Benign WBC Conditions Flashcards
Causes of neutrophilic leukocytosis
acute bacterial infections
sterile inflammation caused by, for example, tissue necrosis (myocardial infarction, burns)
Causes of eosinophilic leukocytosis
allergic disorders
*helminthic parasitic infestations
drug reactions
autoimmune disorders
Causes of basophilic leukocytosis (basophilia)
myeloproliferative disease
causes of monocytosis
chronic infections bacterial endocarditis rickettsiosis malaria autoimmune disorders inflammatory bowel diseases
causes of lymphocytosis
chronic immunological stimulation
viral infections
Bordetella pertussis
Hyper- segmentation
PMNs with 5 or more lobes indicate; seen with megaloblastic anemias, myeloproliferative disorders, and some chemotherapy
Toxic granulation and vacuolization
- increased and prominent azurophilic (primary) granules and cytoplasmic vacuoles; seen with infections
Left shift
An absolute increase in neutrophils with an increase in bands +/- metamyelocytes or myelocytes- seen in infections and leukemias
Lifespan of WBCs in Peripheral Blood
Neutrophils (Granulocytes): 1 - 48 Hours
Eosinophils: 1 – 48 hours (average 8 hours)
Lymphocytes:
Hours to days (B-cells)
Days to years (T-cells)
Neutrophils and their precursors are distributed primarily in five pools…
- Bone marrow- proliferating
- bone marrow- storage
- blood vessel- storage
- blood vessel- circulating
- peripheral tissue- active and storage
Sampling of the peripheral blood assesses only the circulating pool!!!
Changes in Granulocyte Pools: Causes of increased neutrophil count- production in the marrow
Chronic infection or inflammation (growth-factor-dependent)
Paraneoplastic (e.g. hodgkin lymphoma; growth factor-dependent
Myeloproliferative disorders (e.g. chronic myeloid leukemia; growth factor- independent)
Changes in Granulocyte Pools: Causes of increased neutrophil count- increased release from marrow stores
Endotoxemia
Infection
Hypoxia
Changes in Granulocyte Pools: Causes of increased neutrophil count- decreased margination
exercise
catecholamines
Changes in Granulocyte Pools: Causes of increased neutrophil count- decreased extravasation into tissues
glucocorticoids
Leukemoid Reaction– what is it? How do we differentiate between it and leukemia?
looks like a leukemia but it’s not– it’s not neoplastic. Acute stress– like an infection, for example.
marked elevation in white cell count
Simulates chronic myelogenous leukemia
Leukocyte alkaline phosphatase (LAP) score elevated with infections
Low LAP scores in chronic myelogenous leukemia
Leukoerythroblastic reaction– what is it? When do we tend to see it?
Presence of immature granulocytes
and erythroid precursors in the blood
Commonly seen in:
- Severe hemolytic anemia
- Bone marrow infiltration
- —- metastatic tumor
- —- granulomas
- —- infiltrative process (fibrosis)
- Chronic myeloproliferative neoplasms
- —- particularly primary myelofibrosis
Critical Value for Neutropenia (Granulocytopenia)
absolute count less than 500/µL or less than 0.5 x 10^9/L
The lower the absolute neutrophil count
the greater the risk of infection
Infections are the most common cause of acquired neutropenia
Drugs the most common cause of clinically significant neutropenias
Agranulocytosis
severe neutropenia, usually caused by drugs
Neutropenia Pathogenesis
- Decreased or ineffective production
- Inherited, such as severe congenital neutropenia e.g. Kostmann syndrome
- Acquired, such as acquired aplastic anemia, myelodysplastic syndrome, nutritional deficiencies - Accelerated removal or destruction
- Immunologic disorders
- Splenomegaly
- Severe infections, such as overwhelming bacterial infection
Peripheral Blood Eosinophilia: relative & absolute
Relative Eosinophilia: >3% total wbc differential count
***Absolute Eosinophilia: Total Eosinophils >0.5 x 10^9/L
(Variable depending on laboratory, institution & geographic location)
Absolute Eosinophilia subdivisions:
Mild Eosinophilia 0.35-0.90 x 109/LModerate Eosinophilia 1.00-5.00 x 109/LMarked Eosinophilia>5.00 x 109/L
Lymphocytosis
Increased Lymphocytes Above Reference Range
Normal CD4/CD8 ratio
1:1 to 4:1
- Normal kappa/lambda ratio
1:1 to 2:1
Most ( > 80%) of Circulating Lymphocytes
are T cells
most lymphocytes in the lymph nodes are
B Cells
low CD4/CD8 ratio is associated with
HIV
but can also be related to high allergies, as in Dr. Gomez’s case
Infectious Mononucleosis
Acute infectious mononucleosis: Transient disease associated with Epstein Barr virus (EBV)
(sore throat, fatigue, lymphadenopathy)
*** Downey Cells
Epstein Barr virus (EBV) infects B cells
Subsequent B & T cell response
Cytotoxic/supressor CD8+ T cells and CD 16+ NK cells soon predominate in tissues and blood destroying infected B cells (with WBC of 12,000-18,000 cell/ul and atypical lymphocytes)
Monospot test, binds horse erythrocytes
Epstein Barr-Virus antibodies to capsid antigen
Lymphocytopenia
Lymphocytes Decreased Below Reference Range
Absolute lymphocyte count
Mean 2.720; Range 1.359 - 3.479 × 109/L
Relative (%) lymphocyte count Mean 40; Range 20 - 47
Absolute lymphocytopenia (no other abnormality) detected by automated hematology analyzer testing:
Perform a microscopic examination of a peripheral blood smear to examine the lymphocyte morphology
Absolute lymphocytopenia with Hemogram abnormality (anemia,
thrombocytopenia or leukopenia without known clinical cause) – what should we do?
Perform a bone marrow aspirate and biopsy
Absolute lymphocytopenia + suspect immune deficiency
– what should we do?
Flow cytometry immunophenotyping
Serum protein concentration
Serum protein electrophoresis
Quantitative serum immunoglobulins
Lymphocytopenia Common Causes
AIDS Hodgkin's disease Idiopathic or acquired aplastic anemia Acute bacterial infection Cancer stomach, ovary and breast Systemic lupus erythematosus
(less important: Chemotherapy or irradiation therapy Cortisone “Steroid” therapy Administration of erythropoietin Pregnancy )
