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Table of Contents
ORIGINAL ARTICLE
Year : 2022  |  Volume : 13  |  Issue : 2  |  Page : 109-112

Correlation of E1 lesions and CD68 count with proteinuria and clinical outcome in IgA nephropathy


1 Department of Anatomical Pathology and Cytology, Aware Gleneagles Global Hospitals, Hyderabad, Telangana, India
2 Department of Nephrology and Renal Transplantation, Aware Gleneagles Global Hospitals, Hyderabad, Telangana, India
3 Department of Nephrology and Renal Transplantation, Hyderabad Kidney Center, Hyderabad, Telangana, India

Date of Submission07-Sep-2021
Date of Decision13-Nov-2021
Date of Acceptance06-Dec-2021
Date of Web Publication30-Mar-2022

Correspondence Address:
Prof. Sistla Radha
Plot No 20, Road No 1, Alkapuri, Hyderabad, Telangana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/injms.injms_105_21

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  Abstract 


Background: IgA nephropathy (IgAN) has variable course; few patients have a benign presentation and other patients present with late stage disease. Endocapillary hypercellularity has a prognostic significance in IgAN. It is important to identify E1 lesions accurately. The use of CD68 immunohistochemistry marker to identify glomerular macrophages will standardize the reporting and help the clinicians prognosticate the patients. Subjects and Methods: The material is from a referral laboratory for renal biopsies in a tertiary care hospital. Renal biopsies are processed as per protocol including light microscopy, immunofluorescence and electron microscopy where ever required. CD68 was used in this study to identify macrophages in E1 lesions. A total of 1220 primary glomerular diseases were diagnosed from January 2019 till date. Out of these, IgA constituted 11.9% of primary glomerular diseases. Renal biopsies received were from the department of nephrology and various other nephrology centers. Biopsies were received in 10% buffered formalin. Immunofluorescence is done on all biopsies, and electron microscopy was done in few cases to differentiate from other lesions with dominant IgA deposits. CD68 was done in 50 cases of IgAN. Apart from hematoxylin and eosin stains, periodic acid-Schiff, Masson trichrome, Jones silver stain were also done. Results: IgAN constituted 11.9% of cases. Twenty-five cases of E0 and twenty-five cases of E1 lesions were correlated with clinical and morphological features. There was correlation with proteinuria and hypertension in E1 lesions. There was no significant correlation with the morphological variants like crescents, focal segmental glomerulosclerosis. Conclusions: Inter observer correlation of E lesions is poor in classifying IgAN. Use of CD68 is a useful adjunct to identify macrophages. E1 lesions have more proteinuria requiring treatment for delaying the progression to end stage disease. Despite significant association of E1 lesions with progression, there may be many unmeasured factors which would influence the outcome.

Keywords: CD68, endocapillary hypercellularity-E1 lesions, proteinuria


How to cite this article:
Radha S, Afroz T, Reddy Y S, Sridhar G, Rajaram K G. Correlation of E1 lesions and CD68 count with proteinuria and clinical outcome in IgA nephropathy. Indian J Med Spec 2022;13:109-12

How to cite this URL:
Radha S, Afroz T, Reddy Y S, Sridhar G, Rajaram K G. Correlation of E1 lesions and CD68 count with proteinuria and clinical outcome in IgA nephropathy. Indian J Med Spec [serial online] 2022 [cited 2022 Aug 7];13:109-12. Available from: http://www.ijms.in/text.asp?2022/13/2/109/341109




  Introduction Top


IgA nephropathy (IgAN) was first described by Jean Berger in 1968.[1] It has been reported as the most common glomerular disease. The incidence varies across the globe and is around 39.5% in Asia.[2]

IgAN is morphologically heterogeneous. Pathologic classification permits standardization of reporting, and this enables both clinicians and pathologists to improve patient prognostication. The Oxford classification of IgAN represents a novel approach to the disease. The Oxford classification introduced in 2009 has replaced previous classification systems and was proposed by the International IgAN Network and Renal Pathology Society. They have identified the following four histologic variables: mesangial cellularity (M), endocapillary hyper cellularity (E), segmental glomerulosclerosis (S), tubular atrophy, and interstitial fibrosis (T). Additional scoring of Crescents© was introduced creating MEST-C scores. Oxford classification definition of pathological variables is as follows: Mesangial cellularity in <50% of glomeruli is M0, more than 50% of glomeruli is M1. Segmental glomerulosclerosis, Absent is S0, S1 is present Endocapillary hypercellularity, E0 is absent, E1 is present.

