Kidney involvement and histological findings in two pediatric COVID-19 patients.

BACKGROUND: Histological findings of kidney involvement have been rarely reported in pediatric patients with SARS-CoV-2 infection. Here, we describe clinical, laboratory, and histological findings of two pediatric cases with almost exclusive kidney involvement by SARS-CoV-2. RESULTS: A 10-year-old girl with IgA vasculitis nephritis underwent kidney biopsy, showing diffuse and segmental mesangial-proliferative glomerulonephritis, and steroid therapy was initiated. After the worsening of the clinical picture, including an atypical skin rash, she was diagnosed with SARS-CoV-2. The re-evaluation of initial biopsy showed cytoplasmatic blebs and virus-like particles in tubular cells at electron microscopy. Despite SARS-CoV-2 clearance and the intensification of immunosuppression, no improvement was observed. A second kidney biopsy showed a crescentic glomerulonephritis with sclerosis, while virus-like particles were no longer evident. The second patient was a 12-year-old girl with a 3-week history of weakness and weight loss. Rhinitis was reported the month before. No medications were being taken. Blood and urine analysis revealed elevated serum creatinine, hypouricemia, low molecular weight proteinuria, and glycosuria. A high SARS-CoV-2-IgG titre was detected. Kidney biopsy showed acute tubular-interstitial nephritis. Steroid therapy was started with a complete resolution of kidney involvement. CONCLUSION: We can speculate that in both cases SARS-CoV-2 played a major role as inflammatory trigger of the kidney damage. Therefore, we suggest investigating the potential kidney damage by SARS-CoV-2 in children. Moreover, SARS-CoV-2 can be included among infectious agents responsible for pediatric acute tubular interstitial nephritis.

Rapid progression to end-stage renal disease in a child with IgA-dominant infection-related glomerulonephritis associated with parvovirus B19.

Parvovirus B19 (PVB19) has been known to cause acute glomerulonephritis and nephrotic syndrome with various renal histologic patterns, such as endocapillary glomerulonephritis and collapsing glomerulopathy. Remission is achieved spontaneously or by treatment with steroid and/or immunosuppressants in most patients, except those with sickle cell anemia or two APOL1 risk alleles. In this study, we report the case of a previously healthy 5-year-old boy with infection-related glomerulonephritis (IRGN) associated with PVB19 that progressed to end-stage renal disease (ESRD). He presented with macrohematuria, nephrotic-range proteinuria, and progressive renal dysfunction despite treatment with methylprednisolone pulse therapy, plasmapheresis, and intravenous immunoglobulin. The kidney biopsy specimens exhibited endocapillary infiltration and mesangiolysis with cellular crescent formation. Immunofluorescence analysis revealed that IgA was dominantly positive in the glomeruli, with some co-localized with KM55, which is a specific monoclonal antibody for galactose-deficient IgA1 (Gd-IgA1). The intensity of the KM55 signal in the present patient was weaker than that in patients with IgA nephropathy. To our knowledge, this is the first report of IRGN associated with PVB19 that progressed to ESRD without any underlying diseases. Further investigations are needed to determine the significance of IgA and Gd-IgA1 deposition in IRGN associated with PVB19.

Role of Epstein-Barr Virus in Pathogenesis and Racial Distribution of IgA Nephropathy.

