Patho Chapter 12: Disorders of White Blood Cells (WBCs)

WBC (white blood cells)

also called leukocytes, protect the body against infection

they function within the innate and adaptive divisions of the immune system

produced in bone marrow

Innate Immunity

1st line of defense- first ones to respond;

contains Neutrophils, macrophages

Inflammatory response

Adaptive Immunity

like a vaccine

Specific and acquired

contains B and T lymphocytes

Memory cells

Macrophages

are the first line of defense against foreign invaders, or antigens

Monocytes

\
big main first responders

2%-10% of circulating WBC's;
Macrophages: Mature monocytes in tissues
Phagocytosis, cytokine synthesis
Dendritic cells: Antigen-presenting cells

Lymphocytes

specific antigen- like a vaccine

20%-40% of circulating WBC's

Contains T and B cells

Provide long-term immunity

BB cells produce antibodies: Immunoglobulins, Igs

Standard values vary with age

Thymus-derived T cells decrease in number as person ages

Granulocytes

powerful digestive enzymes that help to fight

Cytoplasm contains granules of chemicals
Cells: basophils, eosinophils, neutrophils

B lymphocytes

antibody-producing cells

T lymphocytes

CD4 and CD8 cells

CD4 cells lead the fight against infections.

CD8 cells can kill cancer cells and other invaders. 

Leukemia

neoplastic proliferation of cancerous WBC's

Specific cell type 90% of leukemia cases are diagnosed in adults

Leukemia is the 3rd most common cancer type in children

Lymphoma

Solid tumors of lymphoid cells

Abnormal proliferation of B and T lymphocytes

3% of US population per year

Leukocytosis

WBC above 11,000 cells/microliter

causes- infection or allergic reaction

Neutrophilia

Most common WBC to elevate in leukocytosis
Neutrophil count greater than 7,000/microliter: With total WBC less than 11,000
Very common in response to bacterial infections, inflammation
Smoking elevates neutrophil number: May play a role in inflammation associated with smoking

Neutropenia

Less than 1,500 neutrophils/microliter

Compromises immune response

Several causes: Medications, including chemotherapy, may cause neutropenia

Filgrastim (Neupogen):Stimulates neutrophil synthesis

Hematologic neoplasm

the major disorder of WBCs reviewed in this chapter, include leukemias and lymphomas.

These cancerous disorders target WBCs, but they also have effects on red blood cells (RBCs) and platelets.

symptoms:

Anemia-decreased red blood cells low count

• Leukopenia (dysfunctional WBC’s) low paletes

• Thrombocytopenia (bleeding and bruising)• Bone pain (proliferating cancerous blood cells put pressure in marrow of bones)

• Enlarged lymph node

• Splenomegaly- enlarged spleen from working overtime

Diagnosis:CBC with Differential (to determine specific WBC types)- breaks down in components

Treatment: Chemotherapy and Radiation

Proliferation

rapid cell growth

Common Causes of Elevated Levels of White Blood Cells

Neutrophils (Bacterial infection)

Lymphocytes (Viral infection)

Eosinophils (Allergic reaction)

Basophils (Parasitic infection or allergic reaction), Monocytes (macrophages) (Inflammation, chronic infection, malignancy, autoimmune disease)

Hematologic Neoplasms;

Leukemia and Lymphoma Overwhelm the bone marrow and other lymphoid tissue: Crowd and suppress development of the other blood cells in the bone marrow Lymphomas are more common than leukemia

Leukopenia

WBC less than 4,000/microliter

causes: Any agent that diminishes bone marrow function or any condition that causes destruction of WBCs

Neutrophils most commonly affected

Eosinophils

1%-7% of circulating WBC's
Elevate during parasitic infections and allergies

Basophils

Less than 2% of circulating WBC's
Levels elevate during infection and inflammation
Granules contain histamine which, help signal
neutrophil migration

Neutrophils

40%-80% of circulating WBC's

higher in concentration/have more

First responders, carry out phagocytosis
Release enzymes to destroy microorganisms, releasing free radicals

Acute Lymphocytic Leukemia (ALL)

Stem cell precursors of B cells or T cells do not function and do not mature beyond lymphoblast stage (T or B cells)(referred to as blasts).

