A Case of Polymyositis Associated with Immunoglobulin A Nephropathy

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1 pissn: X, eissn: Journal of Rheumatic Diseases Vol. 24, No. 4, August, Case Report A Case of Polymyositis Associated with Immunoglobulin A Nephropathy Yoon-Jeong Oh 1, Eun Sung Park 1, Mi Jang 2, Ea Wha Kang 3, Jeong-Hae Kie 4, Sang-Won Lee 1, Jason Jungsik Song 1, Yong-Beom Park 1, Chan-Hee Lee 5, Jin-Su Park 5 1 Division of Rheumatology, Department of Internal Medicine, Yonsei University College of Medicine, 2 Department of Pathology, Yonsei University College of Medicine, Seoul, 3 Division of Nephrology, Department of Internal Medicine, National Health Insurance Service Ilsan Hospital, 4 Department of Pathology, National Health Insurance Service Ilsan Hospital, 5 Division of Rheumatology, Department of Internal Medicine, National Health Insurance Service Ilsan Hospital, Goyang, Korea Polymyositis (PM) is a chronic inflammatory disease that predominantly affects muscles. Systemic organ involvement, including the respiratory and gastrointestinal tracts, is frequently observed in PM, but renal involvement is rare. Herein, we report the case of a 56-year-old woman presenting with weight gain, edema, and generalized myalgia. Laboratory tests revealed elevated creatinine kinase level, hypoalbuminemia, and proteinuria. Histopathological examination of muscle biopsy revealed inflammatory myositis, and a renal biopsy confirmed immunoglobulin A (IgA) nephropathy. Based on the clinico-pathological results, the patient was diagnosed with PM with IgA nephropathy. This is a report of a rare occurrence of IgA nephropathy in a patient with PM presenting with chronic glomerulonephritis. (J Rheum Dis 2017;24: ) Key Words. Polymyositis, IgA nephropathy, Proteinuria INTRODUCTION Polymyositis (PM) is a chronic autoimmune inflammatory disease with a progressive course mostly involving muscles. It is characterized by symmetrical proximal muscle weakness, elevation of muscle-enzymes levels, characteristic electromyographic (EMG) features, and specific histopathological findings in a muscle biopsy specimen. Systemic organ involvement, including the respiratory and gastrointestinal tracts, is frequently observed in PM, but renal involvement in patients with idiopathic inflammatory myopathies is rare. We report the case of a patient with PM, who was diagnosed with immunoglobulin A (IgA) nephropathy while being evaluated for the cause of persistent proteinuria. To our knowledge, this is the first case to be reported in Korea and the second in the world. CASE REPORT A 56-year-old woman was admitted for a 1-month history of pruritus, weight gain (3 kg over a month), generalized myalgia, anorexia, and Raynaud s phenomenon. Typical skin lesions were absent. Physical examination showed grade II bilateral pretibial pitting edema and grade IV muscle strength in the proximal muscles of all limbs. Laboratory test results with their corresponding reference ranges were as follows: serum creatine kinase (CK), 8,493 ( IU/L); lactate dehydrogenase, 653 ( IU/L); aldolase, 90.1 (<7.6 U/L); aspartate aminotransferase, 246 (0 37 IU/L); alanine aminotransferase, 190 (0 48 IU/L); C-reactive protein, 5.30 (<1.00 mg/dl); erythrocyte sedimentation rate, 62 (<20 mm/hr); serum albumin, 2.5 ( g/dl); and serum creatinine, 0.8 ( mg/dl). Urinalysis revealed 2+ protein, 2+ red blood cells, spot urine protein-to-crea- Received:October 3, 2016, Revised:January 2, 2017, Accepted:March 16, 2017 Corresponding to:jin-su Park, Division of Rheumatology, Department of Internal Medicine, National Health Insurance Service Ilsan Hospital, 100, Ilsan-ro, Ilsandong-gu, Goyang 10444, Korea. jinsulog@naver.com Copyright c 2017 by The Korean College of Rheumatology. All rights reserved. This is a Open Access article, which permits unrestricted non-commerical use, distribution, and reproduction in any medium, provided the original work is properly cited. 241