IgA nephropathy (IgAN) is the dominant type of primary glomerulonephritis worldwide. However, IgAN rarely affects African Blacks and is uncommon in African Americans. Polymeric IgA1 with galactose-deficient hinge-region glycans is recognized as auto-antigen by glycan-specific antibodies, leading to formation of circulating immune complexes with nephritogenic consequences. Because human B cells infected in vitro with Epstein-Barr virus (EBV) secrete galactose-deficient IgA1, we examined peripheral blood B cells from adult IgAN patients, and relevant controls, for the presence of EBV and their phenotypic markers. We found that IgAN patients had more lymphoblasts/plasmablasts that were surface-positive for IgA, infected with EBV, and displayed increased expression of homing receptors for targeting the upper respiratory tract. Upon polyclonal stimulation, these cells produced more galactose-deficient IgA1 than did cells from healthy controls. Unexpectedly, in healthy African Americans, EBV was detected preferentially in surface IgM- and IgD-positive cells. Importantly, most African Blacks and African Americans acquire EBV within 2 years of birth. At that time, the IgA system is naturally deficient, manifested as low serum IgA levels and few IgA-producing cells. Consequently, EBV infects cells secreting immunoglobulins other than IgA. Our novel data implicate Epstein-Barr virus infected IgA+ cells as the source of galactose-deficient IgA1 and basis for expression of relevant homing receptors. Moreover, the temporal sequence of racial-specific differences in Epstein-Barr virus infection as related to the naturally delayed maturation of the IgA system explains the racial disparity in the prevalence of IgAN.

Targeting C3a/C5a receptors inhibits human mesangial cell proliferation and alleviates immunoglobulin A nephropathy in mice.

Complement activation has a deep pathogenic influence in immunoglobulin (Ig)A nephropathy (IgAN). C3a and C5a, small cleavage fragments generated by complement activation, are key mediators of inflammation. The fragments exert broad proinflammatory effects by binding to specific receptors (C3aR and C5aR, respectively). However, no studies thus far have investigated the effects of C3a, C5a and their receptors on IgAN. We observed that C3aR and C5aR antagonists repressed IgA-induced cell proliferation and interleukin (IL)-6 and monocyte chemotactic protein 1 (MCP-1) production in cultured human mesangial cells (HMCs). Furthermore, an IgAN mouse model induced by Sendai virus infection was employed to investigate the effects of C3aR and C5aR on IgAN in vivo for the first time. Wild-type (WT) and several knock-out mouse strains (C3aR-/- or C5aR-/- ) were immunized intranasally with increasing doses of inactivated virus for 14 weeks and were subjected to two intravenous viral challenges during the time-period indicated. In the Sendai virus-induced IgAN model, C3aR/C5aR-deficient mice had significantly reduced proteinuria, lower renal IgA and C3 deposition, less histological damage and reduced mesangial proliferation compared with WT mice. Both C3aR deficiency and C5aR deficiency, especially C3aR deficiency, inhibited renal tumour necrosis factor (TNF)-α, transforming growth factor (TGF)-ß, IL-1ß, IL-6 and MCP-1 expression significantly. However, C3aR/C5aR-deficient and WT mice with IgAN did not differ with respect to their blood urea nitrogen (BUN) and serum creatinine levels. Our findings provide further support for the idea that C3aR and C5aR are crucially important in IgAN, and suggest that pharmaceutically targeting C3aR/C5aR may hold promise for the treatment of IgAN.

Alloantigen-specific response is preserved and autoimmunity is maintained in an HIV-positive patient with immunoglobulin A nephropathy undergoing renal transplantation: a warning about long-term reduction in immunosuppression--a case report.

We report the case of a 43-year-old patient with HIV infection treated with antiretroviral therapy, which was complicated by immunoglobulin A (IgA) nephropathy and renal failure, who subsequently was transplanted using a deceased donor kidney transplant. During the late posttransplant period we detected specific anti-donor HLA antibodies showing a preserved alloantigen response. A renal biopsy showed no acute cellular or humoral rejection, an absence of pericapillary C4d deposits or SV40 infected cells, but demonstrated IgA mesangial deposits and mild interstitial fibrosis probably related to calcineurin inhibitor toxicity. This case shows that allo- and autoimmune responses are preserved despite immunosuppressive treatment and original HIV disease. It warns of the importance of maintaining optimal monitoring and immunosuppressive strategies among HIV-positive recipients who become solid organ transplant recipients.

Hepatitis C virus-related kidney disease: various histological patterns.

