Clinical analysis of 52 patients with granular lymphocyte proliferative disorder (GLPD) showed frequent anemia in indolent T-cell GLPD in Japan

Large Granular Lymphocytic Leukemia: Clinical Features, Molecular Pathogenesis, Diagnosis and Treatment

Large granular lymphocytic (LGL) leukemia is a lymphoproliferative disorder characterized by persistent clonal expansion of mature T- or natural killer cells in the blood via chronic antigenic stimulation. LGL leukemia is associated with specific immunophenotypic and molecular features, particularly STAT3 and STAT5 mutations and activation of the JAK-STAT3, Fas/Fas-L and NF-κB signaling pathways. Disease-related deaths are mainly due to recurrent infections linked to severe neutropenia. The current treatment is based on immunosuppressive therapies, which frequently produce unsatisfactory long-term responses, and for this reason, personalized approaches and targeted therapies are needed. Here, we discuss molecular pathogenesis, clinical presentation, associated autoimmune disorders, and the available treatment options, including emerging therapies.

Large granular lymphocyte leukemia: An indolent clonal proliferative disease associated with an array of various immunologic disorders

Large granular lymphocyte leukemia (LGLL) is a chronic lymphoproliferative disorder characterized by the proliferation of T or NK cytotoxic cells in the peripheral blood, the spleen and the bone marrow. Neutropenia leading to recurrent infections represents the main manifestation of LGLL. One specificity of LGLL is its frequent association with auto-immune disorders, among them first and foremost rheumatoid arthritis, and other hematologic diseases, including pure red cell aplasia and bone marrow failure. The large spectrum of manifestations and the classical indolent course contribute to the diagnosis difficulties and the frequency of underdiagnosed cases. Of importance, the dysimmune manifestations disappear with the treatment of LGLL as the blood cell counts normalize, giving a strong argument for a pathological link between the two entities. The therapeutic challenge results from the high rate of relapses following the first line of immunosuppressive drugs. New targeted agents, some of which are currently approved in autoimmune diseases, appear to be relevant therapeutic strategies to treat LGLL, by targeting key activated pathways involved in the pathogenesis of the disease, including JAK-STAT signaling.

Incidence of acquired pure red cell aplasia: a nationwide epidemiologic analysis with 2 registry databases in Japan

Acquired pure red cell aplasia (PRCA) is a rare syndrome characterized by anemia with reticulocytopenia and a marked reduction in erythroid precursors. Given its rarity, the true incidence is largely unknown, and epidemiological data representing the general population, with a description of the full spectrum of etiologies, are scarce. An epidemiological study on PRCA in Japan conducted 30 years ago estimated the annual incidence as 0.3 per million. To update the data and investigate the incidence and demographics of PRCA, we conducted a nationwide epidemiological study using the Japanese Society of Hematology (JSH) Hematologic Disease Registry, a hematologic disease registration database managed by the JSH and the Diagnosis Procedure Combination (DPC) study data available at a website of the Ministry of Health, Labor, and Welfare (MHLW) of Japan. A total of 1055 patients with newly diagnosed acquired PRCA were identified between 2012 and 2019, and the average annual incidence was calculated at 1.06 (95% confidence interval [CI], 0.83-1.28) per million. The median age was 73 (range, 18-99) years. The female-to-male ratio was 1.5:1, and the female predominance was most prominent in the child-bearing age group. Sixty-nine percent of acquired PRCA was idiopathic. The incidence of PRCA was approximately 20% of that of aplastic anemia (AA) during the same period. Approximately 0.98 patients per million per year (95% CI, 0.89-1.07) required hospitalization for the treatment of PRCA. These results are expected to contribute to the discussion of resource allocation for PRCA in the aging population in many countries, including Japan.

Clinical characteristics and outcomes of 100 adult patients with pure red cell aplasia

Adult pure red cell aplasia (PRCA) is a rare syndrome characterized by a severe normocytic anemia, reticulocytopenia, and absence of erythroblasts from bone marrow. The standard treatment has not yet been established for PRCA, although cyclosporine (CsA), corticosteroids (CS) showed a response in PRCA. We retrospectively analyzed the clinical data of 60 primary and 40 secondary adult patients with acquired PRCA. The proportion of secondary PRCA is relatively high and commonly associated with large granular lymphocyte leukemia (LGLL) (28 cases, 70.0%). The remission-induced regimens included CS, CsA, or other agents, and the response rate was 66.7%, 71.4%, and 50%, respectively (P = 0.336). When treating with CsA, the response rate of LGLL-associated PRCA was lower than primary PRCA (42.1% vs 85.7%, P = 0.001). Logistic regression analysis showed that ORR was inversely related to LGLL-associated PRCA. LGLL-associated PRCA had poor therapeutic efficacy to CsA.

Pathophysiologic Mechanisms And Management Of Large Granular Lymphocytic Leukemia Associated Pure Red Cell Aplasia

Large granular lymphocytic leukemia (LGLL) is a chronic clonal lymphoproliferative disease of mature T or NK cells, and produces a variety of hematological abnormalities. Pure red cell aplasia (PRCA) is a rare haematological disease and is one of the most common complications of LGLL. LGLL-associated PRCA may represent a relatively indolent type and may be more common than reported, but its natural history and clinical course have not been well described. The ethnic origin of the patients is an important consideration in determining the relationship between PRCA and LGLL. Guidelines and progresses for management of LGLL-associated PRCA rely on accumulation of empirical experiences, integrative analyses of several cases and clinical trials. The purpose of this review is to evaluate occurrence, possible mechanisms, diagnosis, clinical features, treatments and outcomes of LGLL-associated PRCA.

