Adults with partly-controlled asthma who received Bifidobacterium infantis (B.infantis) 35624 had better asthma control and decreased frequency of dysfunctional regulatory T cells after 4 weeks compared with a placebo group, according to research released as an abstract from the American Academy of Allergy, Asthma & Immunology Annual Meeting.
“Probiotics can modulate the immune system by inducing Treg cells, and insufficient exposure to environmental microbes is one of the causes of the development of allergy like asthma, atopic dermatitis, rhinitis and food allergy,” Sasipa Sangkanjanavanich, MD, of the Phramongkutklao Hospital in Bangkok, Thailand, said in an interview with MD /alert.
Sangkanjanavanich and colleagues performed a randomized controlled trial of 63 patients with partly-controlled asthma who received either 4 weeks of B.infantis 35624 or placebo. She said B.infantis 35624 was chosen because previous studies have shown administration of the bacteria reduced plasma C-reactive protein (CRP), pro-inflammatory cytokine levels and increased Treg in both gastrointestinal and non-gastrointestinal inflammatory disorders, although this association has not been shown in patients with asthma.
“We hypothesized that B.infantis 35624 administration together with conventional asthma treatment would improve asthma control in adults,” Sangkanjanavanich said.
Overall, 30 patients were assigned to the probiotic group and 30 patients to the placebo group in the study. The researchers analyzed baseline forced expiratory volume (FEV1), forced vital capacity (FVC), asthma control test (ACT) score and absolute eosinophil counts (AEC), measuring them again after 4 weeks. They also used flow cytometry to examine whole blood for dysfunctional regulatory T cells (CRTH2+ Treg). Regardless of whether they received the probiotic intervention, all patients continued to receive full asthma treatment without full systemic corticosteroids.
Patients in the probiotic group had better asthma control as measured by ACT, Visual Analog Scale, mean change in FEV1 and FVC, and number of times using a rescue inhaler, after 4 weeks of administration. In a subgroup analysis, patients with uncontrolled asthma (ACT < 20) had significantly increased lung function (P = .03) and significantly reduced the number of times they used their rescue inhaler (P = .04) in the probiotic group compared with the placebo group. In addition, the probiotic group also had a decreased frequency of CRTH2+ Treg cells compared with the placebo group. There was 1 case of discontinuation of probiotics due to abdominal discomfort, the researchers said.
“I think probiotics are good, especially in a child and the elderly, but a long-term study should be conducted to support the efficacy of probiotics as an add-on treatment in asthmatic patients,” Sangkanjanavanich said.