Pregnancy does not affect HIV incidence test results obtained using the BED capture enzyme immunoassay or an antibody avidity assay.
BACKGROUND
Accurate incidence estimates are needed for surveillance of the HIV epidemic. HIV surveillance occurs at maternal-child health clinics, but it is not known if pregnancy affects HIV incidence testing.


METHODS
We used the BED capture immunoassay (BED) and an antibody avidity assay to test longitudinal samples from 51 HIV-infected Ugandan women infected with subtype A, C, D and intersubtype recombinant HIV who were enrolled in the HIVNET 012 trial (37 baseline samples collected near the time of delivery and 135 follow-up samples collected 3, 4 or 5 years later). Nineteen of 51 women were also pregnant at the time of one or more of the follow-up visits. The BED assay was performed according to the manufacturer's instructions. The avidity assay was performed using a Genetic Systems HIV-1/HIV-2 + O EIA using 0.1M diethylamine as the chaotropic agent.


RESULTS
During the HIVNET 012 follow-up study, there was no difference in normalized optical density values (OD-n) obtained with the BED assay or in the avidity test results (%) when women were pregnant (n = 20 results) compared to those obtained when women were not pregnant (n = 115; for BED: p = 0.9, generalized estimating equations model; for avidity: p = 0.7, Wilcoxon rank sum). In addition, BED and avidity results were almost exactly the same in longitudinal samples from the 18 women who were pregnant at only one study visit during the follow-up study (p = 0.6, paired t-test).


CONCLUSIONS
These results from 51 Ugandan women suggest that any changes in the antibody response to HIV infection that occur during pregnancy are not sufficient to alter results obtained with the BED and avidity assays. Confirmation with larger studies and with other HIV subtypes is needed.
Laeyendecker
Oliver
O
Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America. olaeyen1@jhmi.edu
Church
Jessica D
JD
Oliver
Amy E
AE
Mwatha
Anthony
A
Owen
S Michele
SM
Donnell
Deborah
D
Brookmeyer
Ron
R
Musoke
Philippa
P
Jackson
J Brooks
JB
Guay
Laura
L
Nakabiito
Clemesia
C
Quinn
Thomas C
TC
Eshleman
Susan H
SH
D000915:Antibody Affinity; D005260:Female; D015483:HIV Antibodies / Q000276:immunology; D015658:HIV Infections / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D011159:Population Surveillance; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis* / Q000453:epidemiology; D014454:Uganda / Q000453:epidemiology
D015483:HIV Antibodies