Saudi Journal of Kidney Diseases and Transplantation

LETTER TO THE EDITOR
Year
: 2012  |  Volume : 23  |  Issue : 1  |  Page : 150--151

C1q nephropathy presenting as nephritic-Nephrotic syndrome


Muhammed Mubarak 
 Associate Professor, Histopathology Department, Sindh Institute of Urology and Transplantation, Karachi - 74200, Pakistan

Correspondence Address:
Muhammed Mubarak
Associate Professor, Histopathology Department, Sindh Institute of Urology and Transplantation, Karachi - 74200
Pakistan




How to cite this article:
Mubarak M. C1q nephropathy presenting as nephritic-Nephrotic syndrome.Saudi J Kidney Dis Transpl 2012;23:150-151


How to cite this URL:
Mubarak M. C1q nephropathy presenting as nephritic-Nephrotic syndrome. Saudi J Kidney Dis Transpl [serial online] 2012 [cited 2020 Apr 6 ];23:150-151
Available from: http://www.sjkdt.org/text.asp?2012/23/1/150/91409


Full Text

To the Editor,

I have read with interest the case report by Bhowmik et al published in your valued journal. [1] The authors have presented an interesting case of C1q nephropathy (C1qN) with a rare combination of renal symptomatology as nephritic-nephrotic syndrome. However, an intriguing finding is the history of fever without localization, which is difficult to explain. One previous report, also from the same country, similarly presented with high-grade fever with chills. [2] This febrile presentation of C1qN is rare in the international literature, and raises questions as to the nature of the febrile illness. It needs to be investigated as to whether the fever is a triggering factor or just an incidental event bringing the underlying renal disease to the forefront. C1qN is a relatively recently discovered and still a controversial disease entity, first described by Jennette and Hipp in 1985. [3] Since then, a number of small case series and case reports, predominantly from the western world, have appeared in the literature, especially in pediatric nephrology, on this subject. [4],[5],[6] Its clinical and histopathological characterization is still in the evolutionary stage, and its clinicopathological correlations are still being sought out. Its etiology and pathogenesis are as elusive today as they were at the time of its first recognition. [7]

Against this background, the occasional reports that emanate from developing countries are an important contribution to the meager literature on this subject. In this context, the authors of the subject study have performed a commendable job. However, a note of caution is in order. One needs to be extremely careful, scrupulous, precise and accurate in the presentation of such novel and controversial diseases. [7] It is worth repeating here that, in the literature, there are many accounts of supposedly C1qN that differ significantly from the classic description of C1qN by Jennette et al, [3] and doubts have been raised on their diagnostic accuracy. [4] I take this opportunity to draw the attention of the learned authors to the following few omissions in the report:



In the first sentence, it is stated that in C1qN, C1q is a dominant or co-dominant immunoglobulin, which is incorrect. C1q is not an immunoglobulin, but rather a component of the complement system, which binds to immune complexes and initiates the classical pathway of complement activation.The intensity of staining of C1q and the immunoglobulins has not been given. The dominance of C1q has to be clearly substantiated by recording accurately the intensity of staining on immunoflourescence (IF) study.There is also no mention of the degree of mesangial proliferation. The grading of mesangial hypercellularity is fairly reproducible and can be easily applied.Was electron microscopy (EM) examination done in this case? Although not confirmatory, it helps in the diagnosis of C1qN by demonstrating electron-dense deposits in at least two locations within the glomerulus. More importantly, it helps to exclude lupus nephritis (LN) by the absence of tubuloreticular inclusions. [5]There is no information on the follow-up and outcome of the disease. But, I suppose, it is very short as is apparent from abrupt termination of the case description. This is one of the major deficiencies of case reports from this part of the world. It is worth reiterating here that some of the cases of so-called "seronegative lupus nephritis," as some researchers call C1qN, may later turn out to be positive for lupus serology. [5],[8]Last but not the least, it is worth remembering that the firm diagnosis of C1qN requires correlation of clinical, serological, light microscopy, IF, EM and follow-up data. There is no specific feature of C1qN in any of the above tests used for the diagnosis of glomerular diseases in general.

I hope that this critique will be helpful to both the authors for their future work and the readers of your esteemed journal in better understanding the entity of C1qN.

References

1Bhowmik DM, Jain S, Dinda AK, Sharma A, Mahajan S, Agarwal SK. C1q nephropathy presenting as nephritic-nephrotic syndrome. Saudi J Kidney Dis Transpl 2011;22(3):561-3.
2Malleshappa P, Ranganath R, Chaudhary AP, Ayiangar A, Lohitaksha S. C1q nephropathy presenting as acute renal failure. Saudi J Kidney Dis Transpl 2011;22:324-6.
3Jennette JC, Hipp CG. C1q nephropathy: a distinct pathologic entity usually causing nephrotic syndrome. Am J Kidney Dis 1985;6:103-10.
4Iskandar SS, Browning MC, Lorentz WB. C1q nephropathy: a pediatric clinicopathologic study. Am J Kidney Dis 1991;18:459-65.
5Sharman A, Furness P, Feehally J. Distinguishing C1q nephropathy from lupus nephritis. Nephrol Dial Transplant 2004;19:1420-6.
6Wong CS, Fink CA, Baechle J, Harris AA, Staples AO, Brandt JR. C1q nephropathy and minimal change nephrotic syndrome. Pediatr Nephrol 2009;24:761-7.
7Mubarak M. C1q nephropathy presenting as acute renal failure. Saudi J Kidney Dis Transpl 2011;22 (5):1046-7.
8Cairns SA, Acheson EJ, Corbett CL, et al. The delayed appearance of an antinuclear factor and the diagnosis of systemic lupus erythematosus in glomerulonephritis. Postgrad Med J 1979;55:723-7.