Generation and External Validation of a Histologic Transformation Risk Model for Patients with Follicular Lymphoma.

Follicular lymphoma (FL) is the most frequent indolent lymphoma. Some patients (10%-15%) experience histologic transformation (HT) to a more aggressive lymphoma, usually diffuse large B-cell lymphoma (DLBCL). This study aimed to validate and improve a genetic risk model to predict HT at diagnosis.We collected mutational data from diagnosis biopsies of 64 FL patients. We combined them with the data from a previously published cohort (total n = 104; 62 from nontransformed and 42 from patients who did transform to DLBCL). This combined cohort was used to develop a nomogram to estimate the risk of HT. Prognostic mutated genes and clinical variables were assessed using Cox regression analysis to generate a risk model. The model was internally validated by bootstrapping and externally validated in an independent cohort. Its performance was evaluated using a concordance index and a calibration curve. The clinicogenetic nomogram included the mutational status of 3 genes (HIST1HE1, KMT2D, and TNFSR14) and high-risk Follicular Lymphoma International Prognostic Index and predicted HT with a concordance index of 0.746. Patients were classified as being at low or high risk of transformation. The probability HT function at 24 months was 0.90 in the low-risk group vs 0.51 in the high-risk group and, at 60 months, 0.71 vs 0.15, respectively. In the external validation cohort, the probability HT function in the low-risk group was 0.86 vs 0.54 in the high-risk group at 24 months, and 0.71 vs 0.32 at 60 months. The concordance index in the external cohort was 0.552. In conclusion, we propose a clinicogenetic risk model to predict FL HT to DLBLC, combining genetic alterations in HIST1H1E, KMT2D, and TNFRSF14 genes and clinical features (Follicular Lymphoma International Prognostic Index) at diagnosis. This model could improve the management of FL patients and allow treatment strategies that would prevent or delay transformation.

A framework for the clinical implementation of optical genome mapping in hematologic malignancies.

Optical Genome Mapping (OGM) is rapidly emerging as an exciting cytogenomic technology both for research and clinical purposes. In the last 2 years alone, multiple studies have demonstrated that OGM not only matches the diagnostic scope of conventional standard of care cytogenomic clinical testing but it also adds significant new information in certain cases. Since OGM consolidates the diagnostic benefits of multiple costly and laborious tests (e.g., karyotyping, fluorescence in situ hybridization, and chromosomal microarrays) in a single cost-effective assay, many clinical laboratories have started to consider utilizing OGM. In 2021, an international working group of early adopters of OGM who are experienced with routine clinical cytogenomic testing in patients with hematological neoplasms formed a consortium (International Consortium for OGM in Hematologic Malignancies, henceforth "the Consortium") to create a consensus framework for implementation of OGM in a clinical setting. The focus of the Consortium is to provide guidance for laboratories implementing OGM in three specific areas: validation, quality control and analysis and interpretation of variants. Since OGM is a complex technology with many variables, we felt that by consolidating our collective experience, we could provide a practical and useful tool for uniform implementation of OGM in hematologic malignancies with the ultimate goal of achieving globally accepted standards.

High-throughput RNA sequencing of the T cell receptor alpha and beta chains for simultaneous clonality and biological analyses in Sezary syndrome.

