We’ve been releasing quiz questions from NephMadness 2019 every week as we count down to the NephMadness 2020 logo reveal at Kidney Week. Did you miss any of the previous quizzes? Catch up here.
This week we focus on the Complement Region. The contemporary complement system lies at the interface of innate and adaptive immunity. Test your knowledge on the complement cascade and C3 glomerulopathy with the quiz* below.
For a PDF version of the questions & answers, please click here.
1. Two sisters aged 14 and 16 years are diagnosed with C3GN. A mutation in the gene encoding which of the following is most likely?
Factor H
Correct! Of those listed, only Factor H mutations have been associated with genetic C3GN. C3 Nephritic Factor is an autoantibody that binds to and stabilize C3 convertase and is a cause of acquired C3GN, not genetic C3GN. C1 is part of the classical complement cascade, not the alternative complement cascade. MASP is part of the Lectin pathway. [Reference: Dragon-Durey, M.A., Fremeaux-Bacchi, V., Loirat, C., et al. Heterozygous and homozygous factor H deficiencies associated with hemolytic uremic syndrome or membranoproliferative glomerulonephritis: report and genetic analysis of 16 cases. JASN 2004; 15(3): 787-95.]
C3 Nephritic Factor
Incorrect.
C1
Incorrect.
MASP
Incorrect.
2. A 60-year-old man with hypertension presents with new onset proteinuria, hematuria, and worsening kidney function. A kidney biopsy is performed that showed C3 glomerulonephritis. Which of the following is most likely to be an associated underlying disorder?
Staphylococcus aureus infection
Incorrect.
Monoclonal gammopathy
Correct! The study referenced showed that 65% of patients older than 50 years with acquired C3GN had a monoclonal gammopathy present. The others are not known to be associated with C3GN. [Reference: Ravindran, A., Fervenza, F.C., Smith, R.J., and Sethi, S. C3 glomerulopathy associated with monoclonal Ig is a distinct subtype. Kidney Int. 2018;94(1):178-86.]
Systemic lupus erythematosus
Incorrect.
Diabetes mellitus
Incorrect.
3. A 25-year-old female with aHUS causing ESRD undergoes a deceased donor kidney transplant. aHUS caused by a mutation in which of the following is LEAST likely to recur post- transplant?
Factor H
Incorrect.
Factor I
Incorrect.
MCP
Correct! As MCP is a membrane-bound protein and the allograft expresses normal membrane-bound, it is the least likely to cause recurrence of aHUS of those listed. The others listed are circulating factors and more likely to be associated with recurrence of aHUS. [Reference: Zuber, J., Le Quintrec, M., Sberro-Soussan, R., Loirat, C., Frémeaux-Bacchi, V., and Legendre, C. New insights into postrenal transplant hemolytic uremic syndrome. Nat Rev Nephrol 2011; 7(1): 23-5.]
C3
Incorrect.
4. A 27-year-old man is diagnosed with aHUS and the decision is made to start eculizumab. He has received the standard Meningococcal vaccine. True or False: He should also be vaccinated against N. meningitidis serotype B.
False
Incorrect.
True
Correct! Patients receiving eculizumab are at high risk of developing N. Meningitis, even with receiving the standard vaccine. It is recommended that they are also vaccinated against serotype B of N. meningitidis. [Reference: McNamara L.A., Topaz N., Wang X., Hariri S., Fox L., and MacNeil J. High risk for invasive meningococcal disease among patients receiving eculizumab (Soliris) despite receipt of meningococcal vaccine. MMWR Morb Mortal Wkly Rep 2017; 66(27): 734–7.]
– Quiz prepared by Anna Burgner, NephMadness Executive Team and AJKD Social Media Advisory Group Member. Follow her @anna_burgner.
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