SAT-411 Anti nuclear Antibody negative Lupus like Nephritis. A 5 case series report

Abstract

Systemic lupus erythematosus (SLE) is a disease due to an autoantibody response to nuclear and cytoplasmic antigen which is associated with the inflammatory cascades and end-organ damage in multiple organs like kidney, skin, brain, etc. In the kidney, immune-complex deposits leads to the deterioration of renal function leading to a condition called lupus nephritis. Lupus nephritis is a common but serious complication in SLE patients. Previously, American College of Rheumatology (ACR) required at least 4 of 11 clinical or laboratory criteria to diagnose SLE which included malar rash, discoid rash, photosensitivity, oral ulcers, nonerosive arthritis, pleuritis or pericarditis, kidney disorder, neurological disorder, hematologic disorder and positive antinuclear antibody. In 2019, there has been an update in this criteria, where positive antinuclear antibody is given as entry level criterion. If negative, cases cannot be classified as Systemic lupus erythematosus. If positive, further accumulation of 10 points is required for diagnosis of SLE. Lupus-like glomerulonephritis is defined as immune complex kidney disease with full house pattern in glomeruli where immunofluorescence staining for immunoglobulin G (IgG), IgA, IgM, complement (C3), and C1q are positive in an ANA negative patients. This findings is otherwise described as diagnostic criteria for lupus nephritis in SLE patients. Extraglomerular immune deposits within tubular basement membranes and tubuloreticular inclusions are other characteristic features that can be found in lupus nephritis. A total of 5 cases of ANA negative lupus like nephritis were reported in the department of renal pathology in University of Alberta between 1st January 2019 to 30th September, 2019. All of our cases were positive (IgG, IgA, IgM, C3, C1q) in immunofluorescence and were described as full house pattern. In light microscopy, 2 of the cases correlated with stage IV lupus nephritis, 2 correlated with stage V lupus nephritis and 1 case correlated with stage I lupus nephritis. Tubuloreticular inclusions were present in the one of the case. All patients responded to prednisolone as suggested by follow up laboratory datas.Table 1Variations in parameters among five cases.Case 1Case 2Case 3Case 4Case 5Age/sex62y/f56y/f24y/m42y/m7y/fANANegativeNegativeNegativeNegativeNegativedsDNANegative (positive after 2 month borderline 127 <120MFU)NegativeNegativeNegativeNegativeProtein creatinine ratio (PCR)306.3553.9(Normal <13.0 mg/mmol)238.57439.33975.52Urine Hemoglobin2+1+3+1+1+Serum. Creatinine121 (40-100 µmol/L)84 (40-100 µmol/L)106 (50-120 µmol/L)146 (50-120 µmol/L)29 (20-75 µmol/L)HematologyNormalNormalNormalNormalNormalLupus Nephritis gradeIVIIVVV Open table in a new tab In ANA negative patients, immune complex mediated glomerulonephritis with full house immunofluorescence pattern may be considered as lupus like glomerulonephritis. Other features like tubuloreticular inclusions, DsDNA might be positive in these patients. These patients present and response to treatment like renal limited lupus nephritis. They may develop full blown SLE in long term; hence close follow up is required. However, other causes of immune complex mediated glomerulonephritis must be ruled out before considering this diagnosis.