A case of canine renal lymphoma of granular lymphocytes with severe polycythemia

Background Renal lymphoma in dogs is rare and has a poor prognosis. Granular lymphocyte morphology is rarely reported in canine renal lymphoma. Mild to moderate polycythemia is reported in a number of canine renal lymphoma cases. Case presentation A 10-year-old Labrador retriever presented to a university veterinary teaching hospital after a 1-month history of polyuria, polydipsia, and pollakiuria and a 2-week history of abdominal distention, lethargy, and increased respiratory effort. Abdominal ultrasound showed a wedge-shaped to rounded, heterogeneously hypoechoic mass lesion in the left kidney. Cytologic analysis of a percutaneous aspirate of the mass was consistent with lymphoma of granular lymphocytes. Severe polycythemia (hematocrit 0.871) was noted on a complete blood cell count. Clonality analysis identified a clonally rearranged T-cell receptor (TCR) gene and immunohistochemical staining was CD3+, CD79a- and CD11d+, supporting cytotoxic T-cell lymphoma. Conclusions To our knowledge, this is the first report of renal cytotoxic T-cell lymphoma with severe polycythemia in a dog. Severe polycythemia and renal cytotoxic T-cell lymphoma are both rare in dogs; this report adds to the body of knowledge on these conditions.

STAT3 and STAT5B Mutations in T/NK-Cell Chronic Lymphoproliferative Disorders of Large Granular Lymphocytes (LGL): Association with Disease Features

STAT3 and STAT5B (STAT3/STAT5B) mutations are the most common mutations in T-cell large granular lymphocytic leukemia (T-LGLL) and chronic lymphoproliferative disorders of NK cells (CLPD-NK), but their clinical impact remains unknown. We investigated the frequency and type of STAT3/STAT5B mutations in FACS-sorted populations of expanded T/NK-LGL from 100 (82 clonal; 6 oligoclonal; 12 polyclonal) patients, and its relationship with disease features. Seventeen non-LGL T-CLPD patients and 628 age-matched healthy donors were analyzed as controls. STAT3 (n = 30) and STAT5B (n = 1) mutations were detected in 28/82 clonal T/NK-LGLL patients (34%), while absent (0/18, 0%) among oligoclonal/polyclonal LGL-lymphocytosis. Mutations were found across all diagnostic subgroups: TCD8+-LGLL, 36%; CLPD-NK, 38%; TCD4+-LGLL, 7%; Tαβ+DP-LGLL, 100%; Tαβ+DN-LGLL, 50%; Tγδ+-LGLL, 44%. STAT3-mutated T-LGLL/CLPD-NK showed overall reduced (p < 0.05) blood counts of most normal leukocyte subsets, with a higher rate (vs. nonmutated LGLL) of neutropenia (p = 0.04), severe neutropenia (p = 0.02), and cases requiring treatment (p = 0.0001), together with a shorter time-to-therapy (p = 0.0001), particularly in non-Y640F STAT3-mutated patients. These findings confirm and extend on previous observations about the high prevalence of STAT3 mutations across different subtypes of LGLL, and its association with a more marked decrease of all major blood-cell subsets and a shortened time-to-therapy.

Emergence of Natural Killer Cell Large Granular Lymphocytes during Gilteritinib Treatment in Acute Myeloid Leukemia with FLT3-ITD Mutation

As the potent, selective Fms-Like Tyrosine Kinase 3 (FLT3) inhibitor gilteritinib has only been approved for use for a few years, its efficacy and complications remain incompletely understood. We herein report an elderly patient with FLT3 internal tandem duplications (FLT3-ITD) mutated acute myeloid leukemia (AML) who developed natural killer cell large granular lymphocytes (NK-LGL) in the bone marrow and peripheral blood during gilteritinib treatment. Case: A 79-year-old Japanese female had been diagnosed with FLT3-ITD-mutated AML. The patient received hydroxycarbamide 2000 mg daily for induction chemotherapy but did not achieve remission at day 28 postinduction. The treatment was then changed to gilteritinib 120 mg daily. Although the reduction of blasts in peripheral blood occurred immediately, it was revealed abnormal lymphocytes with large granules developed in bone marrow and peripheral blood. These lymphocytes were analyzed by flow cytometry, which revealed that these cells were NK-LGL because they expressed CD2, CD7, CD16, and CD56 and did not express CD3, CD19, and CD20. The patient achieved partial remission (PR) in a month with gilteritinib treatment. Leukemia eventually could not be controlled, but PR persisted for about 4 months and leukemia was controlled for 4 months after progression disease (PD) with gilteritinib treatment alone. Conclusion: Gilteritinib may induce the NK-LGL. The exact mechanism and effect of LGL in patients with FLT3 mutated AML treated with gilteritinib warrants further investigation.

