Placental malaria is associated with cell-mediated inflammatory responses with selective absence of natural killer cells.
Immunosuppression, particularly of cell-mediated responses, has classically been thought to play a major role in the increased susceptibility to malaria observed in pregnant women. An immunohistochemical characterization of the inflammatory infiltrate in a group of 41 placentas from women living in a Plasmodium falciparum-hyperendemic area in Tanzania revealed a marked increase in the number of monocytes and macrophages and cytotoxic T cells in the intervillous space of placentas with active malaria infection, compared with noninfected placentas, placentas from women with past infection, and a control group of placentas from Spain. This increase was associated with the severity of the infection. High numbers of monocytes and macrophages were associated with low birth weight. We also detected a complete absence of NK cells in the intervillous space in all placentas. This apparently physiological absence of NK cells may contribute to hindering the clearance of the parasite. These results indicate that placental malaria does not appear to be associated with cell-mediated immunosuppression. The role of the absence of NK cells in increased susceptibility to malaria needs to be further elucidated.
Department of Pathology, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS)/Hospital Clínic, Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain. ordi@medicina.ub.es
J
J
Ordi
C
C
Menendez
M R
MR
Ismail
P J
PJ
Ventura
A
A
Palacín
E
E
Kahigwa
B
B
Ferrer
A
A
Cardesa
P L
PL
Alonso
D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D019002:CD56 Antigen / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D018450:Disease Progression; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D016778:Malaria, Falciparum / Q000276:immunology* / Q000469:parasitology; D009000:Monocytes / Q000276:immunology; D010298:Parity; D010920:Placenta / Q000276:immunology* / Q000469:parasitology; D010963:Plasmodium falciparum; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000276:immunology* / Q000469:parasitology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D000097382:CD68 Molecule
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D019002:CD56 Antigen; D016827:CD8 Antigens; C067980:CD68 antigen, human; D000097382:CD68 Molecule