Tubular atrophy and interstitial fibrosis, 0%–25% of cortical area is T0, 26%–50% is T1 and T2 >50%. C0 is crescents absent, C1 is up to 25% of glomeruli with crescents and C2 is more than 25% glomeruli with crescents.[3]

Patients with E1 scores are treated with Immunosuppression. E scores carry a prognostic significance, hence, it is important to report these lesions accurately. The inter observer reproducibility is poor for these lesions.[4] The glomerular macrophages in E1 lesions can be more accurately diagnosed with the help of CD68+ Immunohistochemical marker.


  Subjects and Methods Top


This is a prospective and retrospective study done in the department of pathology in a tertiary care hospital in Telangana, South India. 50 cases of IgAN selected from 145 cases diagnosed from January 2019 till date were included in the study. Patient age ranged from 18 years to 67 years. Patients presenting to the department of nephrology with various clinical symptoms like hematuria, proteinuria, renal failure were biopsied. We diagnosed 1220 cases as primary glomerular diseases. Out of which 145 cases were IgAN. Biopsies with adequacy criteria of 8 or more than 8 glomeruli were included in the study.

Biopsies were sent in 10% buffered formalin for light microscopy. Hematoxylin and Eosin (H&E), Periodic acid Schiff's (PAS), Masson trichrome and Jones silver stain were done.

Immunofluorescence was done on all biopsies using IgG, IgA, IgM, C3c, C1q, kappa and lambda. IgAN was reported and scored according to Oxford classification. Twenty five E0 lesions and 25 E1 lesions were included in the study. We correlated these lesions with clinical parameters and morphological patterns of IgAN. Follow up and progression of the disease was mentioned where available.


  Results Top


A diagnosis of IgAN was made in cases with deposition of IgA as dominant or co-dominant immunoglobulin in renal biopsies.

IgAN constituted 11.9% of all the primary renal diseases. Male to female ratio was 2.4:1. Mean age of presentation was 31.4 years. Clinical presentation included nephrotic syndrome, microscopic hematuria, macroscopic hematuria, rapidly progressing renal failure, and azotemia [Table 1]. Cases with eight or more viable glomeruli are included in the study with dominant and codominant IgA deposits on immunofluorescence.
Table 1: Clinical presentations

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Morphological patterns varied in our study. Focal segmental glomerulosclerosis was seen in 28.75% of cases, Mesangial proliferation in 51.6% cases, Crescents were seen in 18.03% of cases [Figure 1]. Immunofluorescence was done on all biopsies using IgG, IgA, IgM, C3c, C1q, kappa and lambda. On Immunofluorescence the predominant pattern was IgA and C3C in 56.9% of cases, other associations were IgG and IgM given in [Table 2].
Figure 1: (a) Section showing mesangial proliferation and focal segmental glomerulosclerosis (H and E, ×400). (b) Focal segmental glomerulosclerosis with prominent podocytes (PAS, ×400). (c) Crescents with mesangial proliferation (H and E, ×400). (d) Mesangial proliferation (H and E, ×400)

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Table 2: Immunofluorescence patterns

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Twenty-five cases of E0 lesions and twenty-five cases of E1 lesions were taken for the study. Endocapillary cellularity is defined as “hyper cellularity due to increased number of cells within the glomerular capillary lumen causing narrowing of the lumina.” On immunohistochemistry lesions were classified as E1, where there are six are more than six CD68 positive cells/glomerulus [Figure 2] CD68 was reported positive when there are cells with cytoplasmic CD68 positivity in cells which morphologically looked like macrophages. These were selected basing on the findings of light microscopy and PAS stained slides.
Figure 2: (a) Showing endothelial hypercellularity (H and E, ×200). (b) Showing endocapillary hyper cellularity (PAS, ×400). (c) Glomerulus with negative CD68 cells (×200). (d) Glomerulus showing more than six CD68cells (×200)

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We compared clinical and morphological features with E1 lesions [Table 3] and [Table 4]. Clinical parameters included proteinuria of >2 g/24 h, hypertension, and serum creatinine. There was >2 g proteinuria in only three cases in E0 lesions, whereas 22 cases of E1 lesions had Proteinuria >2 g. There was nephrotic range proteinuria in 7 cases, and all had E1 lesions. Hypertension was present in eighteen cases of E1 lesions and seven cases in E0 lesions. Creatinine levels were more in interstitial fibrosis and tubular atrophy (IFTA). Crescentic presentation and with acute tubular necrosis. We compared morphological features like Crescents, Focal segmental glomerulosclerosis and IFTA. There were more tubulointerstitial changes in E1 lesions, Crescents and FSGS did not show significant difference between E0 or E1 lesions.
Table 3: Correlation of clinical presentation with “E” lesions

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Table 4: Comparison of “E” lesions with morphological features

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  Discussion Top


IgAN is the most common primary kidney disease. Incidence in south India is 10.4% in Hyderabad, 17.1% in Kochi.[5] In our series incidence is11.9%. Oxford classification created by working group from international IgAN network and renal pathology society helps in providing an evidence based classification to predict the outcome. One variable important in deciding the treatment modality is endocapillary hyper cellularity. Endocapillary hypercellularity is defined as “hyper cellularity due to increased number of cells within the glomerular capillary lumen causing narrowing of the lumina.” Presence of endocapillary hypercellularity is classified as E1 and absence as E0 according to Oxford classification.[6] The reproducibility of E score is poor.

