Parenchymal infiltration and lymphoma-associated membranoproliferative pattern of glomerular injury: an unusual presentation of mantle cell lymphoma.

Lymphomatous processes have been shown to involve the kidney by direct and paraneoplastic mechanisms. Direct injury can manifest by effacement of typical parenchymal architecture by the lymphomatous infiltrate, and indirect, paraneoplastic mechanisms have been associated with a variety of glomerular lesions. Mantle cell lymphoma (MCL) has rarely been reported to be associated with both direct infiltration and/ or paraneoplastic glomerular lesions. We describe a patient with rapidly progressive glomerulonephritis whose renal biopsy showed effacement of the renal parenchyma by MCL and a membranoproliferative pattern of glomerular injury. The patient's bone marrow was also involved by MCL, and serology revealed small M-spikes and a positive rheumatoid factor. The clinicopathologic findings were consistent with a membranoproliferative pattern of glomerular injury secondary to MCL with infiltrative destruction of renal parenchyma. This case is unusual in that MCL was diagnosed on renal biopsy, that there was a two-pronged mechanism of renal injury, and that there were two separate monoclonal immunoglobulins elaborated by the lymphoma that could be associated with the glomerular injury. Although it is uncommon to make an initial diagnosis of lymphoma from a renal biopsy, it should be recognized that patients with lymphoma might develop clinically significant renal sequelae secondary to both direct and indirect mechanisms of lymphoma-mediated nephropathy.

The antinuclear antibody dense fine speckled pattern and possible clinical associations: An indication of a proinflammatory microenvironment.

BACKGROUND: Indirect immunofluorescence (IIF) is the most prevalent screening antinuclear antibody test for systemic autoimmune rheumatic disease (SARD). Certain IIF patterns have known antibody and disease associations, but the dense fine speckled (ANA-DFS) pattern has no confirmed clinical associations. Our objective was to determine the prevalence of SARD among a group of ANA-DFS positive individuals and to identify final diagnoses among non-SARD individuals in order to determine possible clinical associations with the ANA-DFS pattern. METHODS: A retrospective study of 425 patients from a university health care system with a positive ANA-DFS pattern consecutively between August 2017 and September 2018. Sera samples underwent ANA testing by IIF on HEp-2 cell substrates (Euroimmun, Germany). Clinical information was retrieved from electronic health records and stored in a de-identified database. RESULTS: The prevalence of SARD was 24%. Undetermined diagnosis (17%), skin disorders (12.1%), and fibromyalgia/chronic pain syndrome/chronic fatigue syndrome (11.8%) were the most common non-SARD diagnoses. Taking into account past medical history, the most common non-SARD were atopic disorders (21.2%), fibromyalgia/chronic pain syndrome/chronic fatigue syndrome (17.6%), and skin disorders (16.7%). CONCLUSIONS: The ANA-DFS pattern may be indicative of an underlying antigen-antibody interaction that plays a role in either the initiation or propagation of immunologic reactions. DFS70/LEDGF is a transcription factor involved in cell survival and stress protection, and autoantibodies may inhibit its function. It is likely that there are other antibodies producing the ANA-DFS pattern besides anti-DFS70/LEDGF, and more research is necessary to identify additional antibody specificities. The ANA-DFS pattern may be an indicator of a proinflammatory microenvironment given the high frequency of symptomatic patients and disease processes with an immunologic basis (including SARD).

Variability in Testing for Antineutrophil Cytoplasmic Antibodies: A Survey of Participants in the College of American Pathologists Proficiency Testing Program.

