Clinicopathological features of adult T-cell leukemia/lymphoma with T-follicular helper phenotype.

AIMS: T-follicular helper (TFH) cells are effector T-cells that are crucial for B-cell selection and differentiation. T-cell lymphomas derived from TFH cells have distinct characteristics. Additionally, in the World Health Organization (WHO) classification 5th edition, three lymphomas were introduced as independent disease entities with TFH cell origin. We aimed to investigate the clinicopathological features of adult T-cell leukemia/lymphoma (ATLL) with a TFH phenotype (TFHP). METHODS AND RESULTS: We performed TFH immunohistochemistry analysis of five biomarkers for the biopsy specimen, with TFHP being indicated by a positive result for more than two markers. Among 75 cases of ATLL, 37.3% of them showed TFHP. Compared with cases of ATLL without TFHP, cases of ATLL with TFHP showed higher C-reactive protein levels (p = 0.0219) and increased high endothelial venule proliferation (p = 0.024). However, there were no significant between-group differences in overall survival as well as other clinical and morphological findings. Furthermore, there was no significant between-group difference in TFH markers and FOXP3 expression. CONCLUSION: Some patients with ATLL may present a TFHP, which should not preclude the diagnosis of ATLL. Although presenting a TFHP does not affect prognosis, it is important to identify cases of ATLL with a TFHP since it may inform future treatment strategies.

Inhibition of choline metabolism in an angioimmunoblastic T-cell lymphoma preclinical model reveals a new metabolic vulnerability as possible target for treatment.

BACKGROUND: Angioimmunoblastic T-cell lymphoma (AITL) is a malignancy with very poor survival outcome, in urgent need of more specific therapeutic strategies. The drivers of malignancy in this disease are CD4+ follicular helper T cells (Tfh). The metabolism of these malignant Tfh cells was not yet elucidated. Therefore, we decided to identify their metabolic requirements with the objective to propose a novel therapeutic option. METHODS: To reveal the prominent metabolic pathways used by the AITL lymphoma cells, we relied on metabolomic and proteomic analysis of murine AITL (mAITL) T cells isolated from our established mAITL model. We confirmed these results using AITL patient and healthy T cell expression data. RESULTS: Strikingly, the mAITL Tfh cells were highly dependent on the second branch of the Kennedy pathway, the choline lipid pathway, responsible for the production of the major membrane constituent phosphatidylcholine. Moreover, gene expression data from Tfh cells isolated from AITL patient tumors, confirmed the upregulation of the choline lipid pathway. Several enzymes involved in this pathway such as choline kinase, catalyzing the first step in the phosphatidylcholine pathway, are upregulated in multiple tumors other than AITL. Here we showed that treatment of our mAITL preclinical mouse model with a fatty acid oxydation inhibitor, significantly increased their survival and even reverted the exhausted CD8 T cells in the tumor into potent cytotoxic anti-tumor cells. Specific inhibition of Chokα confirmed the importance of the phosphatidylcholine production pathway in neoplastic CD4 + T cells, nearly eradicating mAITL Tfh cells from the tumors. Finally, the same inhibitor induced in human AITL lymphoma biopsies cell death of the majority of the hAITL PD-1high neoplastic cells. CONCLUSION: Our results suggest that interfering with choline metabolism in AITL reveals a specific metabolic vulnerability and might represent a new therapeutic strategy for these patients.

Aberrant follicular regulatory T cells associate with immunoglobulin hyperproduction in nasal polyps with ectopic lymphoid tissues.