BACKGROUND: Although hepatitis C virus (HCV) infection is known to be associated with Type 2 cryoglobulinemic glomerulopathy (CG), only a few reports about other types of nephropathy have been published. METHODS: 68 HCV antibody positive patients in whom renal biopsy had been performed for persistent proteinuria, hematuria, and/or renal dysfunction between 1992 and 2008 at our institute were included. The histological, clinical and laboratory characteristics including the age, gender, hypertension, diabetes mellitus, liver histology (chronic hepatitis or liver cirrhosis), HCV-RNA, HCV genotype, splenomegaly, gastroesophageal varices, serum creatinine, hemoglobin, platelet count, rheumatoid factor, cryoglobulin, IgG, IgA, IgM, CH50, C3, C4, creatinine clearance, 24-h protein excretion, and hematuria, between their nephropathy with and without immune deposition were compared. RESULTS: Nephropathy was classified into two groups based on the detection of immune deposits by immunofluorescence microscopy: i.e., a positive group (n = 39) and a negative group (n = 29). The former group was further classified into three types of nephropathy: IgG dominant group (n = 10) (including membranous nephropathy (MN)), IgA dominant group (n = 20) (including IgA nephropathy (IgAN)), membranoproliferative glomerulonephritis (MPGN) (IgA type)), and IgM dominant group (n = 9) (MPGN apart from the IgA type). The latter group included diabetic nephropathy (n = 13), focal glomerular sclerosis (n = 4), and benign nephrosclerosis (n = 3), malignant nephrosclerosis (n = 1), tubulointerstitial nephritis (TIN) (n = 2), minimal change nephrotic syndrome (n = 1), cast nephropathy (n = 1), granulomatous TIN (n = 1), and others (n = 3). An increased serum IgM level, hypocomplementemia, splenomegaly, thrombocytopenia, liver cirrhosis, hematuria, and a high HCV RNA level were features of patients with MPGN of IgM dominant group (consistent with "CG"). CONCLUSIONS: Our results showed various histological patterns of HCV-related kidney disease and the specificity of CG, and revealed that a minority of HCV patients (n = 7) presented typical CG, while IgAN, MN, and diabetic nephropathy were more frequent.

Transient IgA nephropathy with acute kidney injury in a patient with dengue fever.

Dengue virus infection can clinically manifest as dengue fever, dengue shock syndrome and dengue hemorrhagic fever. Acute kidney injury as a result of dengue virus infection can occur due to various reasons including hypotension, rhabdomyolysis, sepsis and rarely immune complex mediated glomerular injury. However, glomerulonephritis associated with IgA Nephropathy in dengue virus infection has not been reported previously. We report a case of 15-year-old boy who was admitted with dengue fever and dialysis dependant acute kidney injury. Urine examination showed microscopic glomerular hematuria and proteinuria. Kidney biopsy showed mesangial proliferation with mesangial IgA dominant immune complex deposits and acute tubular necrosis. A repeated kidney biopsy 6 weeks after clinical recovery showed reversal of glomerular changes as well as resolution of mesangial IgA deposits.

Prevalence of hepatitis B and C markers in glomerular diseases.

OBJECTIVE: To study the prevalence of hepatitis B and C viruses in patients with glomerulonephritis (Gn). Material and methods. This was a retrospective study of 89 patients (36 females, 53 males) diagnosed with Gn. Infection with hepatitis B and C was studied by means of serological methods; if patients presented hepatitis C antibodies, the presence of viral RNA in serum was detected by means of quantitative polymerase chain reaction. The control group comprised 59,546 first-time blood donors. RESULTS: None of the patients were positive for hepatitis B surface antigen (HBsAg). In the control group there were 168 HBsAg positives. The prevalence of HBsAg in the control group (0.28%) was not significantly different (p = 0.614) from that in the patient group. Four patients with Gn were positive for hepatitis C virus (HCV) antibodies, and in three of these RNA HCV was also positive. The histological diagnoses in the four cases with HCV antibodies were: focal and segmental glomerulosclerosis; crescentic IgA nephropathy; diffuse proliferative Gn; and membranous Gn. The first three patients also presented other pathologies potentially linked to Gn, namely left renal agenesis, heavy alcohol intake/chronic liver disease and HIV seropositivity, respectively. Only the patient with membranous Gn, in whom other causes were disregarded, received antiviral treatment, although RNA HCV remained positive. In the control group, 141 cases were positive for HCV antibodies (prevalence 0.24%). The prevalence in the study group was significantly higher (p < 0.001). CONCLUSION: HCV is more prevalent in patients with Gn than in those without, and this is the opposite of the situation with HBsAg.

