Late Corneal Stromal Deposits After COVID-19.

ABSTRACT: We present 2 cases of striking stromal corneal infiltrates months after COVID-19 infection. While we cannot prove that these infiltrates are caused by or directly related to COVID-19, we did not find any other plausible cause that could explain these ophthalmic signs. In these cases, the ongoing process was detected in relatively early stages due to scheduled visits with patients and responded positively to prednisolone acetate 1% ophthalmic suspension. However, we do not know the response to treatment in more advanced cases.

Type 3 hypersensitivity in COVID-19 vasculitis.

Coronavirus Disease 2019 (COVID-19) is an ongoing public health emergency and new knowledge about its immunopathogenic mechanisms is deemed necessary in the attempt to reduce the death burden, globally. For the first time in worldwide literature, we provide scientific evidence that in COVID-19 vasculitis a life-threatening escalation from type 2 T-helper immune response (humoral immunity) to type 3 hypersensitivity (immune complex disease) takes place. The subsequent deposition of immune complexes inside the vascular walls is supposed to induce a severe inflammatory state and a cytokine release syndrome, whose interleukin-6 is the key myokine, from the smooth muscle cells of blood vessels.

Hepatitis B-related glomerulonephritis and optimization of treatment.

Introduction: Multiple studies have revealed a strong relationship between the development of nephropathy and hepatitis B virus (HBV) infection. The underlying pathogenesis of hepatitis B-related glomerulonephritis (HBV-GN) involves immune complexes, which can be isolated from kidney tissues. Clearance of HBV antigenemia improves renal impairment and proteinuria in HBV-GN patients.Areas covered: In this review, we present our current understanding of the epidemiology, pathogenesis, pathology, diagnosis, and treatment of HBV-GN. We discuss the advantages and disadvantages of oral nucleoside/nucleotide analogs (NAs), and the main pharmaceutical treatment for hepatis B.Expert opinion: Currently, antiviral agents are the main HBV-GN therapeutic agents. Although no randomized controlled clinical trials have compared the efficacy of interferon (IFN) and NA, we suggest IFN treatment for pediatric patients (IFN-α in patients ≥1 year; pegIFN-α in patients ≥3 years) considering treatment duration and absence of resistance. Novel NAs have brought about promising treatment options involving high efficacy viral suppression and low resistance rates. NAs with a high barrier to resistance (e.g. entecavir) are recommended as first-line therapy of HBV-GN. Immunosuppression monotherapy, such as corticosteroids, is of little benefit and potentially harmful to HBV-GN patients due to the possibility of viral reactivation.

Common Mechanisms of Viral Injury to the Kidney.

Viral infections in an immunocompetent host can cause both acute and chronic kidney diseases, either by direct damage to the infected kidney cells or as a consequence of systemic immune responses that impact the kidneys' function. Viruses have evolved mechanisms to hijack signaling pathways of the infected cell, including the mammalian target of rapamycin pathway to support viral replication, and to evade antiviral immune responses such as those mediated by miR-155 via microRNA mimetics expressed by the virus. At both the cellular and systemic levels, the host has also evolved mechanisms to counter the viral subversion strategies in the evolutionary battle for mutual survival. In the era of genomic medicine, understanding individual genetic variations that lead to differences in susceptibilities to infection and variabilities in immune responses may open new avenues for treatment, such as the recently described functions of apolipoprotein L1 risk alleles in HIV-associated nephropathy. In addition, state-of-the-art high-throughput sequencing methods have discovered new viruses as the cause for chronic diseases not previously attributed to an infection. The potential application of these methods to idiopathic kidney diseases may reveal similar occult infections by unknown viruses. Precision medicine objectives to optimize host-directed and pathogen-directed therapies for kidney diseases associated with infectious causes will only be achieved through detailed understanding of genetic susceptibility associated with immune responses and viral tropism.

The Changing Face of Human Immunodeficiency Virus-Mediated Kidney Disease.

In nearly 40 years since human immunodeficiency virus (HIV) first emerged, much has changed. Our understanding of the pathogenesis of HIV infection and its effect on the cells within each kidney compartment has progressed, and the natural history of the disease has been transformed. What was once an acutely fatal illness is now a chronic disease managed with oral medications. This change is largely due to the advent of antiretroviral drugs, which have dramatically altered the prognosis and progression of HIV infection. However, the success of antiretroviral therapy has brought with it new challenges for the nephrologist caring for patients with HIV/acquired immune deficiency syndrome, including antiretroviral therapy-induced nephrotoxicity, development of non-HIV chronic kidney disease, and rising incidence of immune-mediated kidney injury. In this review, we discuss the pathogenesis of HIV infection and how it causes pathologic changes in the kidney, review the nephrotoxic effects of select antiretroviral medications, and touch upon other causes of kidney injury in HIV cases, including mechanisms of acute kidney injury, HIV-related immune complex glomerular disease, and thrombotic microangiopathy.

