Classification of T-cell disorders

  Summary: 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 entity	Immunophenotype/ Functional activity	Cytogenetics	Molecular genetics	Disease Features.
T-prolymphocytic leukemia(T-PLL) Variants:small cell and cerebriform cell	TdT-,CD1a-, CD4+ CD8- CD4 - CD8+ CD4+ CD8+	Inv(14)(q11q32) t(14;14)(q11; q32) Xq28 abnorm. idic(8)(p11) t(8; 8)(p11;q1-2) 11q22-23 abnorm. 12p abnorm 13q14.3 deletions	ATMgene (11q22-23) mutated. TCL1 (14q32.1) or MTCP1(Xq28) activated	Aggressive course splenomegaly, high WBC with prolymphocytes
Large granular lymphocyte leukemia(LGL) a.T-cell Type           b.NK type	TdT-,CD1a —     CD3+,CD2+,CD8+ CD4 -,CD57+, CD16+/- Cytotoxic or suppressor activity   CD2+,CD56+, CD16+ ,CD7+/- CD3-, CD5-,TCR- Natural killer Activity.	Clonal abnormalities.in some cases,but no consistent specific abnormalities         del(6)(q21-25)	Clonality established by TCR rearrangements             TCR chain genes in germ line.	Indolent, cytopenias, splenomegaly, lymphocytosis with granular lymphocytes.       Aggressive or indolent lymphocytosis Splenomegaly hepatomegaly
Sezary syndrome (SS)	TdT-, CD1a-, CD3+,CD4+,CD8- Helper or no functional activity.	Complex,clonal,oligoclonal or nonclonal with variable ploidy Abnorm.2p,6q i(17q),del 13q14	P53 gene deletion and protein expression in the absence of gene mutation. Few cases express MDM2	Variable clinical course with skin involvement and cells with cerebriform nuclei
Adult T-cell leukemia lymphoma (ATLL)	TdT-,CD1a-CD7-CD4+CD8-CD25+ Suppressor activity	Complex and often oligoclonal. Numerical abnorm;3,7,X Structural abnorm.1q,3q 6q,14q.	Oligoclonal/mono clonal integration of HTLV-1in host DNA Abnormalities of p53, p16 and p15 genes.	Aggressive , hypercalcaemia Lymph - adenopathy, ‘flower cells’, HTLV-1 Positive.
a/d T-NHL hepatosplenic lymphoma	TdT- CD1a-CD3+/- CD56+, CD7+,granzymeA+,TCR g/d+	Abnorm.7q, i (7p)	TCR genes gamma/delta Rearranged but alpha/beta not rearranged	Aggressive, Hepato splenomegaly
Peripheral/post-thymic T cell lymphoma (pleomorphic and immunoblastic subtypes)	TdT-,CD1a- Variable expression of CD4 or CD8	variable		Aggressive Advanced stages.
Angio immunoblastic T-cell lymphoma	TdT-,CD1a-, CD2+, CD5+,CD3+ CD4+ CD8-	Complex with multiple related or unrelated clones.+3 or i(3q),+5, del(6)(q). Progression from normal karyotype to abnormal clone observed during transition from hyperplasia to neoplasia.	Integrated EBV sequences present in both B-and T-cells and is unlikely to be the etiological agent.	Disproteinemia lymphadenopathy,immune abnormalities
Angiocentric (nasal) T-cell lymphoma	TdT-,CD1a-,T-cell or NK phenotype.	i(1q), del(6)(q),i(6p)	Majority have no TCR rearrangement EBV clonally integrated and plays a role in the etiology of the disease	Prevalent in Asia and south America Extra nodal involvement.
Anaplastic (Ki 1+) large cell lymphoma.	TdT-,CD1a-,CD3+/- CD30+ (Ki 1+),CD15-, CD25+, HLA-Dr+, CD71+.	t(2;5)(p23;q35)	Fusion gene NPM-ALK 2p23 -Nucleolar phosphoprotein-NPM 5q35 -Anaplastic lymphoma kinase-ALK	Aggressive with skin,nodes and extranodal involvement.
Intestinal T-cell lymphoma	TdT — CD1a -, CD3+, CD8+, CD103+ CD4-,CD8-		EBV genome present in mexican population but not in the europeans.	Bone pain Coeliac disease, Mesenteric nodes.
T-lymphoblastic Lymphoma/leukaemia (T-Lbly/T-ALL)	TDT+,CD1a+, CD7+, cytCD3+or+/- Other T-cell antigens.Thymic uncommitted T-cell.	del(6)(q21-q22) t(11;14)(p13;q11) t(1;14)(p34;q11) 1p34 : tal-1gene 14q11:TCR alpha chain gene	TCR chain genes rearranged.	Aggressive, mediastinal mass,high WBC,course similar to ALL

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