Tcelleleukemi

Tcelleleukemi is a group of cancers arising from malignant transformation of T-lymphocytes. The term covers several diseases, most notably T-cell acute lymphoblastic leukemia (T-ALL), T-cell prolymphocytic leukemia (T-PLL), and adult T-cell leukemia/lymphoma (ATLL). T-ALL is the most common T-cell leukemia in children and adolescents, while T-PLL and ATLL occur mainly in adults. ATLL is strongly associated with infection by human T-lymphotropic virus type 1 (HTLV-1). The conditions share a common lineage but differ in clinical course, presentation, and molecular features.

Signs and symptoms typically reflect bone marrow failure and organ involvement. Patients may experience fatigue, fever, frequent infections, easy bruising or bleeding, and weight loss. Swollen lymph nodes, enlarged liver or spleen, and, in T-ALL, a mediastinal mass can occur. CNS involvement may be present in some cases. Prognosis and treatment vary by subtype and patient factors.

Pathophysiology involves the clonal expansion of malignant T-lineage cells. T-ALL arises from malignant thymic or bone marrow T-cell precursors and often features aberrant signaling, such as NOTCH1 alterations. ATLL results from HTLV-1–driven transformation of mature T-cells and shows regional epidemiology linked to HTLV-1 prevalence. Immunophenotyping by flow cytometry typically reveals T-cell surface markers (eg, CD2, CD3, CD5, CD7) with varying CD4/CD8 profiles.

Diagnosis relies on blood counts, bone marrow biopsy, immunophenotyping, and genetic testing. Imaging and CNS assessment help determine organ involvement. Testing for HTLV-1 is relevant in suspected ATLL.

Treatment usually involves intensive multi-agent chemotherapy for T-ALL, CNS preventive measures, and consideration of stem cell transplantation in high-risk cases. Nelarabine is approved for relapsed or refractory T-ALL. ATLL treatment combines antiviral therapy (eg, zidovudine and interferon-α) with chemotherapy in many settings, with transplantation considered for some patients. Outcomes vary by subtype; pediatric T-ALL generally has better long-term survival than adult forms.