Immunology/auto-immune

Question 1

How is common variable immunodeficiency diagnosed?

Answer 1

Very decreased IgG, low levels of IgA and/or IgM. No response to vaccination

Question 2

What kind of infections are patients with common variable immunodeficiency most susceptible to?

Answer 2

Get recurrent respiratory (e.g. pneumonia, sinusitis, otitis) and GI (e.g. Salmonella, Campylobacter) infections

Question 3

How is common variable immunodeficiency treated?

Answer 3

Immunoglobulin replacement therapy

Question 4

How can intestinal bypass surgery (e.g. Crohn’s resection) or celiac sprue lead to ostemalacia?

Answer 4

Can cause vitamin D deficiency leading to decreased calcium and phosphate absorption. PTH increases in response to hypocalcemia, which in turn causes a more marked level of hypophosphatemia

Question 5

What antibody should be tested for in suspected systemic sclerosis?

Answer 5

antitopoisomerase-1

Question 6

What medication is most indicated for primary biliary cholangitis?

Answer 6

Ursodeoxycholic acid (UDCA)

Question 7

What autoantibodies are found in Sjögren syndrome?

Answer 7

Anti-Ro (SSA) &/or anti-La (SSB)

Question 8

What are the major possible complications of ulcerative colitis?

Answer 8

Toxic megacolon, primary sclerosing cholangitis, colorectal cancer (screening begins 8-10 years after dx), erythema nodosum, pyoderma gangrenosum, and spondyloarthritis

Question 9

What are the recommendations for pneumococcal vaccination?

Answer 9

PCV13 for all infants and young children. PPSV23 for adults age <65 with predisposing comorbidities (e.g. chronic heart or lung disease, diabetes, cirrhosis). Immunocompromised patients and all individuals age >65 should receive both vaccines to maximize protection

Question 10

What is the presentation and mechanism of graft-versus-host disease?

Answer 10

Donor T lymphocytes are activated against the host and target the skin (maculopapular rash involving palms, soles, and face), intestine (blood-positive diarrhea), and liver (abnormal liver function tests and jaundice). Can happen a couple weeks after donation, especially in bone marrow donations

Question 11

What bone disease is associated with primary biliary cholangitis?

Answer 11

Osteomalacia (mechanism unknown)

Question 12

What antibody will be positive in drug-induced SLE?

Answer 12

Anti-histone

Question 13

What antibodies are positive in systemic sclerosis?

Answer 13

Anti-Scl-70 and anti-topoisomerase

Question 14

How is HIT diagnosed?

Answer 14

With an immunoassay or a functional assay (eg serotonin release assay)

Question 15

What is mixed cryoglobulinemia ?

Answer 15

90% of cases are associated with hep C. It is thought that the immune reaction to HCV causes the formation of immune complexes with HCV antigen, which subsequently trigger complement activation and inflammation of blood vessels, resulting in palpable purpura (due to cryoglobulinemic vasculitis). Immune-complex mediated damage is also responsible for polyarthralgia. So it presents with arthralgias and palpable purpura. Testing for cryoglobulins will NOT show a precipitate. Patients will be RF positive

Question 16

What stain can help distinguish between acute humoral and T-cell mediated organ rejection?

Answer 16

C4d staining shows the presence of antibodies (humoral)

Question 17

How is vitiligo diagnosed?

Answer 17

Blue-white fluorescence of the light skin areas on Wood’s lamp examination

Question 18

What condition(s) is anticardiolipin antibodies seen in?

Answer 18

In antiphospholipid syndrome (APS) and sometimes in SLE

Question 19

What is a scleroderma renal crisis?

Answer 19

Pts present with acute renal failure and malignant hypertension (e.g. HA, nausea, blurry vision). Urinalysis may show mild proteinuria. Peripheral blood smear shows microangiopathic hemolytic anemia (schistocytes) and thrombocytopenia