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

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