP3-CXCR5hiPD-1hi T follicular helper (TFH) cells contributes to their weak vaccine responses. In previous studies, we measured diminished IgG responses when IL-6 was co-injected with a pneumococcal conjugate vaccine (PCV) in neonatal mice. This is in sharp contrast to adults, where IL-6 improves vaccine responses by downregulating the expression of IL-2Rβ on TFH cells and protecting them from the inhibitory effect of IL-2. In this study, we found that splenic IL-6 levels rapidly increased in both adult and neonatal mice following immunization, but the increase in neonatal mice was significantly more than that of adult mice. Moreover, immunized neonatal TFH cells expressed significantly more IL-2 as well as its receptors, IL-2Rα and IL-2Rβ, than the adult cells. Remarkably, IL-6 co-injection with PCV vaccine further increased the production of IL-2 and the expression of its receptors by neonatal TFH cells, whereas excess IL-6 had totally opposite effect in immunized adult mice. Underscoring the role of IL-6 in activating the IL-2 mediated suppression of vaccine responses, immunization of IL-6 knock-out neonates led to improved antibody responses accompanied by expanded TFH cells as well as lower levels of IL-2 and IL-2 receptors on TFH cells. Moreover, CpG containing PCV improved TFH response in neonates by suppressing the expression of IL-2 receptors on TFH cells and inhibiting IL-2 activity. These findings unveil age-specific differences in IL-6 mediated vaccine responses and highlight the need to consider age-related immunobiological attributes in designing vaccines.

Progressively transformed germinal center-like follicular T-cell lymphoma:a clinicopathological analysis of 14 cases

Objective: To investigate the clinicopathologic features of progressively transformed germinal center-like follicular T-cell lymphoma (PTGC-like FTCL). Methods: The clinicopathologic data of 14 PTGC-like FTCL cases that were diagnosed at the Beijing Friendship Hospital Affiliated to the Capital Medical University from January 2017 to January 2022 were retrospectively collected. Clinicopathological features, immunophenotype, and Epstein-Barr virus (EBV) infection status were analyzed in these cases. Polymerase chain reaction (PCR) was performed to detect the clonal gene rearrangements of T cell receptor (TCR) and the immunoglobulin (Ig) in 10 and 8 cases, respectively. Results: The male to female ratio was 5∶2. The median age was 61 years (range 32-70 years). All patients had lymphadenopathy at the time of diagnosis. By using the Ann Arbor system staging, seven cases were classified as stage Ⅰ-Ⅱ, and seven cases as stage Ⅲ-Ⅳ. Seven cases had B symptoms, four cases had splenomegaly, and two cases had skin rash and pruritus. Previously, three cases were diagnosed as classic Hodgkin's lymphoma, three cases as small B-cell lymphoma, two cases as atypical lymphoid hyperplasia unable to exclude angioimmunoblastic T-cell lymphoma (AITL), one case as EBV-associated lymphoproliferative disorder, and one case as peripheral T-cell lymphoma (PTCL) associated with the proliferation of B cells. All the 14 cases showed that the large nodules were composed of mature CD20+, IgD+B lymphocytes admixed with small aggregates of neoplastic cells with pale to clear cytoplasm. Moreover, hyperplastic germinal centers (GCs) and Hodgkin/Reed-Sternberg-like (HRS-like) cells were seen within these nodules in two and five cases, respectively. The neoplastic cells expressed CD3 (14/14), CD4 (14/14), PD1 (14/14), ICOS (14/14), CD10 (9/14), bcl-6 (12/14), CXCL13 (10/14), and CD30 (10/14). The HRS-like cells in five cases expressed CD20 (2/5), PAX5 (5/5), CD30 (5/5), CD15 (2/5), LCA (0/5), OCT2 (5/5) and BOB1 (2/5). Moreover, neoplastic T cells formed rosettes around HRS-like cells. EBV-encoded RNA (EBER) in situ hybridization showed scattered, small, positive bystander B lymphocytes in 8/14 cases, including 3/5 cases containing HRS-like cells. All tested cases (including five with HRS-like cells) showed monoclonal TCR gene rearrangement and polyclonal Ig gene rearrangement. Conclusions: PTGC-like FTCL is a rare tumor originated from T-follicular helper cells. It could be distinguished from angioimmunoblastic T-cell lymphoma by the formation of follicular structure, and lack of follicular dendritic cell proliferation outside the follicles and the polymorphous inflammatory background. In addition, it should be differentiated from lymphocyte-rich classical Hodgkin's lymphoma and low-grade B cell lymphoma.