BACKGROUND: Ectopic lymphoid tissues (eLTs) and associated follicular helper T (TFH) cells contribute to local immunoglobulin hyperproduction in nasal polyps (NPs). Follicular regulatory T (TFR) cells in secondary lymphoid organs counteract TFH cells and suppress immunoglobulin production; however, the presence and function of TFR cells in eLTs in peripheral diseased tissues remain poorly understood. OBJECTIVE: We sought to investigate the presence, phenotype, and function of TFR cells in NPs. METHODS: The presence, abundance, and phenotype of TFR cells in NPs were examined using single-cell RNA sequencing, immunofluorescence staining, and flow cytometry. Sorted polyp and circulating T-cell subsets were cocultured with autologous circulating naïve B cells, and cytokine and immunoglobulin production were measured by ELISA. RESULTS: TFR cells were primarily localized within eLTs in NPs. TFR cell frequency and TFR cell/TFH cell ratio were decreased in NPs with eLTs compared with NPs without eLTs and control inferior turbinate tissues. TFR cells displayed an overlapping phenotype with TFH cells and FOXP3+ regulatory T cells in NPs. Polyp TFR cells had reduced CTLA-4 expression and decreased capacity to inhibit TFH cell-induced immunoglobulin production compared with their counterpart in blood and tonsils. Blocking CTLA-4 abolished the suppressive effect of TFR cells. Lower vitamin D receptor expression was observed on polyp TFR cells compared with TFR cells in blood and tonsils. Vitamin D treatment upregulated CTLA-4 expression on polyp TFR cells and restored their suppressive function in vitro. CONCLUSIONS: Polyp TFR cells in eLTs have decreased CLTA-4 and vitamin D receptor expression and impaired capacity to suppress TFH cell-induced immunoglobulin production, which can be reversed by vitamin D treatment in vitro.

Th9/IL-9 may participate in the pathogenesis of multiple myeloma.

INTRODUCTION: This research is aimed to evaluate the correlation between Th9-associated cytokine levels in MM patients, clinical features, and therapy. METHODS: Peripheral blood samples were taken in 52 MM patients and 20 healthy volunteers matched by sex and age. The patients with MM were separated into two groups: the untreated group (27) and the remission group (25). An enzyme-linked immunosorbent assay (ELISA) was used to measure the IL-9 plasma levels. The levels of Th9-associated cytokines' mRNA expression (IL-9, PU.1, and IRF4) were measured in RT-qPCR. We also analyzed the correlations between the IL-9 plasma levels and the clinical parameters of newly diagnosed MM patients. RESULTS: The IL-9 plasma levels and the Th9-associated cytokines (IL-9, PU.1, and IRF4) mRNA levels in newly diagnosed MM patients were significantly elevated than those in healthy volunteers and significantly decreased after achieving remission. Moreover, PU.1 and IRF4 had a positive correlation with the IL-9 mRNA expression. Then, we found that the upregulation of IL-9 plasma levels correlates with the severity of anemia and decreased albumin Levels. CONCLUSION: The results demonstrate that Th9/IL-9 may be involved in the pathogenesis of MM and is correlated with worse patient conditions such as lower hemoglobin and serum albumin. More work is necessary to confirm whether they might serve as a useful therapeutic target and prognostic marker for MM.

[Expression and Clinical Significance of Helper T Cells 9 and Its Sytokines Interleukin 9 in Chronic Lymphocytic Leukemia].

OBJECTIVE: To investigate the expression and clinical significance of T helper cell 9 (Th9) and its cytokine interleukin 9(IL-9) in peripheral blood of patients with chronic lymphocytic leukemia(CLL). METHODS: A total of 43 newly diagnosed patients with chronic lymphocytic leukemia in the First Affiliated Hospital of Xinjiang Medical University from June 2021 to June 2022 were selected as the case group. The patients were divided into Binet A group (13 cases), Binet B group (20 cases) and Binet C group (10 cases) by Binet staging system, and 20 healthy volunteers who underwent physical examinationin in our hospital in the same period served as control group. The proportion of Th9 cells in peripheral blood was detected by flow cytometry, the expression level of Th9 specific transcription factors PU.1 and IRF4 was detected by Western blot, and the expression level of serum cytokine IL-9 was detected by ELISA. The proportion of Th9, the expression of PU.1, IRF4 and IL-9 in each group were compared, and the correlation between the proportion of Th9, IL-9 and clinicopathological indexes of CLL patients was analyzed. RESULTS: The proportion of Th9, the expression of PU.1, IRF4 and IL-9 in CLL group were significantly higher than those in control group (P<0.05), the proportion of Th9 and the expression of IL-9 in Binet B and C group were higher than those in Binet A group (P<0.05), but there was no significant difference in the proportion of Th9 cells between Binet B group and C group (P>0.05). The expression of IL-9 in Binet C group was significantly higher than that in Binet B group (P<0.05) . The proportion of Th9 cells and IL-9 were highly expression in patients with ß2 microglobulin abnormality, IGHV unmutation, P53 abnormality and hepatosplenic lymph node enlargement(P<0.05), but not related to age and sex (P>0.05). The results of Spearman correlation analysis showed that the proportion of Th9 in patients with CLL was negatively correlated with the lymphocytic account and lymphocyte proportion(rs=-0.32，rs=-0.34). The proportion of Th9 and IL-9 were positively correlated with Binet stage, Rai stage and CLL-IPI Scoring (rs=0.79，rs=0.54，rs=0.58； rs=0.72，rs=0.63，rs=0.45), but not with WBC, CD4+ T cells and CD8+T cells (P>0.05). The proportion of Th9 was positively correlated with IL-9 (rs=0.53). CONCLUSION: Th9 cells and IL-9 are abnormally highly expressed in CLL, which is related to the poor prognosis of CLL.

