Toxoplasma gondii surface antigen-1 in sera of HIV-infected patients as an indicator of reactivated toxoplasmosis.
The major surface antigen from the proliferative form of Toxoplasma gondii (P-30 of SAG-1) was chosen as a target for exploration of Toxoplasma gondii reactivation in sera from immunocompromised patients. Samples were obtained from 37 HIV-infected subjects with lymphocyte levels of CD4+ < 200/mm3. The prevalence of IgG antibodies to Toxoplasma gondii was 64.9%. Ten patients had clinical symptoms of reactivated toxoplasmosis; eight of these had Toxoplasma encephalitis. The SAG-1 epitopes were found as circulating antigen in five cases with an immunocapture enzyme immunoassay (EIA). The EIA was improved with an IgG1 monoclonal antibody to SAG-1 and a streptavidinbiotin amplification. The sensitivity, specificity and positive predictive value were 30, 92 and 60%, respectively. The SAG-1 levels were compared with different biological parameters such as HIV p24 antigen, beta 2 microglobulin, CD4+ cell count and IgG antibodies to Toxoplasma gondii. The levels of SAG-1 in these patients were significantly higher than those in the 75 healthy control persons with or without a chronic Toxoplasma gondii infection. Therefore, SAG-1 may be involved as a marker of reactivated toxoplasmosis in HIV-infected patients.
Letillois
M F
MF
Service de Parasitologie, Hôpital Albert Michallon, Grenoble, France.
Laigle
V
V
Santoro
F
F
Micoud
M
M
Chumpitazi
B F
BF
D017088:AIDS-Related Opportunistic Infections / Q000175:diagnosis*; D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000097:blood*; D005260:Female; D015497:HIV-1; D006801:Humans; D008297:Male; D015800:Protozoan Proteins / Q000097:blood*; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000175:diagnosis*
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C047168:SAG1 antigen, Toxoplasma