According to KDIGO guidelines,[7] treatment was based on initial evaluation including risk progression. One criterion of assessing risk is evaluation of proteinuria and evaluation of pathological features. We correlated endocapillary hyper cellularity with proteinuria. Hence identification of endocapillary hyper cellularity is very crucial, it increases the reproducibility and helps standardizing the reporting which enables appropriate treatment and prognostication. It is important to understand which cell is contributing to the cellularity and also to determine whether they are pathological inflammatory cells or circulating inflammatory cells in capillary lumina. Another difficulty is in assessing cellularity in segmental lesions. Macrophage infiltration is often seen in glomerular injury. Macrophages mediate immune response and cause tissue injury in glomerulonephritis. CD68 is a robust marker for macrophages and is very useful in classifying E lesions accurately. We correlated clinical parameters with E 1 lesions and there was good correlation with proteinuria and hypertension. This is in accordance with other studies.[8]

We also correlated morphological features with E1 lesions. There was correlation between E1 scores and IFTA. There was no correlation between segmental lesions and crescents. This is different from an earlier study which showed correlation between E1 lesions and Crescents.[4]

Use of steroid in proteinuria improves renal survival. The rate of progression is usually rapid in FSGS And in IFTA lesions. Identifying E1 lesions and initiating appropriate therapy will slow the progression of the disease to end stage.

The follow up of these cases is poor and is a major setback in exactly identifying the duration of progression. The patients were followed for worsening of proteinuria and serum creatinine levels. In our study seven cases with E1 lesions are under regular follow up and showed a significant decrease in proteinuria and stable serum creatinine levels.

It is important to accurately diagnose and have a regular follow up of these patients to preserve the kidney function for a longer duration.

Despite statistically significant association with pathology features and progression, these account to only a few variables which predict the outcome. There may be many unmeasured factors which would influence the outcome requiring further studies.


  Conclusion Top


Interobserver correlation of E1 lesions is poor in classifying IgA nephropathy. Use of CD68 is a useful adjunct to identify macrophages. E1 lesions have more proteinuria requiring treatment for delaying progression to end stage disease.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Berger J, Hinglais N. Intercapillary deposits of IgA-IgG. J Urol Nephrol (Paris) 1968;74:694-5.  Back to cited text no. 1
    
2.
Woo KT, Chan CM, Lim C, Choo J, Chin YM, Teng WL, et al. Changes in primary glomerulonephritis in Singapore over four decades. Clin Nephrol 2019;91:155-61.  Back to cited text no. 2
    
3.
Markowitz G. Glomerular disease: Updated Oxford classification of IgA nephropathy: A new MEST-C score. Nat Rev Nephrol 2017;13:385-6.  Back to cited text no. 3
    
4.
Soares MF, Genitsch V, Chakera A, Smith A, MacEwen C, Bellur SS, et al. Relationship between renal CD68+ infiltrates and the Oxford classification of IgA nephropathy. Histopathology 2019;74:629-37.  Back to cited text no. 4
    
5.
Gowrishankar S, Gupta Y, Vankalakunti M, Gowda KK, Kurien AA, Jansi Prema KS, et al. Correlation of Oxford MEST-C scores with clinical variables for IgA nephropathy in South India. Kidney Int Rep 2019;4:1485-90.  Back to cited text no. 5
    
6.
Trimarchi H, Barratt J, Cattran DC, Cook HT, Coppo R, Haas M, et al. Oxford classification of IgA nephropathy 2016: An update from the IgA nephropathy classification working group. Kidney Int 2017;91:1014-21.  Back to cited text no. 6
    
7.
Kidney Disease: Improving Global Outcomes (KDIGO) Glomerulonephritis Work Group. KDIGO clinical practice guideline for glomerulonephritis. Kidney Int Suppl 2012;2:139-274.  Back to cited text no. 7
    
8.
Agrawal N, Gowrishankar S. The utility of assessing CD68+ glomerular macrophages in assessing endocapillary hypercellularity in IgA nephropathy. Indian J Nephrol 2021;31:16-21.  Back to cited text no. 8
  [Full text]  


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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