As microbiological diagnostic techniques improve and the frequency of nontuberculous mycobacterial pulmonary disease (NTM-PD) infection increases worldwide, NTM-PD is becoming increasingly important to clinicians and researchers. Vitamin activity has been associated with the host immune response in tuberculosis; however, such information is very limited in NTM-PD. We performed a case-control study in 150 patients with NTM-PD and 150 healthy controls to investigate serum vitamin status. We measured concentrations of vitamins A, D, and E along with homocysteine and methylmalonic acid (MMA) as indicators of vitamin B₁₂ deficiency, using high-performance liquid chromatography (HPLC) or HPLC-tandem mass spectrometry. The serum concentrations of vitamins A and E were significantly lower in patients with NTM-PD than in healthy controls (1.5 vs. 2.1 µmol/L, p < 0.01 for vitamin A; and 27.3 vs. 33.1 µmol/L, p < 0.01 for vitamin E). In contrast, the serum concentrations of vitamin D and homocysteine were not significantly different between the two groups. Vitamin A deficiency (< 1.05 µmol/L) was significantly more prevalent in patients with NTM-PD than in healthy controls (p < 0.01) and was associated with an 11-fold increase in risk of NTM-PD. Multiple vitamin deficiencies were only observed in patients with NTM-PD (7.3% of all NTM-PD patients). Positive correlations were observed among vitamins (vitamins A and D; r = 0.200, p < 0.05; vitamins D and E, r = 0.238, p < 0.05; vitamins A and E, r = 0.352, p < 0.05). Serum vitamin status, demographic variables, and biochemical indicators were not associated with treatment outcomes. Vitamin A deficiency was strongly associated with patients with NTM-PD. Our study suggests that altered vitamin status is associated with mycobacterial disease. Future well-designed prospective studies with large patient cohorts addressing these issues are needed to clarify the significance of vitamins in NTM-PD.

Sunghwan Shin, M.D., Jongwon Oh, M.D., and Hyung-Doo Park, M.D., Ph.D.. Ann Lab Med 2021;41:114-9. https://doi.org/10.3343/alm.2021.41.1.114

Measuring nicotine metabolites is the most objective method for identifying smoke exposure. Liquid chromatography--tandem mass spectrometry (LC–MS-MS) can measure multiple metabolites and is sensitive enough to detect low concentrations of metabolites. Therefore, we developed a simple and high-throughput method for measuring nicotine, cotinine, trans-3ʹ-hydroxycotinine (3-OH cotinine), nornicotine and anabasine for population-based studies using LC–MS-MS. Each 30 µL of urine sample was diluted with 90 µL of acetonitrile containing five deuterated internal standards. Chromatographic separation used a C18 column, and LC–MS-MS analysis was performed with a multiple reaction monitoring mode. The chromatographic run time for each sample was 6.5 min. The method was validated by evaluating selectivity, interference, limit of detection, lower limit of quantification, precision, accuracy, linearity, extraction recovery, matrix effect and carryover according to guidelines. Our methods required a short preparation time (∼20 min) while simultaneously measuring five markers for smoking status. No endogenous or exogenous interference was found. Our method showed excellent precision and accuracy: within-run coefficient of variation (CV) 2.9–9.4%, between-run CV 4.8–8.7% and bias −10.1 to 5.3%. Linear dynamic ranges were 1–10,000 ng/mL for nicotine, nornicotine and anabasine; 2–5,000 ng/mL for cotinine and 5–15,000 ng/mL for 3-OH cotinine. Extraction recovery was consistent (87–109%) across concentrations. No significant matrix effect or carryover was observed. The validated method was applied to 849 urine samples. In samples from the 125 current smokers, nicotine, cotinine, 3-OH cotinine, nornicotine and anabasine were detected in 97.6, 99.2, 98.4, 96.8 and 87.2%, respectively. No markers were detected in 93.9% of 609 nonsmokers. The overlapping detection of multiple markers made it possible to identify the smoking status even in current smokers with a low concentration of cotinine. Our LC–MS-MS method using a simple sample preparation technique is sensitive and effective for screening of smoking status in the general population.

We appreciate Hernández-Garduño’s interest in our recent research article