CONTEXT: -Variability in testing for antineutrophil cytoplasmic antibodies (ANCAs) contributes to confusion and controversy related to testing for vasculitis and other ANCA-associated diseases. OBJECTIVES: -To survey laboratory testing practices regarding ANCA testing and to investigate differences in testing algorithms. DESIGN: -Supplemental questions were sent to the 333 laboratories participating in the College of American Pathologists proficiency testing program for ANCA as part of the Special Immunology S2 Survey. RESULTS: -A total of 315 laboratories submitted responses to the supplemental questions. Only 88 of 315 participants (28%) reported using a combination of indirect immunofluorescence (IFA) and enzyme immunoassay (EIA) techniques as recommended by current guidelines, with a few additional labs using IFA and multiplex bead assay as an acceptable alternative to EIA. Other labs reported using only IFA, EIA, or multiplex bead assays. CONCLUSIONS: -A wide variety of testing algorithms are in use for ANCA testing despite evidence to suggest that a combination of IFA and EIA testing provides the most comprehensive information. Laboratories should inform clinicians clearly about testing practices and utility of testing in specific disease states.

Morphine induces albuminuria by compromising podocyte integrity.

Morphine has been reported to accelerate the progression of chronic kidney disease. However, whether morphine affects slit diaphragm (SD), the major constituent of glomerular filtration barrier, is still unclear. In the present study, we examined the effect of morphine on glomerular filtration barrier in general and podocyte integrity in particular. Mice were administered either normal saline or morphine for 72 h, then urine samples were collected and kidneys were subsequently isolated for immunohistochemical studies and Western blot. For in vitro studies, human podocytes were treated with morphine and then probed for the molecular markers of slit diaphragm. Morphine-receiving mice displayed a significant increase in albuminuria and showed effacement of podocyte foot processes. In both in vivo and in vitro studies, the expression of synaptopodin, a molecular marker for podocyte integrity, and the slit diaphragm constituting molecules (SDCM), such as nephrin, podocin, and CD2-associated protein (CD2AP), were decreased in morphine-treated podocytes. In vitro studies indicated that morphine modulated podocyte expression of SDCM through opiate mu (MOR) and kappa (KOR) receptors. Since morphine also enhanced podocyte oxidative stress, the latter seems to contribute to decreased SDCM expression. In addition, AKT, p38, and JNK pathways were involved in morphine-induced down regulation of SDCM in human podocytes. These findings demonstrate that morphine has the potential to alter the glomerular filtration barrier by compromising the integrity of podocytes.

Morphine promotes renal pathology in sickle mice.

Patients with sickle cell disease (SCD) are often treated with opioids for severe pain. Although opioids are known to have renal-specific effects, their role in nephropathy in SCD remains unknown. Because a subset of patients receives opioids for long periods of time, we examined the influence of chronic morphine treatment on mice with pre-existing renal disease expressing varying amounts of sickle hemoglobin. Morphine treatment for 3-6 weeks resulted in a variety of defects in renal morphology observed using light and electron microscopy. Notably, morphine induced glomerular pathology, resulting in increased glomerular volume, mesangial expansion, mesangial cell proliferation, parietal cell metaplasia, podocyte effacement, and microvillus transformation. Cystic tubulopathy and hemeoxygenase-1 expression and activity were also increased in morphine-treated mice. Naloxone, a non-selective opioid receptor (OR) antagonist, ameliorated these effects. Functionally, the urine albumin to creatinine ratio was increased following acute as well as chronic morphine treatment. These results suggest that clinically relevant doses of morphine induce renal pathology and that OR antagonists may be effective for ameliorating morphine-induced renal disease.

Glomerulotubular junction abnormalities are associated with proteinuria in type 1 diabetes.

