Successful abatacept treatment for Felty’s syndrome in a patient with rheumatoid arthritis

Abstract Objectives Approximately 15% of patients with T-cell large granular lymphocytic leukemia (T-LGLL) have rheumatoid arthritis (RA). RA-associated T-LGLL with low large granular lymphocyte counts (aleukemic presentation) and Felty's syndrome (FS) have indistinguishable clinical presentations. These disorders are distinguished by T-cell clonality which is observed in T-LGLL but not in FS. Activating somatic mutations in the signal transducer and activator of transcription 3 (STAT3) and 5 (STAT5b) genes are involved in T-LGLL pathogenesis; however, the prevalence of these mutations in FS is unknown.Methods Based on the rearrangements of T-cell receptor (TCR) gamma and beta genes according to the BIOMED-2 protocol, we examined T-cell clonality in 81 patients with RA and unexplained neutropenia. We stratified these patients by the presence or absence of T-cell clonality, respectively, into 2 groups: RA-associated T-LGLL (56 patients) and FS (25 patients). Allele-specific TaqMan Real-Time polymerase chain reaction assay was employed to detect point somatic mutations in STAT3 and STAT5b genes in each group.Results Mutations of the STAT3 gene were detected in none of the 24 cases of FS and in 22 of 56 cases of RA-associated T-LGLL (39%) (p < 0.001). No mutation of the STAT5b gene was detected in any of the patients in each group.Conclusions Although further data are needed, our results suggest that activating somatic mutations in STAT3 and STAT5b genes are not involved in the pathogenesis of FS.

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Analysis of a single-institution cohort of patients with Felty's syndrome and T-cell large granular lymphocytic leukemia in the setting of rheumatoid arthritis

Rheumatology International ◽

10.1007/s00296-020-04757-4 ◽

2020 ◽

Author(s):

Vadim Romanovich Gorodetskiy ◽

Yulia Vladimirovna Sidorova ◽

Natalia Alexandrovna Kupryshina ◽

Vladimir Ivanovich Vasilyev ◽

Natalya Alexandrovna Probatova ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

T Cell ◽

Laboratory Data ◽

Gene Mutations ◽

Lymphocytic Leukemia ◽

Felty's Syndrome ◽

Large Granular Lymphocytic Leukemia ◽

Felty’S Syndrome ◽

T Cell Clonality ◽

Cell Clonality

AbstractT-cell large granular lymphocytic leukemia (T-LGLL) is a lymphoproliferative disorder characterized by a persistent increase in the number of large granular lymphocytes (LGLs), neutropenia, and splenomegaly. Clinical manifestations of T-LGLL in the setting of rheumatoid arthritis (RA) are often identical to those in which one would suspect Felty's syndrome (FS). These disorders are distinguished by the presence of T-cell clonality, which is present in T-LGLL but not in FS. Mutations in the signal transducer and activator of transcription 3 (STAT3) and 5b (STAT5b) genes can be used as molecular markers of T-LGLL, but their prevalence in FS is unknown.Eighty-one patients with RA and unexplained neutropenia or/and an increase in the number of LGLs above 2 × 109/L were stratified into RA-associated T-LGLL (N = 56) or FS (N = 25) groups based on the presence or absence of T-cell clonality. STAT3 and STAT5b gene mutations were assessed in each group by means of allele-specific polymerase chain reaction assays. Clinical, immunological, laboratory data and the results of immunophenotyping of blood and bone marrow lymphocytes were also evaluated.Mutations of the STAT3 gene and an increase in the number of LGLs above 2 × 109/L were detected in RA-associated T-LGLL, but not in FS (39% vs 0% and 21% vs 0%, respectively). Mutations in the STAT5b gene were not observed in either group. Expression of CD57, CD16, and CD5−/dim on CD3+CD8+ T-lymphocytes was observed in both RA-associated T-LGLL and FS.STAT3 gene mutations or LGL counts over 2 × 109/L in RA patients are indicative of T-LGLL.

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