Myeloperoxidase expression by histiocytes in Kikuchi's and Kikuchi-like lymphadenopathy.
Forty-five examples of Kikuchi's lymphadenitis (KL), 5 Kikuchi-like lupus erythematosus lymphadenopathies, 25 nonnecrotizing lymphadenitidies (5 toxoplasmic, 5 sarcoid-like, 6 dermatopathic, 4 suppurative, 3 tubercular, 2 with sinus histiocytosis), 4 examples of hyaline-vascular Castleman disease (CD), 2 plasmacytoid monocyte tumors (PM-Ts), and 61 accessory cell neoplasms were studied by a panel of antibodies, including the PG-M1 (against a macrophage-restricted CD68 epitope) and a polyclonal anti-myeloperoxidase (MPO). In KL and Kikuchi-like lupus erythematosus lymphadenopathies, 25 to 75% of CD68(+) histiocytes co-expressed MPO. This did not occur in nonnecrotizing lymphadenitidies and accessory cell neoplasms. MPO(+)/CD68(+) elements corresponded to nonphagocytosing mononuclear cells and some crescentic macrophages and phagocytosing histiocytes. Typical PMs were MPO(-)/CD68(+) in all cases, including CD and PM-T. Our observations suggest that in KL and KL-like lymphadenopathies: 1) MPO(+)/CD68(+) blood monocytes might be attracted into tissues because of the lack or paucity of granulocytes and the need of MPO for oxidative processes; 2) PMs are more likely to be involved in the cytotoxic immune reaction than in phagocytic phenomena; 3) the peculiar phenotype of the histiocytic component can be usefully used for the differentiation from malignant lymphoma and PM-T.
Pileri
S A
SA
Pathology and Clinical Units, Institute of Hematology and Clinical Oncology L. & A. Seràgnoli, Bologna University, Bologna, Italy. pileri@almadns.unibo.it
Facchetti
F
F
Ascani
S
S
Sabattini
E
E
Poggi
S
S
Piccioli
M
M
Rondelli
D
D
Vergoni
F
F
Zinzani
P L
PL
Piccaluga
P P
PP
Falini
B
B
Isaacson
P G
PG
D000293:Adolescent; D000328:Adult; D002469:Cell Separation; D005260:Female; D005434:Flow Cytometry; D006644:Histiocytes / Q000378:metabolism* / Q000473:pathology; D020042:Histiocytic Necrotizing Lymphadenitis / Q000201:enzymology* / Q000473:pathology; D006801:Humans; D008206:Lymphatic Diseases / Q000201:enzymology* / Q000473:pathology; D008221:Lymphoid Tissue / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009195:Peroxidase / Q000378:metabolism*; D012016:Reference Values
D009195:Peroxidase