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.

[Analysis of clinicopathological and molecular abnormalities of angioimmunoblastic T-cell lymphoma].

OBJECTIVE: To analyze the clinicopathological features, molecular changes and prognostic factors in angioimmunoblastic T-cell lymphoma (AITL). METHODS: Sixty-one cases AITL diagnosed by Department of Pathology of Peking University Cancer Hospital were collected with their clinical data. Morphologically, they were classified as typeⅠ[lymphoid tissue reactive hyperplasia (LRH) like]; typeⅡ[marginal zone lymphoma(MZL)like] and type Ⅲ [peripheral T-cell lymphoma, not specified (PTCL-NOS) like]. Immunohistochemical staining was used to evaluate the presence of follicular helper T-cell (TFH) phenotype, proliferation of extra germinal center (GC) follicular dendritic cells (FDCs), presence of Hodgkin and Reed-Sternberg (HRS)-like cells and large B transformation. The density of Epstein-Barr virus (EBV) + cells was counted with slides stained by Epstein-Barr virus encoded RNA (EBER) in situ hybridization on high power field (HPF). T-cell receptor / immunoglobulin gene (TCR/IG) clonality and targeted exome sequencing (TES) test were performed when necessary. SPSS 22.0 software was used for statistical analysis. RESULTS: Morphological subtype (%): 11.4% (7/61) cases were classified as type Ⅰ; 50.8% (31/61) as type Ⅱ; 37.8% (23/61) as type Ⅲ. 83.6% (51/61) cases showed classical TFH immunophenotype. With variable extra-GC FDC meshwork proliferation (median 20.0%); 23.0% (14/61) had HRS-like cells; 11.5% (7/61) with large B transformation. 42.6% (26/61) of cases with high counts of EBV. 57.9% (11/19) TCR+/IG-, 26.3% (5/19) TCR+/IG+, 10.5% (2/19) were TCR－/IG－, and 5.3% (1/19) TCR－/IG+. Mutation frequencies by TES were 66.7% (20/30) for RHOA, 23.3% (7/30) for IDH2 mutation, 80.0% (24/30) for TET2 mutation, and 33.3% (10/30) DNMT3A mutation. Integrated analysis divided into four groups: (1) IDH2 and RHOA co-mutation group (7 cases): 6 cases were type Ⅱ, 1 case was type Ⅲ; all with typical TFH phenotype; HRS-like cells and large B transformation were not found; (2) RHOA single mutation group (13 cases): 1 case was type Ⅰ, 6 cases were type Ⅱ, 6 cases were type Ⅲ; 5 cases without typical TFH phenotype; 6 cases had HRS-like cells, and 2 cases with large B transformation. Atypically, 1 case showed TCR－/IG－, 1 case with TCR－/IG+, and 1 case with TCR+/IG+; (3) TET2 and/or DNMT3A mutation alone group (7 cases): 3 cases were type Ⅱ, 4 cases were type Ⅲ, all cases were found with typical TFH phenotype; 2 cases had HRS-like cells, 2 cases with large B transformation, and atypically; (4) non-mutation group (3 cases), all were type Ⅱ, with typical TFH phenotype, with significant extra-GC FDC proliferation, without HRS-like cells and large B transformation. Atypically, 1 case was TCR－/IG－. Univariate analysis confirmed that higher density of EBV positive cell was independent adverse prognostic factors for both overall survival (OS) and progression free survival(PFS), (P=0.017 and P=0.046). CONCLUSION: Pathological diagnoses of ALTL cases with HRS-like cells, large B transformation or type Ⅰ are difficult. Although TCR/IG gene rearrangement test is helpful but still with limitation. TES involving RHOA, IDH2, TET2, DNMT3A can robustly assist in the differential diagnosis of those difficult cases. Higher density of EBV positive cells counts in tumor tissue might be an indicator for poor survival.