Persistent Hypogammaglobulinemia after Receiving Rituximab Post-HSCT Is Not Caused by an Intrinsic B Cell Defect.

In the setting of hematopoietic stem cell transplantation (HSCT), Rituximab (RTX) is used for the treatment and prevention of EBV-associated post-transplantation lymphoproliferative disease or autoimmune phenomena such as autoimmune hemolytic anemia (AIHA). Persistent hypogammaglobulinemia and immunoglobulin substitution dependence has been observed in several patients after RTX treatment despite the normalization of total B cell numbers. We aimed to study whether this is a B cell intrinsic phenomenon. We analyzed four patients with different primary diseases who were treated with myeloablative conditioning and matched unrelated donor HSCT who developed persistent hypogammaglobulinemia after receiving RTX treatment. They all received RTX early after HSCT to treat EBV infection or AIHA post-HSCT. All patients showed normalized total B cell numbers but absent to very low IgG positive memory B cells, and three lacked IgA positive memory B cells. All of the patients had full donor chimerism, and none had encountered graft-versus-host disease. Sorted peripheral blood naïve B cells from these patients, when stimulated with CD40L, IL21, IL10 and anti-IgM, demonstrated intact B cell differentiation including the formation of class-switched memory B cells and IgA and IgG production. Peripheral blood T cell numbers including CD4 follicular T-helper (Tfh) cells were all within the normal reference range. In conclusion, in these four HSCT patients, the persistent hypogammaglobulinemia observed after RTX cannot be attributed to an acquired intrinsic B cell problem nor to a reduction in Tfh cell numbers.

Cumulative Incidence of Myeloid Neoplasms in Patients with Nodal T-Follicular Helper Cell Lymphoma