A case of lupus-like glomerulonephritis in an HIV patient with nephrotic range proteinuria, purpura, and elevated IgA level.

Human immunodeficiency virus (HIV) infection is growing medical concern worldwide. There are many types of glomerulonephritis which are associated with HIV infection. We report a case of a 53-year-old Korean man with an HIV infection, who was developed nephritic range proteinuria and purpura with elevated IgA level rasing a possibility of Henoch-Schölein Purpura (H-S purpura). However, renal biopsy showed "lupus-like feature" glomerulonephritis without clinical or serologic evidence of systemic lupus erythematosus. Although baseline renal function was maintained without further need for maintenance dialysis following anti-retroviral therapy (ART) and steroid, patient died from uncontrolled gastrointestinal bleeding.

Comparison of risk factors and outcomes in HIV immune complex kidney disease and HIV-associated nephropathy.

BACKGROUND AND OBJECTIVES: HIV-associated nephropathy (HIVAN) is well described, but the clinical features of a group of renal pathologies characterized by Ig or immune complex depositions referred to as HIV-associated immune complex kidney disease (HIVICK) have not been well established. The objective of this study is to assess risk factors for HIVICK compared with contemporaneous control participants. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A nested case-control study of 751 HIV-infected patients followed from January 1996 to June 2010 was conducted. Groups were compared using the chi-squared test or rank-sum analysis. Conditional logistic regression was used to estimate odds ratios (ORs) for HIVICK. Incidences of overall ESRD and with/without combined antiretroviral therapy (cART) exposure were calculated. RESULTS: HIVICK patients were predominantly African American (92%). Compared with matched controls, patients with HIVICK were more likely to have HIV RNA >400 copies/ml (OR, 2.5; 95% confidence interval [95% CI], 1.2 to 5.2), diabetes (OR, 2.8; 95% CI, 1.1 to 6.8), and hypertension (OR, 2.3; 95% CI, 1.2 to 4.5). Compared with HIVAN, patients with HIVICK had more antiretroviral therapy exposure, lower HIV viral loads, and higher CD4 and estimated GFR. ESRD was less common in the HIVICK versus the HIVAN group (30% versus 82%; P<0.001), and the use of cART was not associated with ESRD in HIVICK patients (25% versus 26; P=0.39). CONCLUSIONS: HIVICK was predominantly observed in African-American patients and associated with advanced HIV disease. ESRD incidence is lower in HIVICK patients compared with those with HIVAN. Unlike HIVAN, cART use was not associated with the incidence of ESRD in HIVICK.

Recurrent HIV-associated immune complex glomerulonephritis with lupus-like features after kidney transplantation.

A spectrum of kidney diseases besides classic human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) exists in HIV-infected patients. Immune complex-mediated glomerulonephritis has emerged as a significant contributor to the burden of kidney disease in this population, particularly in patients of non-African descent. Lupus-like nephritis, a form of immune complex glomerulonephritis with histologic features identical to lupus nephritis in the absence of clinical or serologic markers of lupus, is well recognized as a cause of end-stage renal disease in HIV-infected patients. None of the HIV-associated kidney lesions, whether classic HIVAN or non-HIVAN, has been reported to recur in kidney transplants. We report here for the first time clinical and histologic recurrence of HIV-associated lupus-like nephritis after successful kidney transplantation, causing proteinuria, hematuria, and impaired kidney transplant function.

Renal involvement in patients with hepatitis C virus infection.

INTRODUCTION: Hepatitis C virus (HCV) infection is a hepatotropic virus causing a variety of extrahepatic immunological manifestations and is a risk factor of a variety of extrahepatic diseases, such as mixed cryoglobulinemia and membranoproliferative glomerulonephritis (MPGN), which is the most common glomerulonephritis. The aim of this study was to evaluate renal involvement in HCV-infected patients. MATERIALS AND METHODS: A total of 300 randomly-selected HCV antibody-positive outpatients at the HCV clinic of Shariati hospital were enrolled. Serum creatinine was measured and glomerular filtration rate was estimated accordingly. Urine proteinuria was measured in 24-hour urine samples. RESULTS: The patients were 249 men (83.2%) and 51 women (16.8%) with a mean age of 37.8 +/- 11.7 years (range, 18 to 70 years). Proteinuria was found in 12 HCV antibody-positive adults (4%), 1 of whom underwent biopsy. He was a 55- year-old man with a 4-month history of facial and lower extremities edema and 3-g proteinuria with a normal kidney function (glomerular filtration rate, 85 mL/min) and normocomplementemia. Kidney biopsy specimens showed MPGN. The frequency of low glomerular filtration rate was 0.7% (2 patients) in the HCV antibody-positive adults. There was no significant relationship between HCV seropositivity and low glomerular filtration rate. CONCLUSIONS: Our observations showed renal involvement in HCV antibody-positive patients. Among immune complex glomerular kidney diseases, MPGN without cryoglobulins is thought to be the most common in these patients.

