Abstract: Objective To determine the levels of serum vitamin A (retinol) and retinol-binding protein-4 (RBP₄) in drug-resistant pulmonary tuberculosis (PTB), susceptible PTB and healthy people; to analyze the related factors to influence the levels of serum retinol and RBP₄.  Methods Outpatients and inpatients with PTB who received treatment in Dalian TB Hospital from July 2011 to August 2013 were recruited in this study, including 128 drug-resistant PTB patients (drug-resistant group) and 152 susceptible PTB patients (non drug-resistant group). Meanwhile, 120 matched healthy persons who received physical examinations in the same hospital were selected as the control group. The levels of serum retinol and serum RBP₄ among all those recruited subjects were tested. The serum retinol was measured by high-performance liquid chromatography (HPLC) and the serum RBP₄ was measured by enzyme-linked immunosorbent assay (ELISA). The results were showed as x±s and all data were analyzed using SPSS software version 15.0. ANOVA and SNK-q test were used for the comparisons among multi groups. P<0.05 was regarded as statistical significance. Linear correlation and multiple stepwise regression analysis were used for correlated factors analysis of the levels serum retinol and RBP₄.  Results The levels of serum retinol and RBP₄ in drug-resistant group and non drug-resistant group were (206.10±10.35) μg/L, (6.22±1.64) μg/ml and (249.61±12.06) μg/L, (8.23±2.31) μg/ml respectively, which were significantly lower than those in the control group ((326.57±11.52) μg/L and (11.52±2.60) μg/ml) (q=12.35, q=10.66, all P<0.01；q=3.86, q=3.36, all P<0.05); Furthermore, the levels of serum retinol and RBP₄ in drug-resistant group were significantly lower than those in non drug-resistant group (q=3.25, q=3.12, all P<0.05). A multiple stepwise regression analysis showed that body mass index (BMI) was the only independent influencing factor of the levels of serum retinol and RBP₄ (t=2.154, t=5.211, all P<0.05).  Conclusion The levels of serum retinol and RBP₄ significantly decreased in PTB patients and the decrease was more obvious in drug-resistant PTB patients.

Key words: Tuberculosis, pulmonary/Blood, Vitamin A, Retinol-binding proteins