Bashir Shaarif, Hussain Mudassar, Afzal Aurangzeb, Hassan Usman, Hameed Maryam, Mushtaq Sajid
Department of Pathology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, 54000, Pakistan.
Department of Nephrology, Lahore General Hospital, Lahore, 54000, Pakistan.
Int J Nephrol Renovasc Dis. 2021 Mar 11;14:87-95. doi: 10.2147/IJNRD.S285302. eCollection 2021.
Post-infectious glomerulonephritis (PIGN) (immune complex-mediated glomerulonephritis) and C3 glomerulopathy are sub-types of glomerulonephritis (GN) with hypercellularity. Both have overlapping clinical and morphologic features on a kidney biopsy, however, the treatment and prognosis of these diseases are quite different making their distinction of utmost importance. Immune complex-mediated glomerulonephritis arises from glomerular deposition of immune-complexes (Igs) and C3 as a result of activation of classical (CP) and lectin pathways (LP). C4d is produced as a result of activation of the CP/LP. On the other hand, C3 glomerulopathy results from activation of alternative pathway of complement.
To distinguish between PIGN and C3 glomerulopathy with the help of C4d IHC stain.
We studied 28 biopsies reported as GN with hypercellularity from January 2015 to January 2020. Clinical information, histological features and immunofluorescence patterns were analyzed. C4d IHC was performed on all the biopsies. Six known cases of immune complex-mediated GN were selected to act as a positive control for C4d staining.
Amongst 28 cases originally reported as GN with hypercellularity, 18 were labeled as post-infectious GN and 10 as C3 glomerulopathy based on clinical information and serological findings. 13 of 18 (72.2%) cases of PIGN had mild to moderate (1-2+) C4d staining, 2 (11.1%) had strong (3+) staining and 3 (16.7%) cases were negative for C4d staining. In the 10 biopsies of C3 glomerulopathy, mild (1+) C4d staining was noted only in 3 (30%) biopsies. C4d had moderate to strong (2-3+) staining in the control group.
C4d IHC stain can be helpful in distinguishing PIGN from C3 glomerulopathy.
感染后肾小球肾炎（PIGN）（免疫复合物介导的肾小球肾炎）和C3肾小球病是肾小球肾炎（GN）中具有细胞增多的亚型。两者在肾活检中具有重叠的临床和形态学特征，然而，这些疾病的治疗和预后有很大不同，因此区分它们至关重要。免疫复合物介导的肾小球肾炎是由于经典途径（CP）和凝集素途径（LP）激活导致免疫复合物（Igs）和C3在肾小球沉积而引起的。C4d是CP/LP激活的产物。另一方面，C3肾小球病是补体替代途径激活的结果。
借助C4d免疫组化染色区分PIGN和C3肾小球病。
我们研究了2015年1月至2020年1月间报告为细胞增多性GN的28例肾活检病例。分析了临床信息、组织学特征和免疫荧光模式。对所有活检标本进行C4d免疫组化检测。选择6例已知的免疫复合物介导的GN病例作为C4d染色的阳性对照。
在最初报告为细胞增多性GN的28例病例中，根据临床信息和血清学检查结果，18例被标记为感染后GN，10例为C3肾小球病。18例PIGN病例中有13例（72.2%）有轻度至中度（1-2+）C4d染色，2例（11.1%）有强（3+）染色，3例（16.7%）C4d染色阴性。在10例C3肾小球病活检标本中，仅3例（30%）有轻度（1+）C4d染色。对照组C4d有中度至强（2-3+）染色。
C4d免疫组化染色有助于区分PIGN和C3肾小球病。
