Minimal change disease with IgM+ immunofluorescence: a subtype of nephrotic syndrome

Abstract

Immunoglobulin (Ig) M nephropathy is defined by electron-dense mesangial deposits and mesangial IgM visible by immunofluorescence (IF) without other histopathologic and immunofluorescent microscopic abnormalities. Certain patients have only immuno-positive (IgM+) IF. Children presenting with steroid-dependent or steroid-resistant nephrotic syndrome have a high prevalence of IgM+ IF with or without electron-dense deposits. We reviewed the clinical course of children with steroid-dependent or steroid-resistant nephrotic syndrome who underwent renal biopsy at Texas Children's Hospital from 1989 to 2006 to further characterize IgM+ IF in children with nephrotic syndrome. Of the 55 children with steroid-resistant or -dependent minimal change disease (MCD), 23 had IgM+ IF. Of these 23 children, 61% had microscopic hematuria at presentation, 48% (11/23) were steroid-dependent, and 48% (11/23) steroid-resistant (one underwent biopsy prior to steroid therapy). We compared the efficacy of adjuvant treatment with cyclophosphamide and cyclosporine: 18% initially treated with cyclophosphamide obtained remission, while 55% had no response; 83% obtained subsequent remission with cyclosporine. Of those initially treated with cyclosporine, 88% obtained complete or partial remission. IgM+ IF may be surrogate marker for the severity of MCD. Based on our results, children with MCD and IgM+ IF have a better response to cyclosporine than cyclophosphamide.

Infant with gross hematuria and nephrotic syndrome: answers

“…Our patient partially responded to steroids and had a good response to calcineurin inhibitor. DMH has been described with MCNS, IgM associated steroid-resistant NS, and FSGS [2,15,16]. Neither IgM deposits in the mesangium nor glomeruli with segmental sclerosis were seen in the renal biopsy specimen in our patient .…”

The prevalence and clinicopathological profile of IgM nephropathy in children with steroid-resistant nephrotic syndrome at a single centre in Pakistan

“…We have earlier reported a frequency of IgMN of 18.5% in children with INS in the largest published series on IgMN in the world to date 8. A very high prevalence of 41.8% of IgM positivity was observed in a study on children with steroid-dependent nephrotic syndrome or SRNS at the Texas Childrens Hospital, USA 14. It is of note that the authors of the above study did not mention the minimum threshold of IgM positivity used for the diagnosis of IgMN.…”

“…There are also very few studies on the long-term evolution and the responses to CNI drugs in this disease 14. To our knowledge, this is first study on the detailed histopathological and clinical characterisation of IgMN patients in SRNS children and their response to CNI drugs in the region and the world.…”

“…Our results indicate that overall 75% of patients in the IgMN group responded to CNI therapy at 3 months and these results are almost similar to those reported from Jordan by Hamed,12 who reported a response rate of 70% in SRNS children with IgMN. Swartz et al 14 found an 88% rate of CR or PR in those children treated initially with CsA.…”

Impact of Immunofluorescence on the Histological Pattern of Pediatric Kidney Biopsies from Northern Pakistan

“…However, many of us regard it as a distinct histological entity with different response to steroid, requiring immunosuppressant therapy. [6][7][8][9][10][11] We believe that IgM nephropathy remains a separate histological entity with steroid responsiveness, course, and prognosis far different from MCD. About 23.5% of our cases showed renal insufficiency with a serum creatinine varying from 1.4 to 5 mg%.…”