RESUMO
Vitamin D affects innate and adaptive immunity processes that impact treatment, severity, and morbidity of acute asthma episodes. Several vitamin D forms may help modulate immunity, including vitamin D2 (D2), vitamin D3 (D3), 25-hydroxyvitamin D3 (25(OH)D3), and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3). This study assessed serum levels of vitamin D derivatives in bronchial asthma patients and their correlation with disease markers. One hundred thirteen subjects, divided into two groups, were enrolled. The first group included 73 asthmatic patients (57 males and 16 females), and the second included 40 healthy adults (31 males and 9 females) as a control group. All subjects were evaluated with a careful history and clinical examination, a chest X-ray with a posteroanterior view, routine laboratory examination, spirometry, and asthma control tests (ACT). Vitamin D serum levels were assessed using ultra-performance liquid chromatography (UPLC) with tandem mass spectrometry. Disease markers were assessed and correlated with serum levels of vitamin D forms. Markers included forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC%, peak expiratory flow (PEF), forced expiratory flow25-75% (FEF25-75%), eosinophilic blood count, and total immunoglobulin E (IgE). Asthmatic patients had significantly lower serum levels of vitamin D than healthy controls (p ≤ 0.001). Further, serum vitamin D levels decreased significantly in uncontrolled asthmatic patients than partially controlled and controlled patients. Correlations for 25(OH)D3 and 1,25-(OH) 2D3 were stronger than for D2 and D3. There were negative correlations for eosinophilic blood count, total IgE, and ACT. Serum levels of all vitamin D forms were reduced in asthmatic patients with moderate to strong correlations with disease severity. Vitamin D deficiency or even insufficiency may thus play a role in disease severity.