From the Guidelines
Blood tests in the workup of cutaneous T-cell lymphoma (CTCL) should include a complete blood count with differential, comprehensive metabolic panel, lactate dehydrogenase (LDH), and flow cytometry to detect circulating Sézary cells, as recommended by the most recent guidelines 1. The initial work-up for patients with CTCL includes complete physical examination, representative skin biopsy, complete and differential blood cell count, routine serum biochemistry with LDH, and appropriate imaging studies 1. Key blood tests to establish baseline values, assess disease extent, and monitor for progression are:
- Complete blood count with differential to identify lymphocytosis, eosinophilia, or anemia
- Comprehensive metabolic panel to assess overall health and detect any abnormalities
- Lactate dehydrogenase (LDH) to correlate with disease burden and prognosis
- Flow cytometry to detect abnormal T-cell populations with characteristic CD4+/CD7- or CD4+/CD26- phenotypes For advanced cases, T-cell receptor gene rearrangement studies should be performed to confirm clonality, and HTLV-1 serology may be ordered to rule out adult T-cell leukemia/lymphoma in patients from endemic regions 1. Regular blood monitoring is essential during treatment to assess response and detect disease progression, particularly transformation to leukemic variants like Sézary syndrome. It is essential to interpret blood test results in the context of clinicopathological features and alongside skin biopsies, which remain the gold standard for diagnosis 1.
From the Research
Blood Test in Workup of Cutaneous T Cell Lymphoma
- The diagnosis of cutaneous T-cell lymphoma (CTCL) can be challenging, and blood tests play a crucial role in the workup of this disease 2, 3, 4, 5, 6.
- Flow cytometry and gene rearrangement analysis are important tools in the diagnosis of CTCL, and can be used to evaluate peripheral blood and lesional tissue 2, 3, 4.
- The sensitivity and specificity of flow cytometry, polymerase chain reaction (PCR), and high-throughput sequencing (HTS) have been evaluated in the diagnosis of CTCL, with HTS showing high specificity in peripheral blood testing 2.
- The role of blood involvement in the assessment and staging of CTCL has evolved, with flow cytometry and PCR becoming important tools in evaluating blood tumor burden 3, 4.
- Standardization of flow cytometry panels is needed to allow for accurate identification and quantification of blood tumor burden in CTCL 3.
- T-cell receptor-Vβ chain restriction analysis by flow cytometry may aid in the diagnosis of CTCL, but its utility in quantifying tumor burden is limited 4.
- The diagnosis of CTCL requires the integration of clinical and histopathologic data, and TNMB staging remains the most important prognostic factor in CTCL 6.
Diagnostic Tools
- Flow cytometry: used to evaluate peripheral blood and lesional tissue, and to detect and quantify aberrant T-cell phenotypes 2, 3, 4.
- Gene rearrangement analysis: used to evaluate T-cell receptor clonality, and to aid in the diagnosis of CTCL 2, 4.
- High-throughput sequencing (HTS): used to identify specific clones of rearranged T-cell receptor genes, and to evaluate peripheral blood and lesional tissue 2.
- Polymerase chain reaction (PCR): used to characterize T-cell receptor gene rearrangements, and to aid in the diagnosis of CTCL 2, 4.
- T-cell receptor-Vβ chain restriction analysis: used to aid in the diagnosis of CTCL, but its utility in quantifying tumor burden is limited 4.