T and NK cell LPD Flashcards
T Follicular Helper immunophenotype
CD10, BCL6, CXCL13, CXCR5, ICOS, PD1, SAP
Clinical features of AITCL
Patients generally present with advanced disease
- Generalised lymphadenopathy
- Hepatosplenomegaly
- Skin rash +/- pruritus
- Ascites, pleural effusion, arthritis
- Often associated with autoimmune conditions
- Immunodeficiency
Laboratory features of AITCL
- Hypergammaglobulinaemia
- RF and anti-smooth muscle antibodies
- Cold agglutinins with haemolytic anaemia
- Circulating immune complexes
Immunophenotype of T-PLL
Positive T cell markers: CD2, CD5, CD3 and CD7 (CD3 can be weak)
CD52 is usually strongly expressed and can be a target of therapy
60% CD4+/CD8-
25% CD4+/CD8+ (dual positivity is not really seen in any other mature T cell neoplasm, ddx T-ALL)
15% CD4-/CD8+
Negative: CD1a, TdT
Features of T-PLL (disease of 52)
Aggressive T-cell leukaemia Affects older adults (52 year olds) PB lymphocyte count > 100 (520) CD2+, CD5+, CD52+ 5 cytogenetic abnormalities, 2 are very common Inv(14) or t(14;14) Trisomy 8 Deletions at 12p and amplification of 5p TP53 Median survival 5 months to 2 years
Anaemia and thrombocytopenia
Lymphadenopathy, hepatosplenomegaly
Skin infiltration in 20% (blebs = skin lumps)
What are the cytogenetics abnormalities in T-PLL?
- Inversions of chromosome 14
- Inv(14) in 80%, t(14;14) in 10% - Abnormalities of chromosome 8
- idic(8), t(8;8) and trisomy 8q are seen in 80% - Deletions at 12p13 and amplification of 5p are also common
- TP53 deletions
Clinical and laboratory features of aggressive NK cell leukaemia
- Patients usually present with fevers, weight loss, fatigue
- Pancytopenia with leukaemic cells
- Hepatosplenomegaly
- Effusions are common
- High LDH
- May have coagulopathy, haemophagocytic syndrome or multiorgan failure
- Median survival < 2months
Is aggressive NK cell leukaemia EBV driven?
Yes - 80-100% association with EBV. Seen in adults, median age is 40 years.
N.B. Chronic lymphoproliferative disorder of NK cells is EBV negative.
Immunophenotype of extranodal NK/T cell lymphoma
CD2+, sCD3- (but CD3ε+), CD56+, usually CD16-, CD4- and CD8-
Cytotoxic molecules positive
(EBV positive)
Immunophenotype of Adult T-cell leukaemia/lymphoma
T cell antigens: CD2+, CD3+, CD5+, usually CD4+
CD7-
CD25 is strongly expressed in nearly all cases
CD30 may be positive
Clinical features of ATLL
Acute - leukaemic presentation with high WBCs, high LDH, hypercalcaemia, hepatosplenomegaly, lytic bone lesions, rash and BM infiltration.
Lymphomatous - LNs but no PB, otherwise similar to acute form.
Chronic - mildly increased lymphocytes, mildly raised LDH. May have hepatosplenomegaly. Ca2+ normal.
Smouldering - leukaemic cells >5% but WBC count normal. No systemic symptoms.
Features of Sezary Syndrome (triad + additional)
- Erythroderma
- Generalised lymphadenopathy
- Leukaemia - abnormal clonal cerebriform T cells circulating
Plus one of the following additional criteria:
Sezary count >1000/uL
CD4:CD8 >10:1
Loss of T cell antigens e.g. CD7 and CD26
Immunophenotype of Sezary Syndrome
CD3+/CD4+/CD8-
CD7- and CD26-
PD1 +
Define T-LGL
Persistent (>6 months) increase in LGLs in the peripheral blood
Usually 2-20
What are reactive causes of increased T-LGLs?
- Infection
- G-CSF
- Immune reconstitution following SCT and chemotherapy
What are the clinical features of T-LGL?
- Usually affects middle aged to older adults
- Indolent
- Symptomatic from cytopenias - neutropenia is common, then anaemia. Thrombocytopenia is rare.
- Splenomegaly
- Associated with RA
- Hypergammaglobulinaemia and immune complexes
Describe morphology in T-LGL
- PB and BM
- Intermediate to large lymphocytes, abundant cytoplasm and fine or coarse azurophilic granules
- BM hypocellular/normocellular /mildly hypercellular
- Intrasinusoidal +/- interstitial infiltrates
- BM fibrosis common
- Granulocytic hypoplasia
- Very common to find reactive lymphoid aggregates (CD4+ lymphocytes rather than CD8+)
What is the immunophenotype of T-LGL?
