Clonal T-cell Receptor Gene Rearrangements Research Articles

Cutaneous lymphoproliferative disorders: Back to the future.

In the 1980s, immunohistochemistry and clonality analyses became instrumental in the recognition and definition of new types of cutaneous T-cell lymphoma (CTCL) and cutaneous B-cell lymphoma (CBCL) and the development of new classifications. By accepting loss of pan-T-cell antigens and clonal T-cell receptor gene rearrangements as important criteria to differentiate between benign and malignant T-cell proliferations, and monotypic immunoglobulin light-chain expression and clonal immunoglobulin gene rearrangements as crucial criteria to distinguish between benign and malignant B-cell proliferations, many cases, until then diagnosed as cutaneous lymphoid hyperplasia or pseudolymphoma, were reclassified as primary cutaneous CD4+ small/medium T-cell lymphoma (PCSM-TCL) or primary cutaneous marginal zone lymphoma (PCMZL), respectively. However, in recent years there is growing awareness that neither these immunohistochemical criteria nor demonstration of T-cell or B-cell clonality is specific for malignant lymphomas. In addition, many studies have reported that these low-grade malignant CTCL and CBCL have an indolent clinical behavior and an excellent prognosis with disease-specific survival rates of or close to 100%. As a result, recent classifications have downgraded several low-grade malignant cutaneous lymphomas to lymphoproliferative disorder (LPD). Both the 5th edition of the WHO classification (2022) and the 2022 International Consensus Classification (ICC) of mature lymphoid neoplasms reclassified PCSM-TCL as primary cutaneous CD4+ small/medium T-cell LPD and primary cutaneous acral CD8+ T-cell lymphoma as primary cutaneous acral CD8+ T cell LPD. While the 2022 ICC introduced the term "primary cutaneous marginal zone LPD," in the 5th edition of the WHO classification PCMZL is maintained. In this review we describe the background and rationale of the continually changing terminology of these conditions and discuss the clinical consequences of downgrading malignant lymphomas to LPDs.

A significant proportion of classic Hodgkin lymphoma recurrences represents clonally unrelated second primary lymphoma

AbstractDespite high cure rates in classic Hodgkin lymphoma (cHL), relapses are observed. Whether relapsed cHL represents second primary lymphoma or an underlying T-cell lymphoma (TCL) mimicking cHL is underinvestigated. To analyze the nature of cHL recurrences, in-depth clonality testing of immunoglobulin (Ig) and T-cell receptor (TCR) rearrangements was performed in paired cHL diagnoses and recurrences among 60 patients, supported by targeted mutation analysis of lymphoma-associated genes. Clonal Ig rearrangements were detected by next-generation sequencing (NGS) in 69 of 120 (58%) diagnoses and recurrence samples. The clonal relationship could be established in 34 cases, identifying clonally related relapsed cHL in 24 of 34 patients (71%). Clonally unrelated cHL was observed in 10 of 34 patients (29%) as determined by IG-NGS clonality assessment and confirmed by the identification of predominantly mutually exclusive gene mutations in the paired cHL samples. In recurrences of >2 years, ∼60% of patients with cHL for whom the clonal relationship could be established showed a second primary cHL. Clonal TCR gene rearrangements were identified in 14 of 125 samples (11%), and TCL-associated gene mutations were detected in 7 of 14 samples. Retrospective pathology review with integration of the molecular findings were consistent with an underlying TCL in 5 patients aged >50 years. This study shows that cHL recurrences, especially after 2 years, sometimes represent a new primary cHL or TCL mimicking cHL, as uncovered by NGS-based Ig/TCR clonality testing and gene mutation analysis. Given the significant therapeutic consequences, molecular testing of a presumed relapse in cHL is crucial for subsequent appropriate treatment strategies adapted to the specific lymphoma presentation.

Gastrointestinal ALK-positive anaplastic large cell lymphoma: a clinicopathological analysis of five cases

Objective: To investigate the clinicpathological characteristics of ALK-positive anaplastic large cell lymphoma (ALCL) of the gastrointestinal tract, and to discuss its diagnosis and differential diagnosis. Methods: Five cases of gastrointestinal ALK-positive ALCL diagnosed and treated in Xijing Hospital of the Fourth Military Medical University, between 2011 and 2019 were collected. There were three male and two female patients, aged 5-42 years (mean 25 years). These patients clinically presented with fever and night sweats, weight loss, abdominal pain, abdominal mass, ulcers, bleeding, or intestinal obstruction, and underwent surgical resection of the tumors or endoscopic biopsy. The clinical manifestations, auxiliary examinations, histopathological characteristics, immunophenotypes and genetic alterations were analyzed. Results: In this cohort, one case was common type, two cases were monomorphic variant of common type, and two cases were small cell variant. The tumor cells in all cases expressed ALK, CD30, and one or more T lymphocyte markers, while all the markers of B lymphocyte and plasmacyte were negative. Clonality analysis showed that two cases had clonal T cell receptor (TCR) and immunoglobulin (Ig) gene rearrangement, one case had no clonal TCR but Ig gene rearrangement, and one case had no clonal TCR and Ig gene rearrangements. During the 4 to 67 months' follow-up, two patients died of the disease, two were alive with free of disease and one had a relapse. Conclusions: ALK-positive ALCL of the gastrointestinal tract is extremely rare, and has poor prognosis. Lymphoma originating from this site with CD30 and ALK-positive phenotypes may be considered to be ALCL; however differentiation from other tumors that had anaplastic features, expressed CD30 and or ALK, in particular, ALK positive large B-cell lymphoma is necessary.

