Immunology & Rheumatology

Question 1

Anticitrullinated Protein Antibodies (ACPAs)

Answer 1

Highly specific for rheumatoid arthritis (RA); especially in patients with rheumatoid factors (RF) (negative) titers

Question 2

Rheumatoid factors (RFs)

Answer 2

Commonly associated with RA, however its not disease specific (meaning RFs could mean other diseases not just RA)

Question 3

Antinuclear Antibodies (ANAs)

Answer 3

Diagnostic criteria:
- Idiopathic systemic lupus erythematosus (SLE)
- Drug-Induced lupus
- Mixed connective tissue disorder (MCTD)
Antibodies affected:
- dsDNA
- ssDNA

Question 4

dsDNA

Answer 4

• Specific for SLE; useful diagnostic tool; correlates with disease activity

Question 5

ssDNA

Answer 5

• Sensitive for SLE; limited utility for diagnosis; does not correlate with disease activity

Question 6

Antineutrophil Cytoplasmic Antibodies (ANCAs)

Answer 6

Helpful to diagnose and classify vasculitis

Question 7

What laboratory tests best correspond with a diagnosis of vasculitis?

Answer 7

ANCAs

Question 8

What lab test is most often commonly associated with RA, but is often present in other rheumatologic and -non-rheumatologic disease?

Answer 8

RFs

Question 9

Complement system

Answer 9

Assessment on labs
- Hypocomplementemia : Immune system activation (hypercatabolism)
Useful for serial measurement; correlates with corresponding clinical pictures
Assay results
- C3 protein
- C4 protein

Question 10

C3 protein

Answer 10

More abundant complement protein

Normal range: 72-156 mg/dL

Question 11

C4 protein

Answer 11

Specific for identifying complement activation

Normal range: 20-50 mg/dL

Question 12

Acute Phase Reactants (APRs)

Answer 12

Assay results
- ESR
- C-RP
APRs are non-specific - it cannot confirm/exclude diagnosis

Question 13

ESR & C-RP are helpful in three ways

Answer 13

• Estimating extent/severity of inflammation
• Monitoring disease activity over time
• Assessing prognosis

Question 14

Erythrocyte Sedimentation Rate (ESRs)

Answer 14

Assay normal results

• Males: 0-15 mm/hr
• Females: 0-20 mm/hr

Question 15

C- Reactive Protein (CRPs)

Answer 15

Precise function is unknown

Question 16

Non-rheumatologic tests

Answer 16

Cannot confirm/exclude diagnosis

Question 17

What best explains hypocomplementemia

Answer 17

Hypercatabolism

Question 18

Which of the following statements regarding ESR & C-RPs (APRs) is false?

a. APRs are helpful in estimating extent or severity of inflammation
b. APRs can be used to monitor disease activity over time
c. APRs can aide with prognosis assessment
d. APRs are vital to confirm and exclude rheumatologic disease

Answer 18

d. APRs are vital to confirm and exclude rheumatologic disease.

Question 19

Rheumatoid arthritis define

Answer 19

Systematic disease; observed symmetrical inflammation of joints (at least one joint)

Question 20

ACPAs can diagnosis or classify prognosis of…

Answer 20

Rheumatoid arthritis

Question 21

RFs can be helpful to diagnosis…

Answer 21

Rheumatoid arthritis

RFs need to be from 75-80% to be considered positive (if increased titers, the disease could be severe)

Question 22

ANAs would usually be negative in…

Answer 22

Rheumatoid arthritis

If it becomes positive, dsDNA needs to be calculated

Question 23

Complement system would be normal or elevated in…

Answer 23

Rheumatoid arthritis

Question 24

APRs (ESRs & C-RPs) would be elevated in…

Answer 24

Rheumatoid arthritis

It would be mostly beneficial in monitoring disease activity

Question 25

Synovial cavity would be classified as what in rheumatoid arthritis?

Answer 25

Mild inflammatory or inflammatory

Question 26

Define idiopathic systemic lupus erythematosus (SLE)

Answer 26

SLE is a chronic inflammatory disease with an unknown etiology

Question 27

What are characteristics of SLE?

Answer 27

SLE affects virtually every organ - Skin: butterfly rash - Musculoskeletal: arthritis - Hematologic: hemolytic anemia, thrombocytopenia, leukopenia

Question 28

Who have a greater chance of developing lupus (male or female)?

Answer 28

Female | - 10:1 ratio (female:male); from ages 15-45

Question 29

ANAs would be usually positive in...

Answer 29

SLE If they are, additional antibodies, anti-dsDNA and anti-ssDNA, should be measured and checked - anti-dsDNA has a high specificity for SLE - anti-ssDNA has a high sensitivity for SLE

Question 30

APRs (ESRs and C-RPs) would be affected how in lupus?

Answer 30

ESRs: elevated | C-RPs: normal

Question 31

Which of the following lab tests best corresponds with a diagnosis of rheumatoid arthritis? a. Antinuclear antibodies (ANAs) [1:720] b. Erythrocyte sedimentation rate (ESR) [44 mm/hr] c. Rheumatoid factor (RF) [1:640] d. Antineutrophil cytoplasmic antibodies (ANCAs) [Positive]

Answer 31

c. Rheumatoid factor (RF) [1:640]

Question 32

Which of the following lab tests best corresponds with a diagnosis of systemic lupus erythematosus ? a. Antinuclear antibody (ANAs) [1:720] b. Erythrocyte sedimentation rate (ESR) [44 mm/hr] c. Rheumatoid factor (RF) [1:640] d. Antineutrophil cytoplasmic antibodies (ANCAs) [Positive]

Answer 32

a. Antinuclear antibody (ANAs) [1:720]

Question 33

Serum uric acid assay results

Answer 33

Males (>17 years): 4.0 - 8.5 mg/dL | Females (>17 years): 2.7 - 7.3 mg/dL

Question 34

Hyperuricemia assay results

Answer 34

Males (>17 years): > 8.5 mg/dL | Females (> 17 years): >7.3 mg/dL

Question 35

GOUT and Hyperuricemias defined as

Answer 35

Acute inflammatory monoarthritis

Question 36

What happens to the complement system in SLE?

Answer 36

Levels C3 and C4 decrease | - Best to follow up lab test w/ patients that undergo low levels because of types of treatments