The patient was a 29-year-old Japanese woman. She had been experiencing a high fever for 2 weeks. In another hospital, she was diagnosed with SLE due to pancytopenia, abnormal urinalysis (proteinuria and hematuria), low complement, positive antinuclear antibody, and anti-dsDNA antibody. In addition, she had multiple small granular lesions in the lungs appearing like miliary tuberculosis (TB) on computed tomography (Fig. 1a). Therefore, she was transferred to the TB ward of our hospital. On physical examination, her height was 160.5 cm and her body weight was 58.8 kg. She had a temperature of 38.8 C. Her blood pressure was normal at 111/77 mm Hg. Oral ulcers and a discoid rash were observed. There was slight edema in the lower extremities. The laboratory tests showed a slightly elevated serum creatinine of 0.91 mg/dL, a normal total cholesterol of 122 mg/dL, a C-reactive protein of 0.57 mg/dL, proteinuria of 5.1 g per day, and microhematuria. On serological testing, antinuclear antibody was positive, the anti-dsDNA antibody titer was very high at 400 IU/mL, and serum C3 and C4 were very low at 26.4 and 4.3 mg/dL, respectively. Anti-neutrophil cytoplasmic antibody was not detected. While awaiting the TB test results, she was isolated in a private room in consultation with the pulmonologist. On day 4, her fever persisted, and laboratory tests revealed progression of pancytopenia. It was thought to be highly likely that she had hemophagocytic syndrome. Thus, we determined that this situation was emergent and initiated intravenous prednisolone (PSL) 60 mg daily. After treatment, she immediately became afebrile. Five days after treatment, we changed from intravenous PSL 60 mg to oral PSL 50 mg daily. After improvement in her general condition, we performed a kidney biopsy 7 days after the start of the initial treatment. The kidney biopsy results are shown in Figure 2. Two cores of kidney tissue containing 55 glomeruli were present, none of which were globally sclerosed. Most of the glomeruli showed multiple wire loop lesions and endocapillary proliferation. The wire loop lesions were more conspicuous than endocapillary proliferation (Fig. 2a). Crescent formation, necrosis, or glomerular sclerosis were not present. In addition, vasculopathy was not present. Immunofluorescence staining demonstrated positive staining of the glomerular tuft, mesangial area, and part of the endothelial area for IgG, IgA, IgM, C3, C1q, and fibrinogen (Fig. 2b). On electron microscopy, the glomeruli revealed massive electron-dense deposits in the endothelial and mesangial areas, but no noticeable subepithelial deposition (Fig. 2c). In addition, electron-dense deposit was present in the peritubular capillaries, but not in the tubulointerstitial area or arteries (Fig. 2d). The histological diagnosis was LN with massive wire loop lesions, ISN/RPS class IV-G (A). We did not add immunosuppressants such as cyclophosphamide or mycophenolate mofetil because we considered that LN would respond well to PSL alone. Her proteinuria and hematuria almost disappeared within 1 month. Furthermore, her lung disease disappeared after immunosuppressive therapy (Fig. 1b). In addition, we did not detect Mycobacterium tuberculosis from the sputum, gastric fluid, or bone marrow. After that, she remained in complete remission for several years using low-dose PSL only.
Multiple small granular lesions (arrow) in the lungs on computed tomography before.