Viral RNA and DNA trigger common antiviral responses in mesangial cells.

Extrarenal viral infections commonly trigger glomerulonephritis, usually in association with immune complex disease. The Ig component of immune complexes can activate glomerular cell Fc receptors, but whether complexed viral nucleic acids contribute to glomerular inflammation remains unknown. Because of the types of Toll-like receptors (Tlrs) expressed by glomerular mesangial cells, we hypothesized that viral single-stranded RNA and DNA would activate mesangial cells via Tlr-independent pathways and trigger overlapping antiviral immune responses. Consistent with this hypothesis, 5'-triphosphate RNA (3P-RNA) and non-CpG DNA activated murine primary glomerular mesangial cells to secrete Cxcl10 and Il-6 even in cells derived from mice deficient in the Tlr adaptor proteins Myd88 and Trif. Transcriptome analysis revealed that 3P-RNA and non-CpG-DNA triggered almost identical gene expression programs, especially the proinflammatory cytokine Il-6, several chemokines, and genes related to type I IFN. We observed similar findings in glomerular preparations after injecting 3P-RNA and non-CpG-DNA in vivo. These effects depended on the formation of complexes with cationic lipids, which enhanced nucleic acid uptake into the cytosol of mesangial cells. Small interfering RNA studies revealed that 3P-RNA recognition involves Rig-1, whereas non-CpG-DNA did not require Rig-1 or Dai to activate glomerular mesangial cells. We conclude that 3P-RNA and double-stranded DNA trigger a common, TLR-independent, antiviral response in glomerular mesangial cells, which may promote glomerulonephritis in the setting of viral infection.

Fibrin ring granuloma in chronic hepatitis C: virus-related vasculitis and/or immune complex disease?

Fibrin ring granulomas are rare lesions whose pathophysiology has remained somewhat elusive. It has been suggested that these peculiar lesions are related to focal vasculitis with endothelial injury and deposition of immune complexes. Fibrin ring granulomas have been described in Q fever; in viral infections such as cytomegalovirus, Epstein-Barr virus, and hepatitis A virus; and in other conditions. We submit the first reported case of fibrin ring granuloma in a patient with chronic hepatitis C infection, in whom other potential etiologies have been excluded, and offer a brief review of available literature on the pathogenesis of both conditions.

Hepatitis B virus replication in damaged endothelial tissues of patients with extrahepatic disease.

Hepatitis B virus (HBV) infection may be complicated by extrahepatic manifestations such as polyarteritis nodosa (PAN), glomerulonephritis, polymyositis, and dermatitis, but the etiology of these processes is not yet clear. HBV replication has been demonstrated in a variety of extrahepatic tissues and cell types, but the possible pathogenetic role of extrahepatic HBV replication has not been fully explored in patients with extrahepatic manifestations of HBV infection. In this case series, immunohistochemistry and in situ hybridization studies were performed on extrahepatic tissues from one HBsAg-positive patient with PAN and another HBsAg-positive patient with polymyositis, using HBsAg-seronegative control subjects with the same vasculitic disorders as controls. Tissue samples from the two study patients had detectable HBV RNA, replicative intermediates of HBV DNA, as well as HBsAg and HBcAg localized to vascular endothelium. In contrast, HBsAg-negative control patients had no tissue reactivity. Our results suggest that patients with HBV-related extrahepatic disease have evidence of viral replication in damaged extrahepatic endothelial tissues. While further studies would be required to support a hypothesis of causality, these findings suggest a role for both immune complex deposition and viral replication within diseased endothelial tissue in the pathogenesis of these poorly understood extrahepatic disorders.

[A case of hepatitis B virus carrier complicated with nephrotic syndrome].

We report a patient, a 23-year-old man, who was a hepatitis B virus(HBV) carrier complicated with nephrotic syndrome. He was admitted to our hospital because of generalized edema and massive ascites. Laboratory data on admission were as follows: proteinuria 9,850 mg/day, Cr 2.7 mg/dl, BUN 73 mg/dl, albumin 1.9 g/dl, cholesterol 501 mg/dl, GOT 23 IU/l, GPT 19 IU/l, HBsAg(+), and HBeAg(222.7). Since his nephrotic symptoms were seriously complicated with renal failure, we selected steroid therapy for nephrosis preference. His renal function was improved and the urinary protein decreased immediately, but his liver function deteriorated. The renal biopsy revealed focal mesangial proliferative glomerulonephritis. Immunofluorescent examination revealed slight deposits of IgG, IgM, and C3 along the glomerular basement membrane and mesangial matrix. He was not compliant and often stopped taking the steroid therapy, thereby causing nephrosis to recur each time. After all, nephrotic symptoms have been well-controlled with cyclosporin and steroid. In spite of the seroconversion of HB virus by formation of HBe antibody, mutant HBV infection continued. The fact that liver biopsy revealed severe lymphoid infiltration at the portal area suggested chronic active hepatitis. His clinicopathologic course suggests that HBV-associated nephropathy does not always remit as there are some cases in whom hepatitis remains in an active state even after seroconversion, due to its mutant status. In these cases, the long-term prognosis of HBV nephropathy has not been defined. Further study is necessary to establish the optimal treatment for HB nephropathy in adults.

