Exam 3 - Instruments and Non-Malignant Disorders

Alder-Reilly Anomaly

Autosomal recessive

Large, purplish granules in all leukocytes due to incompletely degraded mucopolysaccharides

Granules are surrounded by vacuoles

Cells function normally

Associated with Hunter’s and Hurler’s syndromes

Chediak-Higashi Syndrome

Autosomal recessive

Giant, grey-green peroxidase-positive lysosomes in leukocytes, resulting from the fusion of primary and secondary granules

Leads to defective chemotaxis

Associated with neutrophils, thrombocytopenia, skin hypopigmentation, silvery hair, and photophobia

May-Hegglin Anomaly

Not specified inheritance

Granulocytes contain large, round Dohle-like inclusions of crystalline RNA

Accompanied by giant platelets and variable thrombocytopenia, leading to risk of bleeding

Chronic Granulomatous Disease

X-linked (70%) or autosomal recessive (30%)

Defect in the respiratory burst oxidase system; prevents the generation of antimicrobial oxygen metabolites

Neutrophils can phagocytize but cannot kill catalase positive organisms

Diagnosed via the Nitroblue tetrazolium test or Dihydrorhodamine flow cytometry assay

Myeloperoxidase Deficiency

Autosomal recessive

Absence of myeloperoxidase leads to defective, but not absent, bactericidal activity; alternative killing systems are used, but are slower

Generally benign

Lack of myeloperoxidase can interfere with certain laboratory stains and instrumentation

Leukocyte Adhesion Deficiency

Autosomal recessive (type I)

Decreased or absent leukocyte cell-surface adhesion proteins (CD11/CD18 complex)

Results in multiple functional defects, including adhesion to endothelial cells, chemotaxis, phagocytosis, and degranulation

Diagnosed with flow cytometry

Phase I (Early Infection)

Marginated WBCs move into tissues, and the bone marrow releases its storage pools of neutrophisl

This results in a left shift

Phase II (Established Infection)

The marginated and circulating pools re-equilibrate, establishing a stable leukocytosis where marrow release matches the output to tissues

The bone marrow shows and increase in WBC precursors

Phase III (Recovery)

As the infection resolves, bone marrow release of WBCs decreases, the left shift disappears, and the leukocytosis subsides

Alternative Phase III (Exhaustion)

If the demand for WBCs exceeds the marrow’s production capacity, the storage pool of neutrophils becomes depleted, resulting leukopenia

Leukemoid Reaction

Extreme neutrophilic response to severe infections or necrotizing tissue

A benign, transient condition

Leukemoid Reaction Characteristics

WBC count: >25 × 10³/μL

Left shift

Cells exhibit toxic granulation and Dohle bodies

Leukocyte Alkaline Phosphatase (LAP) score: elevated, more neutrophils contain the enzyme

Barr Bodies

Structures found in female neutrophils, appearing as an appendage to the nucleus

Cytoplasmic Vacuoles

Clear, unstained areas in the cytoplasm of neutrophils, representing the end stage of phagocytosis

Seen in severe infections, burns, and cancer

Dihydrorhodamine Test (DHR)

A quantitative flow cytometry test used to diagnose chronic granulomatous disease

Normal cells reduce DHR to a strongly fluorescent compound, while CGD cells show no or minimal activity

Dohle Bodies

Grey-blue inclusions in the cytoplasm of neutrophils or eosinophils, composed of aggregates of RER and rRNA

Seen in severe infections, burns, cancer, and toxic drugs

Gaucher Cells

Large macrophages (20-100 μm) with small eccentric nuclei and wrinkled or striated cytoplasm

Indicative of Gaucher disease, where lipids accumulate

Gaucher Disease

Inherited lysosomal storage disorder caused by a deficiency of the enzyme β-glucosidase, leading to the accumulation of glucocerebroside in macrophages

Hypersegmentation

A nuclear change in neutrophils, often associated with B12/folate deficiency

Hyposegmentation

A nuclear change in neutrophils characterized by a reduced number of nuclear segments, as seen in Pelger-Huet anomaly