Intraepithelial cytotoxic lymphocytes are associated with a poor prognosis in feline intestinal T-cell lymphoma.

The expression of cytotoxic molecules in feline intestinal T-cell lymphoma cells was examined immunohistochemically using endoscopic samples of 50 cases. Cases included 14 large-cell lymphomas (LCLs) and 36 small-cell lymphomas (SCLs). Most LCL and some SCL exhibited marked erosion and villous atrophy. Clonal T-cell receptor (TCR) gene rearrangement was detected in 10/14 (71%) LCL cases and 33/36 (92%) SCL cases. No clonal immunoglobulin heavy chain (IgH) gene rearrangement was detected. Immunohistochemically, all cases were positive for CD3 and negative for CD79α, CD30, CD56, and Foxp3. LCLs were positive for CD8 in 13/14 cases (93%), T-cell intracellular antigen 1 (TIA1) in 14/14 cases (100%), and granzyme B in 6/14 cases (43%). SCLs were positive for CD8 in 28/36 cases (78%), TIA1 in 33/36 cases (92%), and granzyme B in 2/36 cases (6%). TIA1- and granzyme B-positive neoplastic lymphocytes were predominantly observed in the mucosal epithelium of 10/50 cases (20%) and 6/50 cases (12%), respectively. No significant differences in survival time were found based on cell size or epitheliotropism. However, cases with TIA1+ and/or granzyme B+ neoplastic lymphocytes predominantly in the mucosal epithelium had significantly shorter survival times (P < .05), suggesting that mucosal epithelium infiltration of neoplastic cells with a cytotoxic immunophenotype is a negative prognostic factor. Therefore, intraepithelial cytotoxic lymphocytes may be associated with mucosal injury and impaired intestinal function, leading to a poor prognosis in cats with intestinal T-cell lymphoma.

STAT3 mutations in "gray-zone" cases of T-cell large granular lymphocytic leukemia associated with autoimmune rheumatic diseases.

A persistently increased T-cell large granular lymphocyte (T-LGL) count in the blood of more than 2 × 109/L for at least 6 months is necessary for a reliable diagnosis of T-LGL leukemia. In cases with LGL counts of approximately 0.5–2 × 109/L, a diagnosis of T-LGL leukemia can be made if clonal rearrangement of T-cell receptor (TCR) genes is present and if the patient shows typical manifestations of T-LGL leukemia, such as cytopenia, splenomegaly, or concomitant autoimmune disease. However, in cases with LGL counts of less than 0.5 × 109/L, the diagnosis of T-LGL leukemia is questionable (termed as “gray-zone” cases). Although mutations in signal transducer and activator of transcription 3 (STAT3) gene are the molecular hallmark of T-LGL leukemia, their diagnostic value in the “gray-zone” cases of T-LGL leukemia has not been evaluated – our study has been aimed to examine the prevalence of STAT3 mutations in these cases. Herein, we describe 25 patients with autoimmune rheumatic diseases, neutropenia, clonal rearrangement of TCR genes, and circulating LGL count of less than 0.5 × 109/L. Splenomegaly was observed in 19 (76%) patients. Mutations in the STAT3 were detected in 56% of patients using next-generation sequencing. Importantly, in 3 patients, no involvement of the blood and bone marrow by malignant LGLs was noted, but examination of splenic tissue revealed infiltration by clonal cytotoxic T-lymphocytes within the red pulp, with greater prominence in the cords. We suggest using the term “splenic variant of T-LGL leukemia” for such cases.

Clinicopathological features and prognosis of cytotoxic T-cell lymphoma: analysis of 134 cases

Objective: To investigate the clinicopathological features and prognosis of cytotoxic T-cell lymphoma (CTL). Methods: The clinicopathological data of 134 CTL patients in Beijing Friendship Hospital Affiliated to Capital Medical University, the 989 Hospital of PLA Joint Logistics Support force (formerly the 152 Hospital) and the Fourth Hospital of Hebei Medical University from 2008 to 2020 were retrospectively collected. Immunophenotype, Epstein-Barr virus infection status and T cell receptor (TCR) clonality of tumor cells were assessed, and clinicopathological features and prognosis of patients were analyzed. Results: Among the 134 CTL patients, the male to female ratio was 1.7∶1.0, the median age was 49.5 years (range 3-83 years), and 100 cases (74.6%) were under 60 years old. Forty-six point nine percent of the patients (53/113) had B symptoms. Most of the patients presented with systemic superficial lymphadenopathy. According to the Ann Arbor staging system, 36.8% (39/106) of the patients were in stage Ⅰ-Ⅱ, and 63.2% (67/106) in stage Ⅲ-Ⅳ. The rate of extranodal involvement was 51.6% (66/128). Spleen was involved in 24.2% (31/128) of the cases. Morphology showed diffuse growth of abnormal lymphocytes, infiltrating and destroying normal tissue structure. Immunohistochemical staining showed that tumor cells expressed T cell antigens (CD2, CD3, CD5, and CD7), and 72.0% (77/107) of them had decreased or lost expression of one or more antigens. According to the numbers of CD4 and CD8 expression in tumor cells, 70 cases (52.2%) were grouped into CD8+>CD4+group. The expression rates of TIA-1 and granzyme B were 99.2% (119/120) and 79.8% (95/119), respectively. CD20 abnormal expression rate was 27.6% (37/134) and CD56 was negative in all cases. The median Ki-67 proliferative index was 45.0% (range 5%-80%). In situ hybridization of small RNA encoded by Epstein-Barr virus was negative. Clonal TCR gene rearrangement analysis was performed on 49 cases and was positive in all cases. Ninety-one patients were followed up for a median of 36 months (range, 1 to 240 months), and 40 of the 91 patients (44.0%) died. The twenty-three patients were in complete remission (including 13 cases with localized single extranodal mass). The 3-year and 5-year overall survival rates were 53.5% and 49.4%, respectively. Univariate analysis showed that B symptom, spleen involvement, extranodal involvement, clinical stage, CD8+>CD4+phenotype, abnormal expression of CD20 and Ki-67 proliferation index (>60%) were associated with overall survival (P<0.05). The multivariate Cox regression analyses showed that spleen involvement and CD8+>CD4+ phenotype were independent prognostic factors for overall survival in CTL patients. Conclusions: CTL are more commonly found in adult males under 60 years old, often accompanied by B symptom, with a high proportion of extranodal involvement and more CD8 positive phenotypes. Spleen involvement and CD8+>CD4+phenotype are independent predictors of CTL overall survival. Some patients with localized extranodal CTL may have a good prognosis.

