Rheumatology Labs

Question 1

CRP

Answer 1

• Inflammation –> cytokines produces (IL-1, IL-6, TNF-alpha) –> liver where hepatocytes make acute phase proteins (including CRP)
• Timing - CRP rises quickly w/ inflammation while other peak later BUT also goes away quickly
• **CRP can also be elevated in exercise, pregnancy, obesity, URI, MI, bronchitis, major trauma, sepsis, serious infections

Question 2

ESR

Answer 2

if highly inflammatory state the RBCs will cluster and fall more readily (higher ESR)

Question 3

Rheumatoid Factor

Answer 3

• binds Fc region of human immunoglobulin

- NOT specific for rheumatoid arthritis (also in SLE, Sjogrens, elderly, infections)

Question 4

Anti -CCP

Answer 4

(cyclic citrullinated peptide)

• more specific to rheumatoid arthritis

Question 5

ANA

Answer 5

(anti-nuclear)

• pos in almost every SLE pt but can also be seen in normal pop (those w/ SLE usually have much higher titer - get to greater dilution than normal pop)
• Group of multiple types that bind DIFF antigens in nucleus (specific patterns can help distinguish etiologies)
  - Homogeneous - presence of anti-DNA in SLE
  - Speckled - presence of anti-RNP in mixed connective tissue disease
  - Nucleolar
  - Cytoplasmic
  - Centromere - anti-centromere in limited form of scleroderma
  - PCNA

Question 6

ANCA

Answer 6

(anti-neutrophil cytoplasmic antibody)

• Reacts against cytoplasmic granules in neutrophils
• Also has multiple patterns (distinguished diff forms of vasculitis)