The role of regulatory T cells and follicular T helper cells in HBV infection.

Hepatitis B has become one of the major global health threats, especially in developing countries and regions. Hepatitis B virus infection greatly increases the risk for liver diseases such as cirrhosis and cancer. However, treatment for hepatitis B is limited when considering the huge base of infected people. The immune response against hepatitis B is mediated mainly by CD8+ T cells, which are key to fighting invading viruses, while regulatory T cells prevent overreaction of the immune response process. Additionally, follicular T helper cells play a key role in B-cell activation, proliferation, differentiation, and formation of germinal centers. The pathogenic process of hepatitis B virus is generally the result of a disorder or dysfunction of the immune system. Therefore, we present in this review the critical functions and related biological processes of regulatory T cells and follicular T helper cells during HBV infection.

Deciphering the spectrum of cutaneous lymphomas expressing TFH markers.

T-follicular helper (TFH) markers are expressed in the microenvironnement of marginal zone B-cell lymphoma (MZL), and in lymphomas arising from TFH-cells, sometimes making the differential diagnosis difficult. In the skin, the "TFH-spectrum" is poorly defined, going from primary cutaneous lymphoproliferative disorder with small/medium CD4+ T-cells (SMLPD) to cutaneous localizations of systemic angioimmunoblastic T-cell lymphoma (cAITL), and may pass through intermediate forms (primary cutaneous T-follicular helper derived lymphoma, not otherwise specified (PCTFHL,NOS)). We retrospectively analyzed 20 MZL, 13 SMLPD, 5 PCTFHL, and 11 cAITL clinically, histologically, and molecularly, to define tools to differentiate them. Characteristics that might favor the diagnosis of MZL over SMLPD are: multiple skin nodules (p < 0.001), nodular architecture (p < 0.01), residual germinal centers with follicular dendritic cell network (p < 0.001), monotypic plasma cells (p < 0.001), and few staining with PD1 (p = 0.016) or CXCL13 (p = 0.03). PCTFHL and cAITL presented as multiple (p < 0.01) lesions, in older patients (p < 0.01), with systemic symptoms and/or biological alterations (p < 0.01). Immunophenotypic loss of T-cell markers (p < 0.001), BCL6 (p = 0.023) and/or CD10 staining (p = 0.08), and a higher proliferative index (≥ 30%, p = 0.039) favoured these diagnoses over SMLPD. Pathogenic variants were observed by genomic sequencing in 47% of MZL (TNFAIP3 (32%), EP300 (21%), NOTCH2 (16%), KMT2D (16%), CARD11 (10.5%)), 8% of SMLPD (TET2), 40% of PCTFHL (SOCS1 (20%), ARID1A (20%)) and 64% of cAITL (TET2 (63.6%), RHOA (36.4%), NOTCH1 (9%)). This study characterizes the various clinical and histological features between cutaneous lymphomas expressing TFH markers and highlights the value of the interest of screening for genomic mutations in difficult cases.

Urokinase Plasminogen Activator Deficiency Aggravates Cationic Bovine Serum Albumin-Induced Membranous Nephropathy Through T Helper Cell Type 2-Prone Immune Response in Mice.