Clinicopathological features and prognosis of the skeletal-muscle cytotoxic T-cell lymphoma

Objective: To investigate the clinicopathological features and prognosis of skeletal-muscle cytotoxic T-cell lymphoma (CTL). Methods: The clinical data of 14 cases of skeletal muscle CTL and 47 cases of non-skeletal muscle extranodal CTL patients in Beijing Friendship Hospital Affiliated to Capital Medical University and the 989 Hospital of the joint logistics support force of the people's Liberation Army (the former 152 hospital) from 2008 to 2019 were collected retrospectively. Immunophenotype, EBV infection status and T-cell receptor (TCR) clonality of tumor cells were evaluated. The clinicopathological features and prognosis of the two groups were compared. Results: Skeletal-muscle CTL accounted for 23.0% (14/61) of extranodal CTL in the same period. The median age of the patients was 42.3 years (range 11-76 years), including six males and eight females. The main clinical manifestations were painless masses. Two patients (2/14) had B symptoms. The tumors occurred in the cheek (7 cases), the tongue (4 cases), the lower lip (3 cases) and the left upper arm (2 cases), and in two cases had two sites. Ten cases were of stage ⅠE and four cases stage ⅡE. Compared with non-skeletal-muscle extranodal CTL, many patients of skeletal-muscle CTL did not have B symptoms, the clinical stage was lower, and the tumor mainly involved the oral cavity (cheek, tongue and lip, P<0.05). Morphologically, the tumor showed diffuse infiltration of heterotypic lymphocytes in skeletal muscle. Immunohistochemistry showed that in 11/14 cases, there were reduced or loss of expression of some the T cell antigens (CD2, CD3, CD5, CD7). TIA-1, Gr B and CD8 (CD8+>CD4+) were expressed in all cases, and CD56 was negative. The median Ki-67 proliferation index was 35.0% (range 5%-60%). EBER in situ hybridization was negative in all cases. The results of TCR clonality analysis showed clonal TCR gene rearrangement were detected in eight cases. The median follow-up time was 40 months (range 10-67 months). Ten patients were tumor free; the 5-year survival rate of skeletal-muscle CTL was 100%. Compared with non-skeletal-muscle extranodal CTL (5-year overall survival rate was 35.9%), the difference was statistically significant (χ²=8.277, P=0.004). Conclusions: Skeletal-muscle CTL mostly occurs in the skeletal muscle of cheek and mouth. Tumor cells show morphologic characteristics of muscle invasion and myositis-like feature. It also shows CD8+>CD4+immunophenotype, cytotoxic molecular pattern and is associated with low clinical stage and good prognosis.

NGS-Based MRD Quantitation: An Alternative to qPCR Validated on a Large Consecutive Cohort of Children with ALL

