Prevalence of STAT3 mutations in patients with rheumatoid arthritis-associated T-cell large granular lymphocytic leukaemia and Felty syndrome

OBJECTIVES

Neutropenia is a key presentation of Felty syndrome (FS) and rheumatoid arthritis (RA)-associated T-cell large granular lymphocytic (T-LGL) leukaemia. Clonal rearrangement of T-cell receptor (TCR) gene supports the diagnosis of T-LGL leukaemia but not FS. Mutations in the signal transducer and activator of transcription 3 (STAT3) gene are highly specific for T-LGL leukaemia, but their prevalence in FS remains poorly clarified.

METHODS

The study included 100 patients with RA and unexplained neutropenia. TCR rearrangements were examined in blood (100 cases), bone marrow (47 cases), and spleen (12 cases) using the BIOMED-2 protocol. Patients were stratified into RA-associated T-LGL leukaemia cohort if a clonal TCR rearrangement was identified in any of the tested patient samples, and into FS cohort in other cases. Mutations in the STAT3 were examined using next-generation sequencing (NGS) technology in blood (100 cases), bone marrow (37 cases), and spleen (7 cases).

RESULTS

STAT3 mutations were identified in 71% (49/69) patients with RA-associated T-LGL leukaemia and in 10% (3/31) patients with FS (p=4.7×10-8). Three samples from the RA-associated T-LGL leukaemia cohort and 5 samples from the FS cohort had STAT3 mutations in the absence of clonal TCR rearrangement.

CONCLUSIONS

The results suggest that STAT3 mutations are significantly less common in FS than in RA-associated T-LGL leukaemia. Moreover, NGS can detect clones undetectable by fragment analysis. We speculate that in patients with RA and neutropenia, the detection of STAT3 mutations can point to T-LGL leukaemia even in the absence of clonal TCR rearrangement.

Other malignancies in the history of CLL: an international multicenter study conducted by ERIC, the European Research Initiative on CLL, in HARMONY

Background

Patients with chronic lymphocytic leukemia (CLL) have a higher risk of developing other malignancies (OMs) compared to the general population. However, the impact of CLL-related risk factors and CLL-directed treatment is still unclear and represents the focus of this work.

Methods

We conducted a retrospective international multicenter study to assess the incidence of OMs and detect potential risk factors in 19,705 patients with CLL, small lymphocytic lymphoma, or high-count CLL-like monoclonal B-cell lymphocytosis, diagnosed between 2000 and 2016. Data collection took place between October 2020 and March 2022.

Findings

In 129,254 years of follow-up after CLL diagnosis, 3513 OMs were diagnosed (27.2 OMs/1000 person-years). The most common hematological OMs were Richter transformation, myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Non-melanoma skin (NMSC) and prostate cancers were the most common solid tumors (STs).The only predictor for MDS and AML development was treatment with fludarabine and cyclophosphamide with/without rituximab (FC ± R) (OR = 3.7; 95% CI = 2.79-4.91; p < 0.001). STs were more frequent in males and patients with unmutated immunoglobulin heavy variable genes (OR = 1.77; 95% CI = 1.49-2.11; p < 0.001/OR = 1.89; 95% CI = 1.6-2.24; p < 0.001).CLL-directed treatment was associated with non-melanoma skin and prostate cancers (OR = 1.8; 95% CI = 1.36-2.41; p < 0.001/OR = 2.11; 95% CI = 1.12-3.97; p = 0.021). In contrast, breast cancers were more frequent in untreated patients (OR = 0.17; 95% CI = 0.08-0.33; p < 0.001).Patients with CLL and an OM had inferior overall survival (OS) than those without. AML and MDS conferred the worst OS (p < 0.001).

Interpretation

OMs in CLL impact on OS. Treatment for CLL increased the risk for AML/MDS, prostate cancer, and NMSC. FCR was associated with increased risk for AML/MDS.

Funding

AbbVie, and EU/EFPIAInnovative Medicines Initiative Joint Undertaking HARMONY grant n° 116026.

Ibrutinib in combination with rituximab is highly effective in treatment of chronic lymphocytic leukemia patients with steroid refractory and relapsed autoimmune cytopenias

Autoimmune hemolytic anemia (AIHA) and pure red cell aplasia (PRCA) are common complications of CLL. The optimal treatment of steroid refractory AIHA/PRCA is not well established. We conducted a multicenter study of ibrutinib and rituximab in patients with relapsed/refractory to steroids AIHA/PRCA and underlying CLL. Protocol included induction (ibrutinib 420 mg/day and rituximab, 8 weekly and 4 monthly infusions) and maintenance phase with ibrutinib alone until progression or unacceptable toxicity. Fifty patients were recruited (44-warm AIHA, 2-cold AIHA, 4-PRCA). After the induction 34 patients (74%) have achieved complete response, 10 (21.7%) partial response. Median time to hemoglobin normalization was 85 days. With regards to CLL response 9 (19%) patients have achieved CR, 2 (4%) patients-stabilization and 39 (78%)-PR. The median follow-up was 37.56 months. In AIHA group 2 patients had a relapse. Among 4 patients with PRCA 1 patient did not respond, and 1 patient had a relapse after CR, 2 remained in CR. The most common adverse events were neutropenia (62%), infections (72%), gastrointestinal complications (54%). In conclusion ibrutinib in combination with rituximab is an active second-line treatment option for patients with relapsed or refractory AIHA/PRCA and underlying CLL.

