Document 0557
 DOCN  M9550557
 TI    [Pathogenesis, immunobiology and epidemiology of cryptococcosis]
 DT    9505
 AU    Muller J; Sektion Mykologie, Institut fur Medizinische Mikrobiologie
       und; Hygiene, Universitat Freiburg.
 SO    Mycoses. 1994;37 Suppl 1:34-42. Unique Identifier : AIDSLINE
       MED/95157576
 AB    Cryptococcus neoformans is taken up by the human host via the
       respiratory tract. The polysaccharide capsule is regarded as the
       pathogenetic principle inhibiting phagocytosis of the fungus by cells of
       the unspecific host defense. Unspecific opsonization of Cr. n. by early
       phase proteins causes a rapid and successful elimination in the
       non-compromised host. In case of non-elimination the presence of Cr. n.
       capsule antigen in excess results in a downregulation of antibody
       formation thereby inhibiting specific opsonization. Furthermore the
       blockade of specific T cells and cytotoxic cells by means of free
       antigen and/or immunocomplexes causes a downregulation of the cellular
       immunity: Cr. n. antigens of different character induce T suppressor
       cells inhibiting cellular immunity via a cascade of effector cells and
       soluble factors. The AIDS patient enters cryptococcosis in a state
       comparable to a Cr. n.-infected non-AIDS patient whose cellular immunity
       is already downregulated by this mycosis itself. Both phenomena--the
       mycosis-induced downregulation of cellular immunity as well as the
       AIDS-specific lack of CD4 helper cells and its consequences--act,
       therefore, synergistically in the same pathogenetic direction. This
       explains the fulminant development and sequel of cryptococcosis typical
       with AIDS patients. Most probably each exposition of an AIDS patient to
       Cr. n. results in clinically manifest cryptococcosis. The frequence of
       cryptococcosis in AIDS is, therefore, reflecting the general exposure of
       humans to Cr. n. in a given region. Cryptococcosis in AIDS is at least
       about 1000x more frequent than cryptococcosis in non-AIDS
       individuals.(ABSTRACT TRUNCATED AT 250 WORDS)
 DE    Antibodies, Fungal/BLOOD  AIDS-Related Opportunistic
       Infections/EPIDEMIOLOGY/IMMUNOLOGY/  *MICROBIOLOGY
       Cryptococcosis/EPIDEMIOLOGY/IMMUNOLOGY/*MICROBIOLOGY  Cryptococcus
       neoformans/IMMUNOLOGY/*PHYSIOLOGY  English Abstract  Human  Immunity,
       Cellular  Incidence  Opsonins  JOURNAL ARTICLE  REVIEW  REVIEW, TUTORIAL

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).