BACKGROUND: Previous investigations pointed out a role for antigen stimulation in Sezary syndrome (SS). High-throughput sequencing of the T cell receptor (TR) offers several applications beyond diagnostic purposes, including the study of T cell pathogenesis. METHODS: We performed high-throughput RNA sequencing of the TR alpha (TRA) and beta (TRB) genes focusing on the complementarity-determining region 3 (CDR3) in 11 SS and one erythrodermic mycosis fungoides (MF) patients. Five psoriasis patients were employed as controls. Peripheral blood CD4+ cells were isolated and RNA sequenced (HiSeq2500). High-resolution HLA typing was performed in neoplastic patients. RESULTS: Highly expanded predominant TRA and TRB CDR3 were only found in SS patients (median frequency: 94.4% and 93.7%). No remarkable CDR3 expansions were observed in psoriasis patients (median frequency of predominant TRA and TRB CDR3: 0.87% and 0.69%, p < 0.001 compared to SS). CDR3 almost identical to the predominant were identified within each SS patient and were exponentially correlated with frequencies of the predominant CDR3 (R2 = 0.918, p < 0.001). Forty-six different CDR3 were shared between SS patients displaying HLA similarities, including predominant TRA and TRB CDR3 in one patient that were found in other three patients. Additionally, 351 antigen matches were detected (Cytomegalovirus, Epstein-Barr, Influenza virus, and self-antigens), and the predominant CDR3 of two different SS patients matched CDR3 with specificity for Influenza and Epstein-Barr viruses. CONCLUSIONS: Besides detecting clonality, these findings shed light on the nature of SS-related antigens, pointing to RNA sequencing as a useful tool for simultaneous clonality and biological analysis in SS.

Spontaneous Regression Accompanied by Concomitant Immune Alterations in a Patient with Chronic Lymphocytic Leukemia.

Spontaneous regression (SR) of chronic lymphocytic leukemia (CLL) is a rare event (0.2% - 1%). Some advances have been made in understanding the tumor genetic characteristics of such patients, although the immunological mechanisms leading to SR remain unclear. We describe a series of immunological events related to regression dynamics, allowing the identification of a SR phase (associated with >99% reduction of CLL cells in peripheral blood and adenopathy resolution in less than one year, concurrently with a nine-fold increase in monocyte counts, high B2M and the appearance of an oligoclonal serum IgG band), followed by a persistent regression (PR) phase that was maintained for ≥17 months. Our observations highlight a role of monocytes and B2M in SR, potentially related to immune activation. The oligoclonal IgG band detected during SR was maintained in PR, suggesting either a change in the ability of malignant cells (IgM+IgD+IgG‒) to differentiate into IgG-secreting cells, or an anti-tumor humoral response from normal B cells. These findings imply immune and molecular mechanisms required to eliminate malignant cells and might suggest new immunotherapies for CLL.

Complex Karyotype Detection in Chronic Lymphocytic Leukemia: A Comparison of Parallel Cytogenetic Cultures Using TPA and IL2+DSP30 from a Single Center.

Current CLL guidelines recommend a two parallel cultures assessment using TPA and IL2+DSP30 mitogens for complex karyotype (CK) detection. Studies comparing both mitogens for CK identification in the same cohort are lacking. We analyzed the global performance, CK detection, and concordance in the complexity assessment of two cytogenetic cultures from 255 CLL patients. IL2+DSP30 identified more altered karyotypes than TPA (50 vs. 39%, p = 0.031). Moreover, in 71% of those abnormal by both, IL2+DSP30 identified more abnormalities and/or abnormal metaphases. CK detection was similar for TPA and IL2+DSP30 (10% vs. 11%). However, 11/33 CKs (33%) were discordant, mainly due to the detection of a normal karyotype or no metaphases in the other culture. Patients requiring treatment within 12 months after sampling (active CLL) displayed significantly more CKs than those showing a stable disease (55% vs. 12%, p < 0.001). Disease status did not impact cultures' concordance (κ index: 0.735 and 0.754 for stable and active). Although CK was associated with shorter time to first treatment (TTFT) using both methods, IL2+DSP30 displayed better accuracy than TPA for predicting TTFT (C-index: 0.605 vs. 0.580, respectively). In summary, the analysis of two parallel cultures is the best option to detect CKs in CLL. Nonetheless, IL2+DSP30 could be prioritized above TPA to optimize cytogenetic assessment in clinical practice.

