Fogo, Ch. 6 - IgA Nephropathy

Question 1

What is the defining immunologic feature of IgA nephropathy?

Answer 1

Dominant (or codominant) mesangial IgA deposition in the absence of lupus or post-infectious process.

Question 2

What are the LM findings in IgA nephropathy?

Answer 2

Usually nothing, but can have proliferation, crescents, and segmental mesangial hypercellularity.

Question 3

What does the presence of crescents in IgA nephropathy indicate?

Answer 3

Can be a part of IgA nephropathy, but many crescents requires workup for ANCA-associated nephritides.

Question 4

What are the IF findings in IgA nephropathy?

Answer 4

Mesangial IgA (1+ or higher) & C3. IgA should be A1, not A2. May also have IgG/IgA/C1q and capillary wall staining.

Question 5

What should be considered with strong C1q staining in otherwise IgA nephropathy?

Answer 5

Lupus

Question 6

What are the EM findings in IgA nephropathy?

Answer 6

Mesangial dense deposits. Can also have capillary deposits, focal GBM thinning, and podocyte foot effacement.

Question 7

What is the etiology of IgA nephropathy?

Answer 7

Not always known. Probably has to do with abnormal IgA1 hinge region glycosylation. Flares with liver disease and infection.

Question 8

In which patients does IgA nephropathy usually occur?

Answer 8

Asian and north american patients, more often young and male patients.

Question 9

Recall the components of the Oxford classification for IgA nephropathy.

Answer 9

M: Mesangial hypercellularity

E: Endocapillary hypercellularity

S: Segmental glomerulosclerosis

T: Tubular atrophy

C: Crescent formation

Question 10

How is IgA nephropathy treated?

Answer 10

ACE inhibition, steroids, and other immunosuppression.