Hematological diseases are disorders of the blood and hematopoietic organs. The current hematological cohorts are mostly based on single-center or multi-center cases, or cohorts with limited sample size in China. There is a lack of comprehensive and large-scale prospective cohort studies in hematology.

The objectives of this study are to investigate the incidence and risk factors of large granular lymphocytic leukemia (LGLL) and to analyze the treatment effectiveness, patient prognosis, and healthcare costs in China.

1. Analyze the demographic and clinical characteristics of patients with LGLL, including sex, age, disease severity, and other relevant factors.
2. Examine disease features of LGLL patients, such as biochemical and hematological indicators, LGL counts, clonality, bone marrow pathology, and cytogenetics
3. Assess treatment patterns and real-world effectiveness in LGLL patients.
4. Evaluate clinical outcomes, including hematologic response, relapse, and mortality
5. Investigate long-term prognosis, including post-discontinuation outcomes and health-related quality of life.

Inclusion Criteria:

• Subjects diagnosed with LGLL.
• Subjects treated at the Institute of Hematology and Blood Diseases Hospital from Jan 1, 2000.

Exclusion Criteria:

• Subject unlikely to be available for long-term follow-up for any reason (e.g., inability to obtain follow-up data or presence of severe comorbidities).
• Subject with alcohol or drug dependence that may reduce their compliance with the study.
• Subjects that the investigator believes have other reasons that make them unsuitable for inclusion in this study.

Pantients diagnosed as LGLL.

Diagnostic criteria for LGLL (Large Granular Lymphocytic Leukemia):

Increased number of circulating LGL cells (>0.5×10^9/L) identified based on complete blood count and/or a consistent immunophenotypic pattern; Evidence of clonality confirmed by flow cytometry and/or molecular biology techniques; In patients with a low LGL cell count, diagnosis can still be made if there is a characteristic immunophenotype, STAT3 mutation, or bone marrow pathology abnormalities.