Lymphocytes

Question 1

3 types of lymphocytes circulating our blood

Answer 1

T cells
B cells
NK cells

Question 2

T or F. Lymphocytes are polynuclear

Answer 2

F! mononuclear

• round, large and dark-staining nucleus
• 18-42% of circulting WBC

Question 3

Lymphopenia

Answer 3

• decreased lymphocyte count (<1x10^9/L)

- causes: HIV, autoimmune isorders, medications

Question 4

Lymphocytosis

Answer 4

• incrased absolute lymph count (>4.5x10^9/L)

- causes: Hep B, whooping cough, parasites, malignancies

Question 5

IM

Answer 5

• infectious mononucleosis
• EBV
• infection occurs by contact with oral secretions
• “kissing disease”
• teens to adults

Question 6

Cold Agglutinin Disease

Answer 6

• develops secondary to IM
• IgM autoantibodies form against “i” antigen on RBCs
• can lead to hemolytic anemia but not too severe so no treatment needed

Question 7

Lymphocyte development (2)

Answer 7

1. antigen independent: differentiate and mature in thymus and BM (1ry lymphoid organs)
2. antigen dependent: lymphocytes differentiate in spleen, lymph nodes, tonsil, MALT (2ry)

Question 8

Immunoglobulin gene rearrangement

Answer 8

during development in BM for B cells

- each produces unique antigen receptors

Question 9

naive B cells leave BM and migrate to…

Answer 9

2ry lymphoid organs

• encounter a specific antigen and cell division occurs
• memory B cells and plasma cells produced

Question 10

B lymphocyte functions

Answer 10

• humoral immunity by transformation into plasma cells
• present antigens to T cells
• produce cytokines to regulate T cell function

Question 11

T or F. There are more B lymphocytes than T lymphs in blood

Answer 11

F! more T lymphs (50-85%) vs (20% B lymphs)

Question 12

antigen receptor gene rearrangement for T lymphocytes

Answer 12

thymus (development)

NOTE: if receptor reacts with self antigens => apoptosis

Question 13

when T cells encounter antigens

Answer 13

• activated T cells = large lymphs

- effector T cells = reactive lymphs

Question 14

5-30% of lymphs

Answer 14

NK cells

• attack virus-infected cells and tumor cells
• large granular lymphocytes
• part of innate immune system

Question 15

Clinical features of infectious mononucleosis

Answer 15

• fever
• pharyngitis
• lymphadenopathy
• self-limiting => symptomatic therapy
• fatigue
• splenomegaly
• complications rare: splenic rupture, neurologic complications, myocarditis, and pericarditis

Question 16

IgM that react against non-human antigens

Answer 16

heterophile Abs

Question 17

When are EBV serologies done?

Answer 17

• when rapid screen test is negative
• if the patient doesn’t exhibit classic IM symptoms (children)
• immuno suppressed patients
• detect EBV specific antibodies

Question 18

Reactive lymphs

Answer 18

• small, resting lymph becomes proliferating larger cell

- nucleoli might be visible