Is cyclophosphamide effective in patients with IgM-positive minimal change disease?
BACKGROUND
We analyzed the impact of immunoglobulin M (IgM) positivity on the relapse-free interval post completed course of cyclophosphamide (CYC) treatment in patients with steroid-dependent nephrotic syndrome (SDNS) and minimal change disease (MCD).


METHODS
This was a retrospective chart review of all children who received CYC for SDNS and MCD between 1988 and 2009. Patients were divided into three groups based on kidney biopsy: MCD without immunoglobulin M (IgM) positivity (IgM-), MCD with IgM-positive immunofluorescence (IF) only (IgM+), and MCD with IgM-positive IF and electron-dense deposits on electron microscopy (IgM++). The relapse-free time interval to the first relapse post-CYC therapy or up to 48 months of follow-up (if no relapse occurred) was used for survival analysis.


RESULTS
Forty children aged 1.5-12.3 years (15 were IgM-, 16 were IgM+, 9 were IgM++) received a cumulative CYC dose of 175 ± 30 mg/kg. The overall relapse-free survival time was 75 % at 12 months, 64 % at 24 months, 59 % at 36 months, and 56 % at 48 months, with no significant differences between the IgM groups (p = 0.80).


CONCLUSIONS
Based on our results, we conclude that more than 50% of our SDNS patients with MCD remained relapse-free 4 years post-CYC treatment. No significant difference in the response to CYC was observed between patients with or without IgM positivity.
Division of Nephrology, Department of Pediatrics, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, Ontario, K1H 8L1, Canada.
Pavel
P
Geier
Amani
A
Roushdi
Sylva
S
Skálová
Jennifer
J
Vethamuthu
Gabrielle
G
Weiler
Janusz
J
Feber
D002648:Child; D002675:Child, Preschool; D003520:Cyclophosphamide / Q000627:therapeutic use*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D007223:Infant; D008297:Male; D009402:Nephrosis, Lipoid / Q000188:drug therapy* / Q000276:immunology / Q000401:mortality; D009404:Nephrotic Syndrome / Q000188:drug therapy* / Q000276:immunology / Q000401:mortality; D012189:Retrospective Studies; D016896:Treatment Outcome
D007075:Immunoglobulin M; D007166:Immunosuppressive Agents; D003520:Cyclophosphamide