Presenter Disclosure

Faculty/ Presenter Disclosure  Faculty: Will Chen  Relationships with commercial interests:  Grants/Research Support: None  Speakers Bureau...
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Faculty/ Presenter Disclosure



Faculty: Will Chen



Relationships with commercial interests: 

Grants/Research Support: None



Speakers Bureau/Honoraria: None



Consulting Fees: None



Other: Consulting services to DynaLIFEDx Laboratories

Disclosure of Commercial Support 

This program has received financial support from DynaLIFEDx in the form of an Educational Program.



This program has received in-kind support from DynaLIFEDx in the form of logistical support



Potential for conflict(s) of interest: 

Will Chen has received no honorarium, and provides consulting services to DynaLIFEDx.



DynaLIFEDx provides laboratory services which will be discussed in this program.

Mitigating Potential Bias 

DynaLIFEDx operates in accordance with Alberta Health Services, testing and solutions are a direct result of provincial standards.

Leukocytosis on a CBC What to do? Will Chen, MDCM, FRCPC, DABPath Hematopathologist, DynaLIFEDx & Cross Cancer Institute Clinical Lecturer, Dept. of Laboratory Medicine and Pathology, University of Alberta

Objectives 

Review common causes of leukocytosis in the peripheral blood (PB).



Discuss appropriate utilization of flow cytometry in investigation of leukocytosis.



Determine which cases need urgent hematology/oncology referral.

Leukocytes in peripheral blood 

Neutrophils and precursors



Lymphocytes



Eosinophils



Basophils



Monocytes



Normal WBC count: 4.5-11 x 109/L



Order peripheral smear evaluation for further investigation, lab will often reflex.

Neutrophilia 

ANC: > 7.0 x 109/L



Most common cause: infection 

Toxic changes:

toxic granulation

cytoplasmic vacuolation

Dohle bodies (rough endoplasmic reticulum remnant)

Left shift 

Immature granulocytic precursors in peripheral blood (+/- myeloblasts).

http://www.medical-labs.net/neutrophil-maturation-diagram758/granulocytes-series-in-a-smear/

Other benign causes of neutrophilia 

Inflammatory states: burns, postoperative, asthma, MI, gout attack, collage vascular diseases, etc.



Acute hemorrhage



Corticosteroids



Chronic idiopathic neutrophilia

Neoplastic causes of neutrophilia 

Often associated with presence of myeloblasts in PB.



Bone marrow blast %: 

50 x 109/L



Marked left shift with “myelocyte bulge” – myelocytes outnumber more mature forms



Often associated with thrombocytosis.



Often with absolute basophilia (very helpful in distinguishing from benign leukocytosis).

http://imagebank.hematology.org/Content%5C901%5C1022%5C1022_full.JPG

Acute Myeloid Leukemia 

Typically ≥20% blasts in bone marrow or specific cytogenetic abnormalities.



Blast % in PB can vary!



Many subtypes based on morphologic/cytogenetic findings



Median age in 60s, rarer in children



Urgent referral to hematology/ER for bone marrow.

http://drugline.org/img/term/leukemia-acute-myelogenous-8659_0.jpg

Special subtype: Acute promyelocytic leukemia 

t(15;17) PML-RARA translocation



10-15% of AML cases.



Can present with coagulopathy/DIC.



Hemorrhage is major cause of early death.



Often leukopenic with rare blasts (only 1 blast in one case!).



ATRA should be administered at first morphologic/clinical suspicion.



Confirm with FISH studies.



Excellent prognosis/cure rate if treated appropriately.



How I treat acute promyelocytic leukemia. 2009; Blood: 114 (25)

Bone marrow: APL with prominent Auer rods 2009 Blood 114 (25)

Bone marrow: Hypogranular variant with “butterfly” cells 2009 Blood 114 (25)

Other causes of increased blasts 

Blasts in PB are never “normal”, regardless of neutrophil count.



Benign: GCSF therapy (can mimic CML with prominent left shift)



Leukoerythroblastic reaction/picture: presence of circulating nucleated RBCs and myeloid precursors (often blasts) in PB. 

Broad ddx: marrow infiltrative (myelophthisic) process, severe infection, trauma, acute hemorrhage, hemolysis, hypoxia, megaloblastic anemia.

www.cpsa.ab.ca/FLibraries/FPro_QofC_ALQEP_Critiques/FCritique_04-03-S.pdf

Bottom Line 

Consider bone marrow in cases with unexplained circulating blasts in PB.



Be on the lookout for APL and refer immediately for ATRA



Flow cytometry typically not performed on PB in AML/MPN cases. Will be performed on BM.

Other myeloid cells 

Basophilia: Associated with myeloproliferative neoplasms. Also allergic/inflammatory conditions, infection, iron deficiency.