Silent NK/T Cell Reactions Against Dasatinib during Sustained Deep Molecular Response before Discontinuation Are Associated with Longer Treatment-Free Remission: A Multicenter, Single-Arm, Phase 2 Study

Introduction Tyrosine kinase inhibitors (TKIs) markedly enhance the prognosis of chronic myelogenous leukemia (CML), potentially enabling the attainment of deep molecular response (DMR). Subsequently, the discontinuation of TKI became imperative to evade adverse events and financial burden of TKI therapy. In several studies, beginning with the STIM1 (Lancet Oncol 2010;11:1029), nearly 40%-60% of patients with chronic CML who sustained long DMR could discontinue TKI and attain long-term treatment-free remission (TFR). Remarkably, initial dasatinib specifically induces the elevation in lymphocytes, including large granular lymphocytes (LGL), NK cells, and cytotoxic T cells, as well as the decline in regulatory T cells (Tregs) in the early phase of treatment, related to early clinical responses.(Int J Hematol 2014;99:41) Nevertheless, lymphocyte variations by dasatinib during sustained DMR before cessation is an area of growing interest. In the Japanese multicenter prospective D-STOP trial (NCT01627132), we discontinued dasatinib following 2-year consolidation to sustain DMR in chronic CML to assess the TFR rate. We here present the final results of the D-STOP trial, including the peripheral NK/T cell change during dasatinib consolidation associated with successful TFR. Methods: Chronic phase CML patients treated with TKIs who had undetectable BCR-ABL1 mRNA were enrolled. After confirmation of undetectable BCR-ABL1 mRNA (International Scale <0.01%) using a real-time quantitative polymerase chain reaction (RQ-PCR) in the central laboratory, the patient received additional dasatinib treatment for another 2 years as consolidation therapy. Patients who maintained DMR during the consolidation therapy proceeded to discontinue dasatinib. BCR-ABL1 mRNA was monitored every month in year 1 and every 3 months in year 2. Molecular relapse was defined as two successive positive RQ-PCRs for BCR-ABL1 within 1 month. The relapsed patients restarted dasatinib treatment. The primary endpoint was treatment-free survival after 12 months of discontinuation. Lymphocyte subsets were analyzed using flow cytometry during and after the consolidation therapy. Results: Sixty-five patients received consolidation therapy, and 54 discontinued dasatinib treatment after maintenance of DMR for 2 years. Estimated treatment-free remission (TFR) rates at 12 and 36 months were 63.0% [95% confidence interval (CI): 48.7-74.3] and 59.3% (95% CI: 45.0-71.0), respectively.(Figure 1) CD3-CD56+NK, CD16+CD56+NK, CD57+CD56+NK large granular lymphocytes (NK-LGL), CD8+CD4- cytotoxic T, and CD57+CD3+T-LGL cell numbers were relatively elevated throughout 24-month consolidation only in failed patients who molecularly relapsed within 12 months. In successful patients (TFR >12-months), these subsets elevated transiently after 12 months but returned to basal levels after 24-month consolidation. (Figure 2)There were no differences in CD8-CD4+ helper T and Treg. cell numbers during consolidation between 2 groups. Therefore, smaller changes in the NK/T sebsets, particularly NK subset throughout consolidation, exhibited higher TFR rates. TFR rates of those exhibiting elevation in CD3-CD56+NK > 376 cells/mL, CD16+CD56+NK > 241 cells/mL,CD57+CD56+NK-LGL > 242 cells/mL or CD8+CD4- cytotoxic T cells > 212 cells/mL during consolidation compared with others were 26.7% (8.3%-49.6%) versus 78.3% (55.4%-90.3%), HR 0.032 (0.0027-0.38; P = 0.0064) (Figure 3), 31.2% (11.4%-53.6%) versus 85.0% (60.4%-94.9%), HR 0.039 (0.0031-0.48; P = 0.011), 36.8% (16.5%-57.5%) versus 77.3% (53.7%-89.8%), HR 0.21 (0.065-0.69; P = 0.010), or 41.2% (18.6%-62.6%) versus 76.5% (48.8%-84.9%), HR 0.18 (0.019-1.77; P = 0.14), respectively. Conclusion Silent responses of the T/NK subsets to dasatinib throughout consolidation was significant for longer TFR. Elevated NK/T, particularly NK lymphocytes responsive to dasatinib, could be immature cells with little immunosurveillance; their decline subsequently replaced by altered lymphocyte population with less response to dasatinib during sustained DMR might be immunologically significant. Disclosures Kumagai: Pfizer: Honoraria; Otsuka pharmacology: Honoraria; Novartis: Honoraria; Bristol-Myers Squibb: Honoraria. Nakaseko:Bristol-Myers Squibb: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Honoraria. Nishiwaki:Novartis: Research Funding. Yoshida:Otsuka: Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau. Matsue:Janssen Pharmaceutical K.K.: Honoraria; Novartis Pharma K.K: Honoraria; Takeda Pharmaceutical Company Limited: Honoraria; Celgene: Honoraria; Ono Pharmaceutical: Honoraria. Morita:Bristol-Myers Squibb: Honoraria. Sakamoto,:Yakult Honsha Co. Ltd: Other: remuneration. Inokuchi:Bristol-Myers Squibb: Honoraria, Research Funding; Pfizer: Honoraria; Celgene: Honoraria; Novartis: Honoraria.