Aggressive, more common in children than adults (survival rate is over 80% for children)

Etiology: Many chromosomal and genetic alterations: Ph chromosome

Immature T or B cells (lymphoblasts): Bone marrow lymphoblast of greater than 20% of WBC's

Signs and Symptoms: May be nonspecific, anemia, increased bleeding, lymph node enlargements, splenomegaly, increased infection risk, bone pain

May migrate to CNS

Chronic Lymphocytic Leukemia (CLL)

Most common leukemia type in US
Individuals over 70 years of age

Etiology: Any agent that can disrupt DNA Occupational history important- prolonged exposure, plant, radiation

B cell malignancy - constant proliferation

Typical signs and symptoms of leukemia

Diagnosis: Lymphocytosis with WBC greater than 20,000/microliter

Bone marrow biopsy: "smudge cells"—abnormal lymphocytes

Acute Myelogenous Leukemia (AML)

Proliferation of undifferentiated myeloid cells
Myeloid blasts can invade other tissues:Skin, lungs, spleen, liver
Risk increased with previous chemotherapy and radiation treatments for other cancers
Commonly: activation of oncogenes such as FLT3, c-KIT
Typical signs and symptoms of leukemia

Chronic Myelogenous Leukemia (CML)

Overproduction of mature myeloid-bone marrow cells

Age 65 years or older

95% of adults with CML have PhC Usual symptoms of leukemia: Anemia, increased infection, increased bleeding WBC count greater than 100,000 cells per microliter

Staging of Lymphomas

"Bulky"- large tumor

and

"nonbulky" (better prognosis)- small tumor

HL (previously called Hodgkin's disease)

Most common in ages 15 to 20 years and over 50 years of age
~20% of the lymphomas
B cell: Reed-Sternberg cells ("owl eyes")
5 subtypes
Immunosuppressive treatment may increase
Lymph node biopsy
Signs and symptoms
• No dramatic symptoms
• Enlarged lymph node may be present
NHL risk

NHL (NonHodgkin's Lymphoma)

Over 80% of lymphoma cases; more common in older individuals
B or T cells or NK cells
30 subtypes
Enlarged, painless lymph node is often first sign
Lymph node biopsy

Multiple Myeloma

Neoplastic plasma B cells that synthesize abnormal Igs and Ig fragments.

Bone pain is a common complaint, especially in the back MM associated with increased osteoclast activity Osteopenia and lytic lesion of bone may be present

Increased risk of infection as antibodies are abnormal and ineffective

Renal disease is a common manifestation and presence indicates poor prognosis

“Blast cells”

immature, precursor cells

Phagocytosis

the indigestion of bacteria or other bacteria by phagocytes and amoeboid protozoans

Polymorphonuclear (PMNs)

mature neutrophils

AKA: “Segs”

“Bands”-immature neutrophils

“Shift to the left”

High number of bands, indicating high level of neutrophil formation

if you see more, than the bone marrow is working over time

Normal WBC

4,000 to 10,000 cells/microliter

Leukemia reaction

WBC above 50,000 cells/microliter

Due to cause other than leukemia

All WBC types can present with

abnormal numbers

• *Examples:* monocytopenia, eosinophilia, basopenia, etc.

*Signs and Symptoms.* Key symptoms seen in patients with leukemia or lymphoma are those related

bone marrow suppression.

Bone marrow becomes overwhelmed by the proliferation of neoplastic blood cells that crowd out healthy blood cells. 

Physical examination may reveal enlarged lymph nodes, splenomegaly, or both

When the cancer develops in the lymphocytes (lymphoid cells)

it is called lymphocytic leukemia. 

When the cancer develops in the granulocytes or monocytes (myeloid cells

it is called myelogenous leukemia.