Linfocitosis B policlonal persistente: estudio de 35 casos / Persistent polyclonal B-cell lymphocytosis: study of 35 cases

Fundamento y objetivo: La linfocitosis B policlonal persistente (LBPP) es una entidad muy poco frecuente que se relaciona con el tabaquismo e incide especialmente en mujeres. Cursa con aumento de IgM sérica, asociación al haplotipo HLA-DR7, anomalías citogenéticas y múltiples reordenamientos de IgH/BCL-2. Todavía no está clara su naturaleza premaligna o benigna. El objetivo de este trabajo fue analizar las características de la LBPP con especial interés en su evolución. Pacientes y método: Se han estudiado retrospectivamente 35 LBPP de 5 hospitales catalanes. Se realizó una valoración morfológica de las extensiones de sangre por los miembros del Grup Català de Citologia Hematològica (GCCH) en un microscopio de 16 cabezales y se analizaron los datos clínicos y biológicos. Resultados: La LBPP se presentó, en la mayoría de los casos, como linfocitosis en mujeres fumadoras. El distintivo morfológico es la presencia de linfocitos de aspecto activado, en ausencia de enfermedades víricas recientes, y de linfocitos bilobulados y/o hendidos, y algunos con bolsillos nucleares observados por ultraestructura. En la mayoría de los casos estudiados se detectó: aumento policlonal de IgM, expresión del haplotipo HLA-DR7, anomalías cromosómicas como i(3)(q10) y múltiples reordenamientos de IgH/BCL-2. Con una mediana de seguimiento de 70,7 meses, 34 de los 35 pacientes permanecen asintomáticos y vivos, uno falleció por un adenocarcinoma de pulmón y otro desarrolló un linfoma folicular, sin demostración de relación alguna entre éste y la LBPP. Conclusiones: La LBPP presenta un curso estable y asintomático, y se acompaña con frecuencia de alteraciones genéticas. Se desconoce si es una situación premaligna, a semejanza de las gammapatías monoclonales de significado incierto. Por ello, es fundamental una correcta interpretación de la linfocitosis y un seguimiento evolutivo (AU)

Background and objectives: Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare entity, presenting especially in adult smoker women. It is characterized by an increase of serum IgM, DR7-HLA haplotype,cytogenetic abnormalities and multiple IgH/BCL-2 earrangements. To date, it has not been elucidatedwhether this is a benign or premalignant disorder. We analyzed the PPBL characteristics with especial attention to its evolution.Patients and methods: Thirty-five PPBL patients from 5 hospitals in Catalonia were retrospectivelyanalyzed. A simultaneous morphologic review of the blood smears was performed by members of the GCCH in a 16 multiple-observer optic microscope. Clinical and biological data were also analyzed. Results: PPBL presents in the majority of cases with persistent polyclonal B-cell lymphocytosis and affects primarily smoker women. The morphologic hallmark, in absence of viral infections, is the presence of activated lymphocytes with bilobulated and/or cleaved nuclei, and nuclear pockets in theultrastructural study. Increased serum IgM, HLA-DR7 haplotype, chromosomal abnormalities such asi(3)(q10) and multiple IgH/BCL-2 rearrangements were detected. Thirty-four out of 35 patients are alive after a median follow up of 70.7 months. One patient died because of lung adenocarcinoma and another developed a follicular lymphoma without relation to PPBL.Conclusions: PPBL has an asymptomatic and stable evolution, although it frequently presents genetic abnormalities. It remains unknown whether it is a premalignant entity, similar to monoclonal gammopathies of unknown significance. Hence, accurate cytologic diagnosis and follow-up are essential (AU)

Perineurioma intraneural de presentación intramandibular. Estudio histológico, inmunohistoquímico y citogenético / Intraosseous intraneural perineurioma: report of a case with morphological, immunohistochemical and fish study

Presentamos el caso de un perineurioma intraneural del nervio dentario, de localización intramandibular. Se trata de un tumor poco frecuente del que se ha discutido su origen neoplásico o reactivo: La localización intraósea en región de cabeza y cuello es excepcional. Definimos las características histológicas e inmunohistoquímicas de este tumor, estableciendo el diagnóstico diferencial con la variedad extraneural de perineurioma, con otros tumores de la vaina del nervio periférico más frecuentes en esta localización y con la neuropatía hipertrófica localizada, entidad reactiva con la cual se ha identificado a veces. Mediante la hibridización in situ con inmunofluorescencia se confirma el origen neoplásico del perineurioma (AU)