Detection of enteroviruses in renal biopsies from patients with immunoglobulin A nephropathy.

Viruses have been suspected to be one of the causes of IgA nephropathy (IgAN). Recent studies have detected viruses in renal tissues of patients with IgAN. Enteroviruses have been reported as pathogenic agents in some renal diseases. We previously reported that group B coxsackieviruses cause pathological changes in experimentally infected mouse kidney. The aim of the present study was to examine the participation of enteroviruses in the pathogenesis of renal diseases including IgAN. Renal biopsies of ten patients with IgAN (group 1) and of 19 patients with non-IgAN renal disease (group 2) were analyzed by polymerase chain reaction (PCR) for the presence of enteroviral RNA. Positive PCR results were obtained for three patients (30%) of group 1. We confirmed by sequencing that the positive PCR products were derived from strains of enteroviruses. One of these three patients also had a positive result for lymphocytes from peripheral blood. In contrast, enteroviral RNA was detected in none of the 19 patients of group 2. The incidence of enteroviral RNA detection in patients of group 1 was higher than that in group 2 (P<0.05). Our findings suggest that enteroviral infection may have the possibility of becoming one of the factors involved in the mechanism of onset or evolution of IgAN.

Hepatitis C virus RNA and core protein in kidney glomerular and tubular structures isolated with laser capture microdissection.

The role of hepatitis C virus (HCV) in the production of renal injury has been extensively investigated, though with conflicting results. Laser capture microdissection (LCM) was performed to isolate and collect glomeruli and tubules from 20 consecutive chronically HCV-infected patients, namely 6 with membranoproliferative glomerulonephritis, 4 with membranous glomerulonephritis, 7 with focal segmental glomerulosclerosis and 3 with IgA-nephropathy. RNA for amplification of specific viral sequences was provided by terminal continuation methodology and compared with the expression profile of HCV core protein. For each case two glomeruli and two tubular structures were microdissected and processed. HCV RNA sequences were demonstrated in 26 (65%) of 40 glomeruli, but in only 4 (10%) of the tubules (P < 0.05). HCV core protein was concomitant with viral sequences in the glomeruli and present in 31 of the 40 tubules. HCV RNA and/or HCV core protein was found in all four disease types. The immunohistochemical picture of HCV core protein was compared with the LCM-based immunoassays of the adjacent tissue sections. Immune deposits were detected in 7 (44%) of 16 biopsy samples shown to be positive by extraction methods. The present study indicates that LCM is a reliable method for measuring both HCV RNA genomic sequences and HCV core protein in kidney functional structures from chronically HCV-infected patients with different glomerulopathies and provides a useful baseline estimate to define the role of HCV in the production of renal injury. The different distribution of HCV RNA and HCV-related proteins may reflect a peculiar 'affinity' of kidney microenvironments for HCV and point to distinct pathways of HCV-related damage in glomeruli and tubules.

Differential effects of Sendai virus infection on mediator synthesis by mesangial cells from two mouse strains.

