Immunoglobulin-Negative Fibrillary Glomerulonephritis Masked in Diabetic Nephropathy: A Case Report and Discussion of a Diagnostic Pitfall.

Introduction: Fibrillary glomerulonephritis (FGN) is a rare glomerular disease with poor prognosis, characterized by deposition of randomly arranged fibrillar material measuring 10-30 nm in diameter. This diagnosis is confirmed with DNAJB9 immunohistochemistry as well as ultrastructural examination. Ultrastructurally, the fibrillary material seen in this entity may be confused with diabetic fibrillosis occurring in diabetic nephropathy. Case Presentation: We present a case of a 63-year-old African American male with remote hepatitis C virus (HCV) infection and type II diabetes mellitus who presented with chronic kidney disease and nephrotic range proteinuria. A kidney biopsy revealed PAS-positive mesangial matrix expansion consistent with diabetic nephropathy and focal randomly oriented fibril deposition on ultrastructural examination. Immunofluorescence for immunoglobulin G and light chains was negative by both routine and paraffin immunofluorescence. Immunohistochemistry for DNAJB9 was diffusely positive, confirming co-existing FGN. Discussion/Conclusion: Patients with diabetic nephropathy and FGN have similar clinicopathologic presentations with a slowly progressive onset of kidney failure and proteinuria. In diabetic patients with fibrillary deposits under ultrastructural examination, concurrence of these disease entities must be considered. In this patient with remote HCV infection that was successfully treated years before, it is possible that in the absence of an FGN trigger, there was a loss of antigenicity with a loss of immunoglobulin staining. Therefore, we recommend DNAJB9 immunostaining for patients with remote HCV infection to avoid this diagnostic pitfall. Further studies are needed to determine the potential role of HCV infection in the initiation and etiopathogenesis of FGN.

Short course induction immunosuppression with thymoglobulin for renal transplant recipients.

BACKGROUND: The aim of this study was to demonstrate that 3-days of induction immunosuppression with thymoglobulin was as effective and safe as a 7-day course and reduced initial hospitalization after transplantation. METHODS: This was a prospective, nonrandomized trial of 40 consecutive patients receiving thymoglobulin induction for 3 days and followed for 1 year. An historical group of 48 patients that received 7 days of thymoglobulin served as controls. RESULTS: At 1 year, acute rejection (5 vs. 4%), graft survival (95 vs. 98%) and patient survival were similar; a composite end point of freedom from death, rejection, or graft loss, the event-free graft survival, was similar as was the safety profile. In the 3-day group, lymphocyte depletion was more sustained and initial hospitalization was significantly shorter (6 vs. 8 days). CONCLUSION: Three-day induction with thymoglobulin is as effective and safe as seven days, decreases initial hospitalization and causes more sustained lymphocyte depletion.

In vitro T cell proliferation from kidney allograft biopsies with unremarkable pathology: new strategies for an old problem.

Acute rejection of renal allografts is mediated by infiltrating alloreactive T cells. The goals of this study were to correlate T cell proliferation with rejection and to determine whether T cell proliferation in the absence of rejection would predict future rejection episodes. Toward this, kidney biopsies (n=100) were cultured in the presence of interleukin-2. Cultures were examined at 4, 24, and 48 hr for T cell proliferation. A strong correlation was observed between T cell proliferation at any time point and rejection. There was not a significant correlation between T cell proliferation in biopsies with no rejection and the occurrence of a rejection episode within 2 months. However, T cell proliferation after 4 hr was a better predictor of the occurrence of rejection within 2 months compared with observations after 24 and 48 hr. Therefore, a subgroup of patients with unremarkable biopsies but T cell proliferation may be at risk for rejection and warrant closer observation and possible tailoring of immunosuppression.