2 Yoon-Jeong Oh et al. tinine ratio (PCR) of 2,066.9 mg/g and urine albumin-to-creatinine ratio (ACR) of 81.1 mg/g. Anti Jo-1, anti-double stranded DNA, anti-ribonucleoprotein, anti SS-A(Ro), anti SS-B(La), anti-histone, anti-smith, anti-cardiolipin IgM/IgG, and anti-beta 2 glycoprotein IgM/IgG antibodies were all absent, except for antinuclear antibody (1:320 positive, speckled pattern). Serum complement and immunoglobulin G, A, and M levels were within normal limits. EMG showed low amplitude polyphasic motor potentials of short duration in the upper and lower proximal muscles. Examination of the biopsy specimen from the left vastus lateralis revealed myopathic changes associated with inflammatory cell infiltrates (Figure 1), and immunofluorescence of the renal biopsy showed diffuse deposition of IgA in the mesangium, suggestive of IgA nephropathy (Figure 2). The following biochemical parameters were elevated: CK, up to 11,312 IU/L; serum aldolase, up to U/L; spot urine PCR, up to 4,345.5 mg/g and spot urine ACR, up to mg/g. Administration of 60 mg oral prednisolone daily was initiated under the presumptive diagnosis of PM, according to the criteria of Bohan and Peter [1]. However, the severity of proximal muscle weakness was aggravated from grade IV to II. Muscle weakness deteriorated despite administrating methylprednisolone (3 doses of 1 g daily each) and cyclophosphamide pulse therapies. Intravenous immunoglobulin was administered at a dose of 2 g/kg for 5 days. Thereafter, the patient s proximal muscle strength gradually improved from grade Figure 1. Muscle biopsy. (A) Light microgram of a muscle biopsy specimen (H&E, 40). (B) Light microgram showing inflammatory cell infiltrates (black arrows) scattered throughout the endomysium, invading individual muscle fibers (H&E, 200). (C) On immunohistochemistry, the inflammatory cells express leukocyte common antigen (black arrows) (Immunohistochemistry, 200). (D) Anti CD 68 staining of the muscle biopsy specimen (Immunohistochemistry, 200). 242 J Rheum Dis Vol. 24, No. 4, August, 2017

3 Polymyositis Associated with IgA Nephropathy Figure 2. Renal biopsy. (A) Light microgram showing mild mesangial expansion (black arrows) without cellular proliferation (Periodic acid Schiff, 400). (B) Some glomeruli showed segmental sclerotic change and synechia with Bowman s capsule (PAS-silver stain, 400). (C) Immunofluorescence staining revealed moderate positivity for IgA on the mesangium and paramesangium (Immunofluorescence staining, 400). (D) Electron microgram demonstrating deposits in the mesangium and paramesangium (Uranyl acetate, 6,000). II to IV and the CK level decreased to 780 IU/L. Malignancy workup to identify the cause of the rapid aggravation of PM revealed a 1.1 cm thyroid papillary carcinoma for which the patient underwent total thyroidectomy. CK level and PCR rapidly decreased to 300 IU/L and 60.1 mg/g, respectively, after surgery. The patient was maintained on oral prednisolone therapy. Up to 6 months after total thyroidectomy, disease activity of PM was well controlled and microscopic hematuria/proteinuria was not observed, even with low dose steroids alone. DISCUSSION PM not only affects muscles but also involves systemic organs. However, unlike respiratory and gastrointestinal tract involvement, renal involvement is infrequent in PM in comparison to other autoimmune diseases [2,3]. Acute kidney injury secondary to rhabdomyolysis and PM-associated glomerulonephritis are reported as the 2 chief renal signs of PM [4,5]. Otherwise, PM-associated IgA nephropathy is relatively uncommon. The histopathological features of PM include myofiber injury caused by macrophages and activated CD8+ cytotoxic T cells that attack non-necrotic muscle fibers expressing class I major histocompatibility complex (MHC-I) [6-8]. Patients with IgA nephropathy are reported to be relatively deficient in suppressor T-cell activity and to have hyperactive IgA-specific helper T-cell [9]. Although 243