L.E. Cells

Found in Systemic Lupus Erythematosus (SLE)

Phagocytic cells that have engulfed the nuclear material of another cell, requiring an antinuclear antibody

Morulae

Dense, basophilic inclusions seen within neutrophils, representing intracellular organisms such as Erlichia

Niemann-Pick Cells

Large (20-100 μm) “foamy” macrophages with an eccentric nucleus and globular cytoplasmic inclusions

Found in Niemann-Pick disease

Niemann-Pick Disease

An inherited lysosomal storage disorder caused by a deficiency in sphingomyelinase, leading to an excess accumulation of sphingomyelin

Often fatal by 3 years of age

Pelger-Huet Anomaly

An autosomal dominant inherited condition causing decreased segmentation of the granulocyte nucleus with coarse chromatin clumping

Cells are functionally normal

Pince-nez

An eyeglass shape of the nucleus seen in mature neutrophils in heterozygous Pelger-Huet anomaly

Pseudo-Pelger-Huet

An acquired form of hyposegmentation seen in myeloproliferative/myelodysplastic states, where the nucleus is round and often hypogranular

Sea-Blue Histiocytes

Large cells (20-60 μm) with dense eccentric nucleus and cytoplasm containing blue or blue-green granules

Found in the liver, spleen, and bone marrow in certain lipid metabolism disorders

Toxic Granulation

Large, deeply staining blue-black or reddish-purple primary granules in segmented neutrophils, bands, and metamyelocytes

Seen in the same severe inflammatory response as Dohle bodies

B. pertussis

A bacterial infection, also known as whooping cough

A condition associated with lymphocytosis

Cytomegalovirus (CMV)

A virus that can cause an asymptomatic or mild flu-like illness

Associated with leukocytosis, lymphocytosis, reactive lymphocytes, and a negative Monospot test

Epstein-Barr Virus (EBV)

A virus that is the causative agent of infectious mononucleosis

Hepatomegaly

Enlargement of the liver

Potential complication in 25% of symptomatic infectious mononucleosis patients

Heterophile Ab Test (Monospot)

A serological test used to help diagnose infectious mononucleosis

Test is negative in similar conditions like toxoplasmosis and CMV

Immune Deficiency Disorder

A condition characterized by the impaired function of one or more components of the immune system (T, B, or NK lymphocytes), leading to an inability to mount a normal adaptive immune response

Ex: AIDS and SCID

Infectious Mononucleosis

A disease caused by the Epstein-Barr virus, transmitted through saliva

Common symptoms include fever, pharyngitis, and lymphadenopathy

Leukocytosis

An increase in the total number of WBCs

A laboratory finding in toxoplasmosis and CMV

Lymphadenopathy

The swelling of the lymph nodes

One of three symptoms in the classic triad of infectious mononucleosis

Lymphocytosis

An increase in the number of lymphocytes

Associated with MONO, B. pertussis, toxoplasmosis, CMV, syphilis, and other conditions

Pharyngitis

Inflammation of the pharynx, causing a sore throat

One of the three symptoms in the classic triad of infectious mononucleosis

Reactive lymphocytes

A type of lymphocyte observed in peripheral blood in response to certain infections

Presence is noted in MONO, toxoplasmosis, and CMV

Splenomegaly

Enlargement of the spleen

A potential complication in 50-75% of symptomatic infectious mononucleosis patients

Syphilis

A bacterial infection caused by Treponema pallidum that is listed as a condition associated with lymphocytosis

Toxoplasma gondii

The parasite responsible for causing the disease toxoplasmosis

Toxoplasmosis

A parasitic disease that can be asymptomatic or present with symptoms similar to MONO

Characterized by a negative Monospot test

Mono demographics

Peak incidence occurs between 14-24 years of age

80-90% of adults have been exposed to EBV

3-Part Differential

An automated WBC differential that categorizes cells into three groups:

• lymphocytes (small size and complexity)

• monocytes (moderate size and complexity)

• granulocytes (large size and complexity)

Can be achieved using either flow cytometry or electrical impedance technology

5-Part Differential

An automated WBC differential that provides counts for neutrophils, lymphocytes, monocytes, eosinophils, and basophils

Technologies used include Coulter’s VCS and Abbott’s MAPSS

6-Part Differential

An advanced automated WBC differential that separates the five main types of leukocytes and also identifies an additional population, such as immature granulocytes or nucleated RBCs

Examples include the Siemens ADVIA and Sysmex XE/XN series

CellaVision

A brand of instrumentation that performs an “automated” manual differential by digitally scanning a stained blood smear, locating leukocytes and platelets, and pre-classifying them for operator review

Coincidence Error

An error in particle counting that occurs when more than one cell passes through the aperture at the same time, causing them to be counted as a single, larger particle

Conductivity (RF)

A cell measurement principle using high-frequency alternating current (AC) resistance

Measures the internal density of a cell, primarily its nuclear volume, as it passes through an aperture

Cyanmethemoglobin

A stable colored compound formed when hemoglobin is mixed with a reagent containing potassium cyanide

Absorbance is measured by a spectrophotometer to determine hemoglobin concentration

Also known as the HiCN or hemiglobincyanide method

Electrical Impedance (DC)

The most common methodology for cell counting, using a low voltage direct current (DC)

Changes in electrical resistance are measured as voltage pulses when cells pass through an aperture, with pulse height being proportional to cell volume

Flow Cytometry

A technology used in hematology analyzers where cells in a hydrodynamically focused stream pass one by one through a laser beam

The way cells scatter light (forward and side scatter) and emit fluorescence is measured to determine their size, internal complexity, and other characteristics

Forward Scatter (FSC)

In flow cytometry, the measurement of light scattered in the forward direction as a cell passes through a laser

The intensity of FSC is proportional to the cell’s size

Hydrodynamic Focusing

A process that uses a sheath fluid to narrow a stream of sample fluid, forcing cells to align in a single file line as they pass through the detection point of an analyzer

MAPSS

Multi-Angle Polarized Scatter Separation

The proprietary technology used by Abbott Cell-Dyn analyzers for their 5-part differential

Uses multiple angles of light scatter (0°, 7°/10°, 90°, 90D°) to differentiate cells based on size, complexity, granularity, and lobularity

Optical Scatter

A cell analysis method where a focused light source (typically a laser) is directed as a stream of cells

The patterns of light scattered by the cells are measured to evaluate their size and internal structure

Peroxidase Staining

A cytochemical staining method used by Siemens ADVIA analyzers

Peroxidase is an enzyme present in the granules of neutrophils, eosinophils, and monocytes

The instrument measures the intensity of the stain to help classify these cell types

Side Scatter (SSC)

In flow cytometry, the measurement of light scattered at a 90-degree angle as a cell passes through a laser

The intensity of SSC is proportional to the cell’s internal complexity or granularity

Stromatolyser

A family proprietary lysing and/or staining reagents used in Sysmex instruments

Different Stromatolyser reagents are used in specific channels to selectively lyse certain cells or stain cellular components like nucleic acids

Supravital Staining

A method of staining live cells that have been removed from an organism

In hematology, it is used for reticulocyte counts with dyes like new methylene blue, auramine O, or oxazine 750 that stain residual RNA in young RBCs

VCS Technology

A technology used by Coulter instruments for 5-part differentials that simultaneously measures three parameters for each cell

Volume: electrical impedance

Conductivity: radiofrequency

Light Scatter: laser

MAPSS 0° Scatter

Measures cell size

MAPSS 7/10° Scatter

Measures cellular complexity

MAPSS 90° Scatter

Measures lobularity

MAPSS 90° Depolarized Scatter

Measures granularity, particularly for identifying eosinophils

MAPSS Fluorescence (FL3)

Measures DNA content to identify nucleated RBCs