In a randomized, double-blind, placebo-controlled trial, 114 patients with birch pollinosis received Lactococcus lactis subsp. cremoris YRC3780 (YRC3780) powder (n = 28, 29, 28, in each dose group) or a placebo (1 g starch powder, n = 29) daily for 12 weeks during the 2016 pollen season. Patients self-recorded their symptom and medication scores daily, and blood samples were evaluated every 4 weeks throughout the treatment observation periods. Symptom and medication scores during the intake period were grouped into 6 consecutive periods of 2 weeks each, and average values were compared between periods. In the YRC3780-treated groups, medication scores were significantly lower than scores in the placebo group during intake periods 3 (P < 0.05). In addition, blood levels of thymus- and activation-regulated chemokines (TARC) at 12 weeks were significantly decreased. Consuming at least 10⁹ CFU of YRC3780 daily ameliorated the symptoms of birch pollinosis, likely by improving Th1/Th2 balance.

在一项随机，双盲，安慰剂对照试验中，有114名桦木花粉症患者接受了乳酸乳球菌亚种。乳脂YRC3780（YRC3780）粉末（N = 28，29，28，每个剂量组中）或者在2016花粉季节安慰剂（1克淀粉粉末中，n = 29）每天12周。患者每天自行记录症状和用药得分，并在整个治疗观察期内每4周评估一次血样。摄入期间的症状和药物评分分为连续的6个阶段，每个阶段2周，并比较各个阶段之间的平均值。在接受YRC3780治疗的组中，在服用期间3的药物评分显着低于安慰剂组的评分（P <0.05）。此外，在第12周时，胸腺和激活调节趋化因子（TARC）的血液水平显着降低。每天至少摄入10 ⁹ CFU的YRC3780可改善Th1 / Th2平衡，从而减轻桦木花粉症的症状。