CD3+, CD8+, CD16+, CD57+ (CD56-, dim CD5 and dim CD7) with alpha/beta TCR gene rearrangement
TIA1, granzyme
Rare variants:
- alpha/beta with CD4+
- gamma/delta type rare and may be CD8+ or CD4-/CD8-
Definition of chronic lymphoproliferative disorder of NK cells
Rare and heterogenous disorder characterised by persistent (>6 months) increase in NK cells in the peripheral blood (>2)
Morphology of NK-LGL
- Intermediate to large lymphocytes, abundant cytoplasm and fine or coarse azurophilic granules
- Intrasinusoidal +/- interstitial infiltrates
Immunophenotype of NK-LGL
sCD3-, CD8+, CD16+, CD56+(dim) and cytotoxic markers
Often loss of CD2, CD5 and/or CD57
Morphology of aggressive NK cell leukaemia
Variable - ranging from normal appearing LGLs through to cells with atypical nuclei, open chromatin and nucleoli
BM - interstitial or focal infiltrate +/- haemophagocytosis
Immunophenotype of NK cell leukaemia?
CD2+, sCD3-, CD5-, CD16+, CD56+
Definition of ATLL
Aggressive lymphoma/leukaemia caused by HTLV1 infection.
HTLV1 infections occur in childhood but disease has long latency and presents in adulthood
2.5% of carriers develop ATLL
Flowery lymphocytes
Prognosis and predictive factors in ATLL
Acute and lymphomatous form 2weeks - 1 year
Chronic and smouldering forms progress to acute phase in 25%
Death from opportunistic infections is common e.g. PJP and strongyloides
Definition of hepatosplenic T cell lymphoma
Aggressive extranodal T cell lymphoma with proliferation of cytotoxic T cells that are usually the gamma/delta TCR type
Clinical features of hepatosplenic T cell lymphoma
Young adults (median age 35 years)
20% of cases arise in the setting of chronic immunosuppression e.g. infliximab + azathioprine in IBD patients.
Hepatosplenomegaly without lymphadenopathy
Marked thrombocytopenia +/- anaemia
BM almost always involved
Morphology of hepatosplenic T cell lymphoma
Monotonous medium sized lymphocytes with a pale rim of cytoplasm and loosely condensed chromatin
Prominent intrasinusoidal pattern in liver and BM
Immunophenotype of hepatosplenic T cell lymphoma
CD3+, CD8+/-, CD56+/-, gamma/delta
CD4-, CD5-
DDx T-LGL (57+)
Definition of Peripheral T cell lymphoma, NOS
Heterogenous group of nodal and extranodal T cell lymphoma that don’t fit in any other WHO category. Excludes those with a T follicular helper phenotype
Clinical Features of Peripheral T cell lymphoma, NOS
Aggressive
Mostly seen in adults
B symptoms common
Usually nodal but can be extranodal, rarely leukaemic
Eosinophilia, pruritus and rarely HLH can occur
Immunophenotype of PTCL
Frequent loss of T cell antigens
CD3+
CD4+>CD8+ but can get double positive and double negative
Can have CD56+ and cytotoxic markers positive
CD15 and/or CD30
Morphology of PTCL, NOS
Diffuse infiltrate which may be monomorphic or polymorphic
Medium to large cells, may have RS like cells
Can have histiocyte rich form
Definition of AITLC
Neoplasm of mature T cells with a T follicular helper cell phenotype
Always associated with EBV positive B cells but the neoplastic T cells are negative
Morphology of AITCL (PB, BM)
Blood film - may see rouleaux or eosinophilia
BM - small to intermediate sized T cells surrounded by inflammatory cells e.g. eosinophils, plasma cells, histiocytes, reactive lymphocytes
Increased bone marrow vascularity
May have follicular architecture or this may be effaced
Immunophenotype of AITCL
CD10, BCL6, PD1, CXCL13, CXCR5, SAP, ICOS
CD2+, CD3+, CD4+, CD5+
EBV positive cells = B cells
Anaplastic large cell lymphoma - Definition
T cell lymphoma characterised by large and pleomorphic lymphoid cells with horse shoe shaped nuclei and abundant cytoplasm.
Most common translocation involving ALK gene?
t(2;5) = ALK on chromosome 2, NPM1 on chromosome 5
But there are many partners and the partner doesn’t alter prognosis.
Clinical features of ALCL
Children and young adults
ALK+ has a better prognosis
Advanced stage disease and B symptoms at presentation are common
LNs and extranodal
Less likely to have mediastinal disease compared to cHL
30% have BM involvement - need IHC to diagnose
Name the 4 morphologic variants of ALCL
- Common
- Lymphohistiocytic
- Small cell
- Hodgkin like
* *all variants have Hallmark cells in them**
IHC and immunophenotype in ALCL
CD30+ (uniform)
EMA+ (100% of ALK+ but 50% of ALK-) EMA is negative in PTCL.
CD4+, CD2+, CD5+
CD3- in 75%
ALK+
PAX5- (differentiates it from cHL)
N.B. There can be a “null phenotype” but TCR gene rearrangement is clonal
Breast lymphoma
90% B cell
10% T cell - systemic ALCL, breast implant associated ALCL
What mutations are seen in ~1/3 of T and NK cell LGL
STAT3 mutations
Immunophenotype of ATLL
CD3+, CD4+, CD2+, CD5+, CD25+
CD7-
+/- CD30
Differential diagnosis of T cell leukaemias
T-PLL (CD4+/CD8+, CD7 strong, CD52+)
T-LGL (CD8+, CD16+, CD57+)
Sezary (CD7-, CD26-, PD1+)
ATLL (CD7-, CD25+)