Update on Membranous Nephropathy

U Penn established an annual one-day seminar in nephrology symposium. This year was titled “New Horizons in Nephrology: Updates in Glomerular Disease”.

Dr. Beck from Boston University gave the update on membranous nephropathy (MN). Previously, we discussed his article in the NEJM in detail, and today we will go over some key points and updates:

• 75% of MN is considered primary (idiopathic).
• IgG4 subclass is predominant in idiopathic MN.
• Anti-PLA2R is highly specific for primary MN
• Co-localization of PLA2R and IgG4 within immune deposits on biopsy.
• The majority of patients with primary MN have circulating autoantibodies against PLA2R.

There is a clear association of anti-PLA2R with disease activity.

- Positive in nephrotic state.

- Declines prior to the decrease in proteinuria.

- Absent in remission.

- Returns with (or prior to) relapse.

- Associated with recurrent MN

Methods of testing:

- Western blot

- Indirect immunofluorescence test

- ELISA : Will likely be the test of choice. Available in Europe, not yet in the US.

Treatment:

- Do NOT use corticosteroid monotherapy or MMF monotherapy for initial therapy of MN.

- No single definitive immunosuppression could be easily identified.

Current Initial therapy :

• Ponticelli regimen: methylprednisolone 1g/d iv x 3 doses followed by oral prednisone 0.5mg/kg/d in months 1,3,5; oral cyclophosphamide (2mg/kg/d) in months 2,4,6.
• Alternative initial therapy for those who refuse or have contraindications to cyclophosphamide is Calcineurin inhibitor (CNI) for at least 6 months.
• Stop if no remission in 6 months.
• If remission is attained, reduce dose every 1-2 mo by 50% and continue for at least 12 months 

Posted by Tarek Alhamad