TABLE 2.

Randomized, controlled trials of vitamin A in relation to T-cell function^a

Study site (reference[s])	Intervention groups	Population	End point	Result for the indicated measure of effectb		P value
South Africa (28)	Vitamin A (200,000 IU, or 100,000 IU if <12 mo) vs placebo on days 0, 2, 8, and 42	60 infants age 4-24 mo hospitalized with measles	Lymphocyte count (109/liter) Difference at day 42 Change from day 0 to day 42 IL-2 (IU/ml) at day: 8 42	Vitamin A 8.10 3.40 1.76 1.74	Placebo 6.45 1.96 1.72 1.70	0.05 0.06 >0.05 >0.05
Indonesia (132)	Vitamin A (200,000 IU) vs placebo,	55 children age	CD4/CD8 ratio at 5 wk from	Vitamin A	Placebo
	single dose, 2 wk before antitetanus	3-6 yr. 30	supplementation	1.32	0.97	<0.0001
	immunization	xerophthalmic	% CD4 naive T cells at 5 wk	Higher in vitamin A group			<0.01
			Change in T-cell subsets after 5 wk
			CD4/CD8 ratio	Significant increase, P < 0.007	No significant change
			% CD4+ CD45RA+	Significant increase, P < 0.003	No significant change
			% CD4+ CD45RO+	No change in any group, no significant difference in change
			% CD8+ CD45RA+	No change in any group, no significant difference in change
			% CD8+ CD45RO+	Significant decrease	No significant change
Guinea-Bissau (13)	Vitamin A (100,000 IU) at age 6 mo vs placebo	276 infants	T-cell subset change between 6 and 9 mo of age	Vitamin A	No vitamin A
			% CD4	−0.11	0.45	0.31
			% CD8	1.21	1.61	0.21
			CD4/CD8 ratio	−0.15	−0.07	0.26
	Vitamin A (100,000 IU) at age 6 and 9 mo vs placebo	185 infants	T-cell subset change at 18 mo	Vitamin A	No vitamin A
			% CD4	2.50	−2.72	0.07
			% CD8	−1.93	0.49	0.12
			CD4/CD8 ratio	0.28	−0.20	0.06
South Africa (66)	Vitamin A (200,000 IU) on 2 consecutive days vs placebo	75 HIV+ infants	Absolute lymphocyte count at 4 wk	Vitamin A	Placebo
				Increase			0.05
			CD4 cell count at 4 wk	Increase			0.03
			CD56 cell count at 4 wk	Increase			0.05
			CD29 cell count at 4 wk	Increase			0.07
				Vitamin A	Placebo
South Africa (76)	Vitamin A (5,000 IU) + β-carotene (30 mg) daily during pregnancy + vitamin A (200,000 IU) at delivery to mothers vs placebo	33 infants born to 728 HIV+ women	T-helper cell responses to HIV in cord blood (infants)	Slightly more frequent in vitamin A arm but not significant
Tanzania (40,44-46)	Vitamin A (5,000 IU) + β-carotene (30 mg) daily during	1,078 HIV+	Woman's T-cell subset counts (/μl)	Vitamin A	Placebo
	pregnancy and breast feeding to mothers vs placebo	pregnant women	CD4 at 6 wk postpartum	558	562	0.13
			CD4 at 30 wk postpartum	496	509	0.23
			Overall effect			0.29
			CD8 at 6 wk postpartum	1,061	1,094	0.32
			CD8 at 30 wk postpartum	943	909	0.26
			Overall effect			0.13
			CD3 at 6 wk postpartum	1,698	1,741	0.20
			CD3 at 30 wk postpartum	1,515	1,494	0.68
			Overall effect			0.25
		393 HIV+ pregnant women	IL-1β in CVL (μg/ml)	218c	219c	0.41
		664 infants born to 1,078 HIV+ women	Infant's CD4 cell count during first 2 yr	No effect
	Vitamin A (5,000 IU) + β-carotene (30 mg) daily for ≈3-5 yr	1,078 HIV+ women	T-cell subsets (/μl) at >4 yr after enrollment
			CD4	434	449	0.30
			CD8	920	968	0.07
			CD3	1,425	1,497	0.05
United States (129)	Vitamin A (200,000 IU) single dose vs placebo	120 HIV+		Vitamin A	Placebo
