Dr. Asa Deep Koganti (ADK), from John H. Stroger Jr. Hospital of Cook County, Chicago, Illinois, discusses his abstract for the National Kidney Foundation’s 2015 Spring Clinical Meetings (SCM15), Novel Amyloid Protein: A Cause of Nonproteinuric Kidney Disease, with Dr. Kenar Jhaveri, AJKD Blog Editor.
AJKDblog: Why don’t you tell us a little bit about your research and abstract being presented at the NKF 2015 Spring meetings?
ADK: The abstract is about a case of renal amyloidosis. A Hispanic male was evaluated for elevated creatinine with no protein or RBCs in urine. His serological work up for secondary glomerular etiologies was negative which also included serum and urine protein immunofixation and electrophoresis studies. His creatinine continued to rise so the case was pursued further by doing a kidney biopsy. Congo Red staining showed intense apple green birefringence under polarized light in the tubulo-interstitial compartments. The glomerulus was negative for this staining. Immunofluorescence for kappa and lambda chains and immunohistochemistry studies for Amyloid A protein were negative. A bone marrow biopsy was done which was negative for plasma cell dyscrasia. At this point we knew that his kidney disease is due to amyloidosis even though he was non proteinuric but we were not sure about the protein that is deposited in amyloid fibrils. Hence, liquid chromatography mass spectrometry (LCMS) was done to understand the proteomics of these fibrils which gave us the diagnosis of leukocyte chemotactic factor 2 (LECT 2) amyloid.
AJKDblog: Do you think every amyloidosis case should be sent for LCMS testing?
ADK: The most common cause of amyloidosis is light chain associated or Primary Amyloidosis (AL) which can be diagnosed without doing LCMS studies (which is available at limited centers). The fluorescein tagged antibodies for kappa and lambda light chains are widely available and can be used reliably to diagnose primary amyloidosis. LECT 2 amyloidosis is increasingly being reported approximately over the last 5 years. With limited knowledge available on this protein and disease, currently data is conflicting whether LECT 2 can be diagnosed with immunological studies and also that the fluorescein tagged antibodies for LECT 2 protein may not be available at all centers which makes this mode not feasible for diagnosing LECT 2. Hence LCMS is the best option available to diagnose LECT 2 but we do not believe that every amyloidosis case should be sent for LCMS testing. On reviewing the available literature on LECT 2 and also taking our case into consideration we want to emphasize that there are some unique features of LECT 2 amyloidosis which include tubulo-interstitial, arteriolar amyloid deposits, minimal glomerular involvement, predisposition to Hispanic population and renal limited disease with slow decline in renal function. These features in association with preliminary inconclusive biopsy findings should guide us in deciding whether LCMS should be pursued further or not. It is essential to know the etiology of amyloidosis as different types of amyloid proteins have different therapeutic and prognostic implications.
AJKDblog: Where do you and your group go from here?
ADK: Within a year of the above stated case, we have another Hispanic individual whom we diagnosed to have LECT2 amyloidosis by doing proteomic studies or LCMS. Our hospital, John H. Stroger Jr. Hospital of Cook County is a Chicago downtown public hospital with large Hispanic patient population. We are planning to do analysis of our previous renal biopsies with evidence of deposition disease and are negative for AA and AL stains. This will allow us to understand the true prevalence of this entity and also will assist us in determining any environmental or genetic factors involved in pathogenesis of this disease.