[Antibody avidity: use for the diagnosis of HIV early infection].
Determination of IgG avidity is useful to distinguish primary infection from reactivation or reinfection in viral, parasitic or bacterial infections. For diagnosis of HIV type 1 primary infection, the detection of IgM antibodies is often useless since they are also found in chronic infection. The usual serology (Elisa, western-blot, p24 antigen) may present no interest if done too late (more than 2 or 3 months after infection). Therefore, we have developed a test to determine the avidity of anti-HIV1 antibodies, using 1 M guanidine as denaturing agent. We have adapted the measurement of avidity to the Axsym automatic system for a routine use. Indeed, since requests for avidity determinations are sporadic, the use of microplates is not convenient. Using this assay, we found a low avidity (less than 50%) in immunocompetent and recent infected patients (less than 6 months), compared to old infected patients (more than 12 months) who had high avidity (80 to 100%). However, early treated patients (in the 6 months after contamination) had also low avidities but with a slower development of antibody maturation (8 to 27 months versus 2 to 8 months in non treated patients). To conclude, the determination of the anti-HIV1 avidity, according to the proper procedures explained here (notion of treatment and/or serious immunodepression), may help the physician to date the infection in each new infected patient who might benefit from an early treatment.
Le Guillou
H
H
Laboratoire de bactériologie-virologie, CHU, 4, rue Larrey, 49033 Angers cedex.
Le Meur
A
A
Bourdon
S
S
Riou
M
M
Loison
J
J
Fialaire
P
P
Chennebault
J M
JM
Kouyoumdjian
S
S
Payan
C
C
D000163:Acquired Immunodeficiency Syndrome / Q000175:diagnosis* / Q000276:immunology; D000328:Adult; D000915:Antibody Affinity; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D015497:HIV-1 / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged