Serum High-Sensitivity C-Reactive Protein Is Not Increased in Patients with IgA Nephropathy

Abstract

Background/Aims: The development of renal injury in glomerulonephritis (GN) has been related to systemic inflammatory mediators. We investigated whether serum high-sensitivity C-reactive protein (hs-CRP) is a marker reflecting the inflammatory pathogenesis of primary GN. Methods: We compared serum hs-CRP levels in 192 patients with IgA nephropathy (IgAN), 43 patients with membranous nephropathy (MN), and 25 patients with minimal change disease (MCD) undergoing kidney biopsy and 638 matched controls. Results: There were no differences in hs-CRP levels between controls (median 0.08 mg/dl; range 0.03–1.87 mg/dl) and patients with IgAN (0.08 mg/dl; 0.03–3.13 mg/dl), MN (0.07 mg/dl; 0.03–0.99 mg/dl) or MCD (0.08 mg/dl; 0.03–1.75 mg/dl). In patients with IgAN, hs-CRP levels did not differ according to Haas’ pathological subclasses or subsequent renal outcomes. In the IgAN group, hs-CRP showed positive correlations with IgA, uric acid, systolic blood pressure, BMI and age. Hs-CRP level was significantly higher in male than in female IgAN patients. Serum IgA concentration was the strongest independent correlate with hs-CRP levels, and gender and BMI were also independently associated with hs-CRP. There were no correlations between hs-CRP and markers of disease activity. Conclusion: It is likely that hs-CRP does not closely reflect inflammatory pathogenesis in patients with IgAN, MN and MCD.

Atypical Presentation of IgA Nephropathy Mimicking Acute Pyelonephritis

“…The very high CRP in our case is an unexpected finding for IgA nephropathy in the absence of infection, since such high elevations have not been described in prior studies [ 12 – 14 ]. It is unclear however if in these studies any measurements were obtained during an acute episode of gross hematuria, like in our case.…”

Exploratory classification of clinical phenotypes in Japanese patients with antineutrophil cytoplasmic antibody-associated vasculitis using cluster analysis

“…CRP is a surrogate marker for important organ involvements, except for renal symptoms. The CRP levels have not been observed to increase in patients with glomerulonephritis including IgA nephropathy, membranous nephropathy, and minimal change disease compared to that in controls 27 . Consistent with these previous observations, the CRP levels associated with fever, myalgia, and pulmonary and neurological vasculitis but not with renal symptoms in the present study.…”

IFI27 Is a Useful Genetic Marker for Diagnosis of Immunoglobulin A Nephropathy and Membranous Nephropathy Using Peripheral Blood

“…IgAN is thought to be induced by oral or tonsillar bacterial infection; consistent with this, specific bacterial infections have been detected in specimens obtained by IgAN tonsillectomy, a useful standard therapy for IgAN [ 11 ], and other groups also reported a relationship between oral bacterial infections and IgAN [ 10 ], [ 34 ]. Notably, highly sensitive CRP is not a useful indicator of these infections, probably because they are limited to the tonsillar areas [ 35 ]. Toll-like receptor 9 (TLR9) is expressed at higher levels in both IgAN model mice [ 36 ] and IgAN patients [ 37 ], perhaps because a variable copy-number region at 3p21.1 influences TLR9 expression levels in IgAN patients [ 38 ].…”