Study Challenges Link Between Psoriasis and Vitiligo

Psoriasis and vitiligo have a connection through the immune system, however, the search that one causes the other could continue, according to research published in the July issue of Skin Research & Technology.

Psoriasis is a long-lasting condition where the immune system causes skin cells to grow too fast, leading to scaly patches, while vitiligo is an autoimmune disorder that makes skin lose its color in certain areas. Around 125 million people have psoriasis, according to the World Psoriasis Day consortium, and about 70 million people have vitiligo worldwide, per the Global Vitiligo Foundation.

Previous studies have suggested that these two autoimmune diseases may be linked.

For over a century, doctors have noticed that some patients have both conditions, but it’s still unclear whether there’s a direct connection or if it's just a coincidence.

Recent research suggests that people with both diseases may be more prone to issues such as cardiovascular disease and other autoimmune disorders. However, previous studies on this relationship have had some limitations, making it difficult to draw clear conclusions.

To better understand the connection between psoriasis and vitiligo, researchers from Tianjin University and the China Academy of Chinese Medical Sciences focused on patients with both conditions.

The study first began with a case report of a 32-year-old male patient who had both psoriasis and vitiligo. The patient’s skin was examined through various tests, and skin samples were taken and analyzed for genetic activity using advanced sequencing techniques.

The study also used data from a European population of roughly 261,000 to explore the genetic connections between psoriasis and vitiligo.

Researchers applied a method called Mendelian randomization, which uses specific genetic markers to determine if one condition might cause the other.

Genetic markers were carefully selected to ensure accuracy and used multiple statistical methods to analyze the data.

Researchers also they tested for any bias and connections between the genes studied and other diseases.

Data found that out of each analysis, the affected skin showed signs of both conditions.

When researchers analyzed the skin cells, they noticed an increase in certain immune cells such as CD8+ T cells and natural killer cells compared to normal and psoriasis-only skin.

In the Mendelian randomization analysis, results showed no clear causal link between the two conditions, meaning having one doesn’t necessarily cause the other.

This study aimed to understand the genetic link between psoriasis and vitiligo, but the findings challenge previous research.

While earlier studies suggested a connection between these two conditions, the use of the Mendelian randomization did not find a relationship in the European population. This result might be due to differences in the groups studied, suggesting that more diverse populations need to be examined.

Though the study has strengths, it also has limitations, including the small sample size: only one patient was studied, which limits how widely the results can be applied.

Researchers note the Mendelian randomization is a strong method for reducing errors, but it’s important to be cautious about extending these findings to other populations.

It’s suggested that more research is needed with larger, more diverse groups to fully explore this relationship.