Introduction: Certain T-cell lymphomas (TCL), in particular nodal T-follicular helper (TFH) cell lymphomas, including angioimmunoblastic TCL (AITL), commonly develop on a background of mutations identified in clonal hematopoiesis (CH). Divergent clonal evolution can result in both nodal TFH cell lymphomas and myeloid neoplasms (MN). As peripheral TCLs are commonly treated with combination and dose intensive chemotherapy, there is a risk that these therapies could promote an evolution to MN. The frequency at which this occurs is unclear. Methods: We conducted a retrospective search for any patient with an International Classification of Disease (ICD) code referring to a TCL. Then, we identified patients with a concomitant ICD code referring to either myelodysplastic syndromes (MDS), acutemyeloid leukemia (AML), or a myeloproliferative neoplasm (MPN). Once the initial query was performed, we individually reviewed each patient and included only patients meeting the following criteria: (1) A histologically-confirmed diagnosis of either peripheral TCL, not otherwise specified (PTCL-NOS) or nodal TFH cell lymphoma by an MSK hematopathologist between 1/1/02 and 7/1/23; (2) Presentation to MSK at lymphoma diagnosis; (3) At least 6 months of follow-up (unless death from lymphoma); (4) if relevant, a histologically-confirmed diagnosis of a MN by an MSK hematopathologist. Histological diagnoses were recorded as documented in the pathology electronic record in accordance with the WHO criteria in place at the time of diagnosis. In particular, at our center, prior to 2016, cases of PTCL-NOS were not routinely assessed for TFH phenotype, as nodal TFH cell lymphoma was only added to the WHO classification in 2016. Cases documented herein as PTCL-NOS were not re-reviewed to determine TFH phenotype. Only patients who received systemic treatment were included (systemic steroids were not considered systemic treatment). CI of MN was evaluated using the reverse Kaplan-Meier method treating death as a competing risk. Results: We identified a total of 376 patients with either PTCL-NOS (N=178) or nodal TFH cell lymphoma (N=198; AITL N=184; nodal TFH cell lymphoma, NOS N=13; nodal TFH cell lymphoma, follicular-type=1). In total, 24 patients with a MN and either PTCL-NOS or nodal TFH cell lymphoma were identified. Nine had a MN that preceded the TCL diagnosis (AML: 2; MDS: 1; myelofibrosis: 2; CMML: 2; MDS/MPN: 1; polycythemia vera: 1)-these patients were excluded for CI calculation. Fifteen patients were diagnosed with a MN subsequent to lymphoma diagnosis and treatment (AML: 5; MDS: 8; CMML: 1; chronic neutrophilic leukemia: 1). Of the 198 patients with nodal TFH cell lymphoma, nine developed a MN. The CI of developing a MN among all patients at 2, 5, 10, and 15 years was 1.1%, 4.4%, 4.8%, and 5.8%. The CI of developing a MN among those with known nodal TFH cell lymphoma at the same timepoints were 1.6%, 4.5%, 5.3% and 7.1%. The median follow up among survivors was 4.1 years (range: 0.5-18). The median age at MN diagnosis was 72.6 years (range: 45-81), and the median time from lymphoma diagnosis to MN diagnosis was 2.6 years (range: 0.3-10.4). Four patients had either prior RT or chemotherapy for non-lymphoma conditions. Prior to MN diagnosis, ten patients (67%) received etoposide and seven patients (47%) received autologous stem cell transplant (ASCT) (six with BEAM, one with cyclophosphamide plus total body irradiation). The median number of therapies (including ASCT) prior to MN diagnosis was 2 (range: 1-5). At the time of MN diagnosis, 10 patients had relapsed TCL and were receiving lymphoma therapy. No patients had undergone alloSCT prior to the diagnosis of a MN. Next generation mutational profiling with MSK-IMPACT-Heme had previously been performed for eight of the 15 patients (on lymphoma tissue). All except one had mutations in TET2 and/or DNMT3A. Conclusions: Herein we report the CI of MN in a cohort of patients with TCL, with particular attention to nodal TFH cell lymphomas given known CH mutations and the genotoxic stress of combination chemotherapy. As more patients have prolonged survival after initial therapy for TCL, further analysis, including baseline genetics and prospective characterization for clonal expansion and acquired mutations during therapy, could identify those at highest risk for developing a MN. Further characterization of our cohort and comparison to patients who did not develop a MN is ongoing.

Integrative Genomic and Transcriptomic Analysis Reveals Targetable Vulnerabilities in Angioimmunoblastic T-Cell Lymphoma

Follicular helper T-cell lymphoma of the angioimmunoblastic type (AITL) is associated with dismal prognosis. We performed functional genomic approaches including whole-exome sequencing (WES; n=119), transcriptomic (n=78) and methylation (n=40) analysis. We identified recurrent mutations in known epigenetic drivers ( TET2, DNMT3A, IDH2 R172), and also identified novel ones (TET3, KMT2D). Somatic mutation of all three epigenetic drivers ( TET2, IDH2, and DNMT3A) was associated with poor prognosis (p<.001). Mutations in genes regulating T-cell receptor (TCR) signaling ( CD28 VAV1, FYN, PLCG1) or activation ( RHOA G17V), and regulators of the PI3K pathway (PIK(3)C members, PTEN,PHLPP-1/-2) were also found. Genome-wide DNA-methylation analysis integrated with mRNA expression profiling also revealed epigenetic alterations in genes regulating TCR-RHOA/B/C or PI3K-signaling. TET2 loss was noted in 85% AITLs and was significantly associated with RHOA G17V, CD28 and IDH2 R172mutations. AITLs lacking RHOA G17V tended to have mutations regulating the JAK-STAT pathway ( JAK2, JAK3, STAT1, STAT3, SOCS1). RNA-seq analysis identified fusion transcripts in genes regulating TCR activation (8%), revealed a restricted TCR repertoire in the majority of cases (a=87%, b=72%), and showed the presence of Epstein-Barr virus transcriptome (73%). GEP demonstrated association of B-cells in the tumor-milieu with better prognosis (p=.006), while dendritic cells were associated with worse prognosis (p=.001), which was further validated by immunohistochemistry using CD20, CD68, and CD163 antibodies. RNA-seq and corresponding WES analysis of 12 AITL patient-derived-xenografts (PDX) showed that bi-allelic TET2 mutations, DNMT3A mutations or sub-clonal mutations ( PLCG1 PHLPP2) werepropagated in sequential passages. Gene signatures related to T FH (follicular helper) and T CM (central memory) were also well-maintained in secondary passages in PDX models. Gene signatures of late PDX passages (3 rd-5 th) were enriched with genes related to proliferation and metabolic reprogramming, and in an independent cohort of AITLs, high expression of T3/T5 related signatures was associated with worse outcome (p=0.02/p=0.009). Low mRNA expression of PHLPP2 predicted poor prognosis (p=.03) and engineered PHLPP2 loss showed enhanced PI(3)K activation and FOXO1 inactivation in CD4+ T-cells in-vitro. Thus, we defined the genomic landscape for AITL, which is largely characterized by epigenetic alterations, TCR signaling and PI3K/AKT dysregulation, which may be amenable for therapeutic targeting.

