IgA nephropathy in a patient with systemic lupus erythematosus

Lupus and IgA nephropathy: coexistence or coincident?

BACKGROUND

Systemic lupus erythematosus is a multisystem autoimmune disease primarily manifesting as lupus nephritis. While lupus nephritis is the most common renal pathology in lupus, non-lupus nephropathies such as IgA nephropathy occasionally occur. This study aims to evaluate the clinical features and outcomes of lupus patients with IgA nephropathy, comparing them with those of primary IgA nephropathy and lupus nephritis.

METHODS

A comprehensive literature review was conducted using the PubMed and Google Scholar databases to identify cases of systemic lupus erythematosus with IgA nephropathy reported between 1995 and December 2023. A total of 16 cases were identified and 2 additional cases from our clinic were included. These cases were compared with 47 lupus nephritis patients from our clinic and 215 primary IgA nephropathy patients from the literature. Data were collected on demographics, serology, renal biopsy findings, treatment, progression to renal failure and mortality.

RESULTS

We identified 18 cases of lupus with IgA nephropathy with a median age of 41.6 years and a female predominance (72.2%). In comparison to the primary IgA nephropathy cohort, lupus with IgA nephropathy group exhibited a lower rate of renal failure (11.1% vs. 34%) and mortality (5.6% vs. 20%). Additionally, the lupus-IgA nephropathy group showed a slightly lower mortality rate compared to the lupus nephritis cohort (5.6% vs. 10.6%).

CONCLUSION

Lupus with predominantly IgA deposits often follows a more indolent course than primary IgA nephropathy but severe cases with crescentic glomerulonephritis can still progress to renal failure.

Lupus Nephritis with Obvious IgA deposits in the Kidneys

OBJECTIVE

The purpose of the current study was to describe the clinico-pathological characteristics and outcomes in patients with lupus nephritis with IgA deposits in the kidneys.

MATERIALS AND METHODS

A total of 258 patients with lupus nephritis with complete clinical data and follow-up was enrolled. They were divided into two groups: the IgA deposits group and the non-IgA deposits group. Their clinico-pathological features and outcomes between the two groups were further compared.

RESULTS

Patients with IgA deposits had significantly lower prevalence of acute kidney failure, higher eGFR, lower plasma levels of C3a, and lower renal pathological chronicity indices scores than those with non-IgA deposits (19.4% vs. 31.8%, 80.9±35.6 vs. 69.1±39.6 ml/min/1.73m², 1045.48 [559.41, 1796.34] vs. 1920.77 [1155.08, 2986.96]ng/ml, and 2 [1, 3] vs. 2.5 [2, 4], respectively, all P<0.05). Patients with IgA deposits also had a higher frequency of the CFH rs6677604-AA/GA genotype in comparison with those with non-IgA deposits (12.0% vs. 8.2%, P=0.469). Using the multivariable Cox hazard analysis, the IgA deposits were identified as a protective factor of survival from the composite events (HR 0.423; 95% CI, 0.219 to 0.816; P=0.01).

CONCLUSIONS

Patients with IgA deposits presented with milder renal damage and a good prognosis, which suggested its protective role in lupus nephritis.

Diagnostic Utility of Galactose-Deficient Immunoglobulin A1 Immunostaining in the Differentiation of Lupus Nephritis and Immunoglobulin A Nephropathy

Background

Renal biopsy plays an important role in the establishment of the diagnosis and the management of patients with lupus nephritis. Immunoglobulin A (IgA) nephropathy rarely has been reported in kidney biopsy of lupus patients. Lupus nephritis and IgA nephropathy can be readily diagnosed on renal biopsy when the classic patterns are present. However, atypical patterns can become a diagnostic challenge. Galactose-deficient IgA1 (Gd-IgA1) is a key element in the pathogenesis of primary IgA nephropathy. Glomerular Gd-IgA1 deposits, detected by immunofluorescent staining of KM-55 (a Gd-IgA1-specific monoclonal antibody), are consistently identified in the mesangium of IgA nephropathy but are significantly less or absent in lupus nephritis accompanied by significant IgA deposition.

Case Presentation

Here we report the case of an 11-year-old girl who was recently diagnosed with systemic lupus erythematosus (SLE) and was found to have hematuria and proteinuria. Renal biopsy showed focal mesangial hypercellularity with IgA dominant, "full house" like pattern of mesangial deposition. The biopsy findings present a diagnostic dilemma with the differential diagnosis of IgA nephropathy versus lupus nephritis with atypical immunofluorescence, and IgA nephropathy is favored, in the absence of strong straining of C1q or C3, extraglomerular deposits, tissue antinuclear antibodies, and endothelial tubuloreticular inclusions. However, no detectable glomerular KM-55 staining was seen in the kidney biopsy.

Conclusions

We demonstrate the unique diagnostic utility of immunostaining for KM-55 in a challenging kidney biopsy of an SLE patient with features suggestive of IgA nephropathy. The absence of KM-55 staining excludes IgA nephropathy, supporting a diagnosis of lupus nephritis with atypical immunofluorescence in this patient with SLE.

IgA nephropathy in systemic lupus erythematosus patients: case report and literature review

Systemic erythematosus lupus (SLE) is a multisystemic autoimmune disease which has nephritis as one of the most striking manifestations. Although it can coexist with other autoimmune diseases, and determine the predisposition to various infectious complications, SLE is rarely described in association with non-lupus nephropathies etiologies. We report the rare association of SLE and primary IgA nephropathy (IgAN), the most frequent primary glomerulopathy in the world population. The patient was diagnosed with SLE due to the occurrence of malar rash, alopecia, pleural effusion, proteinuria, ANA 1: 1280, nuclear fine speckled pattern, and anticardiolipin IgM and 280U/mL. Renal biopsy revealed mesangial hypercellularity with isolated IgA deposits, consistent with primary IgAN. It was treated with antimalarial drug, prednisone and inhibitor of angiotensin converting enzyme, showing good progress. Since they are relatively common diseases, the coexistence of SLE and IgAN may in fact be an uncommon finding for unknown reasons or an underdiagnosed condition. This report focus on the importance of the distinction between the activity of renal disease in SLE and non-SLE nephropathy, especially IgAN, a definition that has important implications on renal prognosis and therapeutic regimens to be adopted in both the short and long terms.

