PMC5491813_01
The clinical course of the case from admission to the renal biopsy. HDF: hemodiafiltration, HD: hemodialysis, NA: norepinephrine, MEPM: meropenem, VCM: vancomycin, TM: thrombomodulin, PSL: prednisone (with daily oral dosage)
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These treatments resulted in improvement in his general condition and laboratory data, including platelet counts and CRP and bilirubin levels (Fig. 1). Four weeks after starting the treatment, his serum creatinine levels returned to the normal range (Fig. 1).
Renal imaging. a: Computed tomography showed slight bilateral renal swelling. b: 67Ga-citrate scintigraphy demonstrated prominent tracer accumulation in the bilateral kidneys.
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CT showed slight bilateral renal swelling. 67Ga-citrate scintigraphy demonstrated prominent accumulation in the bilateral kidneys (Fig. 2).
Renal histology of biopsy specimens. a, b: Marked mononuclear cell infiltration in the tubules and interstitium on Masson's trichrome stained section. c, d: Hematoxylin and Eosin stainingshowed that almost all of the mononuclear cells were lymphocytes/monocytes. 100x and 400x original magnification, respectively. e, g: Immunohistochemistry for CD68 revealed that many of the inflammatory cells were monocytes/macrophages (long arrows). Further study demonstrated that these macrophages were predominantly HLA-DR-positive M1 phenotype (f, h; arrow heads) versus the CD163-positive M2 phenotype (i; short arrow) on serial sections. 200x and 400x original magnification.
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We also noted tubulitis lesions with marked mononuclear cell infiltration in the tubules and interstitium (Fig. 3a and b). Eosin (H&E) staining, these mononuclear cells were compatible with lymphocytes/monocytes (Fig. 3c and d). Eosinophils and plasma cells were scarcely seen among the mononuclear cells. In the section containing marked inflammatory infiltration in the renal interstitium, immunohistochemistry demonstrated that some of the mononuclear cells were positive for CD68 antigen, which is a marker for monocytes/macrophages (Fig. 3e). HLA-DR (M1 antigen) and CD163 (M2 antigen). HLA-DR-positive mononuclear cells representing M1 macrophages obviously predominated in the renal interstitium (Fig. 3f) compared with CD163-positive M2 macrophages, as shown on the serial sections under high magnification (Fig. 3g-i).