Stem Cells For Healing Allergies

The reaction to a foreign substance termed as allergen is termed as an allergy. According to the Asthma and Allergy Foundation of America, allergies rank 6^th as the cause of chronic illness in the US with more than $18 billion spent a year for allergies. Allergies currently lack treatments with most patients reporting “management” of symptoms.

An example of an allergy is allergic asthma whose incidence is on the rise: globally, 235 million people have asthma of which 50 percent of adults and 90 percent of children have allergic asthma (US National Library of Medicine, Genetics Home Reference). Allergic asthma is due to increased T helper 2 (Th2) activities that cause eosinophil infiltration that leads to inflammation and symptoms. Common treatment involves the inhalation of β2-agonists and inhalation or orally-consumed glucocorticosteroids. While these treatments have side effects they also do not address the root causes of the condition.

The field of Mesenchymal Stem Cells (MSCs) can show promise in the treatment of such allergies given that these cells have mediated or ameliorated cell-responses due to immune cells in allergic rhinitis, inflammatory bowel disease and lung injury. A team led by Habibian (2018) reported the use of mesenchymal stem cells from the bone marrow in mice models of allergic asthma. Animals that received the MSCs showed a lowering of eosinophilia as well as IgE levels. The levels of Treg cytokines involved in inflammation were not decreased by dexamethasone but were lowered by MSCs showing the edge of stem cells over corticosteroids.

Looking at another allergy, food allergy is termed as a “second wave” of allergy epidemics with asthma as the first. According to Alessandro Fiocchi, MD and Vincenzo Fierro, MD, The Bambino Gesù Children’s Research Hospital, of the World Allergy Organization, 1% to 10% of the general population suffers from food allergy. According to a study by Hill and team (2016), 6.7% of children in the United States have food allergies while according to Yang and team (2015), 3.5-4% of Chinese children showed food allergies.

Food allergies have been on the rise the past few years in both in Westernized countries and developing countries. Given this situation, the search for appropriate therapies and preventive treatments is the need of the hour.  Studies in mice and humans have shown the involvement of immune molecules called cytokines that lead to the activation of what is termed as the Th2 response of T cells resulting in inflammation.

A team led by Xia reported the beneficial effects of using MSCs from the human umbilical cord in Experimental and therapeutic medicine. Administering the stem cells in a mouse model of food allergy intraperitoneally along with an oral application of the culture medium lowered the levels of Th2 cells and IgE: both of which were initially high in the allergic condition. Additionally, the goblet cells involved in protecting the mucosa and the microbial gut flora that was disturbed by the allergy were also re-established.

These studies show the application of MSCs in treating allergies given the repairing of damaged cells and their surroundings by the MSCs. This becomes significant given that research shows that a quarter of the Indian population is sensitized with some allergen (Bhattacharya et al, 2018)! The roadmap ahead for treatment using MSCs for treating these allergies can “heal” the damage and enable patients to “breathe” and “eat” freely.

References:

https://ghr.nlm.nih.gov/condition/allergic-asthma#statistics

Habibian, R., Delirezh, N., &Farshid, A. A. (2018).The effects of bone marrow-derived mesenchymal stem cells on ovalbumin-induced allergic asthma and cytokine responses in mice. Iranian journal of basic medical sciences, 21(5), 483–488.

Loh, W., & Tang, M. (2018).The Epidemiology of Food Allergy in the Global Context. International journal of environmental research and public health, 15(9), 2043.

Hill DA, Grundmeier RW, Ram G, Spergel JM. The epidemiologic characteristics of healthcare provider-diagnosed eczema, asthma, allergic rhinitis, and food allergy in children: a retrospective cohort study. BMC Pediatr. 2016 Aug 20; 16:133.

Yang Z, Zheng W, Yung E, Zhong N, Wong GW, Li J. Frequency of food group consumption and risk of allergic disease and sensitization in schoolchildren in urban and rural China. Clin Exp Allergy. 2015; 45:1823–1832.

Yan, N., Xu, J., Zhao, C., Wu, Y., Gao, F., Li, C., Zhou, W., Xiao, T., Zhou, X., Shao, Q., & Xia, S. (2018). Human umbilical cord-derived mesenchymal stem cells ameliorate the enteropathy of food allergies in mice. Experimental and therapeutic medicine, 16(6), 4445–4456.

Bhattacharya K, Sircar G, Dasgupta A, Gupta Bhattacharya S: Spectrum of Allergens and Allergen Biology in India. Int Arch Allergy Immunol 2018;177:219-237.