TFH lymphoma and associated clonal hematopoiesis

T‑follicular helper (TFH) cell lymphoma (TFHL) is alymphoma of mature Tcells with phenotypic characteristics and gene expression signature of TFH cells. The lymphoma harbors recurrent mutations of RHOAG17V, IDH2R172, TET2 and DNMT3A. Whereas RHOAG17V and IDH2R172 are almost exclusively found in this entity, TET2 and DNMT3A mutations occur in abroad variety of hematological neoplasms and are the most frequently affected genes in clonal hematopoiesis (CH). CH in humans shows aprogression rate to overt hematologic neoplasia of about 0.5to 1% per year, depending on clone size, number of mutations and affected genes. In 2018, the first case was described in which alymphoid (TFHL) and myeloid (acute myeloid leukemia) neoplasm arose from acommon mutated progenitor cell with shared mutations and additional private mutations. In recent years, further studies showed in up to 70% of patients with TFHL the occurrence of identical mutations of TET2 and/or DNMT3A in the myeloid cells, irrespective of bone marrow involvement, indicating aprominent role of CH in the pathogenesis of TFHL. In up to 18%, these patients show also additional synchronous or metachronous overt myeloid neoplasms, often with private myelodysplastic-type mutations, most often myelodysplastic syndrome, chronic myelomonocytic leukemia and acute myeloid leukemia. Recently, there is also evidence for two distinct lymphoid neoplasms arising from CH. TFH lymphoma cases with antecedent or concomitant hematologic neoplasm often show high variant allelic frequencies of TET2 and often more than one mutation, suggesting arole for surveillance in these patients.

Biological insights into the role of TET2 in T cell lymphomas.

Peripheral T cell lymphomas (PTCL) are a heterogenous group of mature T cell lymphomas with an overall poor prognosis. Understanding the molecular heterogeneity in PTCL subtypes may lead to improved understanding of the underlying biological mechanisms driving these diseases. Mutations in the epigenetic regulator TET2 are among the most frequent mutations identified in PTCL, with the highest frequency in angioimmunoblastic T cell lymphomas and other nodal T follicular helper (TFH) lymphomas. This review dissects the role of TET2 in nodal TFH cell lymphomas with a focus on emerging biological insights into the molecular mechanism promoting lymphomagenesis and the potential for epigenetic therapies to improve clinical outcomes.

Advances in the pathogenesis and therapeutic strategies of angioimmunoblastic T-cell lymphoma.

