Diseases of B cells Deficiency

Question 1

Explain the cell signaling pathway for BCR

Answer 1

BCR has accessory molecules associated with it called the IgAlpha and IgBeta. A kinase comes in which is associated with BCR, like a Lyn, which p’s the accessory molecules. Then there Syk is recruited (analogous to ZAP70) which then recruits BTK when then recruits BLNK which then eventually leads to PLC gamma to form DAG and IP3.

Question 2

What is the clinical significance of spleen

Answer 2

Spleen has a marginal zone that is not found in any other. There are 2 clinical functions of this marginal zone and/or spleen: 1. Spleen filters blood and finds antigens that are present in the blood. Once an antigens is found, they are presented to the B cells, B cell beat up the pathogen and then start making antibodies 2. There are marginal zone B cells present in the marginal zone that detects antigens that are not protein, so a Pnemococcus bacterium which is covered in a polysaccharide coat can only be detected by the B-1 B cells in the peritoneal cavity and by the marginal zone B cells in the spleen

Question 3

What do you make when you have a T independent antigen (TIA)

Answer 3

Mostly IgM and IgG2

Question 4

What should a primary care physician do if a patient presents with infection who doesn’t have a spleen

Answer 4

1. IVIG 2. Vaccinate the patient, with conjugated vaccine 3. Admit the patient and closely monitor him

Question 5

Howell-Jolly body

Answer 5

RBCs that are normally cleared when the patient has a spleen, seen in patients without a spleen