Aggressive NK-cell leukemia

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Aggressive NK-cell leukemia
Other namesNK-cell large granular lymphocyte leukemia
NK cell
SpecialtyHematology and oncology

Aggressive NK-cell leukemia is a disease with an aggressive, systemic proliferation of

natural killer cells (NK cells) and a rapidly declining clinical course.[1]
[2] [3]

It is also called aggressive NK-cell lymphoma.[4]

Signs and symptoms

Patients usually present with constitutional symptoms (

multi-organ failure.[1][2][5][6][7] Rarely, individuals who have an aggressive NK cell lymphoma that is associated with latent infection with the Epstein-Barr virus (see next section) present with or develop extensive allergic reactions to mosquito bites. The symptoms of these reactions range from a greatly enlarged bite site that may be painful and involve necrosis to systemic symptoms (e.g. fever, swollen lymph nodes, abdominal pain, and diarrhea), or, in extremely rare cases, to life-threatening anaphylaxis.[8]

Cause

This disease has a strong association with the

NK cell.[4] Blastoid NK cell lymphoma appears to be a different entity and shows no association with EBV.[1]

Sites of involvement

This disease is typically found and diagnosed in peripheral blood, and while it can involve any organ, it is usually found in the spleen, liver, and bone marrow.[4]

Diagnosis

Leukemic cells are invariably present in samples of peripheral blood to a variable extent. Pancytopenia (anemia, neutropenia, thrombocytopenia) is commonly seen as well.[4]

Peripheral blood

The leukemic cells have a diameter mildly greater than a

large granular lymphocyte (LGL) and have azurophilic granules and nucleoli of varying prominence. Nuclei may be irregular and hyperchromatic.[4]

Bone marrow

Bone marrow involvement runs the spectrum between an inconspicuous infiltrate to extensive marrow replacement by leukemic cells. Reactive

neoplastic infiltrate.[4]

Other organs

Leukemic involvement of organs is typically destructive on tissue sections with necrosis and possibly angioinvasion, and the monotonous infiltrate may be diffuse or patchy.[4]

Immunophenotype

The immunophenotype of this disease is the same as extranodal NK/T-cell lymphoma, nasal type and is shown in the table below.

CD11b and CD16 show variable expression.[1][10]

Status Antigens
Positive
TIA-1, CCR5
Negative
CD57

Genetic findings

Due to the NK lineage, clonal rearrangements of

Epstein Barr virus (EBV) is detected in many cases,[9] along with a variety of chromosomal abnormalities.[11]

Treatment

Currently Aggressive NK-cell leukemia, being a subtype of PTCL, is treated similarly to B-cell lymphomas. However, in recent years, scientists have developed techniques to better recognize the different types of lymphomas, such as PTCL. It is now understood that PTCL behaves differently from B-cell lymphomas and therapies are being developed that specifically target these types of lymphoma. Currently, however, there are no therapies approved by the

stem cell transplant.[12][13][14][15][16]
Novel approaches to the treatment of PTCL in the relapsed or refractory setting are under investigation.

Epidemiology

This rare form of leukemia is more common among Asians in comparison to other ethnic groups. It is typically diagnosed in adolescents and young adults, with a slight predominance in males.[1][2][3][5][17][9][10]

Research directions

Pralatrexate is one compound currently under investigations for the treatment of PTCL.

References

  1. ^ a b c d e Chan JK, Sin VC, Wong KF, et al. (June 1997). "Nonnasal lymphoma expressing the natural killer cell marker CD56: a clinicopathologic study of 49 cases of an uncommon aggressive neoplasm". Blood. 89 (12): 4501–13.
    PMID 9192774
    .
  2. ^
    S2CID 45676891
    .
  3. ^
    PMID 10389582
    .
  4. ^
    ISBN 978-92-832-2411-2
    .
  5. ^ a b Kwong YL, Wong KF, Chan LC, et al. (January 1995). "Large granular lymphocyte leukemia. A study of nine cases in a Chinese population". Am. J. Clin. Pathol. 103 (1): 76–81.
    PMID 7817949
    .
  6. PMID 8854571
    .
  7. S2CID 6708698
    .
  8. S2CID 42534926
    .
  9. ^
    PMID 8088773
    .
  10. ^
    PMID 8762811
    .
  11. PMID 10439361
    .
  12. PMID 19029417. Archived from the original
    on 2012-08-03.
  13. PMID 18303032
    .
  14. S2CID 32509254
    .
  15. PMID 16871285
    .
  16. ^ d'Amore F, et al. Blood. 2006;108:A401
  17. S2CID 43307154
    .

External links

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