Angioimmunoblastic T-cell lymphoma (AITL) is an aggressive subtype of peripheral T-cell lymphomas with its cell origin determined to be follicular helper T-cells. AITL is characterized by a prominent tumor microenvironment involving dysregulation of immune cells, signaling pathways, and extracellular matrix. Significant progress has been made in the molecular pathophysiology of AITL, including genetic mutations, immune metabolism, hematopoietic-derived microenvironment, and non-hematopoietic microenvironment cells. Early diagnosis, detection of severe complications, and timely effective treatment are crucial for managing AITL. Treatment typically involves various combination chemotherapies, but the prognosis is often poor, and relapsed and refractory AITL remains challenging, necessitating improved treatment strategies. Therefore, this article provides an overview of the pathogenesis and latest advances in the treatment of AITL, with a focus on potential therapeutic targets, novel treatment strategies, and emerging immunotherapeutic approaches.

Nodal T-follicular helper cell lymphoma, angioimmunoblastic-type associated with diffuse large B-cell lymphoma: a clinicopathological study

Objective: To investigate the clinicopathological features and molecular genetics of diffuse large B-cell lymphomas (DLBCL) with concurrent or secondary to nodal T-follicular helper cell lymphoma, angioimmunoblastic-type (nTFHL-AI). Methods: The clinicopathological features and molecular genetics of DLBCL associated with nTFHL-AI diagnosed between January 2015 and October 2022 at the First Affiliated Hospital of Zhengzhou University were analyzed using histology, immunohistochemistry, PCR, EBV-encoded RNA in situ hybridization and fluorescence in situ hybridization (FISH). Clinical information was collected and analyzed. Results: A total of 6 cases including 3 nTFHL-AI with secondary DLBCL and 3 composite lymphomas were reviewed. There were 4 male and 2 female patients, whose ages ranged from 40 to 74 years (median 57 years). All patients presented with nodal lesions at an advanced Ann Arbor stage Ⅲ/Ⅳ (6/6). Bone marrow involvement was detected in 4 patients. All cases showed typical histologic and immunophenotypic characteristics of nTFHL-AI. Among them, 5 cases of DLBCL with concurrent nTFHL-AI exhibited numerous large atypical lymphoid cells and the tumor cells were CD20 and CD79α positive. The only case of DLBCL secondary to nTFHL-AI showed plasma cell differentiation and reduced expression of CD20. All of cases were activated B-cell (ABC)/non-germinal center B-cell (non-GCB) subtype. Three of the 6 cases were EBV positive with>100 positive cells/high power field, meeting the diagnostic criteria of EBV+DLBCL. The expression of MYC and CD30 protein in the DLBCL region was higher than that in the nTFHL-AI region (n=5). C-MYC, bcl-6 and bcl-2 translocations were not detected in the 4 cases that were subject to FISH. Four of the 6 patients received chemotherapy after diagnosis. For the DLBCL cases of nTFHL-AI with secondary DLBCL, the interval was between 2-20 months. During the follow-up period ranging from 3-29 months, 3 of the 6 patients died of the disease. Conclusions: DLBCL associated with nTFHL-AI is very rare. The expansion of EBV-infected B cells in nTFHL-AI may progress to secondary EBV+DLBCL. However, EBV-negative cases have also been reported, suggesting possible other mechanisms. The up-regulation of MYC expression in these cases suggests a possible role in B-cell lymphomagenesis. Clinicians should be aware that another biopsy is still necessary to rule out concurrent or secondary DLBCL when nodal and extranodal lesions are noted after nTFHL-AI treatment.

Development of a prognostic model for anoikis and identifies hub genes in hepatocellular carcinoma

Considering the high fatality of hepatocellular carcinoma (HCC), current prognostic systems are insufficient to accurately forecast HCC patients' outcomes. In our study, nine anoikis‑related genes (PTRH2, ITGAV, ANXA5, BIRC5, BDNF, BSG, DAP3, SKP2, and EGF) were determined to establish a risk scoring model using LASSO regression, which could be validated in ICGC dataset. Kaplan–Meier curves and time-dependent receiver operating characteristic (ROC) curve analysis confirmed the risk score possessed an accurate predictive value for the prognosis of HCC patients. The high-risk group showed a higher infiltration of aDCs, macrophages, T-follicular helper cells, and Th2 cells. Besides, PD-L1 was significantly higher in the high-risk group compared to the low-risk group. Several anoikis‑related genes, such as ANX5, ITGAV, BDNF and SKP2, were associated with drug sensitivity in HCC. Finally, we identified BIRC5 and SKP2 as hub genes among the nine model genes using WGCNA analysis. BIRC5 and SKP2 were over-expressed in HCC tissues, and their over-expression was associated with poor prognosis, no matter in our cohort by immunohistochemical staining or in the TCGA cohort by mRNA-Seq. In our cohort, BIRC5 expression was highly associated with the T stage, pathologic stage, histologic grade and AFP of HCC patients. In general, our anoikis-related risk model can enhance the ability to predict the survival outcomes of HCC patients and provide a feasible therapeutic strategy for immunotherapy and drug resistance in HCC. BIRC5 and SKP2 are hub genes of anoikis‑related genes in HCC.