		injection drug users	CD4 cells (/μl) at 4 wk			0.17
United States (65)	Vitamin A (300,000 IU) single dose vs placebo	40 HIV+ women		Vitamin A	Placebo
			% CD4 at 8 wk			0.56
			% CD8 that are CD38+			>0.05
			Lymphocyte proliferation in response to:
			PHA			>0.05
			Candida			>0.05
Kenya (5)	Vitamin A (10,000 IU) daily for 6 wk vs placebo	400 HIV+ women	T-cell subsets at 6 wk (/μl)	Vitamin A	Placebo
			CD4	272	225	0.04
			CD8	719	581	0.08
Italy (50)	Vitamin A (≈1,500 IU) daily for 3 mo vs. placebo, in both	118 men and	Total leucocytes (/μl)	Vitamin A	No Vitamin A
	groups, half also received 25 mg zinc zulfate	women age >65	Baseline	6,149	6,206
			Change from baseline	138	361	0.30
			Lymphocytes (/μl)
			Baseline	1,977	1,942
			Change from baseline	−73	62	0.05
			CD3+ (/μl)
			Baseline	1,260	1,123
			Change from baseline	−109	49	0.01
			CD4+ (/μl)
			Baseline	712	711
			Change from baseline	−125	−23	0.01
			CD4+ DR+ (/μl)
			Baseline	76	70
			Change from baseline	6	18	0.12
			CD8+ (/μl)
			Baseline	665	629
			Change from baseline	−70	30	0.12
			CD8+ DR+ (μl)
			Baseline	139	116
			Change from baseline	−0.8	−0.7	0.64
			CD4/CD8 ratio
			Baseline	1.17	1.16
			Change from baseline	−0.10	−0.05	0.55
			Cytotoxic T lymphocytes
			Baseline	70	84
			Change from baseline	23	51	0.19
			NK cells (/μl)
			Baseline	225	252
			Change from baseline	−4	45	0.11
				Vitamin A	Control
Bangladesh (20)	Vitamin A (200,000 IU intramuscularly) vs no intervention at the time of first of 3 antitetanus immunizations	91 children 1-6 yr	% of positive cutaneous DTH responses (≥5 mm) to a protein derivative and Candida after 4 wk	29.5	31.9	>0.05
Zambia (116)	Vitamin A (200,000 IU) single dose vs placebo	200 children age	Cutaneous DTH response at 2 wk	Vitamin A	Placebo
		5 mo-17 yr	% Children with reactions	44.4	61.3	0.04
		hospitalized	Sum of indurations ≥2 mm	6.9	8.4	0.20
		with measles	Mean induration per reaction	4.1	3.9	0.50
			% of children unresponsive to specific antigens
			Tetanus	82.8	81.0	>0.05
			Diphtheria	81.8	82.5	>0.05
			Tuberculin (PPD)	86.6	72.1	<0.05
			Streptococcus	100.0	90.1	>0.05
			Candida	97.1	85.5	<0.05
			Trichophyton	97.1	92.8	>0.05
			Proteus	97.1	86.8	<0.05
			IL-4, % change from baseline to 2 wk	9.0	35.0	0.18
Bangladesh (106)	Vitamin A (50,000 IU) vs placebo at each time of DPT/OPV vaccination (0, 4, and 8 wk)	120 infants age 6-17 wk	Cutaneous DTH response (% children) after 1 mo after last dose	Vitamin A	Placebo
			Tetanus	30.6	32.8	>0.05
			Diphtheria	30.6	22.4	>0.05
			Tuberculin (PPD)	59.7	46.6	>0.05
			Streptococcus	4.8	6.9	>0.05
			Candida	3.2	8.6	>0.05
			Trichophyton	1.6	3.4	>0.05
			Proteus	4.8	1.7	>0.05
			Total (sum induration)	72.6	67.2	>0.05
			Total among children with baseline retinol ≥0.7 μmol/liter	93.3	57.9	0.008
			Avg induration (mm) among children with baseline retinol ≥0.7 μmol/liter	7.0	4.2	0.01
			% Anergic infants	27.4	32.8	>0.05

^aPHA: phytohemagglutinin; CVL: cervicovaginal lavage; DPT: diphtheria, pertussis, and tetanus vaccine; OPV: oral polio vaccine; PPD: purified protein derivative;

^bAll values presented are means unless noted otherwise. Verbal descriptions of results correspond to those in the indicated references when numerical data were not presented.

^cMedian.