Acute Interstitial Nephritis With Predominant Plasmacytic Infiltration in Patients With HIV-1 Infection

Updates on HIV and Kidney Disease

PURPOSE OF REVIEW

With the advent of antiretroviral therapy, HIV infection has become a chronic disease in developed countries.

RECENT FINDINGS

Non-HIV-driven risk factors for kidney disease, such as APOL1 risk variants and other genetic and environmental factors, have been discovered and are better described. Consequently, the field of HIV-associated kidney disease has evolved with greater attention given to traditional risk factors of CKD and antiretroviral treatment's nephrotoxicity. In this review, we explore risk factors of HIV-associated kidney disease, diagnostic tools, kidney pathology in HIV-positive individuals, and antiretroviral therapy-associated nephrotoxicity.

Microsporidium Infection–Associated Acute Kidney Injury in a Patient With HIV

Patients infected with HIV (human immunodeficiency virus) are at an increased risk of developing acute kidney injury (AKI) compared with patients without HIV infection. We report a rare case of disseminated Microsporidium infection–associated AKI affecting the native kidneys in a 30-year-old Asian woman with HIV infection. She initially presented to an outside institution with AKI after completing treatment with trimethoprim-sulfamethoxazole (Bactrim [Hoffmann-La Roche]) and prednisone for Pneumocystis pneumonia. She was empirically treated with prednisone for presumed acute interstitial nephritis due to Bactrim, and her serum creatinine concentration improved from 3.0 mg/dL to 1.8 mg/dL. She was subsequently initiated on antiretroviral therapy and was also treated with ganciclovir for cytomegalovirus viremia. Because of persistent fever, she was transferred to our institution and was diagnosed with a disseminated Mycobacterium avium complex infection and a disseminated Microsporidium infection. Her serum creatinine concentration increased to 4.2 mg/dL. A kidney biopsy was performed because of her worsening kidney function, which revealed plasma cell–rich acute interstitial nephritis associated with disseminated Microsporidium infection. She was maintained on antiretroviral therapy and was treated with albendazole. This case highlights the fact that there are various etiologies and kidney manifestations of AKI in patients infected with HIV with equally various implications for management; thus, performing a kidney biopsy is often crucial to help elucidate the underlying pathology and guide management.

Endothelial progenitor cells-derived exosomal microRNA-21-5p alleviates sepsis-induced acute kidney injury by inhibiting RUNX1 expression

The role of microRNA-21-5p (miR-21-5p) in sepsis-induced acute kidney injury (AKI) has been seldom discussed. Therefore, the objective of this present study was to investigate the mechanism of endothelial progenitor cells-derived exosomes (EPCs-exos) in sepsis-induced AKI via miR-21-5p/runt-related transcription factor 1 (RUNX1) axis. miR-21-5p was downregulated and RUNX1 was upregulated in the kidney of cecal ligation and puncture (CLP) rats, and miR-21-5p targeted RUNX1. Elevation of miR-21-5p improved renal function and renal tissue pathological damage, attenuated serum inflammatory response, as well as reduced apoptosis and oxidative stress response in renal tissues, and regulated endothelial glycocalyx damage marker proteins syndecan-1 and heparanase-1 in CLP rats. Overexpression of RUNX1 abolished the impacts of elevated miR-21-5p in CLP rats. Also, EPCs-exos upregulated miR-21-5p expression, and functioned similar to elevation of miR-21-5p for CLP rats. Downregulating miR-21-5p partially reversed the effects of EPCs-exos on sepsis-induced AKI. Collectively, our study suggests that EPCs release miR-21-5p-containing exosomes to alleviate sepsis-induced AKI through RUNX1 silencing.

Monotypic plasma cell interstitial nephritis as the only clinical manifestation in a patient with previously undiagnosed indolent multiple myeloma: A case report

INTRODUCTION

Predominantly monotypic plasma cell infiltrates are an uncommon renal finding in patients with malignant lymphoplasmacytic proliferation.

CASE PRESENTATION

We report the case of a 52-year-old man with chronic kidney disease and significant proteinuria associated with a monoclonal immunoglobulin spike (IgGκ). Kidney biopsy revealed the presence of atypical multinucleated CD138 plasma cells with voluminous nuclei stained exclusively with a κ antibody. Electron microscopy showed mesangial and segmental parietal electron-dense, nonorganized hyaline deposits without immunogold labeling for the κ light chain. The bone marrow aspirate revealed 6% of apparently mature plasmocytes without dystrophy. We therefore concluded that the patient had an indolent multiple myeloma with specific renal involvement in the form of malignant monotypic interstitial plasmacytic infiltration. We initiated a specific chemotherapy regimen including bortezomib-cyclophosphamide-dexamethasone. After 4 months of follow-up, creatinine levels had improved slightly and free κ light-chain levels had decreased significantly within the normal range.

CONCLUSION

This case highlights the need to consider neoplastic interstitial plasma cell infiltration systematically in patients diagnosed with an apparently benign monoclonal gammopathy and to consider adaptation of the chemotherapy regimen, to improve renal function.