PGNMID and Progression of Renal Disease

Philadelphia—Even with treatment, proliferative glomerulonephritis associated with non-organized monoclonal Immunoglobulin (Ig) deposits (PGNMID) has poor renal outcomes, according to Gauri Bhutani, MD, and colleagues.

That was one of the findings of a study conducted by Dr. Bhutani et al. during a poster session at Kidney Week 2014. The poster was titled Progression of Renal Disease and Treatment Outcomes in Proliferative Glomerulonephritis Associated with Non-Organized Monoclonal Immunoglobulin Deposits.

There are few data on prognosis and treatment of PGNMID, according to the researchers. “As initially described, most cases have monoclonal IgG deposits but rare ones show IgM/IgA,” they said.

The retrospective chart review study utilized the pathology database at the Mayo Clinic in Rochester, Minnesota, to identify patients with PGNMID on kidney biopsy between January 1, 2008, and December 31, 2012. Patients with native kidney disease were included in the chart review. Kaplan-Meier curve, Log Rank text, and Cox proportional hazard models were used in the statistical analyses.

The chart review included 38 patients. Of those, there were 34 with monoclonal IgG, three with IgM, and one with IgA. Median follow-up was 1036 days (range, 608 to 1960 days). Median age was 56 (range, 48-62) years, 87% were white, and females equaled males. At diagnosis, median creatinine and proteinuria were 1.6 (range, 1.4 to 2.9) ng/dL and 6.2 (range, 3 to 9.3) g/day, respectively.

Over the follow-up period, 39% (n=15) reached end-stage renal disease (ESRD) and there were no deaths. At the 1-year point, 40% had ESRD or doubling of creatinine; median time to this combined outcome was 24 (range, 4 to 103) months. Most of the patients (87%) received treatment ranging from steroids to mycophenolate to chemotherapy agents.

Higher initial creatinine was a risk factor for the combined outcome of ESRD or doubling of creatinine (P<.01; RR 1.14-1.84). Normal serum C3 and C4 (P =.010); mesangioproliferative histology may be protective (P=.09). There was no observed relationship between renal survival and detectability of pathologic Ig or clone, Ig isotype, IgG subtype, light chain, age, or sex.

In conclusion, the researchers said, “PGNMID has poor renal outcomes even with treatment and especially in those presenting with lower glomerular filtration rate. Subgroup outcome comparisons were limited by small cohort size. Evaluation of individual treatment agents and outcomes after transplant recurrence (n=14) will be performed.”