Together with multicolor flow cytometry, quantitation of clonal immunoglobulin (IG) and T-cell receptor (TR) gene rearrangements represents the current standard for the detection of minimal / measurable residual disease (MRD) in treatment protocols for pediatric acute lymphoblastic leukemia (ALL) patients. Despite the adoption of next generation sequencing (NGS) in the routine identification of clonal IG/TR gene rearrangements as markers for MRD detection, real-time quantitative (q)PCR is still the standard for MRD quantitation in follow-up samples. So far, no large-scale direct comparison of qPCR- and NGS-based MRD quantitation has been performed.We compared qPCR- and NGS-MRD evaluation in a cohort of children with B-cell precursor (BCP) ALL treated on the AIEOP-BFM ALL 2009 protocol and assessed the feasibility and relevance of this method for the stratification at day 33 (EOI).In total, 459 patients were diagnosed with BCP-ALL from 2010 to 2018, and 437 of them were included in our study based on the availability of residual DNA material isolated from day 33 bone marrow aspirates and having at least one IG/TR MRD marker detectable by standard qPCR with protocol-required sensitivity of 10 -4. Sequencing libraries were prepared according to the EuroClonality-NGS group SOP (Brüggemann et al, Leukemia 2019) with the total DNA input normalized to the equivalent of 150,000 nucleated cells to reach MRD sensitivity of 10 -5 and sequenced on Illumina NovaSeq and MiSeq instruments. In total of 780 IG/TR markers evaluated by both NGS and qPCR. Sequencing data were analyzed using the ARResT/Interrogate (Bystry et at, Bioinformatics 2017) pipeline and a custom bioinformatic analysis process and the NGS-MRD results were normalized to the EuroClonality-NGS central in-tube quality/quantification control (cIT-QC; Knecht et al, Leukemia 2019).From the total 780 IG/TR MRD markers evaluated by both methods, 629 (80.6%) were concordant with 242 markers being MRD positive and 387 negative. From 82 markers that were only positive by qPCR and not by NGS, 76 were positive below the quantitative range (positive non-quantifiable). Specificity analysis was performed for each marker by searching for the junction sequence across the dataset of all patients' NGS results. Based on these results, 22 out of 82 markers positive only by qPCR were classified as potentially unspecific (false positive) and similarly 32 unspecific markers were identified among the 69 positive only by NGS. This was also supported by unspecific amplification of the polyclonal control in 27 out of these 32 corresponding qPCR systems, in some cases leading to qPCR negative classification determined by the EuroMRD guidelines.Overall stratification of patients based only on day 33 MRD by qPCR or NGS was concordant in 76% of patients by both methods, while in 19% of patients, NGS-MRD quantitation led to the assignment to a lower-risk group, mainly due to the elimination of false-positive results. Furthermore, analysis of all positive markers across all patients' NGS libraries showed, that one out of 10 markers (mainly in the IGK, TRG and TRD loci) used for qPCR-MRD stratification did not provide satisfactory specificity, although they fully met EuroMRD criteria during the optimization of qPCR patient-specific assays.Our results show that NGS-MRD is highly concordant with traditional qPCR-based strategy and has comparable sensitivity and clinical value in the setting of a BFM-based clinical protocol, while being less laborious and providing significantly more specific results and additional information on the IG/TR repertoire (Kotrova et al, Blood 2016). Our study also emphasizes the importance of selecting MRD markers of adequate specificity at diagnosis. Currently, this selection can be assisted by these broad sequencing data on IG/TR repertoire of large number of patients. Based on these results, we propose that frontline NGS-MRD evaluation developed by the EuroClonality-NGS working group can be used as an alternative to traditional qPCR-based MRD quantitation in future MRD-based treatment protocols.Supported by grants NU20-03-00284 and NU20-07-00322 from the Czech Health Research Council and 534120 from Charles University. All methods were established through collaboration within the EuroClonality-NGS and EuroMRD groups. Disclosuresvan der Velden: Agilent: Research Funding; Navigate: Other: Service Level Agreement; Janssen: Other: Service Level Agreement; EuroFlow: Other: Service Level Agreement, Patents & Royalties: for network, not personally; BD Biosciences: Other: Service Level Agreement. Brüggemann: Incyte: Other: Advisory Board; Janssen: Speakers Bureau; Amgen: Other: Advisory Board, Travel support, Research Funding, Speakers Bureau. Langerak: Erasmus MS, University Medical Center: Current Employment; F. Hoffmann-La Roche Ltd/Genentech, Inc.: Research Funding; Gilead: Research Funding; Janssen: Speakers Bureau.

Extranodal nasal type natural killer/T-cell lymphoma of the digestive system: a clinicopathological study of thirteen cases

Objective: To investigate the clinicopathological features, and diagnostic and differential diagnostic characteristics of extranodal nasal type natural killer/T-cell lymphoma (ENKTCL) of the digestive system. Methods: Thirteen cases of ENKTCL in the digestive system were collected at the Henan Provincial People's Hospital, Zhengzhou, China, from August 2000 to August 2020. The histopathological, immunohistochemical and in situ hybridization features were analyzed, as well as those of T-cell receptor (TCR) gene rearrangement in some cases. The patients were followed up. Results: There were 11 males and 2 females. The age ranged from 28 to 80 years (median=53 years). Seven cases were present in the colorectum, and 3 cases were present in the small intestine. The other three cases were in stomach, gallbladder and liver (one case each). The main clinical symptoms were fever, and abdominal pain, often accompanied by fatigue, diarrhea, hematochezia, elevated serum albumin, elevated lactate dehydrogenase, and increased peripheral blood EB virus DNA copy. Histologically, the tumor accompanied by a heavy admixture of inflammatory cells (small lymphocytes, plasma cells and histiocytes). There was diffuse dense tumor cell infiltrate, with prominent coagulative necrosis. The lymphomatous infiltrate had angiocentric and angio-necrotic changes. Immunohistochemically, lymphoid cells expressed CD3 in all cases. Some of them showed weakened/absent other T cell markers, while all of them expressed CD56 except 1 case. A few of the cases showed CD4-/CD8+ killer T cell phenotypes. In situ hybridization showed EB virus encoded RNA (EBER) was positive in all cases. Clonal TCR gene rearrangement was not detected in all 7 cases tested. The median survival time was 9 months. Conclusions: ENKTCL of the digestive system is extremely rare. It often predisposes the patients to acute abdomen such as perforation of the gastrointestinal tract. The treatment outcomes are dismal, and the prognosis is poor. Clinical and imaging studies are often non-specific. It is also easy to be misdiagnosed as non-specific ulcers. Combined with immunohistochemistry, in situ hybridization and TCR gene rearrangement analysis and better understanding of this tumor's clinicopathological characteristics can help improve its diagnosis and early treatment.

