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Abstract: SA-PO361

An Unusual Case of Diffuse Proliferative Lupus Nephritis Presenting with Predominant C1q Deposition and No IgG Deposits That Is Responsive to Treatment

Session Information

Category: Trainee Case Report

  • 102 AKI: Clinical, Outcomes, and Trials

Authors

  • Kareem, Samer, Westchester Medical Center, Valhalla, New York, United States
  • Pandav, Jay A., Westchester Medical Center, Valhalla, New York, United States
  • Connery, Michael, Westchester Medical Center, Valhalla, New York, United States
  • Gupta, Sanjeev, Westchester county medical center, Hartsdale, New York, United States
Introduction

Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease, with nephritis as one of the most striking manifestations. Renal biopsy usually reveals glomerular deposits that stain predominantly for IgG and contain co-deposits of IgA, IgM, and C3. It is rare to have C1q as a dominant deposit with no IgG deposits on renal biopsy. We are presenting a case of lupus nephritis with predominant C1q deposits.

Case Description

34-years-old female with history of idiopathic thrombocytopenia (10 years ago), SLE (1 year ago), antiphospholipid syndrome with history of stroke and one 2nd trimester miscarriage admitted with dyspnea, fever and AKI and suspicion of thrombotic thrombocytopenic purpura. Laboratory work up showed serum creatinine (SCr) of 2.13mg/dl, low complements C3/C4, positive cardiolipin IgM, anti-dsDNA and lupus anticoagulant. UA was positive for 2+ blood and 3+ protein with urine protein to creatinine ratio of 3.2. Echocardiogram was suggestive of libman sachs endocarditis. Patient underwent kidney biopsy which revealed endocapillary proliferative GN (class IV lupus). It was negative for IgG but had 3+ C1q deposits, 2+ C3, 1+ IgA and trace IgM deposits. The patient was started on methylprednisone & mycophenolate and within a month her SCr returned to baseline with complete resolution of proteinuria and hematuria.

Discussion

C1q nephropathy is considered to be a variant of FSGS. It presents as mesangial proliferation with prominent C1q deposits on immunofluorescence microscopy and negative lupus serology. It typically has a poor response with immunosuppression. On the contrary, lupus nephritis presents as a ‘full house pattern’ with predominant IgG deposits. Our patient with predominant capillary and mesangial C1q deposits in lupus nephritis hasn’t been described in the literature hence clinician needs to be aware that C1q deposits can be a variant of lupus nephritis and can be very responsive to immunosuppression.