T-LGLL and CLPD-NK

Question 1

In T-LGLL what is typically the level of lymphocytosis seen?

Answer 1

> 5 x10 9/ L
- reactive conditions tend to have numbers less than this

Question 2

What is the differential diagnosis T-LGLL and CLPD-NK ?

Answer 2

• viral infections
• autoimmune disorders
• patients with HCL or CLL
• after chemotherapy or after organ transplant (allogeneic BM transplant)
• T cell clones of uncertain significance

Question 3

In what condition can expansions of T-LGLL sometimes be seen?

Answer 3

• CML

Question 4

T cell clones of uncertain significance can be seen in what situations?

Answer 4

• patients with other malignancies or in healthy individiuals
• may have a phenotype similar to T-LGLL but with brighter CD2 and CD7 and dimmer CD3

Question 5

In what situation is the diagnosis of T-LGLL unlikely?

Answer 5

• negative TCR gene rearrangement
• No B symptoms, cytopenias, infections, infections, rheumatoid arthritis and or splenomegaly
• LGL count in blood <0.5 x 109/L

**should be followed with FC every 6 months

Question 6

Outside of indolent NK cell proliferations, what other diagnostic entities should be considered with CLPD-NK?

Answer 6

• Extranodal nasal type NK cell lymphoma
  *may involve the BM but leukemic involvement is rare
• Aggressive NK cell leukemia
  
  • the clinical presentation is different and there is EBV association

Question 7

In what clinical situation can you see increased, maybe immature NK cells?

Answer 7

• CMML or non-hematopoietic neoplasms or after treatment
• The immature NK cells can express CD117