The predictive value of PNH clones, 6p CN-LOH, and clonal TCR gene rearrangement for aplastic anemia diagnosis

AbstractAcquired aplastic anemia (AA) is a life-threatening bone marrow aplasia caused by the autoimmune destruction of hematopoietic stem and progenitor cells. There are no existing diagnostic tests that definitively establish AA, and diagnosis is currently made via systematic exclusion of various alternative etiologies, including inherited bone marrow failure syndromes (IBMFSs). The exclusion of IBMFSs, which requires syndrome-specific functional and genetic testing, can substantially delay treatment. AA and IBMFSs can have mimicking clinical presentations, and their distinction has significant implications for treatment and family planning, making accurate and prompt diagnosis imperative to optimal patient outcomes. We hypothesized that AA could be distinguished from IBMFSs using 3 laboratory findings specific to the autoimmune pathogenesis of AA: paroxysmal nocturnal hemoglobinuria (PNH) clones, copy-number–neutral loss of heterozygosity in chromosome arm 6p (6p CN-LOH), and clonal T-cell receptor (TCR) γ gene (TRG) rearrangement. To test our hypothesis, we determined the prevalence of PNH, acquired 6p CN-LOH, and clonal TRG rearrangement in 454 consecutive pediatric and adult patients diagnosed with AA, IBMFSs, and other hematologic diseases. Our results indicated that PNH and acquired 6p CN-LOH clones encompassing HLA genes have ∽100% positive predictive value for AA, and they can facilitate diagnosis in approximately one-half of AA patients. In contrast, clonal TRG rearrangement is not specific for AA. Our analysis demonstrates that PNH and 6p CN-LOH clones effectively distinguish AA from IBMFSs, and both measures should be incorporated early in the diagnostic evaluation of suspected AA using the included Bayesian nomogram to inform clinical application.

Comparison of Two Quantitative PCR–Based Assays for Detection of Minimal Residual Disease in B-Precursor Acute Lymphoblastic Leukemia Harboring Three Major Fusion Transcripts

Two quantitative PCR (qPCR)-based methods, for clonal immunoglobulin or T-cell receptor gene (Ig/TCR) rearrangements and for fusion transcripts, are widely used for the measurement of minimal residual disease (MRD) in patients with B-precursor acute lymphoblastic leukemia (ALL). MRD of bone marrow samples from 165 patients carrying the three major fusion transcripts, including 74 BCR-ABL1, 54 ETV6-RUNX1, and 37 TCF3-PBX1, was analyzed by using the two qPCR-based methods. The correlation coefficient of both methods was good for TCF3-PBX1 (R2=0.8088) and BCR-ABL1 (R2=0.8094) ALL and moderate for ETV6-RUNX1 (R2=0.5972). The concordance was perfect for TCF3-PBX1 ALL (97.2%), substantially concordant for ETV6-RUNX1 ALL (87.1%), and only moderate for BCR-ABL1 ALL (70.6%). The discordant MRD, positive for only one method with a difference greater than one log, was found in 4 of 93 samples (4.3%) with ETV6-RUNX1, 31 of 245 samples (12.7%) with BCR-ABL1, and none of TCF3-PBX1 ALL. None of the eight non-transplanted patients with BCR-ABL1-MRD (+)/Ig/TCR-MRD (-) with a median follow-up time of 73.5 months had hematologic relapses. Our study showed an excellent MRD concordance between the two qPCR-based methods in TCF3-PBX1 ALL, whereas qPCR for Ig/TCR is more reliable in BCR-ABL1 ALL.

Germline Mutations in CTLA4 and Spectrum of Bone Marrow Features Overlapping with Aplastic Anemia and Large Granular Lymphocyte Lymphocytosis

Introduction: CTLA4 haploinsufficiency due to germline heterozygous mutations in the cytotoxic T-lymphocyte antigen-4 gene (CTLA4) results in severe systemic immune dysregulation; infiltrative lymphocytic lesions of lungs (e.g. lymphocytic pneumonitis), GI tract (e.g.lymphocytic colitis), and CNS; and a spectrum of autoimmunity, immunodeficiency and peripheral blood cytopenias. We describe the hematologic, bone marrow (BM), and flow cytometry (FC) features of CTLA4 haploinsufficiency of a cohort of 14 patients, which show overlapping morphologic features with acquired aplastic anemia (acAA), and large granular lymphocyte lymphocytosis (LGL) in a subset of patients. We compared the findings to those in a separate cohort of 20 age matched patients diagnosed with acAA. There were significant differences between acAA and CTLA4 deficiency based on analysis of BM lymphocyte subsets and marrow lymphocyte infiltration patterns.Materials and Methods: Peripheral blood (PB), BM and FC analysis of patients with germline mutations in CTLA4, and acAA was performed along with review of clinical, molecular and laboratory data. Statistical comparisons were made using Mann Whitney test, with p < 0.05 for significance.Results: Median age at initial evaluation for patients with CTLA4 haploinsufficiency was 23.5 years (range 11-71 years), with a male-to-female ratio of 11:3. 11 out of 14 patients had cytopenias. Of those with cytopenias 2/11 had pancytopenia, 4/11 had bicytopenia and 5/11 had unilineage cytopenia. Hypogammaglobulinemia was common (13/14). In some cases cytopenias were recognized as autoimmune in etiology with immune thrombocytopenic purpura and autoimmune hemolytic anemia, among the most common hematologic manifestations. Three patients met criteria for a diagnosis of moderate AA, 1 for severe AA, and 1 for LGL. Overall bone marrow biopsies were hypocellular for age (10/14) with a subset (29% [4/14]) showing severe trilineage hypoplasia with ≤20% cellularity. Atypical interstitial CD8-positive T-cell infiltrates with prominent non-paratrabecular CD4-positive T-cell aggregates were evident by immunohistochemistry in most cases (10/14), accompanied by a near absence of B-cells. T-cell clonality was assessed by T-cell receptor (TCR) gamma PCR and showed abnormal oligoclonal T-cell populations in 3/8, and one case with a clonal T-cell receptor gene rearrangement. B-cell IgH PCR reactions were polyclonal. In all cases, cytogenetic studies were either negative or showed only minor abnormalities (i.e. loss of Y chromosome). Given the morphologic overlap of a subset of CTLA4 cases with acAA, we compared bone marrow flow cytometry analysis of 8 CTLA4 cases with 20 acAA cases. CTLA4 patients showed >5 fold reduction in the median percentage of B-cells in comparison to acAA (p=0.0005). While acAA cases demonstrated relative preservation the B-cell compartment with intact B-cell maturation sequence; in contrast CTLA4 cases showed abnormal B-cell maturation patterns in half of cases characterized by few detectable early B-cell precursors, and progressive loss of intermediate and mature forms. T-cell populations in CTLA4 showed inverted CD4:CD8 ratios with relatively increased CD57+ T-cells, and atypical dim expression of CD20 on T-cells. Morphologically, when the markedly hypocellular CTLA4 cases were compared to acAA on core biopsies, little difference in marrow cellularity was seen; however, the CTLA4 cases showed multiple large atypical T-cell aggregates and near total absence of B-cells, which was not seen in acAA; acAA cases showed scattered background T-cells and B-cells.Conclusions: CTLA-4 deficiency presents with cytopenias, autoimmunity, and immunodeficiency with a subset of patients that have features overlapping with bone marrow failure, specifically AA and LGL. Herein we demonstrate a combination of abnormal BM findings, previously unreported, comprising hypocellularity, CD8-positive interstitial T-cell infiltrates with atypical CD4-positive T-cell aggregates, marked B-cell lymphopenia, increased LGLs and abnormal T-cell clonality patterns by PCR. These features may help identify patients harboring CTLA4 mutations for early detection and optimal therapeutic management. DisclosuresYoung:Novartis/GSK to institute: Research Funding. Townsley:Novartis/GSK to institute: Research Funding.

