Auto-inflammatory Syndromes and Complement Deficiency

Question 1

What are auto-inflammatory syndromes?

How do they present?

Answer 1

Caused by a dysregulated innate immune response with resultant activation of the inflammasome and cytokine excess. Also known as Periodic Fever Syndromes

Recurrent fever
Inflammation in multiple organs

Question 2

3 types covered:

Familial Mediterranean Fever (FMF)

Cryopyrin Associated Periodic Fever Syndrome (CAPS)

TRAPS

Answer 2

3 types covered:

Familial Mediterranean Fever (FMF)

Cryopyrin Associated Periodic Fever Syndrome (CAPS)

TRAPS

Question 3

Complement:

What are the 3 pathways?

What can cause acquired loss? (remember, complement is a protein)

Complement deficiencies:
- Classical pathway (C1/C2/C4) - What autoimmune disease is this linked to? What does this increase your risk of?

Answer 3

Classical
Alternative
Lectin

They all bind to C3 and activate it.

Decreased synthesis - liver
Loss - nephrotic syndrome or enteropathies
Increased consumption

Lupus

Increased risk of infections

Question 4

Properdin deficiency:

Properdin is a protein needed to stabilise C3.

X-linked as well.

What does it increase your risk of in childhood?

Answer 4

Meningitis due to Neisseria Meningitides

Question 5

Mannan binding lectin (MBL):

MBL is the first protein in the lectin pathway

Increased risk of encapsulated bacterial infections!

Answer 5

Mannan binding lectin (MBL):

MBL is the first protein in the lectin pathway

Increased risk of encapsulated bacterial infections!

Question 6

C3 deficiency:

What pathway is this?

Childhood

Increased risk of encapsulated bacterial infections!

Answer 6

Common pathway

Question 7

What is the key point with complement disorders?

Answer 7

In patients with a history of recurrent infection with encapsulated bacteria* from a YOUNG AGE – particularly meningitis – need to exclude complement deficiency

Question 8

What are some investigations for complement deficiency?

Management ABs

Answer 8

CH100 and AP100