Eosinophilia: drugs, parasitic infection, autoimmune disease, malignancies, hypereosinophilic syndromes



Monocytosis: infection, inflammatory disorders, often associated with neutrophilia. Also seen in CMML.

Lymphocytes 

Normal range: 0.8-4.8 x 109/L



Include T-cells, B-cell and natural killer cells.



Morphologic types of lymphocytes in PB: 

“Mature-appearing”: includes normal and neoplastic



Reactive/large granular lymphocytes



Lymphoblasts (normally never present)

“Mature” lymphocytes



Increased in infectious/inflammatory conditions.



Persistent lymphocytosis in absence of underlying condition 

consider lymphoproliferative disorder



order flow cytometry

Flow Cytometry 

Living cells stained with fluorescently-labeled antibodies to various lymphocyte antigens



Cells passed through suspension in single file and fluorescent signals detected



Data collected on each cell and examined in aggregate as dot plots



Expensive! ($ hundreds)

Test Utilization 

When to order flow cytometry on lymphocytosis cases? 

No guidelines available.



Some studies suggest optimal “cutoff” = 7.0 x 109/L and PB smear showing “malignant” features (J Clin Pathol. 2014 Dec;67(12)).

My approach Absolute lymphocytosis on CBC/diff Order blood smear evaluation if not reflexed Smear suggestive of malignancy? Not definite

Yes

Unexplained lymphocytosis persistent for 3-6 months Yes Order flow cytometry (lymphoid flow at CCI)

No Repeat CBC/diff + smear in 3-6 months

Most common “mature” LPD in PB 

Chronic lymphocytic leukemia.



Most common in men > age 50.



Indolent B-cell lymphoma.



Many smudge cells on PB with “soccer ball” cells.



B-cell count non-urgent referral to heme/onc.

http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/ hematology-oncology/chronic-leukemias/images/figure-5.jpg

Other common B-cell LPDs 

Follicular lymphoma



Hairy cell leukemia: 

Often pancytopenia



Monocytopenia is a “classic” feature



Splenomegaly very common



Villous cytoplasmic projections (“hairs”)



Mantle cell lymphoma



Marginal zone lymphoma



Lymphoplasmacytic lymphoma

Reactive lymphocytes/Large granular lymphocytes 

Large, reactive lymphocytes seen in viral infections, esp. mononucleosis.



LGLs are normal component of PB, representing NK/Tcells. Can be increased in infectious/immune conditions 

Also seen in LGL leukemia

Infectious mononucleosis: Reactive lymphocytes

https://classconnection.s3.amazonaws.com/595/flashcards/15 00595/png/picture11351649570766.png

http://imagebank.hematology.org/Content%5C908%5C1050%5C1050_full. JPG

Downey cells: blue cytoplasm with “skirting” around other cells

Large granular lymphocyte

http://imagebank.hematology.org/Content%5C381%5C2785%5C2785_ful G

LGL Leukemia 

Rare indolent T-cell lymphoma.



Incidental finding, often in rheumatoid arthritis patients (Felty syndrome: RA, splenomegaly, neutropenia).



Requires lymphocyte count ≥ 2.0 x 109/L.



Typically involves blood, marrow, spleen and liver; nodal involvement rare.

Lymphoblasts 

Never normal: urgent referral to hematology for bone marrow.



Flow cytometry can be performed on marrow.



Acute lymphoblastic leukemia: 

B-cell or T-cell: morphologically indistinguishable



Most common childhood cancer (highest incidence age range 2-5). In adults AML > ALL.

https://s3.amazonaws.com/classconnection/632/flashcards/2652632/jpg/l2149E3E6EF0B58C945D8.jpg

“L3” lymphoblast = Burkitt lymphoma 

Aggressive mature B-cell lymphoma, not ALL

http://atlasgeneticsoncology.org/Anomalies/Images/FlandrinBurkitt.jpg

Take Home Message 

Immediate hematology referral/ER visit: 





Acute myeloid leukemia 

Particularly APL which requires immediate ATRA therapy



Cases of unexplained pancytopenia with rare blasts should also have bone marrow to exclude acute leukemia



Acute lymphoblastic leukemia



Burkitt lymphoma/other aggressive lymphomas

Semi-urgent referral: 

Chronic myelogenous leukemia/other MPNs



Lymphomas

Non-urgent referral (3-6 months): 

Monoclonal B-cell lymphocytosis

Use of flow cytometry 

Expensive test



Order for investigation of lymphocytosis



Consider only after smear review



Highest yield in cases with unexplained, persistent lymphocytosis



Unnecessary on PB for myeloid neoplasms

Questions? Email: [email protected]

Thank You!