Classification of T-Cell disorders

Atlas of Genetics and Cytogenetics in Oncology and Haematology

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Classification of T-Cell disorders

Identity

Note

T-cell lymphoid disorders include a variety of disease entities which result from the clonal neoplastic expansion of an uncommitted (thymic) or a committed (post thymic) T-cell. Some of these diseases have distinct cytogenetic/molecular genetic features which allow to better define the various entities and understand their pathogenesis.

Disease	T-prolymphocytic leukemia (T-PLL) Variants: small cell and cerebriform cell.
Phenotype / cell stem origin	TdT-, CD1a-, CD4+ CD8- CD4- CD8+ CD4+ CD8+
Clinics	Aggressive course Splenomegaly, high WBC with prolymphocytes.
Cytogenetics	inv(14)(q11q32), t(14;14)(q11;q32) Xq28 abnormalities idic(8)(p11), t(8;8)(p11;q1-2) 11q22-23 abnormalities 12p abnormalities 13q14.3 deletions
Genes	ATM gene (11q22-23) mutated. TCL1 (14q32.1) or MTCP1 (Xq28) activated.

Disease	Large granular lymphocyte leukemia (LGL) - T-cell Type
Phenotype / cell stem origin	TdT-, CD1a CD3+, CD2+, CD8+ CD4-, CD57+, CD16+/-Cytotoxic or suppressor activity.
Clinics	Indolent Cytopenias, splenomegaly, lymphocytosis with granular lymphocytes.
Cytogenetics	Clonal abnormalities. In some cases, but no consistent specific abnormalities.
Genes	Clonality established by TCR rearrangements.

Disease	Sezary syndrome (SS)
Phenotype / cell stem origin	TdT-, CD1a-, CD3+, CD4+, CD8-, Helper or no functional activity.
Clinics	Variable clinical course with skin involvement and cells with cerebriform nuclei.
Cytogenetics	Complex, clonal, oligoclonal or nonclonal with variable ploidy. Abnormal.2p, Abnormal.6q, i(17q), del(13)(q14)
Genes	P53 gene deletion and protein expression in the absence of gene mutation. Few cases express MDM2

Disease	Adult T-cell leukemia lymphoma (ATLL)
Phenotype / cell stem origin	TdT-, CD1a-, CD7- CD4+ CD8- CD25+, Suppressor activity.
Clinics	Aggressive, Hypercalcaemia, lymphadenopathy, Œflower cells', HTLV-1 Positive.
Cytogenetics	Complex and often oligoclonal. Numerical abnormalities: 3, 7, X. Structural abnormalities: 1q, 3q, 6q, 14q.
Genes	Oligoclonal/mono clonal integration of HTLV-1in host DNA. Abnormalities of p53, p16 and p15 genes.

Disease	T-NHL hepatosplenic lymphoma
Phenotype / cell stem origin	TdT-, CD1a-, CD3+/- CD56+, CD7+, granzyme A+, TCR g/d+
Clinics	Aggressive, Hepato splenomegaly
Cytogenetics	Abnormal.7q, i(7q)
Genes	TCR genes gamma/delta rearranged but alpha/beta not rearranged.

Disease	Peripheral/post-thymic T-cell lymphoma (pleomorphic and immunoblastic subtypes)
Phenotype / cell stem origin	TdT-, CD1a-, Variable expression of CD4 or CD8
Clinics	Aggressive; advanced stages.
Cytogenetics	Variable

Disease	Angio immunoblastic T-cell lymphoma
Phenotype / cell stem origin	TdT-, CD1a-, CD2+, CD5+, CD3+ CD4+ CD8-
Clinics	Disproteinemia, lymphadenopathy, immune abnormalities.
Cytogenetics	Complex with multiple related or unrelated clones. +3 or i(3q), +5, del(6q). Progression from normal karyotype to abnormal clone observed during transition from hyperplasia to neoplasia.
Genes	Integrated EBV sequences present in both B-and T-cells and is unlikely to be the etiological agent.

Disease	Angiocentric (nasal) T-cell lymphoma
Phenotype / cell stem origin	TdT-, CD1a-, T-cell or NK phenotype.
Clinics	Prevalent in Asia and south America; extra nodal involvement.
Cytogenetics	i(1q), del(6q), i(6p)
Genes	Majority have no TCR rearrangement; EBV clonally integrated and plays a role in the etiology of the disease.

Disease	Anaplastic (Ki 1+) large cell lymphoma
Phenotype / cell stem origin	TdT-, CD1a-, CD3+/- CD30+ (Ki 1+), CD15-, CD25+, HLA-Dr+, CD71+
Clinics	Aggressive with skin nodes and extranodal involvement.
Cytogenetics	t(2;5)(p23;q35)
Genes	Fusion gene NPM-ALK; 2p23 -Nucleolar phosphoprotein- NPM; 5q35 -Anaplastic lymphoma kinase- ALK.

Disease	Intestinal T-cell lymphoma
Phenotype / cell stem origin	TdT, CD1a-, CD3+, CD8+, CD103+, CD4-, CD8-
Clinics	Bone pain, coeliac disease, mesenteric nodes.
Genes	EBV genome present in mexican population but not in the europeans.

Disease	T-lymphoblastic Lymphoma/leukaemia (T-Lbly/T-ALL)
Phenotype / cell stem origin	TDT+, CD1a+, CD7+, cytCD3+ or +/-, other T-cell antigens.Thymic uncommitted T-cell.
Clinics	Aggressive; course similar to ALL. Mediastinal mass, high WBC.
Cytogenetics	del(6)(q21-q22) t(11;14)(p13;q11) t(1;14)(p34;q11); 1p34: tal-1gene; 14q11: TCR alpha
Genes	TCR chain genes rearranged.

Written	02-2001	Vasantha Brito-Babapulle, Estella Matutes, Daniel Catovsky
		Academic Department of Haematology and Cytogenetics, The Royal Marsden NHS Trust, London, UK