AB0183 T-CELL LARGE GRANULAR LYMPHOCYTE LEUKEMIA IN PATIENTS WITH FELTY’S SYNDROME
Authors: V. Vasiliev, V. Gorodetskiy, B. Chalcev, S. Palshina, E. Sokol, A. Torgashina, J. Khvan
Journal: Annals of the Rheumatic Diseases (2021)

Background: Felty’s syndrome (FS) is a rare subtype of seropositive rheumatoid arthritis (RA) and is characterized by neutropenia and splenomegaly. Some researchers suggest that FS and T-cell large granular leukemia (T-LGLL) may have common pathogenetic relationships [1]. Objectives: to characterize the clinical and laboratory manifestations of FS, to evaluate the frequency of T-LGLL and Sjogren’s syndrome (SS) in this group of patients with RA, neutropenia and splenomegaly (pts). Methods: We observed 18 pts with ACCP-positive (100%) and RF-positive (94.5%) RA diagnosed according to ACR 2010 criteria, who also had neutropenia and hepatosplenomegaly. All 18 pts underwent T-LGLL diagnostics using blood smears and phenotyping of peripheral lymphocytes for the presence of granular lymphocytes, determination of T-cell clonality using the rearrangement of the γ-chain of the T-cell receptor of lymphocytes by PCR, histological/immunohistochemical study of bone marrow biopsy specimens for the presence of LGL invasion studies, as well as the study of 4 spleens after splenectomy. SS was diagnosed in 8 out of 18 pts (44.5%) according ACR 2016 criteria. Results: Twelve (66.6%) of 18 pts with RA, neutropenia and splenomegaly were diagnosed with T-LGLL, the patients were divided in 2 groups: FS (6 pts) and RA+T-LGL (12 pts). Pts with FS debuted with arthritis of small hand joints, extremely rarely with extra-articular manifestations, mainly at a young age (36.5±3.9 years), and developed neutropenia after 10 years of RA. Pts with T-LGLL debuted at a younger age (39,5±4,5 and 51,5 + 7,8 years, respectively), had a longer course of RA before the development of neutropenia (14.3±3.3 and 5±1.5 years, respectively, p=0.03), and more often had extra-articular manifestations at the onset of the disease. RA activity did not differ between groups and in most cases was characterized by a mild course of articular syndrome. Though the course of RA+T-LGLL group was characterized by low (50%) and moderate (33%) DAS28-CRP activity and active synovitis in only 41.5% of pts, severe joint deformities (stage III and IV) developed in 58.5% of pts. Pts with T-LGLL showed a higher incidence of hepatomegaly (75% and 16.5%, respectively, p=0.02) and more severe neutropenia (p=0.02). The development of severe leukopenia (&lt;1x10 9 ) and massive hepatosplenomegaly was observed only in pts with T-LGLL, which required splenectomy in 4 cases. SS was more often detected in the FS group than in the RA+T-LGLL group (83.5% and 25%, respectively, p = 0.02). Conclusion: Clinical and laboratory manifestations of FS and T-LGLL are extremely close, therefore, pts who are diagnosed with FS should be examined to exclude T-LGLL. References: [1]Liu, Xin, and Thomas P Loughran Jr. “The spectrum of large granular lymphocyte leukemia and Felty’s syndrome.” Current opinion in hematology vol. 18,4 (2011): 254-9. doi:10.1097/MOH.0b013e32834760fb. Disclosure of Interests: None declared