Chapter 12: White cell disorders Flashcards
What is leukopenia?
A decrease in white blood cells
What are the two general causes of leukopenia?
Decreased production or increased destruction of white blood cells
What are causes of decreased production of white blood cells?
- Bone marrrow hypoplasia due to chemotherapy or aplastic anamia
- Drugs
- Neoplastic proliferations (lymphoma, metastasis)
- Myelodysplastic syndrome (neoplasic disease of the bone marrow)
What are causes of increased destruction of white blood cells?
Severe infections that trigger immune mediation.
What are symptoms of leukopenia?
Large ulcera (the ‘mess’ cannot be removed), infection and sepsis.
When is leukopenia referred to as neutropenia and when as agranulocytosis?
Neutropenia: reduction in the number of granulocytes. Agranulocytosis is severe neutropenia.
When is bone marrow hypercellularity seen?
When there is excessive neutrophil destruction or ineffective granulopoiesis.
What is leukocytosis?
An increase in the number of white cells in the blood.
Just know that there are different types of leukocytosis: neutrophillic, eosinophillic and basophillic leukocytosis, monocytosis and lymphocytosis. For illustration see Tabel 12.6 (Robbins Basic Pathology)
All these immune cells have been discussed in the previous exam. So (for example) if you have remembered that eosinophils are present during allergies you can remember that eosinophillic leukocytosis occurs during allergic disorders.
By what is infectious mononucleosis caused?
Disease caused by Epstein Barr Virus (EBV).
What are characteristics of infectious mononucleosis?
- Fever, sore throat and generalized lymphadenitis
- lymphocytosis of CD8+ T cells.
What are three general steps of EBV infection?
- Virus infiltrates epithelial cells and after this lymphoid tissue where mature B cells reside get infected.
- Infected B cells become activated and proliferate
- Regulation of proliferation of B cells by (mostly) CD8+ T cells. Some EBV-positive B cells escape this immune respons and persist for the life of the patient
Describe what happens to the peripheral blood, lymph nodes and spleen during EBV-infection.
- There is leukocytosis in the peripheral blood, mostly consisting of atypical lymphocytes.
- Lymph nodes are inflamed (lymphadenopathy)
- Spleen is enlarged (splenomegaly).
What cells can be seen in this picture?

Atypical lymphocytes (in infectious mononucleosis), with an oval, indented, or folded nucleus and abundant cytoplasm with a few azurophilic granules
What is acute nonspecific lymphadenitis?
Group of enlarged lymph nodes due to a local infection or generalized, systemic infection and inflammation.
What are characteristics of acute nonspecific lymphadenitis (i don’t think this is very important)?
Inflamed nodes are swollen, gray-red and engorged. Histologically, there are large germinal centers containing numerous mitotic figures.
Chronic nonspecific lymphadenitis can assume one of three patterns: follicular hyperplasia, paracortical hyperplasia or sinus histiocytosis.
Okay
When does follicular hyperplasia occur during chronic nonspecific lymphadenitis?
It occurs with infections or inflammatory processes that activate B cells, which migrate into B cell follicles and create a follicular reaction.
What can be causes of follicular hyperplasia?
Rheumatoid arthritis, toxoplasmosis and early HIV infection
When does paracortical hyperplasia occur during chronic nonspecific lymphadenitis?
It is caused by immune reactions involving T cells regions. When activated, parafollicular T cells transform into large proliferating immunoblasts that can efface the B cell follicles.
What can be causes of paracortical hyperplasia?
Viral infections, certain vaccinations and immune reactions induces by drugs.
When does sinus histiocytosis occur during chronic nonspecific lymphadenitis?
It usually is encountered in lymph nodes draining cancers and may represent an immune respons to the tumor.
What is characteristic for sinus histiocytosis?
Hypertrophy of lining endothelial cells and infiltrate of macrophages (histiocytes).
What is Cat-Scratch Disease (don’t learn this by heart)?
A self-limited lymphadenitis caused by the bacterium Bartonella henselae. It manifests with regional lymphadenopathy, most frequently in the axilla and the neck. The nodal enlargement appears approximately 2 weeks after a feline scratch or, less commonly, after a splinter or thorn injury.



