vitiligo and alopecia: cousins? 

Vitiligo and Alopecia: Cousins? by Jaylyn Porras and Mariana Turner

Natural killer (NK) cells have recently come into focus when researching alopecia areata (AA). It is suggested that alopecia areata is a T-cell mediated autoimmune disease, but this supposition does not include the possible contribution of natural killer cells. These findings show the need to carefully distinguish between pure NK cells and defined subsets due to their seemingly opposite functions, through experiments.  

A Hair Raiser

T-cell mediated autoimmune diseases:

“An Unexpected Twist in Alopecia Areata Pathogenesis: Are NK Cells Protective and CD49b+ T Cells Pathogenic?”

To investigate the role of NK in AA, a lesioned skin from older C3H/HeJ mice with AA was grafted to young C3H/HeJ female mice. As the NK cells were depleted, the number of NK cells in murine skin was significantly reduced. However, hair loss was accelerated rather than stopped. The depletion of NK cells was also accompanied by an increase in the number CD49b+ cells in the alopecic skin of the treated mice. 

Vitiligo and Alopecia: 

  •  “Vitiligo and alopecia areata are common disfiguring autoimmune skin diseases with limited treatment options.”
  •  “The identification of IFN-γ as the primary contributing signaling pathway has enabled us to strategize new treatment approaches for vitiligo and alopecia areata.”
  •   “Proof of concept case studies and small clinical trials have shown promise for inhibitors of IFN-γ, including JAK inhibitors, STAT1 inhibitors, and IL-12.”
  • “Vitiligo and alopecia are common autoimmune diseases of the skin.” The two are commonly compared to apples and oranges due to their obvious differences, but their similarities abound. 
  • “Vitiligo is caused by the destruction of melanocytes and results in the appearance of white patches on any part of the body, while alopecia areata is characterized by patchy hair loss primarily on the scalp but may also involve other areas as well.”
  • “The immune cell populations and cytokines that drive each disease are similar. They are closely associated within patients and their family members, and vitiligo and alopecia areata have common genetic risk factors, suggesting that they share a similar pathogenesis. Both vitiligo and alopecia areata have also been described as TH1-driven diseases, based on the involvement of CD8+ T cells and the clear, consistent production of IFN-γ within lesional skin.”

Epidermal melanocytes have been recognized as the autoimmune cellular targets in vitiligo, while in alopecia it is unclear  if the immune response is to a specific cell type. 

What can we learn about T1D from these disease “cousins”? 

Hair growth impairment is a common side effect of diabetes. It may impact the growth cycle of hair by deteriorating hair growth, causing more hair to grow than normal or completely stopping new hair in certain areas. Too high or low blood sugar, which most diabetics have, can restrict a healthy amount of blood and oxygen to the scalp in order to grow hair. People with type 1 diabetes are more likely to develop alopecia areata, and. a controlled diet, medication and blood sugar control can help to prevent their significant hair loss. Diabetic patients can recover from alopecia but should be further examined for autoimmune polyglandular syndrome (APS). 

Vitiligo is a relatively rare disease that is only found in 1% to 2% of the world’s population. Based on a preponderance of circumstantial evidence, it is known to occur with increased frequency in patients with type 1 diabetes. Vitiligo attacks the melanocytes in the skin, which are skin cells that produce melanin, a pigment that gives skin its color and sun protection. This signifies that those with vitiligo have patches of skin that are much lighter than others and which spread at random, taking weeks, months or even years to appear. Although there is therapy that can be done to try to restore skin tone, there are no treatments for vitiligo.

What companies are studying these diseases?

  •     National Alopecia Areata Foundation 
  •     University of California, Irvine, Department of Dermatology, Dermatology Clinical research Center
  •     Dermatology Specialist, Inc.
  •     Ache Laboratories Farmaceuticos 
  •     Arcutis Biotheraputics’ 

 Who are experts in the field?

  •     Madeleine Duvic, M.D. 
  •     Joyce S. Osei, MPH, MHA. 
  •     John E. Harris, MD, PhD.
  •     Mehdi Rashighi, MD.
  •     Dori Goldberg, MD.

sources

  • Kaufman G, d’Ovidio R, Kaldawy A, et al. An unexpected twist in alopecia areata pathogenesis: are NK cells protective and CD49b+ T cells pathogenic? Exp Dermatol. 2010;19(8):e347-e349. doi:10.1111/j.1600-0625.2010.01106.x
  • Rork, J. F., Rashighi, M., & Harris, J. E. (2016). Understanding autoimmunity of vitiligo and alopecia areata. Current opinion in pediatrics, 28(4), 463–469. https://doi.org/10.1097/MOP.0000000000000375
  • Makino, S., Uchihashi, T., Kataoka, Y., & Fujiwara, M. (2015). Recovery from alopecia areata in a patient with autoimmune polyglandular syndrome type 3, Endocrinology, Diabetes & Metabolism Case Reports, 2015, 14-0084. Retrieved Jul 9, 2020, from https://edm.bioscientifica.com/view/journals/edm/2015/1/EDM14-0084.xml
  • Fletcher , Jenna, and Stacy Sampson . “Does Diabetes Cause Hair Loss?: Causes and Treatment Options.” Medical News Today, MediLexicon International, 27 Nov. 2018, www.medicalnewstoday.com/articles/323810.
  • Macaron C;Winter RJ;Traisman HS;Kahan BD;Lasser AE;Green OC;. (2020, January 13). Vitiligo and Juvenile Diabetes Mellitus. Retrieved from https://pubmed.ncbi.nlm.nih.gov/931387/
  • Harris, J. E. (2013, December). Vitiligo and alopecia areata: Apples and oranges? Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3867815/
  • Macaron C;Winter RJ;Traisman HS;Kahan BD;Lasser AE;Green OC;. (n.d.). Vitiligo and Juvenile Diabetes Mellitus. Retrieved from https://pubmed.ncbi.nlm.nih.gov/931387/

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