BACKGROUND: Recently, we observed that the severity of glomerulonephritis in an experimental model of immunoglobulin A nephropathy (IgAN) induced by Sendai virus differs between C57BL/6 and BALB/c mouse strains. The determinants of differing renal insufficiency are not understood. In the present study, we examine the capacity for mesangial cells to support Sendai viral replication and assess the direct effects of Sendai virus on the production of selected cytokines, chemokines, and eicosanoids by mesangial cells, comparing C57BL/6 to BALB/c mouse strains. METHODS: Sendai virus replication was measured by viral plaque assay using LLCMK2 cells. Production of cytokines [interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha)], chemokines (JE and KC), and eicosanoids [prostaglandin E2 (PGE2) and thromboxane B2 (TxB2)] in culture medium was evaluated by sandwich enzyme-linked immunosorbent assay (ELISA) or competitive enzyme immunoassay (EIA) after 48 hours' incubation with infectious or inactivated Sendai virus. RESULTS: Sendai virus replicates equally well in mesangial cells from both strains, and infection evokes increased IL-6, JE, KC, and PGE2 production in relation to viral dose. BALB/c mesangial cells produce significantly more IL-6 and JE than those from C57BL/6, and the dose response for KC is steeper in BALB/c mesangial cells than those from C57BL/6. Synthesis of PGE2 in BALB/c mesangial cells is higher than that of C57BL/6 mesangial cells, both under basal conditions and in response to infectious Sendai virus, again in a dose-dependent manner. There is no TNF-alpha or thromboxane response to viral stimulation. CONCLUSION: We conclude that different mesangial cell responses to this common mucosal viral pathogen might influence the severity of IgAN in our model system.

Is the simian virus SV40 associated with idiopathic focal segmental glomerulosclerosis in humans?

BACKGROUND: Glomerulosclerosis was reported in mice transgenic for the simian polyomavirus SV40 early region that contains the transforming sequences encoding the SV40 large T-antigen (TAG). This was discovered when an SV40 epidemic occurred following the use of contaminated polio vaccines during 1955-1963, and led to investigations that showed an association between SV40 infection and tumors in humans. We investigated the possible association of SV40 infection and idiopathic focal segmental glomerulosclerosis (FSGS). METHODS: The study was performed in 17 Bouin-fixed, paraffin-embedded renal biopsies from FSGS patients and 10 matched biopsies from patients with IgA glomerulonephritis; all patients had undergone polio vaccination in the early 1960s. Extracted DNA was polymerase chain reaction (PCR) amplified using SV.for3/SV.rev primers and GabE1/GabE2 primers; both sets of primers map in the region of SV40 TAG sequences, and amplify a fragment of respectively 105-bp and 135-bp. The biopsies considered were those in which the DNA was sufficiently intact to allow amplification of a fragment of 102-bp of the ApoE gene. RESULTS: Three FSGS and none of the IgA biopsies were positive for the SV.for3/SV.rev fragment. Conversely, amplification with GabE1/GabE2 primers did not lead to any specific product in either the IgA or FSGS biopsies. Restriction fragment length polymorphism and sequencing analyses revealed that the positive results obtained with the SV.for3/SV.rev primers were due to amplicons generated by multiple dimerization of forward and reverse primers. CONCLUSIONS: With the limited number of patients investigated, this study excludes the hypothesis that SV40 is associated with idiopathic FSGS.

[The relationship between IgA nephropathy and HBV infection].

OBJECTIVE: To clarify the correlation between hepatitis B virus (HBV) infection and the pathogenesis of IgA nephropathy. METHODS: Ninety-one cases of primary IgA nephropathy were investigated by using in situ hybridization(HBV DNA), immunohistochemistry (HBAg) and HBV DNA-HBAg double staining techniques. In some of the cases, Southern blot analysis and serologic HBV infectious markers were detected also. RESULTS: The positive rate of HBAg in renal tissue detected by immunohistochemistry was 69% (63/91) and that of the HBV DNA detected by in situ hybridization was 43% (39/91). Eighteen of 27 cases showed HBV DNA positive in Southern blot analysis, and all of the positive cases were identified to be the integrated form. Among them, 17 cases were HBAg detectable in renal tissue by immunohistochemistry and 16 cases were HBV DNA detectable by in situ hybridization simultaneously. The positive rate of the expression of HBcAg [77% (30/39)] and HBsAg [72% (28/39)] of the tubular epithelial cells with HBV DNA signals in nuclears by in situ hybridization was significantly higher than that of the cells without HBV DNA signals(10%, 21%). The double staining showed that most of the HBV DNA positive tubular epithelial cells coexpressed HBsAg and(or) HBcAg. CONCLUSION: The renal tissue of some of IgA nephropathy infected with HBV directly and express HBAg in situ.