Urokinase plasminogen activator (uPA) is a crucial activator of the fibrinolytic system that modulates tissue remodeling, cancer progression, and inflammation. However, its role in membranous nephropathy (MN) remains unclear. To clarify this issue, an established BALB/c mouse model mimicking human MN induced by cationic bovine serum albumin (cBSA), with a T helper cell type 2-prone genetic background, was used. To induce MN, cBSA was injected into Plau knockout (Plau-/-) and wild-type (WT) mice. The blood and urine samples were collected to measure biochemical parameters, such as serum concentrations of immunoglobulin (Ig)G1 and IgG2a, using enzyme-linked immunoassay. The kidneys were histologically examined for the presence of glomerular polyanions, reactive oxygen species (ROS), and apoptosis, and transmission electron microscopy was used to examine subepithelial deposits. Lymphocyte subsets were determined using flow cytometry. Four weeks post-cBSA administration, Plau-/- mice exhibited a significantly higher urine protein-to-creatine ratio, hypoalbuminemia, and hypercholesterolemia than WT mice. Histologically, compared to WT mice, Plau-/- mice showed more severe glomerular basement thickening, mesangial expansion, IgG granular deposition, intensified podocyte effacement, irregular thickening of glomerular basement membrane and subepithelial deposits, and abolishment of the glycocalyx. Moreover, increased renal ROS levels and apoptosis were observed in Plau-/- mice with MN. B-lymphocyte subsets and the IgG1-to-IgG2a ratio were significantly higher in Plau-/- mice after MN induction. Thus, uPA deficiency induces a T helper cell type 2-dominant immune response, leading to increased subepithelial deposits, ROS levels, and apoptosis in the kidneys, subsequently exacerbating MN progression in mice. This study provides a novel insight into the role of uPA in MN progression.

Benefit of prednisolone alone in nodal peripheral T-cell lymphoma with T follicular helper phenotype.

A 71-year-old Japanese man presented with severe thrombocytopenia. A whole-body CT at presentation showed small cervical, axillary, and para-aortic lymphadenopathy, leading to suspicion of immune thrombocytopenia due to lymphoma. Biopsy was difficult to perform because of severe thrombocytopenia. Thus, he received prednisolone (PSL) therapy and his platelet count gradually recovered. Two and a half years after PSL therapy initiation, his cervical lymphadenopathy slightly progressed without other clinical symptoms. Hence, a biopsy from the left cervical lymph node was performed, and he was diagnosed with nodal peripheral T-cell lymphoma (PTCL) with T follicular helper (TFH) phenotype. Due to various complications, we continued treatment with prednisolone alone after the diagnosis of lymphoma; however, there was no further increase in lymph node enlargement and no other lymphoma-related symptoms for one and a half years after diagnosis. Although immunosuppressive therapy has been reported to produce a response in some patients with angioimmunoblastic T-cell lymphoma, our experience suggests that a similar subset may exist in patients with nodal PTCL with TFH phenotype, which has the same cellular origin. Immunosuppressive therapies may constitute an alternative treatment option even in the era of novel molecular-targeted therapies, especially for elderly patients who are ineligible for chemotherapy.

Exosome inspired photo-triggered gelation hydrogel composite on modulating immune pathogenesis for treating rheumatoid arthritis.

Although exosome therapy has been recognized as a promising strategy in the treatment of rheumatoid arthritis (RA), sustained modulation on RA specific pathogenesis and desirable protective effects for attenuating joint destruction still remain challenges. Here, silk fibroin hydrogel encapsulated with olfactory ecto-mesenchymal stem cell-derived exosomes (Exos@SFMA) was photo-crosslinked in situ to yield long-lasting therapeutic effect on modulating the immune microenvironment in RA. This in situ hydrogel system exhibited flexible mechanical properties and excellent biocompatibility for protecting tissue surfaces in joint. Moreover, the promising PD-L1 expression was identified on the exosomes, which potently suppressed Tfh cell polarization via inhibiting the PI3K/AKT pathway. Importantly, Exos@SFMA effectively relieved synovial inflammation and joint destruction by significantly reducing T follicular helper (Tfh) cell response and further suppressing the differentiation of germinal center (GC) B cells into plasma cells. Taken together, this exosome enhanced silk fibroin hydrogel provides an effective strategy for the treatment of RA and other autoimmune diseases.

