Pauci-immune Crescentic Glomerulonephritis in a Patient With Immunoglobulin A Nephropathy and Serum Antineutrophil Cytoplasmic Autoantibody Positivity.
A 65-year-old male patient was referred for evaluation of a serum creatinine of 1.32 mg/dL. Antinuclear antibodies were positive in a low titer (1:40) and perinuclear ANCA tested positive on indirect immunofluorescence at a titer of 1:160. Anti-myeloperoxidase antibodies measured 108 units (normal range 0-20) by enzyme-linked immunosorbent assay. Urinalysis showed hematuria and proteinuria (652 mg/24-hour). Renal biopsy showed mild focal glomerular mesangial expansion. There were no crescents or evidence of vasculitis. On immunofluorescence, there was moderately intense staining for IgA in the mesangium (Figure 1a). These findings were consistent with the diagnosis of IgAN. The patient was administered a six-month course of steroids. This, however, resulted in no improvement in his proteinuria or glomerular filtration rate.
Over the following four years, a progressive increase in serum creatinine was noted, initially at a slow rate (1.32 mg/dL to 1.63 mg/dL) over two years and then at an accelerated pace (1.82 mg/dL to a peak 6.5 mg/dL) over six months. Proteinuria at this stage was 6897 mg/24-hour. A repeat renal biopsy was performed. This time, there were 14 glomeruli of which 10 (71.4%) had a cellular crescent (Figure 1b). Immunofluorescence for IgG, IgM, IgA, and complement components 3 and 4 were negative.
With the diagnosis of a perinuclear ANCA associated pauci-immune crescentic glomerulonephritis, the patient was administered steroids and intravenous cyclophosphamide. On this treatment, serum creatinine declined to his current 3.05 mg/dL. In parallel, perinuclear ANCA at this stage was found to be negative.
Despite the common prevalence of both IgAN and AAV as separate entities, their co-existence is rare. In fact, to our knowledge, no more than 50 cases of co-existing IgAN and ANCA serum positivity have been described thus far. These consist mainly of case reports and three case series. (2-4) Haas et al. (2) reported six patients with more than 50% crescents of glomeruli. The histological features and clinical response to aggressive immunosuppressive treatment resembled AAV. In a retrospective study of 393 patients with biopsy proven IgAN, Bantis et al. (3) found eight with ANCA positivity (five antimyeloperoxidase and three anti-proteinase 3). They were compared to 26 IgAN patients with negative ANCA and >10% crescentic glomeruli. Similar to Haas et al.'s series, (2) those with ANCA positivity were characterized by a more severe clinical course and histological lesions but a better response to therapy. Similar conclusions were also reached by Yang et al., (4) who compared 20 ANCA positive IgAN patients to 40 ANCA negative IgAN patients and 40 AAV patients.
Whether the association of IgAN with ANCA positivity is coincidental or representative of a novel entity remains an open question. Elevated levels of serum tumor necrosis factor, soluble forms of intercellular adhesion molecule 1 and urinary interleukin-8 have been documented in the deteriorating phase of IgAN. Potentially, these could lead to activation of polyclonal B cells and the formation of ANCA. (5) Interestingly, the pauci-immune glomerulonephritis demonstrated in our patient's second biopsy was devoid of IgA deposits. IgAN is usually typified by lifelong persistence of IgA deposits. Regression of these deposits has, however, been reported in IgAN presenting with a nephrotic syndrome after steroid induced remission. (6) One possible explanation for the disappearance of the IgA deposits is their degradation by enzymes provoked by the immune response to ANCA. (4) In conclusion, the coexistence of IgAN and AAV is rare and should be treated as AAV.
Declaration of conflicting interests
The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.
The authors received no financial support for the research and/or authorship of this article.
(1.) Tumlin JA, Madaio MP, Hennigar R. Idiopathic IgA nephropathy: pathogenesis, histopathology, and therapeutic options. Clin J Am Soc Nephrol 2007;2:1054-61.
(2.) Haas M, Jafri J, Bartosh SM, Karp SL, Adler SG, Meehan SM. ANCA-associated crescentic glomerulonephritis with mesangial IgA deposits. Am J Kidney Dis 2000;36:709-18.
(3.) Bantis C, Stangou M, Schlaugat C, Alexopoulos E, Pantzaki A, Memmos D, et al. Is presence of ANCA in crescentic IgA nephropathy a coincidence or novel clinical entity? A case series. Am J Kidney Dis 2010;55:259-68.
(4.) Yang YZ, Shi SF, Chen YQ, Chen M, Yang YH, Xie XF, et al. Clinical features of IgA nephropathy with serum ANCA positivity: a retrospective case-control study. Clin Kidney J 2015;8:482-8.
(5.) Shimizu M, Wada T, Sakai N, Izumiya Y, Furuichi K, Misaki T, et al. Clinicopathological features of antineutrophil cytoplasmic antibodies associated vasculitis in Japanese patients with IgA nephropathy. Clin Exp Nephrol 2000;4:251-6.
(6.) Cheng IK, Chan KW, Chan MK. Mesangial IgA nephropathy with steroid-responsive nephrotic syndrome: disappearance of mesangial IgA deposits following steroid-induced remission. Am J Kidney Dis 1989;14:361-4.
Keren COHEN-HAGAI,  Sydney BENCHETRIT,  Osnat KLEIN,  Yona KITAY-COHEN,  Ze'ev KORZETS 
 Department of Nephrology, Meir Medical Center, Kfar Saba, Israel
 Departmert of Internal Medicine C, Meir Medical Center, Kfar Saba, Israel
Received: May 07, 2017 Accepted: May 09, 2017 Published online: September 13, 2017
Correspondence: Ze'ev Korzets, MD. Departmert of Internal Medicine C, Meir Medical Center, 44281 Kfar Saba, Israel. Tel: 97297472517 e-mail: firstname.lastname@example.org
Caption: Figure 1. (a) Immunofluorescence of kidney biopsy demonstrating a moderately intense staining for immunoglobulin A in mesangium. (b) Periodic acid-Schiff staining demonstrating cellular crescents in two glomeruli and inflammatory infiltrate in surrounding interstitium.
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|Author:||Cohen-Hagai, Keren; Benchetrit, Sydney; Klein, Osnat; Kitay-Cohen, Yona; Korzets, Ze'ev|
|Publication:||Turkish Journal of Rheumatology|
|Article Type:||Letter to the editor|
|Date:||Mar 1, 2018|
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