Loss of Heterozygosity in the Circulating Tumor DNA and CD138+ Bone Marrow Cells in Multiple Myeloma

Multiple myeloma (MM) is characterized by heterogeneity of tumor cells. The study of tumor cells from blood, bone marrow, plasmacytoma, etc., allows us to identify similarities and differences in tumor lesions of various anatomical localizations. The aim of this study was to compare the loss of heterozygosity (LOH) by tumor cells by assessing STR profiles of different MM lesions. We examined paired samples of plasma circulating tumor DNA (ctDNA) and CD138+ bone marrow cells in MM patients. For patients with plasmacytomas (66% of 38 patients included), the STR profile of plasmacytomas was also studied when biopsy samples were available. Diverse patterns of LOH were found in lesions of different localization for most patients. LOH in plasma ctDNA, bone marrow, and plasmacytoma samples was found for 55%, 71%, and 100% of patients, respectively. One could expect a greater variety of STR profiles in aberrant loci for patients with plasmacytomas. This hypothesis was not confirmed-no difference in the frequency of LOH in MM patients with or without plasmacytomas was found. This indicates the genetic diversity of tumor clones in MM, regardless of the presence of extramedullar lesions. Therefore, we conclude that risk stratification based on molecular tests performed solely on bone marrow samples may not be sufficient for all MM patients, including those without plasmacytomas. Due to genetic heterogeneity of MM tumor cells from various lesions, the high diagnostic value of liquid biopsy approaches becomes obvious.

Clinical Study of the Relationship between Sjögren Syndrome and T-Cell Large Granular Lymphocytic Leukemia: Single-Center Experience

The relationship between Sjögren syndrome (SS) and T-cell large granular lymphocytic (T-LGL) leukemia remains unclear. In this paper, we report for the first time a large case series of 21 patients with primary and secondary SS associated with T-LGL leukemia. Our results suggest the importance of considering T-LGL leukemia in the diagnostic evaluation of SS patients, particularly when neutropenia occurs. We also postulate that elevated antinuclear antibody titers in patients with T-LGL leukemia indicate the need for the clinical assessment of SS. To assess whether SS affects the frequency of the signal transducer and activator of transcription 3 (STAT3) gene mutations in T-LGL leukemia, we examined STAT3 mutations by next-generation sequencing in two cohorts of patients: with SS-associated T-LGL leukemia and T-LGL leukemia in the setting of rheumatic diseases but without SS. While our results suggest that SS, per se, is not associated with an increased frequency of STAT3 mutations in T-LGL leukemia, further studies are needed to better assess the role of the STAT pathway in the development of concomitant SS and T-LGL leukemia.

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.

SARS-CoV-2 Epitopes Are Recognized by a Public and Diverse Repertoire of Human T Cell Receptors

Understanding the hallmarks of the immune response to SARS-CoV-2 is critical for fighting the COVID-19 pandemic. We assessed antibody and T cell reactivity in convalescent COVID-19 patients and healthy donors sampled both prior to and during the pandemic. Healthy donors examined during the pandemic exhibited increased numbers of SARS-CoV-2-specific T cells, but no humoral response. Their probable exposure to the virus resulted in either asymptomatic infection without antibody secretion or activation of preexisting immunity. In convalescent patients, we observed a public and diverse T cell response to SARS-CoV-2 epitopes, revealing T cell receptor (TCR) motifs with germline-encoded features. Bulk CD4+ and CD8+ T cell responses to the spike protein were mediated by groups of homologous TCRs, some of them shared across multiple donors. Overall, our results demonstrate that the T cell response to SARS-CoV-2, including the identified set of TCRs, can serve as a useful biomarker for surveying antiviral immunity.

Inhibition of potassium currents as a pharmacologic target for investigation in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) represents 22-30% of all leukemia cases, thus being the most commonly diagnosed form of adult leukemia in the Western world. On a cellular level, the disease progresses due to the prolonged survival of B-cell CLL cells arrested in the G₀ stage of the cell cycle. The current standard treatment for CLL is a combination regimen containing purine analogues and monoclonal antibodies. Although response rates to such regimens in previously untreated patients are high, patients with CLL invariably experience relapse and often acquire high-risk chromosomal abnormalities. Therefore, the search for novel avenues in CLL treatment is warranted. In this manuscript, we will describe theoretical premises and some preliminary data making the case for inhibitors of the potassium currents as possible proapoptotic agents that warrant investigation as a potential pharmacologic target in CLL.