Mixed cryoglobulinemia in hepatitis C patients. GERMIVIC.

Cryoglobulins are immunoglobulins that persist in the serum, precipitate with cold temperature and resolubilize when rewarmed. Types II and III are mixed cryoglobulins (MC), composed of different immunoglobulins, with a monoclonal component in type II and only polyclonal immunoglobulins in type III. Mixed cryoglobulins are associated with connective-tissue disease, malignant hematological disorder (type B lymphoproliferation) or obvious infectious process. Mixed cryoglobulinemia syndrome is characterized by the clinical triad of purpura, arthralgia and asthenia associated with type II or type III MC. The disorder is the consequence of an immune-complex-type vasculitis as supported by clinical features, analysis of the cryoglobulins, the usually depressed level of complement during the active phase of the disease, and the deposition of immunoglobulins and complement in the lesions. Such cryoglobulinemia vasculitis may involve numerous organs, particularly the peripheral nervous system and the kidneys. MC is frequently associated with clinical and biological evidence of liver disease. There has been some controversy about which comes first, MC or chronic liver disease, but it seems fairly clear that MC is often a manifestation of underlying chronic active or persistent hepatitis. In MC patients, the hepatotropic antigen(s) capable of triggering production of antibodies which can later form immune complexes has been sought for many years. In the last ten years, numerous studies have demonstrated that infection with hepatitis C virus is involved in the pathogenesis of most mixed cryoglobulinemia. This review analyzes the main published data on hepatitis C virus-mixed cryoglobulinemia, the role of liver alterations, the predictive factors associated with MC production in HCV patients and its symptomatic nature or not, and the different types of vasculitis associated with HCV chronic infection.

Treatment of autoimmune and extra-hepatic manifestations of HCV infection.

Hepatitis C virus (HCV) infects mononuclear cells and may, like other viruses, cause immunological disorders. Immunological abnormalities observed in HCV infections are usually nonspecific (e.g. cryoglobulinemia, immune complex deposits, autoantibodies). There is a clear association between cryoglobulinemia and hepatitis C and cryoglobulinemia related symptoms are usually improved by treatment with interferon alpha, although patients usually relapse after treatment end. The relationships between hepatitis C and other immunological abnormalities are unclear. The association between chronic hepatitis C and anti-smooth muscle or anti-nuclear antibodies does not appear to be significantly different from that in other hepatic disorders, particularly hepatitis B. Conversely, patients with hepatitis C have significantly more often anti-liver kidney microsomal (LKM1) antibodies than patients with other causes of liver diseases. When clinical, histological and biological findings are indicative of HCV infection with chronic hepatitis, interferon alpha or combination therapy with ribavirin are treatments options. Conversely, when clinical context and results of laboratory tests are in favor of an autoimmune disorder or of overlap-syndromes (i.e. both autoimmune and viral hepatitis), interferon should not be given in first intention, since revelation or exacerbation of autoimmune hepatitis have been reported under interferon. An important prevalence of anti-HCV antibodies has also been reported in patients with sialadenitis, lichen planus and thyroiditis. It has been clearly demonstrated that interferon may induce or worsen such immunological diseases, but there are very few studies showing improvement of these manifestations under interferon. In conclusion, interferon may be appropriate in patients with HCV infection and extrahepatic manifestations linked to immune complex deposition, whereas, in other cases, careful assessment of patients with autoimmune processes is necessary before choosing any treatment strategy.

The nephropathies of HIV infection: pathogenesis and treatment.

Several different renal syndromes have been reported in patients with HIV infection. Patient characteristics and a syndrome approach may help the clinician formulate a tentative diagnosis, but a renal biopsy is necessary to make a firm diagnosis in patients with chronic renal disease in the setting of HIV infection. The pathogenesis of the HIV nephropathies can teach us much about the pathophysiology of common renal problems such as IgA nephropathy, immune complex glomerulonephritis, focal segmental glomerulosclerosis, and diabetic renal disease. HIV-associated renal disease may be the result of the interaction of the expression of specific HIV genes in patients with distinct genetic susceptibilities to disease in particular environments. New treatment approaches have provided hope for patients with classic HIV-associated nephropathy.