Association of systemic lupus erythematosus susceptibility genes with IgA nephropathy in a Chinese cohort

BACKGROUND AND OBJECTIVES

One hypothesis states that IgA nephropathy (IgAN) is a syndrome with an autoimmune component. Recent studies strongly support the notion of shared genetics between immune-related diseases. This study investigated single-nucleotide polymorphisms (SNPs) reported to be associated with systemic lupus erythematosus (SLE) in a Chinese cohort of patients with IgAN and in controls.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study investigated whether SNP markers that had been reported to be associated with SLE were also associated with IgAN in a Chinese population. The study cohort consisted of 1194 patients with IgAN and 902 controls enrolled in Peking University First Hospital from 1997 to 2008.

RESULTS

Ninety-six SNPs mapping to 60 SLE loci with reported P values <1 × 10(-5) were investigated. CFH (P=8.41 × 10(-6)), HLA-DRA (P=4.91 × 10(-6)), HLA-DRB1 (P=9.46 × 10(-9)), PXK (P=3.62 × 10(-4)), BLK (P=9.32 × 10(-3)), and UBE2L3 (P=4.07 × 10(-3)) were identified as shared genes between IgAN and SLE. All associations reported herein were corroborated by associations at neighboring SNPs. Many of the alleles that are risk alleles for SLE are protective alleles for IgAN. By analyses of two open independent expression quantitative trait loci (eQTL) databases, correlations between genotypes and corresponding gene expression were observed (P<0.05 in multiple populations), suggesting a cis-eQTL effect. From gene-expression databases, differential expressions of these genes were observed in IgAN. Additive interactions between PXK rs6445961 and HLA-DRA rs9501626 (P=1.51 × 10(-2)), as well as multiplicative interactions between CFH rs6677604 and HLA-DRB1 rs9271366 (P=1.77 × 10(-2)), and between HLA-DRA rs9501626 and HLA-DRB1 rs9271366 (P=3.23 × 10(-2)) were observed. Disease risk decreased with accumulation of protective alleles. Network analyses highlighted four pathways: MHC class II antigen presentation, complement regulation, signaling by the B-cell receptor, and ubiquitin/proteasome-dependent degradation.

CONCLUSION

From this "systems genetics" perspective, these data provide important clues for future studies on pleiotropy in IgAN and lupus nephritis.

A study on clinical and pathologic features in lupus nephritis with mainly IgA deposits and a literature review

Objective. To study the clinical and pathologic features of systemic lupus erythematosus (SLE) that has atypical lupus nephritis (LN) with mainly IgA deposits. Methods. We searched the SLE patients who had nephritis with mainly IgA deposits in our hospital and selected the information including clinical manifestations, laboratory tests, treatments, and prognosis. Results. From January 2009 to June 2012, 5 patients were definitely diagnosed as SLE according to both 1982 and 2009 ACR classification criteria. But renal biopsy showed that all cases had mainly IgA deposits and were free of IgG, C1q, and fibrinogen-related antigen deposits under immunofluorescent microscopy, which did not match with typical LN. There were 2 males and 3 females, aging from 31 to 64 years and with an average of (42.20 ± 13.59) years. The 5 cases had multiple-system involvements, mainly the renal system. Compared to primary IgAN, the atypical LN showed some differences: older than primary IgAN, more women than men, no previous infection history, lower incidence of serum IgA elevation, and ACL positive rate as high as 100%. Conclusion. Nephritis with mainly IgAN deposits, as an atypical LN, may be a special subtype of SLE.

Genetic risk factors in lupus nephritis and IgA nephropathy--no support of an overlap

Background

IgA nephropathy (IgAN) and nephritis in Systemic Lupus Erythematosus (SLE) are two common forms of glomerulonephritis in which genetic findings are of importance for disease development. We have recently reported an association of IgAN with variants of TGFB1. In several autoimmune diseases, particularly in SLE, IRF5, STAT4 genes and TRAF1-C5 locus have been shown to be important candidate genes. The aim of this study was to compare genetic variants from the TGFB1, IRF5, STAT4 genes and TRAF1-C5 locus with susceptibility to IgAN and lupus nephritis in two Swedish cohorts.

Patients and Methods

We genotyped 13 single nucleotide polymorphisms (SNPs) in four genetic loci in 1252 DNA samples from patients with biopsy proven IgAN or with SLE (with and without nephritis) and healthy age- and sex-matched controls from the same population in Sweden.

Results

Genotype and allelic frequencies for SNPs from selected genes did not differ significantly between lupus nephritis patients and SLE patients without nephritis. In addition, haplotype analysis for seven selected SNPs did not reveal a difference for the SLE patient groups with and without nephritis. Moreover, none of these SPNs showed a significant difference between IgAN patients and healthy controls. IRF5 and STAT4 variants remained significantly different between SLE cases and healthy controls. In addition, the data did not show an association of TRAF1-C5 polymorphism with susceptibility to SLE in this Swedish population.

Conclusion

Our data do not support an overlap in genetic susceptibility between patients with IgAN or SLE and reveal no specific importance of SLE associated SNPs for the presence of lupus nephritis.