INTRODUCTION
IgA nephropathy (IgAN), characterized by predominant IgA deposition in
the glomerular mesangium, is the most common form of primary
glomerulonephritis worldwide[1, 2].The other histological features
of IgA nephropathy are mesangial cell proliferation with complement 3
(C3) and variable IgG and / or IgM co-deposits[3]. IgAN presented
with a wide range of histology and clinical features, among which about
one-third of patients develop into ESRD within 25 years[1, 4, 5]. As
no specific treatment is available for IgAN, it is particularly
important to find the potential risk factors for the long-term prognosis
of IgAN. It is well established that risk factors for the progression of
IgAN include the presence of proteinuria, high blood pressure, and
declined eGFR[6, 7]. The MEST scoring system including mesangium
hypercellularity (M), endocapillary hypercellularity (E), segmental
glomerulosclerosis (S), and tubular atrophy/interstitial fibrosis (T),
was also validated in a variety of studies for the prediction of
clinical outcomes[8, 9]. T cell subpopulations were also identified
to be associated with the severity of proteinuria and hematuria,
elevated serum creatinine levels and reduced GFR in IgAN[10].
Glomerular co-deposition of C3 and IgA1 was observed in at least 90% of
IgAN renal biopsies[3, 11]. Previous studies have shown that the
pathogenic co-deposition of C3 and IgA1 induces proliferation of
mesangial cells and secretion of cytokines and extracellular matrix,
which plays a key role in the pathogenesis of IgAN[12, 13]. However,
the role of complement activation on the progression and prognosis of
IgAN remains unclear. Although renal biopsy remains the gold standard
diagnosis, recent efforts have been made to find new biomarkers that
might predict progression and prognosis of IgAN.
In this observational cohort study, we analyzed clinical features
according to the pathologic findings and glomerular immune complex
deposition and then investigated the predictive value of
glomerular C3 deposition in
predicting the prognosis of patients with IgAN.
MATERIALS AND METHODS