Clinicopathologic Features of IgG4-Related Kidney Disease.
IgG4-related disease (IgG4-RD) is a systemic immune-mediated disease that can involve nearly any organ. IgG4-RD can affect the kidney in different disease patterns, collectively referred to as IgG4-related kidney disease (IgG4-RKD).
We conducted a tissue-based cohort study with clinicopathological correlation in 125 patients with IgG4-RKD.
The mean age at biopsy (n = 120) or nephrectomy (n = 5) was 63 years; 80% were male. One hundred eighteen patients (94%) had IgG4-related tubulointerstitial nephritis (IgG4-TIN); 20 patients (16%) had IgG4-related membranous glomerulonephritis (IgG4-MGN; 13 with concurrent IgG4-TIN). The primary clinical indication for biopsy/nephrectomy was acute or chronic renal failure in 78%, proteinuria in 17%, and mass lesion(s) in 15% (with overlap in primary indication). Fifty-two percent patients (41/79) had abnormal radiographic findings, including masses in 30% (24/79). All patients with IgG4-MGN had proteinuria. Extrarenal involvement by IgG4-RD was present in 79%. Median serum creatinine at presentation was 2.5 mg/dl (range 0.7-12). Serum IgG and/or IgG4 was increased in 91% (53/58); hypocomplementemia was present in 56% (43/77). Light microscopy showed plasma cell-rich interstitial nephritis in all cases of IgG4-TIN. Ninety-two percent of patients showed increased IgG4+ plasma cells. Seven percent showed an acute interstitial nephritis (AIN) pattern, and 5% showed non-necrotizing arteritis. Tubular basement membrane immune deposits were present in 83% of IgG4-TIN. Treatment information was available for 71 patients; 62 were treated with immunosuppression. Of those with elevated creatinine, 72% (41/57) showed a treatment response.
This largest tissue-based series more clearly defines the disease phenotype of IgG4-RKD.
Buglioni A
,Jenkins SM
,Nasr SH
,Zhang P
,Gibson IW
,Alexander MP
,Herrera Hernandez LP
,Fidler ME
,Takahashi N
,Hogan MC
,Cornell LD
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《Kidney International Reports》
Clinicopathological Patterns and Predictors of the Functional Restoration of Immunoglobulin G4-Related Kidney Disease: A Chinese Single-Center Cohort Study.
Background: Immunoglobulin G4-related disease (IgG4-RD) is a systemic immunoreactivity-based fibro-inflammatory disease. Immunoglobulin G4-related kidney disease (IgG4-RKD) is a frequently overlooked diagnosis. This study aimed to describe IgG4-RKD and examine the factors relevant to the renal outcomes of IgG4-RD. Methods: We studied a prospective IgG4-RKD cohort between January 2012 and December 2020 with close follow-up. Clinicopathologic data at kidney biopsy were collected and analyzed. We aimed to explore independent risk factors for long-term renal outcome and disease relapse. Patients with an eGFR<45 ml/min per 1.73m2 at 12 months were defined as having poor outcomes. Results: The included 42 patients with IgG4-RKD had a mean age of 58.5 ± 8.7 years (male-to-female ratio = 5:1). The IgG4-RD responder index (RI) was 12.2 ± 3.3. A total of 66.7% of the patients presented with acute on kidney disease or acute on chronic kidney disease. Eight patients (19.0%) showed nephrotic-range proteinuria, and nine (21.4%) had high-titer IgG4-autoantibodies, including antineutrophil cytoplasmic antibody and anti-phospholipase A2 receptor. A kidney biopsy was conducted in 40 patients. Thirty-seven (90.0%) patients were diagnosed with IgG4-related tubulointerstitial nephritis, and 19 (47.5%) of them had concurrent glomerular diseases (membranous nephropathy [MN], n = 3; crescentic glomerulonephritis [CrGN], n = 11; diabetic kidney disease, n = 3; and both MN and CrGN, n = 2). IgG4-RD RI had a close relationship with serum C3 (R = -0.509, P = 0.001), C4 (R = -0.314, P = 0.049) levels, and peripheral blood eosinophil count (PBEC; R = 0.377, P = 0.024), factors that were not included in RI scores. Correlation analysis disclosed that IgG4-RD RI (R = 0.422, P = 0.007), organs involved (R = 0.452, P = 0.003), and C3 (R = -0.487, R = 0.002) were correlated with the percentage decrease of serum creatinine at 1 month. However, multivariate regression analysis failed to identify any clinicopathological parameters that could predict short-term renal restoration and IgG4-RKD relapse. Ten out of 29 variables, of most importance, were identified by the least absolute shrinkage and selection operator (LASSO) regression analysis. By multivariate logistic regression a higher serum IgG4 (OR = 0.671, P = 0.010), IgG1 (OR = 1.396, P = 0.049), IgG3 (OR = 19.154, P = 0.039), and erythrocyte sedimentation rate (ESR; OR = 1.042, P = 0.032) were found to be independent factors for poor long-term outcome. Conventional immunosuppressive medications and/or rituximab were prescribed, and in 83.3% of the patients, the kidney function improved. Repeat kidney biopsies confirmed the remission of interstitial inflammation in two patients under immunosuppressive therapy. However, the disease relapse rate was as high as 31.0%. Conclusions: We strongly recommend a kidney biopsy in active IgG4-RD, especially when there is proteinuria and renal dysfunction, because concurrent glomerular involvement and active interstitial inflammation should be assessed. A higher serum IgG1, IgG3, and ESR were independent factors for the poor long-term renal outcome; however, elevated IgG4 predicted a good renal prognosis, and appropriate and timely immunosuppressive therapy can help achieve a better prognosis.
Su T
,Wang H
,Wang S
,Yang L
... -
《Frontiers in Medicine》
IgG4-related kidney disease--A review.
IgG4-related disease (IgG4-RD) is a recently recognized systemic autoimmune disorder characterized by high levels of serum IgG4 and dense infiltration of IgG4-positive plasma cells in multiple organs. The condition was first described as a disease of the pancreas, and has since been recognized in various organ systems including the kidneys. IgG4 related kidney disease (IgG4-RKD) signifies any form of renal involvement by IgG4-RD. The most common renal involvement by IgG4-RD is tubulointerstitial nephritis. Glomerular disease, in particular membranous glomerulonephritis, may also be seen. Other co-existent glomerular diseases such as IgA nephropathy, membranoproliferative glomerulonephritis, and mesangioproliferative immune complex glomerulonephritis may be identified. IgG4-related plasma cell arteritis has also been noted in the kidney. As with IgG4-RD in general, IgG4 related kidney disease (IgG4-RKD) usually occurs in middle-aged to elderly men. Common findings in IgG4-RKD are plasma cell-rich interstitial inflammatory infiltrate either in a focal or diffuse pattern with increased IgG4+ plasma cells, expansile swirling interstitial fibrosis, high levels of serum IgG and IgG4, hypocomplementemia, high serum IgE levels and/or peripheral blood eosinophilia. By immunofluorescence, most of the cases show IgG4 dominant tubular basement membrane immune complex deposits. Similar to IgG4-RD, IgG4-RKD often shows a rapid response to steroid therapy. In this review, we discuss the current knowledge on IgG4-RKD and its clinical relevance.
Pradhan D
,Pattnaik N
,Silowash R
,Mohanty SK
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