Vitamin A status in HIV infection

HIV⁺ individuals may be at particular risk for deficiency of vitamin A, a critical micronutrient in the maintenance of epithelial barriers and normal immune function. We studied 25 HIV⁺ outpatients with CD4⁺ T cell counts less than 800: 5 had AIDS, 2 had diarrhea and weight loss and 18 were asymptomatic. Vitamin A status was assessed with a battery of tests; conjunctival impression cytology (CIC), relative dose responses (RDR) and serum retinol and retinol binding protein (RBP) levels. We also measured mitogen-induced lymphoproliferation and in vitro cytokine production (soluble IL-2 receptor (sIL-2R) and interferon-γ (IFN-γ)) with and without supplemental retinol. Eight subjects (32%) had one or more tests suggestive of vitamin A deficiency: serum retinol levels <1.05 μM/L (4), abnormal CIC (6), abnormal RDR (1), RBP <7 (1). Correspondence between the various measures of vitamin status was limited but subjects with abnormal CIC tended to have lower serum retinol levels than those with normal CIC (1.54±0.30 vs 2.20±0.21 μM/L; P=.15). 60% of subjects with AIDS had abnormal CIC (vs 17% in non-AIDs subjects; P<.04). Retinol levels in subjects with CD4⁺ counts ≤300 tended to be lower than in those with CD4⁺ counts >300 (1.80±0.24 vs 2.20±0.24 μM/L; P=.15). Subjects taking a daily multivitamin containing modest amounts of vitamin A had higher serum retinol levels than those taking no supplements (2.50±0.24 vs 1.47±0.21 μM/L; P<.009), an association which remained after stratification by CD4⁺ cell counts. In vitro proliferation and cytokine production were not correlated with measures of vitamin A status. Retinol supplementation in cultures with the lowest baseline cytokine levels increased production of sIL-2R (>27-fold; P<.03) and IFN-γ (>3.1-fold; P<.02) regardless of apparent vitamin A status. These preliminary observations suggest that vitamin A status may deteriorate with advancing HIV and that even modest doses of vitamin A can have significant impact on serum retinol levels. Increased cytokine production with supplemental retinol in vitro demonstrates that lymphocytes can be retinoid responsive despite apparently normal vitamin A status.