Causes of double-negative T-cell lymphocytosis in children and adults. Issue 7 (6th December 2019)

• Record Type: Journal Article
• Authors: Liapis, Konstantinos; Tsagarakis, Nikolaos J; Panitsas, Fotis; Taparkou, Anna; Liapis, Ioannis; Roubakis, Christophoros; Tsokanas, Dimitris; Vasileiou, Paraskevi; Grigoriou, Eirini; Kakiopoulos, Georgios; Psarra, Katerina; Farmaki, Evangelia; Paterakis, George
• Is Part Of: Journal of clinical pathology. Volume 73:Issue 7(2020)
• Page Start: 431
• Page End: 438
• Publication Date: 2019-12-06
• Subjects: haematology -- haemato-oncology -- haematopathology -- flow cytometry -- morphology; Pathology -- Periodicals; Pathology, Molecular -- Periodicals; 616.0705
• DOI: 10.1136/jclinpath-2019-206255
• Languages: English
• ISSNs: 0021-9746

Abstract

Abstract : Aims: The causes and diagnosis of 'double-negative' (CD3+CD4−CD8−) T-cell lymphocytosis are not well studied. We aimed to define the causes of double-negative T-cell lymphocytosis in children and adults, and to identify simple clinical and laboratory features that would help to differentiate between the underlying conditions. Methods: We collected clinical and laboratory data on 10 children and 30 adults with significantly increased peripheral-blood double-negative T-cells (>10% of total lymphocytes). We identified conditions associated with double-negative T-lymphocytosis with flow cytometry, peripheral-blood morphology and T-cell receptor-gene rearrangement studies. Patients were assigned to diagnostic categories on the basis of these test results. Results and conclusions: The causes of double-negative T-cell lymphocytosis in children were autoimmune lymphoproliferative syndrome (ALPS) and reactive γ/δ Τ-lymphocytosis. T-cell large granular lymphocyte (T-LGL) leukaemia, reactive γ/δ T-lymphocytosis and hepatosplenic T-cell lymphoma (HSTL) were the the most common disorders underlying double-negative T-cell lymphocytosis in adults. Less common causes included hypereosinophilic syndrome, peripheral T-cell lymphoma, ALPS and monoclonal, double-negative T-lymphocytosis of uncertain significance. CD5/CD7/Vδ2 expression and absolute double-negative lymphocyte count (<1.8×10 9 /L) were useful discriminators for distinguishing patients with reactive γ/δ T-lymphocytosis from those with γ/δ lymphoproliferative disorders. Differentiating between γ/δ T-LGL and HSTL can be difficult. Expression of CD57 and cellular morphology (pale cytoplasm with distinct granules) would support a diagnosis of γ/δ T-LGL.