Dear Colleagues,
Good new for people involved in the Immunology of schistosomiasis mansoni,
with the 'official' launching of a 'new' (previously named CEA..)
circulating antigen. In addition to the (now classical, thanks to André
Deelder's laboratory in Leiden, The Netherlands..) adult worms
gut-associated glycoconjugates CAA (for Circulating Anodic Antigen) and CCA
(its cathodic counterpart), another marker called CSEA (for Circulating
Soluble Egg Antigen) is completely validated at both the laboratory and
field levels.
CAA and CCA (worm adults antigens, with a short (a few days) half-life in
serum and a quick response (a substantial drop in the first week following
treatment) to praziquantel therapy, are obviously good markers of active
infection with Schistosma parasites (see DEELDER et al. Trop. Geogr. Med.
1994, 46: 233-238 and also the very interesting VAN LIESHOUT et al. Trans.
Roy. Soc. Trop. Med. Hyg. 1998, 92: 115-119).
CSEA can be dosed by ELISA-based immunoassay using antibody against
carbohydrate epitopes present in excreted egg antigens, and this marker has
been validated both at the laboratory level (see NOUREL DIN et al. Am. J.
Trop. Med. Hyg., 1994, 50: 585-594) and in field situation (NIBBELING et
al. Trans. Roy. Soc. Trop. Med. Hyg.) even after specific chemotherapy
(NIBBELING et al. Trans. Roy. Soc. Trop. Med. Hyg. 1998, 92: 675-677).
With its long half-life (a few weeks), it seems to have a different
interest from CAA and CCA. As proposed by the authors, more than a new
diagnosis and follow-up marker, CSEA might be better considered as a
morbidity marker, correlated with the number of eggs trapped in tissues.
It would be interesting now to compare the levels of CSEA, in the various
patient groups, with the different morbidity markers validated by
comparison with ultrasonographical data, both soluble ICAM-1 but nor
selectins (see ESTERRE et al. Parasite Immunol., 1998, 20: 369-376) and
serum Hyaluronan or PIIINP (better than previously described urinary
Pyridinolines- see RICARD-BLUM et al. Am. J. Trop. Med. Hyg., 1998, 61(2):
in press).
In conclusion, researchers working on schistomiasis mansoni (and perhaps
japonicum, but the work has still to be done ?) have the chance to take
advantage of an interesting pannel of circulating (infection and
morbidity..) markers. A situation which, in addition to the direct
detection of periportal fibrosis by ultrasonography, can cause envy for
other helminth diseases 'linked' researchers (true for Lymphatic
Filariasis, for example) !
I'd appreciate anyone's comments. Sincerely - PHILIPPE.
************************************************
THE MALARDE INSTITUTE, 1949 - 1999 :
50 YEARS AT THE SERVICE OF HEALTH IN POLYNESIA !
************************************************
Dr. Philippe ESTERRE - Head of Immunology Unit
Institut de Recherches Médicales L. Malardé BP30
98713 - Papeete (TAHITI / French Polynesia)
Phone: 689 41 64 67 - Fax: 689 43 15 90
E-mail : esterre at malarde.pf
Dr.Christoph G.Grevelding
Genetic Parasitology
Institute of Genetic &
Center for Biological and Medical Research
Heinrich-Heine-Universitaet
Universitaetsstrasse 1
40225 Duesseldorf
Tel.:(49)-211-81-13070
Fax :(49)-211-81-12333
(49)-211-81-12279
e-mail: Christoph.Grevelding at uni-duesseldorf.dehttp://www.uni-duesseldorf.de/WWW/MathNat/Parasitologie/gen_para.htm