T follicular helper phenotype mycosis fungoides associated with acanthosis nigricans.

The association between acanthosis nigricans (AN) and mycosis fungoides (MF) has rarely been described, but it is known that MF may appear as AN-like vegetating and papillomatous plaques in skin folds, or may be associated with paraneoplastic AN. There have also been recent descriptions of a form of "intertriginous MF" that is characterized by skin fold involvement and the expression of T follicular helper (TFH) markers, and that often has an aggressive course. We describe the case of a 48-year-old man affected by MF associated with AN, whose lesions were characterized by a TFH immunophenotype and the expression of the GATA-3 nuclear master regulator that may be related to a TFH-2 subpopulation or possible disease progression.

Follicular Helper T-Cell-derived Nodal Lymphomas: Study of Histomorphologic, Immunophenotypic, Clinical, and RHOA G17V Mutational Profile.

The study was designed to review the demographic, clinical, and pathologic characteristics of follicular helper T cells (TFH)-derived nodal PTCL in India including angioimmunoblastic T-cell lymphoma (AITL), peripheral T-cell lymphoma (PTCL) with follicular helper T cell phenotype (P-TFH), and follicular T-cell lymphoma with additional immunohistochemistry (IHC) and RHOAG17V mutational analysis, as well as their impact on survival. This retrospective study included 88 cases of PTCL that were reclassified using IHC for TFH markers (PD1, ICOS, BCL6, and CD10) and dendritic-meshwork markers (CD21, CD23). Cases of TFH cell origin were evaluated for RHOAG17V mutation using Sanger sequencing and amplification-refractory mutation system-polymerase chain reaction (PCR) (validated using cloning and quantitative PCR) with detailed clinicopathologic correlation. Extensive re-evaluation with added IHC panel resulted in a total of 19 cases being reclassified, and the final subtypes were AITL (37 cases, 42%), PTCL-not otherwise specified (44, 50%), P-TFH (6, 7%), and follicular T-cell lymphoma (1, 1%). The presence of at least 2 TFH markers (>20% immunopositivity) determined the TFH origin. AITL patients tended to be male and showed increased presence of B-symptoms and hepatosplenomegaly. Histomorphology revealed that 92% of AITL cases had pattern 3 involvement. Sanger sequencing with conventional PCR did not yield any mutation, while RHOAG17V was detected by amplification-refractory mutation system-PCR in AITL (51%, P =0.027) and P-TFH (17%), which was validated with cloning followed by sequencing. Cases of RHOAG17V-mutant AITL had a worse Eastern Cooperative Oncology Group performance status initially but fared better in terms of overall outcome ( P =0.029). Although not specific for AITL, RHOAG17V mutation shows an association with diagnosis and requires sensitive methods for detection due to low-tumor burden. The mutant status of AITL could have prognostic implications and translational relevance.

Romidepsin-induced durable remission for relapsed nodal peripheral T-cell lymphoma with T follicular helper phenotype after allogeneic hematopoietic cell transplantation.

Patients with recurrent peripheral T-cell lymphoma (PTCL) after allogeneic hematopoietic cell transplantation (HCT) have dismal outcomes. Nodal PTCL with the T follicular helper phenotype (PTCL-TFH) is uniquely sensitive to histone deacetylase inhibitors compared to non-TFH phenotypes. We report the case of a 19-year-old man who experienced recurrence of PTCL-TFH shortly after allogeneic HCT and subsequently achieved durable remission with romidepsin. Before HCT, the patient had refractory disease after CHOP and ESHAP chemotherapies but achieved a partial response after two cycles of romidepsin as salvage treatment. HLA-haploidentical peripheral blood stem cell transplantation was performed using conditioning with fludarabine 180 mg/sqm, melphalan 80 mg/sqm, and total body irradiation 2 Gy, and graft-versus-host disease (GVHD) prophylaxis with post-transplantation cyclophosphamide. One month after HCT, disease progression was observed in the lung. Romidepsin was readministered every 2 weeks at a reduced dose of 12 mg/sqm. After two cycles of romidepsin, the patient achieved a complete metabolic response without severe GVHD or other non-hematological toxicities. Romidepsin was discontinued after seven treatment cycles due to prolonged lymphopenia. The patient remains in complete remission 30 months after the last dose of romidepsin. Our experience suggests that romidepsin could be safely administered soon after allogeneic transplantation.