Epstein-Barr virus detection in kidney biopsy specimens correlates with glomerular mesangial injury.

To determine the relationship between the detection of Epstein-Barr virus (EBV)-specific DNA and glomerular injury, 33 renal needle-biopsy specimens that had been formalin-fixed and paraffin-embedded were analyzed using polymerase chain reaction (PCR) with subsequent nonradioactive Southern blot technique. Light microscopic examination and immunofluorescence were also performed. In 30 of 33 renal biopsy specimens, the beta globin gene could be successfully amplified as integrity controls. These 30 patients consisted of 12 patients with immunoglobulin A nephropathy (IgAN), 10 patients with minor glomerular abnormalities, 6 patients with membranous nephropathy, and 2 patients with focal/segmental lesions. EBV was detected in 7 of 12 patients with IgAN (58%), 3 of 6 patients with membranous nephropathy (50%), 0 of 10 patients with minor glomerular abnormalities (0%), and 2 of 2 patients with focal/segmental lesions. EBV detection was not disease specific. The EBV detection ratio of the group with glomerular mesangial lesions (64%; 9 of 14 patients) was significantly greater than those without (19%; 3 of 16 patients; P < 0.012, chi-square test). The EBV detection ratio of the group with glomerular lesions (60%; 12 of 20 patients) was significantly greater than those without (0%; 0 of 10 patients; P < 0.0016, Fisher's exact test), and the EBV detection ratio of the group with fibrinogen deposits observed in immunofluorescence (73%; 11 of 15 patients) was significantly greater than those without (7%; 1 of 15 patients; P < 0.0002, chi-square test). The EBV detection ratio of the group with immunoglobulin deposits (57%; 12 of 21 patients) was also significantly greater than those without (0%; 0 of 9 patients; P < 0.0040, Fisher's exact test). These data suggest that EBV can damage the glomerular mesangium beyond disease units and be mediated by immunoglobulin in patients with various chronic glomerulonephritides.

Remission of IgA nephropathy following treatment of cytomegalovirus infection with ganciclovir.

Following the detection of cytomegalovirus antigen in mesangial cells of some patients with IgA nephropathy, an important role of human cytomegalovirus in the pathogenesis of IgA nephropathy has been discussed. We studied a case of IgA nephropathy with rapid deterioration of renal function associated with cytomegalovirus infection. Following an infection of the upper respiratory tract, a 57-year-old woman developed with hematuria and acute renal failure. The histological diagnosis of IgA nephropathy was established and renal function transiently improved during immunosuppressive therapy. However, the ensuing clinical course was complicated by severe bleeding from intestinal ulcera, thrombocytopenia, pneumonia and relapse of renal failure. The histological investigation of colonic mucosa showed characteristic "owl's eye" cells leading to the diagnosis of cytomegalovirus disease as the cause of intestinal bleeding. Immunosuppression was stopped and treatment with ganciclovir started. Pneumonia as well as intestinal bleeding disappeared and, of particular note, renal function improved considerably. Following discontinuation of antiviral therapy CMV-disease reoccurred and renal function deteriorated again. The patient was restarted on ganciclovir therapy and, again, serum creatinine fell quickly. This impressive and reproducible clinical improvement of renal insufficiency under antiviral therapy with ganciclovir provides some evidence for an important role of cytomegalovirus in the pathogenesis of this case of IgA nephropathy.

[The relationship between HBV infection and injury of tubuli and interstitium in IgA nephropathy].