Evaluation of Minimal Residual Disease (MRD) and MRD-Based Treatment Decisions in Ph/BCR-ABL Negative Adult Acute Lymphoblastic Leukemia (ALL): Experience from the German Multicenter Study Group for Adult ALL (GMALL)

Abstract Detectable MRD during chemotherapy is considered to be the most important prognostic factor in ALL. Pts with molecular failure (MolF) have a poorer overall survival (OS), inferior remission duration (RD) and poorer prognosis even after stem cell transplantation (SCT) compared to pts with molecular CR (MolCR) (Gokbuget et al, Blood 2012: 120(9): 1868). Little is known however on the outcome of pts with MRD results not fitting in the above categories e.g. MRD low positive and on the impact of additional treatments in pts with MolF. We report an expanded cohort of pts treated according to protocol 07/03 (within the trial or in GMALL registry). MRD was tested by real-time PCR of clonal TCR and Ig gene rearrangements in a reference laboratory (Kiel). The analysis refers to molecular response in ‘wk 16‘ after induction/1st consolidation and to molecular relapse (MolR) later than wk 16 (all definitions see table). The GMALL recommended referral of MolF and MolR pts to SCT in CR1. The median age of 2061 pts with Ph-neg ALL (1484 trial, N=577 registry) was 34 (16-65) yrs. Pts 625 (59%)/1857 pts had a MolCR and196 (18%) MolF. In addition 7% were MRDneg and 16% MRDpos - both not fulfilling the criteria of MolCR or MolF (definitions see table). Results for OS at 5 yrs (MolCR vs MolF vs MRDneg vs MRDpos) were 83% vs 43% vs 78% vs 68% resp. and for RD 80% vs 38% vs 76% vs 56% resp. Differences were significant (p In 196 MolF pts OS and RD from wk16 onward was 43% and 38% at 5 yrs resp. 121 (62%) MolF pts received SCT in ongoing 1st CR. The SCT rate in MolF pts increased from 54% (2003-2009) to 72% (2010-2016)(p=.008). OS and RD for non-SCT vs SCT pts was 28% vs 53% (p Out of 196 MolF pts, 19 relapsed shortly after wk 16, 2 pts were withdrawn, 1 pt died in CR and data were missing in 6 pts. Of the remaining 168 pts, 52 received immediate SCT (31%), whereas 115 pts received consolidation. Data on molecular response after the next 1-3 cycles or after SCT were available for 142 pts. In B-prec ALL (N=95) and T-ALL (N=47) the MolCR rate was 34% and 43% resp. for non-SCT approaches, whereas 75% and 71% resp. achieved a Mol CR after immediate SCT (table). However, the OS with immediate SCT vs later SCT was 34% (N=52) vs 63% (N=69) at 5 yrs resp (p=.002) and the corresp. RD was 42% vs 66% (p=.001) resp. Furthermore, pts with next consolidation leading to molCR had a superior OS (76% at 5yrs) vs those who did not (44% at 5yrs) (p=.02). A similar difference was seen for RD (60% vs 36% resp.; p=.08). In addition 102 pts with MolR during/after chemo were observed (median time to MolR: 18 mo). OS and RD from MolR onwards were 51% and 35% at 5 yrs. 38 pts were transplanted in ongoing 1st CR. OS w/o and with SCT was 37% vs 71% (p=.001) resp. with corresp. RD of 5% vs 70% (p Important conclusions for future MRD based therapy can be drawn from this large adult ALL cohort: 1) a similar poor prognostic impact of MolF and MolR is underlined; 2) it is demonstrated that pts with any detectable MRD (MRDpos) have an intermediate prognosis and require regular follow-up MRD testing; 3) SCT offers an advantage in MolF and MolR pts, however 4) evidence was provided that later SCT (i.e. in better molecular status) could be superior to immediate SCT; 5) compliance with MRD testing and SCT in MolF increased over time; 6) many MolF pts relapsed quickly; 7) additional chemotherapy offered limited chances to achieve a MolCR, but 8) promising MolCR rates were observed for targeted therapies. For future optimisation of MRD based therapy, logistics for decisions have been implemented earlier in the GMALL trial 08 in order to avoid rapid relapses. A first stratification takes place already after induction and targeted therapies are recommended in all MolF pts before SCT. Download : Download high-res image (209KB) Download : Download full-size image Disclosures Rollig: Janssen: Research Funding; Bayer: Research Funding. Kneba: AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding; F. Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding; Mundipharma: Consultancy, Honoraria, Other: travel support, Research Funding.

