Clinicopathologic characteristics and steroid response of IgM nephropathy in children presenting with idiopathic nephrotic syndrome

Abstract

There is no detailed information on clinical and immunopathologic features of immunoglobulin M nephropathy (IgMN) in children with idiopathic nephrotic syndrome (INS) in Pakistan. We reviewed our native renal biopsies over 15 years (July 1995-July 2010) and identified 135 cases of IgMN in nephrotic children (≤17 years). Their demographic, clinical and immunopathologic data were retrieved from biopsy reports and case notes. Mean age of this cohort was 7.6 ± 4.2 years. Males were 92 (68.1%) and females were 43 (31.9%). Steroid-dependent NS was seen in 88 (65.2%) cases and steroid-resistant NS in 47 (34.2%). Hematuria was found in 42 cases (31.2%) and hypertension in 27 (19.5%). The most common morphologic change was glomerular mesangial proliferation, found in 89 (65.9%) biopsies. Minor changes were seen in 46 (34.1%) cases and focal segmental glomerulosclerosis (FSGS) in 37 (27.4%). Immunofluorescence microscopy showed diffuse mesangial positivity of IgM in all cases. C3 and C1q were found in 72 (53.3%) and 40 (29.7%) cases, respectively. Our results show that IgMN is a fairly common cause of INS in children in Pakistan. It shows a spectrum of morphologic changes ranging from minor changes to FSGS.

Clinical Profile &Treatment Outcome in Children with IgM Nephropathy

“…This is not as per our study as we had a majority of cases with SDNS (65%) with 30% having SRNS. But our data correlates with another study done from South Asia (Pakistan) who found 34.2% children to have SRNS [6] . However, there is an inherent bias in the selection of paediatric patients with NS for renal biopsy (indications are as mentioned in our methodology).…”

“…A study done in Saudi Arabia [23] showed that 18 out 36 patients had hematuria whereas another study from neighbouring Bangladesh [24] showed a case report which also had hematuria on presentation. Another article from neighbouring Pakistan [6] showed presence of hematuria in 31.2% children (42/135). The detailed analyses are as mentioned in TABLE 2.…”

“…Two articles published in 1978 by independent groups [4,5] are considered by many authors to be the first descriptions of a glomerulopathy characterised by diffuse mesangial deposits of immunoglobulin M (IgM) in patients with relatively normal light microscopy. The disease, like IgA nephropathy (IgAN), is defined by its immunohistologic features: the presence of IgM as the sole or dominant immunoglobulin in the mesangial regions of the glomeruli in a diffuse (all glomeruli) and global (the entire glomerulus) distribution [4][5][6][7] . Its incidence varies, in accordance with different series, between 4.8% and 8.6% of all renal biopsies, affecting all ages and without predilection for gender [6,8,9,10] .…”

“…The disease, like IgA nephropathy (IgAN), is defined by its immunohistologic features: the presence of IgM as the sole or dominant immunoglobulin in the mesangial regions of the glomeruli in a diffuse (all glomeruli) and global (the entire glomerulus) distribution [4][5][6][7] . Its incidence varies, in accordance with different series, between 4.8% and 8.6% of all renal biopsies, affecting all ages and without predilection for gender [6,8,9,10] . Some authors report a higher frequency of glucocorticoidresistance or glucocorticoid-dependence with relatively few cases of complete remission [2,11,12] .…”

IgM nephropathy; can we still ignore it

“…Most of the studies have reported on prevalence of IgMN as frequency/ percentage of renal biopsies with diagnosis of IgMN reported from 2 % to 18.5 % in native biopsies (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). Occasional cases of IgMN in transplant biopsies have also been reported (14).…”