OBJECTIVE: To clarify the correlation between HBV infection and the injury of tubuli and interstitium of IgA nephropathy. METHODS: Renal biopsy specimens from 91 patients with primary IgA nephropathy were investigated by use of in situ hybridization (HBV DNA), immunohistochemistry (HBsAg, HBcAg, CD3, CD8) and HBV DNA, HBAg-CD43 double staining techniques. RESULTS: The positive rate of HBAg in renal tissue as detected by immunohistochemistry was 69.2% and that of HBV DNA detected by in situ hybridization was 42.9%. Double staining showed that HBV DNA positive tubular epithelial cells might coexpress HBsAg and/or HBcAg. The numbers of the infiltrated CD3+ cells and CD8+ cells in cases with positive HBV infections markers were significantly higher than those of cases without infection (P < 0.01). In addition, CD43+ T lymphocytes infiltrated around or invaded into the tubuli walls which had positive HBcAg or HBsAg expression. CONCLUSION: After HBV infection, the renal cells could express HBAg and induce infiltration of CD3+ cells and CD8+ cells, resulting in aggravation of the injury of tubuli and interstitium. Therefore, it is considered that HBV infection might play an important role in the occurrence and progress of IgA nephropathy.

Retroviral infection in peripheral mononuclear cells in patients with IgA nephropathy.

An etiologic agent directly linked to the development of IgA nephropathy (IgAN) has not been identified, despite the fact that various causes, including viral infections, have been implicated in the pathogenesis of this disease. Human immunodeficiency virus (HIV) infection has been linked with the development of IgAN in several clinical studies, and retroviral infection may be associated with the pathogenesis of IgAN in some patients. The incidence of IgAN has been found to possess distinct geographical distributions, and familial genetic clustering. To determine if retroviral infection is associated with IgAN in a large population of patients, genomic DNA from peripheral blood mononuclear cells from 90 patients seronegative for HIV and human T-cell leukemia virus type 1 (HTLV-1) (37 IgAN, 33 other glomerulonephritis, and 20 healthy controls) was evaluated by nested PCR using a pan-lentivirus-specific primer set (PLSPS), targeting the consensus sequence of the lentiviral pol gene. In 37.8% (14 of 37) of the patients with IgAN, the PCR products migrated in parallel with bands produced by PCR of simian immunodeficiency virus (SIV) infected cells. No products of the expected size were detected in the other patient groups (p < 0.0001, Chi-square). These results suggest that exposure to retroviral infection is more common in patients with IgAN, compared with patients with other proliferative glomerulonephritides, or patients without renal disease. These data demonstrate a possible association of IgAN with infection with non-HIV, non-HTLV-1 retrovirus.

Altered humoral immunity against cytomegalovirus and Epstein-Barr virus without detectable virus antigens and virus-DNA in the glomeruli of patients with IGA nephropathy in remission phase.

Herpes viruses, such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV), very often occur in the nasopharynx. A pathogenetic role of these viruses in immunoglobulin A nephropathy (IgA NP) is a challenging hypothesis, since upper respiratory tract infections are frequently and closely related in time to the acute episodes of IgA NP. However, conflicting reports have been published in this field. We compared the IgA and IgG antibody (AB) titres against cytomegalovirus (CMV) in sera of 41 IgANP patients with 80 healthy controls. The prevalence rates of CMV-IgA and CMV-IgG AB were significantly higher in patients with IgA NP than in healthy controls (CMV-IgA, titre > = 8, p < 0.001; CMV-IgG, titre > = 16, p < 0.05). There was also a significant difference in the concentration of CMV-IgA AB between IgANP patients and controls (IgA NP: 0.34 +/- 0.66, healthy controls: 0.06 +/- 0.33, mean +/- SD, p = < 0.002), but not in the concentration of CMV-IgG AB between NP patients and controls. While examining 60 patients with IgA NP and 75 healthy controls a significantly elevated prevalence rate of IgA AB against EBV capsid antigen (EBV-VCA) was also detected in the sera of IgA NP patients vs controls (titre > = 16; p < 0.05). There was no significant difference in the prevalence of IgG AB to EBV-VCA between patients with IgA NP and healthy controls, except at titre = 1024 (p < 0.05). At a follow-up, CMV-IgA persisted in 4 of 5, and EBV-VCA-IgA in 8 of 12 seropositive patients with IgA NP. We could not detect virus antigens or virus deoxyribonucleic acid (DNA) in the glomeruli of NP patients either with immunohistology using a monoclonal antibody or with the DNA in situ hybridization technique.(ABSTRACT TRUNCATED AT 250 WORDS)