Detection of recent HIV infections in African individuals infected by HIV-1 non-B subtypes using HIV antibody avidity.
BACKGROUND
To estimate HIV incidence several methods have been used to discriminate recent HIV infections from long-standing infections using a single serum sample.


OBJECTIVE
To evaluate the performance of the anti-HIV avidity index (AI) for identifying recent HIV infections in individuals with a known date of seroconversion from Uganda, where the predominant HIV subtypes are A and D.


METHODS
We selected 149 repository serum samples from Ugandan HIV-positive individuals and evaluated the AI. Specimens collected < or =6 months after seroconversion were considered as recent infections, and those collected >6 months as long-standing infections. All specimens were serotyped using a V3 peptide enzyme immunoassay.


RESULTS
The mean AI was 0.55+/-0.21 among the 108 patients with recent infections and 0.93+/-0.14 among the 41 samples from long-standing infections (p<0.0001). The AI test showed a sensitivity of 85.2% and a specificity of 85.4% at a cutoff of 0.80. No significant association was observed between serotype and the misclassification of samples by AI.


CONCLUSIONS
The AI, which is inexpensive and easy-to-perform, can be useful in identifying recent HIV infections in countries where HIV-1 non-B subtypes are prevalent.
Suligoi
Barbara
B
Dipartimento di Malattie Infettive, Parassitarie e Immunomediate, Istituto Superiore di Sanità, Rome, Italy. barbara.suligoi@iss.it
Buttò
Stefano
S
Galli
Claudio
C
Bernasconi
Daniela
D
Salata
Robert A
RA
Tavoschi
Lara
L
Chiappi
Michele
M
Mugyenyi
Peter
P
Pimpinelli
Fulvia
F
Kityo
Cissy
C
Regine
Vincenza
V
Rezza
Giovanni
G
D000915:Antibody Affinity; D005260:Female; D005838:Genotype; D015483:HIV Antibodies / Q000097:blood*; D015658:HIV Infections / Q000175:diagnosis* / Q000276:immunology; D015497:HIV-1 / Q000145:classification / Q000235:genetics / Q000276:immunology*; D006801:Humans; D015994:Incidence; D008297:Male; D012680:Sensitivity and Specificity; D012703:Serotyping; D013997:Time Factors; D014454:Uganda
D015483:HIV Antibodies