T-cell clonality in peripheral blood as a predictor of progression to systemic treatment in patients with stage IB mycosis fungoides (MF).

e19538 Background: A major unmet clinical need in the care of early-stage MF patients is the identification of those with a high risk of failing skin directed therapy or progressing to advanced disease. Herein, we inquired if the identification of a clonal T-cell receptor (TCR) gene rearrangement by PCR in peripheral blood could predict the clinical outcome, particularly the need for systemic treatment, in patients with stage IB MF. Methods: This is a retrospective cohort study of patients with stage IB MF who underwent peripheral blood TCR clonality analysis by PCR. The primary outcome of the study was time from diagnosis to initiation of systemic treatment. Secondary outcomes were: (1) time to progression to advanced-stage disease (stages IIB-IV) and (2) overall survival. Patients were censored at time of last clinical follow up. Log rank test was used to compare the survival distributions of the two groups; p value &lt; 0.05 was considered significant. Results: From May 2014 to October 2019, 56 consecutive stage IB pts with &gt; 6 months follow up were included in this analysis. Peripheral blood TCR clonality status was available in 42 patients: 18 pts had a positive TCR clone and 24 did not. Median follow up time was 36 months (range 8.5 – 198 months). At 3 years, 39% of patients with peripheral clone had progressed to systemic treatment versus 8% of those without a peripheral clone (log rank test, p-value = 0.003). For the secondary outcomes, at 3 years 17% of patients with peripheral clone had progressed to advanced stage versus 4% of those without (log rank test, p-value = 0.10); 5% of patients with peripheral clone had died versus 0% of those without (log rank test, p-value = 0.03). Conclusions: Detection of a predominant TCR clone by PCR in the peripheral blood is an important prognostic marker in the initial workup of MF, as its presence is highly correlated with subsequent progression to systemic treatment and death. If this finding is validated, it can be used to risk stratify and individualize therapy for MF patients.[Table: see text]

T-lymphoblastic leukemia/lymphoma with interfollicular growth pattern and Castleman-like morphologic features

Indolent T-lymphoblastic proliferation (iT-LBP) is a recently recognized benign pathologic condition commonly associated with Castleman disease. The lymph node of this condition shows preserved lymphoid architecture with proliferation of nonclonal T-lymphoblasts in the interfollicular area. iT-LBP is a rare condition and a diagnosis of exclusion. As a rule, it requires sophisticated techniques to exclude T-lymphoblastic leukemia/lymphoma (T-LBL/L). We present an unusual T-LBL/L in a lymph node mimicking iT-LBP. The case showed preserved nodal architecture, morphologic features of hyaline vascular Castleman disease, proliferation of T-lymphoblasts in the interfollicular area, and no clonal T-cell receptor gene rearrangement. The follow-up lymph node specimen excised 6 months later showed full-blown lymphoblastic lymphoma with an abnormal karyotype, near-early-T-precursor phenotype, partial CD19 expression, and SETD2 mutation.

CD3−CD4+ Lymphocytic Variant Hypereosinophilic Syndrome: Diagnostic Tools Revisited

Identification of patients with lymphocytic variant hypereosinophilic syndrome (L-HES) is challenging, and has important prognostic and therapeutic implications. This study was undertaken to assess diagnostic tools for L-HES and to develop evidence-based diagnostic recommendations. Biomarkers of T-cell-driven disease were compared between patients with L-HES versus idiopathic HES (I-HES) variants. Those performed routinely (serum immunoglobulin levels, T-cell phenotyping, T-cell receptor [TCR] gene rearrangement patterns) were collected from medical files, whereas others were prospectively assessed on stored blood samples (serum CCL17/thymus and activation regulated chemokine [TARC] levels, invitro cytokine production). This study included 48 patients with I-HES and 20 with L-HES associated with a CD3-CD4+ T-cell subset, including 7 with less than 5% aberrant cells. Neither increased serum immunoglobulin levels nor clonal TCR gene rearrangements were sufficiently sensitive or specific for L-HES. In contrast, systematically enhanced expression of the T-cell surface antigens CD2, CD5, CD45RO, and CD95 by these cells allowed for accurate detection by flow cytometry. Serum CCL17/TARC levels were significantly higher in patients with L-HES compared with those with I-HES, and a threshold of 3000 pg/mL allowed for detection of all subjects with L-HES with 75% specificity. Quantification of intracytoplasmic cytokine production by flow cytometry is the most reliable method for detection of enhanced type 2 cytokine expression, most notably for IL-4 and IL-13. Adapting the standard of procedure for T-cell phenotyping in patients with unexplained hypereosinophilia is currently the most reliable means of identifying those with CD3-CD4+ L-HES.

Utility of clonal T-cell rearrangement study in the diagnosis of early mycosis fungoides

To the Editor: The diagnosis of early mycosis fungoides (MF) is challenging, as clinical and histopathologic presentation can mimic inflammatory dermatoses. In 2005, the International Society for Cutaneous Lymphoma (ISCL) established a clinicopathologic algorithm for the diagnosis of early MF based on clinical, histopathologic, molecular, and immunopathologic criteria, requiring a total of 4 points (Table I).1 One criterion, the clonal T-cell receptor (TCR) gene rearrangement analysis, represents a significant cost in the workup of early MF and is often unavailable in-house.

Cutaneous T-cell lymphomas with pathogenic somatic mutations and absence of detectable clonal T-cell receptor gene rearrangement: two case reports

BackgroundCutaneous T-cell lymphomas (CTCL) are a heterogeneous group of extranodal non-Hodgkin lymphomas for which diagnosis can be challenging given the potential for overlap with inflammatory dermatoses. Current diagnostic criteria for CTCL incorporate clinical and histopathologic findings as well as results of T-cell receptor (TCR) gene sequencing. Molecular interrogation of TCR genes, TRG and TRB, has proven to be a critical tool for confirming diagnoses of CTCL and for disease tracking after initiation of therapy or after stem cell transplant. Methods for confirming a diagnosis of lymphoma in the absence of TCR gene clonality are lacking. We present two patients with CTCL with pathogenic somatic mutations in the absence of TRG and TRB clonality.Case presentationsCase 1: A 38-year-old male had a 19-year history of a diffuse skin rash with papulosquamous, granulomatous, and verrucous features and progressive ulcerated plaques and tumors demonstrating an atypical CD4+ T-cell infiltrate with expression of cytotoxic markers CD56, TIA-1, granzyme, and perforin on histopathology. No definitive evidence for T-cell clonality was detected by conventional PCR of 6 biopsies or by next-generation sequencing (NGS) of 14 biopsies. Somatic mutational profiling of a skin biopsy revealed pathogenic mutations in PIKC3D and TERT promoter hotspots, confirming the presence of a clonal process. Case 2: A 69-year-old male with a 13-year history of progressive, diffuse hypertrophic and eroded plaques showed an atypical CD4+ T-cell infiltrate with subset expression of TIA-1 and granzyme on histopathology. No TCR clonality was detected by TCR-NGS of 6 biopsies. Somatic mutational profiling of a skin biopsy detected a pathogenic mutation in TP53, confirming the presence of a clonal process.ConclusionsThese cases highlight how detection of pathogenic somatic mutations can confirm a diagnosis of lymphoma in a clinically and histopathologically suspicious cutaneous lymphoid proliferation without detectable TCR clonality.

B-cell lymphomas associated with breast implants: Report of three cases and review of the literature

Since the first reported case in 1997, over 600 women with breast implant-associated anaplastic large cell lymphoma (BI ALCL) have been reported. BI ALCL is a CD30-positive T-cell lymphoma that carries clonal T-cell receptor gene rearrangements, and a subset of cases harbors mutations in the JAK-STAT signaling pathway. Rarely, other histologic types of lymphoma have been reported in association with breast implants, including fewer than 10 cases of B-cell origin. Here, we describe three additional patients with B-cell lymphoma occurring around breast implants. Two of these patients developed extranodal marginal zone lymphoma in the peri-implant capsule, one of which had a concurrent ALCL within the superficial lining of the capsule. The third patient presented with diffuse large B-cell lymphoma inside the breast parenchyma surrounding her implant. Determining the etiology and risk factors for the development of B-cell lymphomas associated with breast implants remains challenging, given the wide spectrum of histologic features and the rarity of these neoplasms. Ultimately, we document three new cases of B-cell lymphoma arising around breast implants and highlight their clinical and pathologic features in order to expand our understanding of this rare disease presentation.

Prevalence and spectrum of T-cell lymphoproliferative disorders in patients with Hypereosinophilia: A reference laboratory experience

Hypereosinophilia (HE) is defined as persistently elevated absolute eosinophil count (AEC) ≥ 1.5 × 109/L, which can be due to a variety of underlying causes. In this study, we investigated the prevalence and spectrum of T-cell lymphoproliferative disorders in 124 consecutive patients with HE by flow cytometric immunophenotyping. Available medical records, pathology reports and T-cell receptor (TCR) gene rearrangement were reviewed. Fifteen patients (12%) with HE had abnormal T-cell populations that were initially detected by flow cytometry. The presence of immunophenotypically abnormal T cells was not associated with higher AEC or higher absolute lymphocyte count levels, in comparison to those without abnormal T cells. Molecular studies concordantly identified a clonal TCR gene rearrangement in 8 of 10 cases tested. Based on the combination of clinical presentation, morphologic findings and laboratory studies, seven patients were diagnosed with the lymphocytic variant of hypereosinophilic syndrome and five with overt T-cell lymphoma (4 peripheral T-cell lymphoma NOS, 1 primary cutaneous T-cell lymphoma). The remaining three had an unknown diagnosis due to lack of information and additional workup would be warranted. These findings underscore the importance of flow cytometry as a screening tool to identify T-cell lymphoproliferative disorders in patients with HE.