Lower magnitude and faster waning of antibody responses to SARS-CoV-2 vaccination in anti-TNF-α-treated IBD patients are linked to lack of activation and expansion of cTfh1 cells and impaired B memory cell formation

Patients with inflammatory bowel disease (IBD) and healthy controls received primary SARS-CoV-2-mRNA vaccination and a booster after six months. Anti-TNF-α-treated patients showed significantly lower antibody (Ab) levels and faster waning than α4β7-integrin-antagonist recipients and controls. This prospective cohort study aimed to elucidate the underlying mechanisms on the basis of circulating T-follicular helper cells (cTfh) and B memory cells. We measured SARS-CoV-2- Wuhan and Omicron specific Abs, B- and T-cell subsets at baseline and kinetics of Spike (S)-specific B memory cells along with distributions of activated cTfh subsets before and after primary and booster vaccination. Lower and faster waning of Ab levels in anti-TNF-α treated IBD patients was associated with low numbers of total and naïve B cells vs. expanded plasmablasts prior to vaccination. Along with their low Ab levels against Wuhan and Omicron VOCs, reduced S-specific B memory cells were identified after the 2nd dose which declined to non-detectable after 6 months. In contrast, IBD patients with α4β7-integrin-antagonists and controls mounted and retained high Ab levels after the 2nd dose, which was associated with a pronounced increase in S-specific B memory cells that were maintained or expanded up to 6 months. Booster vaccination led to a strong increase of Abs with neutralizing capacity and S-specific B memory cells in these groups, which was not the case in anti-TNF-α treated IBD patients. Of note, Ab levels and S-specific B memory cells in particular post-booster correlated with the activation of cTfh1 cells after primary vaccination. The reduced magnitude, persistence and neutralization capacity of SARS-CoV-2 specific Abs after vaccination in anti-TNF-α-treated IBD patients were associated with impaired formation and maintenance of S-specific B memory cells, likely due to absent cTfh1 activation leading to extra-follicular immune responses and diminished B memory cell diversification. These observations have implications for patient-tailored vaccination schedules/vaccines in anti-TNF-α-treated patients, irrespective of their underlying disease. The study was funded by third party funding of the Institute of Specific Prophylaxis and Tropical Medicine at the Medical University Vienna. The funders had no role in study design, data collection, data analyses, interpretation, or writing of report.

O-129 - Skin involvement in systemic lymphoma of follicular helper T-cell origin: a cohort study of 57 patients

O-129 - Skin involvement in systemic lymphoma of follicular helper T-cell origin: a cohort study of 57 patients

POSTER: TCL-330 RHOA G17V Potentiates CD28-Induced NFAT Transcriptional Activity by Modulating p300 Activity: A Step Further in the Understanding of Follicular Helper T-Cell Lymphoma

POSTER: TCL-330 RHOA G17V Potentiates CD28-Induced NFAT Transcriptional Activity by Modulating p300 Activity: A Step Further in the Understanding of Follicular Helper T-Cell Lymphoma

TCL-330 RHOA G17V Potentiates CD28-Induced NFAT Transcriptional Activity by Modulating p300 Activity: A Step Further in the Understanding of Follicular Helper T-Cell Lymphoma

TCL-330 RHOA G17V Potentiates CD28-Induced NFAT Transcriptional Activity by Modulating p300 Activity: A Step Further in the Understanding of Follicular Helper T-Cell Lymphoma