Clinical Features, Pathogenesis, and Treatment of Large Granular Lymphocyte Leukemias

Large granular lymphocytes (LGLs) are large lymphocytes with azurophilic granules in their cytoplasm. LGLs are either natural killer (NK) cells or T lymphocytes. Expansions of the LGLs in the peripheral blood are seen in various conditions, including three clonal disorders: T-cell LGL (T-LGL) leukemia, chronic lymphoproliferative disorders of NK cells (CLPD-NK), and aggressive NK-cell leukemia (ANKL). However, the monoclonal and polyclonal expansion of LGLs has been associated with many other conditions. The present article describes these LGL disorders, with special emphasis on the clinical features, pathogenesis, and treatments of the three above-mentioned clonal disorders.

Cell size variations of large granular lymphocyte leukemia: Implication of a small cell subtype of granular lymphocyte leukemia with STAT3 mutations

Large granular lymphocyte leukemia (LGL-L) has been morphologically defined as a group of lymphoproliferative disorders, including T-cell large granular lymphocytic leukemia (T-LGL-L), chronic lymphoproliferative disorders of NK cells (CLPD-NK) and aggressive NK cell leukemia. We investigated the morphological features of LGL leukemic cells in 26 LGL-L patients in order to elucidate relationships with current classifications and molecular backgrounds. LGL-L cells were mostly indistinguishable from normal LGL. Patients with STAT3 SH2 domain mutations showed significantly smaller cells compared with patients without STAT3 mutations. Four patients with T-LGL-L showed smaller granular lymphocytes with a median diameter of less than 13μm, which were rarely seen in normal subjects. This small subtype of T-LGL-L was recognized among rather young patients and was associated with D661Y mutations in the STAT3 gene SH2 domain. In addition, all of them showed anemia including two cases with pure red cell aplasia. These results suggest the heterogeneity of T-LGL-L and a specific subtype with small variants of T-LGL-L.

STAT3 gene mutations and their association with pure red cell aplasia in large granular lymphocyte leukemia

Large granular lymphocyte leukemia (LGL L) has been morphologically characterized as a group of lymphoproliferative diseases that include T-cell large granular lymphocytic leukemia (T-LGL L) and chronic lymphoproliferative disorders of natural killer cells (CLPD-NK). We investigated mutations in the Src homology 2 (SH2) domain of the signal transducer and activator of transcription 3 (STAT3) gene in Asian cohorts of T-LGL L and CLPD-NK (n = 42 and 11, respectively). Two mutations, Y640F and D661Y, were identified using direct sequencing or allele-specific (AS) PCR. Y640F and D661Y mutations were found in seven and 18 patients, respectively. Two patients were positive for both mutations. Frequencies of STAT3 mutations in T-LGL L and CLPD-NK were 47.6% and 27.2%, respectively. Pure red cell aplasia (PRCA) was associated with the mutations (P = 0.005). The mutations were persistently found at stable levels in some patients after more than 5 years using AS-quantitative PCR. The results of the present study indicate that the SH2 domain of the STAT3 gene is frequently mutated in Asian T-LGL L and CLPD-NK, and that PRCA is closely correlated with the mutations.

STAT3 mutations are frequent in T-cell large granular lymphocytic leukemia with pure red cell aplasia

T-cell large granular lymphocytic leukemia (T-LGLL) is a rare lymphoproliferative disorder and can cooccur in the context of pure red cell aplasia (PRCA). The aim of the current study was to analyze the signal transducer and activator of transcription 3 (STAT3) mutation status and its clinical significance in T-LGLL. We found STAT3 mutations in 21.4% of patients with T-LGLL. High β2-MG (β2-microglobulin) levels (P = 0.005), neutropenia (P = 0.018) and PRCA (P = 0.001) all displayed a significant association with STAT3 mutations. In univariate analysis, treatment-free survival (TFS) was affected by STAT3 mutation status (P = 0.008) and β2-MG (P = 0.006). Our results demonstrate the remarkable correlation of STAT3 mutation with PRCA, neutropenia and β2-MG.

T-cell large granular lymphocyte leukemia: an Asian perspective

To characterize T-cell large granular leukemia in Asia, 22 Chinese patients from a single institute were reported, together with an analysis of 88 Asian and 272 Western patients identified from the literature. In our cohort, anemia due to pure red cell aplasia (PRCA) occurred in 15/22 (68%) of cases, being the most common indication for treatment. Neutropenia was only found in 8/22 (36%) cases, and recurrent infections, the most important clinical problem in Western patients, were not observed. None of our cases presented with rheumatoid arthritis. These clinical features were consistently observed when compared with the 88 other Asian patients. Combined data from our cohort and other Asian cases showed that Asian patients, compared with Western patients, had more frequent anemia (66/110, 60% versus 113/240, 47%; p=0.044), attributable to a much higher incidence of PRCA (52/110, 47% versus 6/143, 4%; p<0.001). However, Western patients presented more frequently than Asian patients with neutropenia (146/235, 62% versus 33/110, 30%; p<0.001) and splenomegaly (99/246, 40% versus 16/110, 15%; p< 0.001). Notably, Western patients were about eight to ten times more likely than Asian patients to have rheumatoid arthritis (73/272, 27% versus 4/106, 4%; p<0.001) and recurrent infections (81/272, 30% versus 3/107, 3%; p<0.001). These clinicopathologic differences have important implications on disease pathogenesis and treatment.