Regarding the LP in PIGN, the association of activated LP with the occurrence of PSAGN has been reported [30]. the term infection-related glomerulonephritis (IRGN) has been proposed [6] as the comprehensive concept including PSAGN and atypical types of adult-onset of AGN related to numerous infections (e.g., staphylococci, Gram-negative bacteria, numerous viruses, fungi, or protozoa) [7]. Match 3 glomerulopathy (C3G) is usually a recently recognized disease entity caused by acquired or genetic dysregulation of the match option pathway Rabbit polyclonal to ANTXR1 (AP) [8,9,10,11,12]. The estimated annual incidence is usually 1C3 per 1,000,000 populace [13]. Most patients with C3G show hematuria and nephrotic range proteinuria (NRP) [3]. The renal prognosis of C3G is not usually good, and some patients progress to end-stage renal disease [13,14,15]. C3G can be further subdivided into dense deposit disease (DDD) and C3 glomerulonephritis (C3GN) [8,9,13,14,16,17,18]. In the clinical setting, C3GN is usually a rare kidney disease, thereby making diagnosis by physicians hard. Furthermore, an expert in renal pathology may be required to confirm the diagnosis of C3G, since other glomerular lesions, such as IRGN or immune complex (IC) forms of membranoproliferative glomerulonephritis (MPGN), can mimic C3G. In particular, it is extremely hard to morphologically differentiate C3GN from C3-dominant IRGN. Thus, a reliable biomarker for the differential diagnosis of C3G and IRGN is needed. Assays for match components and gene analysis are the first step to determine the presence or absence of match AP dysregulation in C3G patients. Positivity for glomerular nephritis-associated plasmin receptor (NAPlr) and related plasmin activity are anticipated as important diagnostic biomarkers for IRGN [19,20,21,22,23,24]. According to previous reports, a genetic variant in the match AP factors or autoantibodies (C3 nephritic factor (C3NeF), anti-factor H (anti-FH) antibody, and anti-factor B (anti-FB) antibody) that induce a defect in the regulation of AP can be detected in approximately half of the cases with C3G [25,26,27,28]. It was recently reported that hypocomplementemia did not necessarily occur in all cases of C3G, despite the presence of underlying AP dysregulation [3]. In the mean time, some patients with IRGN show persistent hypocomplementemia during their clinical course [3]. The association of improper AP activation with the exacerbation of IRGN was emphasized in recent review articles [19,20]. Moreover, recent reports demonstrated a significant elevation of anti-FB autoantibodies in Taxifolin pediatric patients with PIGN compared to C3G [29,30]. C3G with glomerular NAPlr deposition without evidence of infection was noted [19]. Taken together, the clinico-pathogenic features of IRGN overlap considerably with those of C3G, which may lead clinicians in the field of nephrology to confuse them. In this review, the similarities and differences between these two diseases are highlighted, and the details of their clinico-pathogenic features are offered. 2. Method for Literature Search PubMed was searched for articles in English using the search terms GN, contamination, C3G, and option pathway in studies in humans. Review articles, observational studies, and case reports were selected as the available literature. We focused on articles published between 1 January 2012 and 31 December 2022. Relevant older articles were also retrieved by a manual search of reference lists. Strong evidence in this field is generally limited, since no large prospective clinical studies have been performed due to the rarity of IRGN and C3G. In addition, a reliable animal model has not been established to date. Therefore, the contents of this review are mostly based on detailed evaluations of observational studies and case reports. 2.1. Pathomorphological Characteristics of IRGN and C3G Differentiation between IRGN and C3G Based on the Diagnostic Taxifolin CriteriaIn accordance with the previous review by Nasr et al., the diagnosis of IRGN is based on the constellation of several clinical features and pathological findings, as follows: (1) clinical or laboratory evidence of infection preceding or at the onset of GN; (2) depressed serum complement; (3) endocapillary proliferative and exudative GN on light microscopy (LM); (4) C3-dominant or co-dominant glomerular deposition on immunofluorescence (IF) microscopy; and (5) hump-shaped subepithelial deposits on electron microscopy (EM) [2,31,32]. They mentioned Taxifolin that fulfilling all five criteria is not necessary, and at least three of the above-described criteria are sufficient for a diagnosis of IRGN. In other words, apparent evidence of infection is not necessary to diagnose IRGN, which indicates the possibility of misdiagnosing similar.