Table 1. Timing of systemic and mucosal gp41-specific IgA antibodies.

	gp41		Gag		RT		Nef		gp120		P31
Fiebig stage	No./totala	%	No./total	%	No./total	%	No./total	%	No./total	%	No./total	%
(a) Plasma IgA
I/II	6/23	26.1	2/23	8.7	NT	—	NT	—	NT	—	NT	—
III	7/14	50.0	3/14	21.4	NT	—	NT	—	NT	—	NT	—
IV	15/17	88.2	10/17	58.8	3/7	42.9	3/7	42.9	2/8	25.0	0/7	0.0
V/VI	39/40	97.5	35/40	87.5	13/15	86.7	8/14	57.1	11/29	37.9	2/14	14.3
(b) Mucosal IgA
I/II	0/1	0	0/1	0	NT	—	NT	—	NT	—	NT	—
III	0/2	0	0/2	0	NT	—	NT	—	NT	—	NT	—
IV	7/21	33.3	4/8	50.0	0/7	0	0/7	0	1/7	14.3	0/7	0
V/VI	18/23	78.3	17/23	73.9	5/14	35.7	1/14	7.1	4/14	28.6	1/14	7.1

(c)
Antigen	No. of subjectsb	Median time to antibody response (range (days))c
gp41	14	13.5 (9–18)
p55	6	25.5 (14–40)

Abbreviations: Ig, immunoglobulin; NT, not tested.

(a) Frequency of HIV-1-specific plasma IgA responses per Fiebig²⁵ stage in up to 30 CHAVI and 25 plasma donor patients is shown. Frequency was calculated by the number of plasma samples positive per each Fiebig stage over the total number plasma samples measured in that stage. (b) Frequency of HIV-specific mucosal IgA responses were measured in mucosal samples per Fiebig stage from up to 23 acute HIV-1 infection (AHI) patients. (c) Systemic HIV-1 gp41-specific IgA appears before anti-Gag IgA antibodies. HIV-specific IgA responses were measured in 25 HIV+ seroconversion plasma donor panels by standard enzyme-linked immunosorbent assay and aligned to T₀ (the time at which viral load is first detectable), as previously described.

^aNumber of subjects having an antigen-specific IgA positive sample in the designated Fiebig stage divided by the total number of subjects in that designated Fiebig stage.

^bNumber of plasma donor subjects with positive IgA response.

^cMedian time from T₀ (the first day the viral load reaches 100 copies/ml).