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1996-03-09
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Document 0108
DOCN M9650108
TI Pregnancy, immunosuppression and reactivation of latent toxoplasmosis.
DT 9605
AU Biedermann K; Flepp M; Fierz W; Joller-Jemelka H; Kleihues P; Department
of Gynecology and Obstetrics, University Hospital of; Zurich,
Switzerland.
SO J Perinat Med. 1995;23(3):191-203. Unique Identifier : AIDSLINE
MED/96026972
AB Toxoplasmosis is a chronic, latent infection which can be reactivated in
the presence of immunosuppression. The critical question in obstetrics
is whether toxoplasmosis may be reactivated in the presence of the
physiological immunosuppression of pregnancy. Standard in vitro tests,
done in 24 healthy pregnant women and compared with the literature, show
no significant changes in humoral and cellular immunity during
pregnancy. However, the fact that some infections occur more frequently
and more severely than in non-pregnant women (e.g. those due to
cytomegalovirus (CMV) and human papilloma virus (HPV) points to a degree
of pregnancy-associated immunosuppression. Non-rejection of the
semiallogenic fetus is achieved in presence of maternal immunocompetence
and is explained mainly by local changes in immune function, mediated by
inhibitors of decidual, placental and fetal origin, and by the absence
of class II histocompatibility antigens at the fetomaternal interface.
Immune status allowing reactivation of toxoplasmosis was studied in a
selected group of (predominantly male) AIDS patients from the Swiss HIV
Cohort study. Shortly before (cerebral) reactivation of toxoplasmosis,
92% of these patients had very low CD4 lymphocyte counts (mean 50
cells/microliters, i.e. lower than ever recorded in a normal
uncomplicated pregnancy). In a larger population of 48 women receiving
immunosuppressive therapy after organ transplantation, not a single case
of cerebral toxoplasmosis was observed during pregnancy, while in the
105 HIV-positive women in the Swiss HIV and Pregnancy study, there was
only one case of cerebral toxoplasmosis during pregnancy and the
puerperium (20 CD4/microliters), even though some 17% of those sampled
(18/105) had CD4 levels below 200 cells/microliters on at least one
occasion during pregnancy. These findings explain why latent
toxoplasmosis is not reactivated in normal pregnancy, and why it is only
likely in an immunosuppressed mother when her CD4 lymphocyte count is
very low (< 200 cells/microliters). In such cases, a prophylactic
treatment to prevent maternal reactivation and vertical transmission of
toxoplasmosis may be useful.
DE Adjuvants, Immunologic/PHARMACOLOGY Adult Antibody Formation
Antigens, CD4/ANALYSIS AIDS-Related Opportunistic Infections/IMMUNOLOGY
Cell Division Cohort Studies Disease Transmission, Vertical Female
Human HIV Infections/COMPLICATIONS/IMMUNOLOGY *Immune Tolerance
Immunity, Cellular Killer Cells, Natural/IMMUNOLOGY/PATHOLOGY Male
Pregnancy Pregnancy Complications, Parasitic/*IMMUNOLOGY Recurrence
T-Lymphocytes/CHEMISTRY/IMMUNOLOGY/PHYSIOLOGY
Toxoplasmosis/COMPLICATIONS/*IMMUNOLOGY/*TRANSMISSION
Trophoblast/IMMUNOLOGY JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).