Glomerulotubular junction abnormalities, frequent in proteinuric patients with type 1 diabetes, may contribute to the progressive GFR loss in overt diabetic nephropathy. Glomerulotubular junction abnormalities were examined in patients who have type 1 diabetes with a wide range of albumin excretion rates (AER). Renal biopsies from five normoalbuminuric patients, five microalbuminuric patients, six proteinuric patients, and five control subjects were studied by light and electron microscopy. Light microscopy specimens were serially sectioned to find and classify glomerulotubular junctions. Glomerular structural parameters were estimated using stereologic methods. Glomerulotubular junction abnormalities were found in 2% of glomeruli from control and normoalbuminuric patients and in 4% of glomeruli from microalbuminuric patients. In contrast, 71% of glomeruli from proteinuric patients had glomerulotubular junction abnormalities, including five (8%) atubular glomeruli. Electron microscopy findings were typical of diabetic nephropathy. Piece-wise linear regression models with glomerular, glomerulotubular junction, and interstitial parameters as independent variables provided greater GFR (92%; P < 0.005) and AER (95%; P < 0.01) prediction than multiple regression models (81% for GFR and 72% for AER). Thus, glomerular adhesions and glomerulotubular junction abnormalities help to explain the progressive GFR loss that is associated with onset of proteinuria in type 1 diabetes. Moreover, nonlinear models provide better fit for structural-functional relationships in patients with type 1 diabetes.

Atubular glomeruli and glomerulotubular junction abnormalities in diabetic nephropathy.

Atubular glomeruli (AG) have been described in several renal disorders. However, little attention has been paid to AG in diabetic nephropathy (DN). Preliminary studies suggested that tip lesions were frequently present in type 1 diabetic (D) patients with proteinuria. The aim of this study was to determine the frequency of AG and their possible relationship with tip lesions in DN. Renal biopsies from eight proteinuric type 1 D patients with normal to moderately reduced GFR (76 +/- 26 ml/min per 1.73 m(2)) and eight normal subjects were studied by light (LM) and electron microscopy (EM). Glomerular volume, volume of the glomerular corpuscle, which is tuft, and the fractional volumes of proximal, distal, and atrophic tubules per cortex were estimated using appropriate stereologic methods. Glomerulotubular junctions were examined on serial sections and classified into glomeruli attached to: normal tubules (NT); short atrophic tubules (SAT); long atrophic tubules (LAT); atrophic tubules with no observable glomerular opening (ATNO); and atubular glomeruli (AG). EM studies showed typical diabetic changes in biopsies, including increased GBM width (P < 0.00001) and mesangial fractional volume (P < 0.0001) and decreased filtration surface density (P < 0.01) compared with normal subjects. Seventeen percent of glomeruli in the D patients were atubular, and 51% were attached to atrophic tubules. Tip lesions were present in all SAT, 64% of LAT, 82% of ATNO, and only 9% of NT and were never observed in normal subjects. The relative volume of AG was smaller than glomeruli in other categories (P < 0.05). Fractional volume of proximal (P < 0.01) and distal (P <0.01) tubules per cortex were decreased, while fractional volume of cortical interstitium (P <0.00001) and atrophic tubules (P <0.01) were increased in D patients. Fractional volume of atrophic tubules, %AG, and percent of glomeruli with tip lesion explained 94% of the GFR variability in diabetic patients (P <0.05). Thus, AG and glomerulotubular junction abnormalities may be important in the development and progression of DN.

Mouse model of X-linked Alport syndrome.

X-linked Alport syndrome (XLAS) is a progressive disorder of basement membranes caused by mutations in the COL4A5 gene, encoding the alpha5 chain of type IV collagen. A mouse model of this disorder was generated by targeting a human nonsense mutation, G5X, to the mouse Col4a5 gene. As predicted for a nonsense mutation, hemizygous mutant male mice are null and heterozygous carrier female mice are mosaic for alpha5(IV) chain expression. Mutant male mice and carrier female mice are viable through reproductive age and fertile. Mutant male mice died spontaneously at 6 to 34 wk of age, and carrier female mice died at 8 to 45 wk of age, manifesting proteinuria, azotemia, and progressive and manifold histologic abnormalities of the kidney glomerulus and tubulointerstitium. Ultrastructural abnormalities of the glomerular basement membrane, including lamellation and splitting, were characteristic of human XLAS. The mouse model described here recapitulates essential clinical and pathologic findings of human XLAS. With alpha5(IV) expression reflecting X-inactivation patterns, it will be especially useful in studying determinants of disease variability in the carrier state.