Primary Cutaneous Peripheral T-Cell Lymphoma With Follicular Helper T-Cell Phenotype: Report of 2 Epstein-Barr Virus-Positive Cases.

ABSTRACT: Primary cutaneous T-cell lymphoma is distinct from nodal T-cell lymphoma clinically and pathologically. Recently, primary cutaneous follicular helper T-cell lymphoma (PC-TFHL) has been described as a peripheral T-cell lymphoma with T-follicular helper (TFH) cell phenotype. PC-TFHL usually presents as multiple plaques and nodules of skin with an indolent clinical course, but without association with Epstein-Barr virus. In this article, we report 2 rare cases of PC-TFHL which are Epstein-Barr virus-positive and with an aggressive clinical course. We discuss the challenges in the differential diagnoses, particularly with primary cutaneous extranodal NK/T-cell lymphoma, and nodal T-cell lymphoma of TFH origin with secondary cutaneous involvement.

Distinct and overlapping features of nodal peripheral T-cell lymphomas exhibiting a follicular helper T-cell phenotype: a multicenter study emphasizing the clinicopathological significance of follicular helper T-cell marker expression.

Nodal peripheral T-cell lymphoma (PTCL) is a heterogeneous category including angioimmunoblastic T-cell lymphoma (AITL), PTCL of follicular helper T-cell (Tfh) phenotype (PTCL-Tfh), and PTCL, not otherwise specified (PTCL-NOS). We explored Tfh marker profiles in nodal PTCL. Nodal PTCLs (n = 129) were reclassified into AITL (58%; 75/129), PTCL-Tfh (26%; 34/129), and PTCL-NOS (16%; 20/129). Histologically, clear cell clusters, high endothelial venules, follicular dendritic cell proliferation, EBV+ cells, and Hodgkin-Reed-Sternberg (HRS)-like cells were more common in AITL than PTCL-Tfh (HRS-like cells, P = .005; otherwise, P < .001) and PTCL-NOS (HRS-like cells, P = .028; otherwise, P < .001). PTCL-NOS had a higher Ki-67 index than AITL (P = .001) and PTCL-Tfh (P = .002). Clinically, AITL had frequent B symptoms (versus PTCL-Tfh, P = .010), while PTCL-NOS exhibited low stage (versus AITL + PTCL-Tfh, P = .036). Positive Tfh markers were greater in AITL (3.5 ± 1.1) than PTCL-Tfh (2.9 ± 0.9; P = .006) and PTCL-NOS (0.5 ± 0.5; P < .001). Tfh markers showed close correlations among them and AITL-defining histology. By clustering analysis, AITL and PTCL-NOS were relatively exclusively clustered, while PTCL-Tfh overlapped with them. Survival was not different among the PTCL entities. By Cox regression, sex and ECOG performance status (PS) independently predicted shorter progression-free survival in the whole cohort (male, P = .001, HR = 2.5; PS ≥ 2, P = .010, HR = 1.9) and in 'Tfh-lymphomas' (ie, AITL + PTCL-Tfh) (male, P = .001, HR = 2.6; PS ≥ 2, P = .016, HR = 2.1), while only PS predicted shorter overall survival (OS) in the whole cohort (P = .012, HR = 2.7) and in 'Tfh-lymphomas' (P = .001; HR = 3.2). ICOS predicted favorable OS in 'Tfh-lymphomas' (log-rank; P = .016). Despite the overlapping features, nodal PTCL entities could be characterized by Tfh markers revealing clinicopathologic implications.