4 Yoon-Jeong Oh et al. cellular immunity is the main player in PM, humoral immunity may also be involved via the production of IgG that reacts with IgA, causing IgA nephropathy. The pathophysiological mechanisms linking IgA nephropathy to PM remain unknown [10]. IgA nephropathy is a primary glomerulonephritis characterized by IgA deposition in the glomerular mesangia Most patients with IgA nephropathy have primary disease, but a secondary form is frequently reported with liver disease, inflammatory bowel disease and connective tissue disorders [11]. Very little is known about the incidence of secondary IgA nephropathy compared to that of primary IgA nephropathy. Moreover, the specific interrelations between autoimmune status, regulation of IgA synthesis, and development of IgA nephropathy remain uncertain. The lack of renal biopsy result after improvement of the underlying autoimmune disease, due to the patient s refusal to repeat it, was a limitation in this report. Determining whether the cause was primary or secondary to other diseases such as autoimmune disease was very challenging. Moreover, a repeat renal biopsy would not discriminate between primary and secondary IgA nephropathy. Although our patient showed hypoalbuminemia with nephrotic range proteinuria and was diagnosed with IgA nephropathy, the proteinuria might have been of non-glomerular origin because urinary albumin to total protein concentration ratio was 0.4. Since most patients with IgA nephropathy have isolated hematuria or hematuria with glomerular proteinuria, the non-glomerular proteinuria in this case suggests secondary IgA nephropathy, or incidental IgA nephropathy combined with PM. Furthermore, the decrease in CK level and resolution of hematuria after treatment of PM indicate the secondary nature of IgA nephropathy. Our patient was found to have thyroid cancer shortly after being diagnosed with PM. The relationship between inflammatory myopathy and malignancy has been well known since PM associated with stomach cancer was first report by Stertz in 1916 [12]. Further studies suggest that cancer and myositis have common autoantigens such as Mi-2, HRS, DNA-PKc [13]. However, the presence of these antibodies was not checked in this patient because most of them are not used clinically. Based on the timing of muscle weakness onset, worsening pattern of PM despite methylprednisolone pulse therapy, and dramatic decrease in disease activity after total thyroidectomy [13], PM in this case was more likely to be a paraneoplastic syndrome secondary to thyroid cancer. To the best of our knowledge, this is the first case of idiopathic inflammatory myopathy, particularly PM, diagnosed with IgA nephropathy to be reported in Korea, and the second worldwide [14]. SUMMARY Renal involvement makes the poor prognosis in many autoimmune diseases. Renal biopsy is important for diagnosis in patients with worsening renal function or increasing proteinuria. Our findings suggest that IgA nephropathy secondary to PM may cause proteinuria; therefore, renal biopsy should be considered in patients with myositis presenting with proteinuria. CONFLICT OF INTEREST No potential conflict of interest relevant to this article was reported. REFERENCES 1. Bohan A, Peter JB. Polymyositis and dermatomyositis (first of two parts). N Engl J Med 1975;292: Takizawa Y, Kanda H, Sato K, Kawahata K, Yamaguchi A, Uozaki H, et al. Polymyositis associated with focal mesangial proliferative glomerulonephritis with depositions of immune complexes. Clin Rheumatol 2007;26: Cucchiari D, Angelini C. Renal involvement in idiopathic inflammatory myopathies. Clin Rev Allergy Immunol 2017;52: Wu Y, Chhaya S, Hurowitz B, Ardiles T, Carlson R. Clinically amyopathic dermatomyositis complicated by pleural effusion case report, literature review, and proposed mechanism. Bull Hosp Jt Dis (2013) 2015;73: Qian Y, Ren H, Zhang W, Chen N. Clinical features of polymyositis and dermatomyositis in four patients with renal involvement as mainly presentation. Zhonghua Nei Ke Za Zhi 2009;48: Nickavar A, Mehr Azma M. Nephrotic syndrome and juvenile dermatomyositis. Rheumatol Int 2012;32: Findlay AR, Goyal NA, Mozaffar T. An overview of polymyositis and dermatomyositis. Muscle Nerve 2015;51: Couvrat-Desvergnes G, Masseau A, Benveniste O, Bruel A, Hervier B, Mussini JM, et al. The spectrum of renal involvement in patients with inflammatory myopathies. Medicine (Baltimore) 2014;93: Shin DH, Lim BJ, Han IM, Han SG, Kwon YE, Park KS, et al. Glomerular IgG deposition predicts renal outcome in patients with IgA nephropathy. Mod Pathol 2016;29: Civilibal M, Selcuk Duru N, Ozagari A, Durali K, Elevli M. Immunoglobulin A nephropathy associated with juvenile dermatomyositis. Pediatr Nephrol 2009;24: Pouria S, Barratt J. Secondary IgA nephropathy. Semin Nephrol 2008;28: J Rheum Dis Vol. 24, No. 4, August, 2017

5 Polymyositis Associated with IgA Nephropathy 12. Stertz G. Polymyositis. Berl Klin Wochenschr 1916;53: Levine SM. Cancer and myositis: new insights into an old association. Curr Opin Rheumatol 2006;18: Barros TB, de Souza FH, Malheiros DM, Levy-Neto M, Shinjo SK. IgA nephropathy and polymyositis: a rare association. Rev Bras Reumatol 2014;54: