How Sunlight and UV Light Treatment Can Help Autoimmune Disorders

by Nelson Montelauro

Living with an autoimmune condition can feel like a constant uphill climb. You might be looking for answers, for something that brings relief. This is where the idea of UV light autoimmune treatment enters the discussion, offering a different path for some individuals.

Many people are now exploring what UV light autoimmune treatment might mean for their health and for managing conditions such as lupus erythematosus. It's a topic sparking hope and curiosity among autoimmune patients. This article examines what this approach involves and what current science suggests about its potential and limitations, including its effects on cell death and the body's immune system.

Table of Contents:

Understanding Autoimmune Diseases: A Constant Battle

Autoimmune diseases occur when the body's defense system, designed to fight external threats, mistakenly attacks its own healthy cells and tissues. This internal conflict triggers a significant inflammatory response. This battle within can cause a wide range of symptoms, profoundly affecting a person's quality of life.

Consider conditions like multiple sclerosis, type 1 diabetes, or rheumatoid arthritis; these are prevalent examples of illnesses impacting millions globally. Lupus patients, for instance, often grapple with systemic lupus erythematosus, a condition where UV exposure can sometimes be a trigger. Finding effective management strategies for these systemic diseases presents a substantial challenge for medical science.

Current treatments frequently aim to suppress or calm the immune system to reduce the inflammatory response. However, these interventions can sometimes carry their own set of side effects. This ongoing need for better options drives the investigation into new therapeutic approaches, such as specific light treatment modalities.

The Light at the End of the Tunnel: What is UV Light Autoimmune Treatment?

What precisely does UV light autoimmune treatment involve? This therapeutic approach uses specific wavelengths of ultraviolet light, often UVB light or sometimes UVA light, directed at the skin for controlled periods. The goal is to modulate the immune system, not to replicate the effects of prolonged natural sunlight exposure.

The concept is not entirely new; light boxes emitting narrow bandwidth UV light have been a treatment for psoriasis, an inflammatory skin condition, for many years. This specific type of UV radiation is distinct from the broader spectrum associated with skin cancer concerns. Researchers are now investigating if this targeted UV exposure could benefit other autoimmune problems by influencing immune cells like dendritic cells.

The objective is to determine if controlled exposure to ultraviolet radiation can help temper an overactive immune system, aiming to restore a healthier balance within the body. This is a precise medical intervention, far removed from casual sunbathing, and considers factors like potential DNA damage while seeking beneficial effects on skin inflammation and systemic disease.

Kathy's Story: A Personal Glimpse into UV Therapy's Potential

Kathy Reagan Young's experience provides a human perspective on this treatment's potential. Each morning, Kathy uses a special light box at her Virginia Beach home. This routine has become integral to her management of multiple sclerosis.

She stands a short distance from the device, wearing protective goggles, as a gentle purple light bathes her torso for several minutes. This simple, consistent action has significantly improved her daily life. Kathy's story highlights the hope that such therapies offer to MS patients and potentially others with similar conditions.

In 2008, Kathy received a diagnosis of multiple sclerosis (MS), a challenging illness where the immune system attacks the protective coverings of nerves. Symptoms of MS include muscle weakness, vision problems, and profound tiredness. She also experienced "cog fog," a term she uses for a type of mental cloudiness that can be very disruptive.

Flare-ups could result in a loss of motor control, making everyday tasks difficult. However, her condition changed after she began using the light box. It was prescribed by her doctor as part of providing feedback to Cytokind, a medical device company investigating light boxes for MS and other autoimmune diseases, possibly including certain skin conditions where UV-mediated inflammation plays a role.

Kathy offered valuable suggestions to the company. She proposed making the device smaller and easier to handle, noting that MS can cause numbness in the hands. She also recommended timed reminders to assist with the cognitive fog that often accompanies the condition.

A few months into using the device, she noticed a remarkable change: her fatigue vanished. For years, Kathy had needed to rest in bed multiple times a day to cope with her energy levels. That necessity ceased after what she describes as her rebirth, significantly aided by UV light.

She remembers a meeting where someone commented on her high energy levels. Her daughter also observed the transformation, asking, "Mom, what are you on?" The improvement was both swift and evident. Her MS Disease Activity score dropped to the best possible level and has remained low for over a year.

MS currently has no cure, and Kathy still manages some pain and tingling sensations. However, regaining her energy has made all aspects of her life more manageable. "It's incredible," she shares. "My friends used to invite me to things, and I'd say yes, but I always canceled because I was wiped out. Well, not anymore."

Kathy is among the first individuals in the U.S. to test UV phototherapy for MS. Her compelling story could signal a significant shift. It suggests a new way of thinking about light's role in managing these difficult diseases and the body's immune response.

The Science Bit: How Does Sunlight Affect Immunity?

Scientists are actively working to understand the mechanisms by which UV light, particularly UVB light, calms the immune system. They are tracking molecules in the human skin, such as urocanic acid and lumisterol. These substances are known to affect immune activity and the behavior of white blood cells following UV exposure.

When photons, or light particles from sources like natural sunlight or medical devices, strike these molecules, a cascade of signals begins. These signals can influence various organs throughout the body. Some researchers believe this line of inquiry could lead to major new medicines for autoimmune patients.

Prue Hart, an immunologist, states, "UV light calms inflammation in the skin, the nervous system, the pancreas and the gut. Its potential is not fully realized." This suggests that controlled ultraviolet radiation might offer benefits far beyond currently understood applications, possibly impacting systemic disease processes.

Other scientists adopt a more cautious stance. Annette Langer Gould, an MS researcher, acknowledges that UV light therapy shows promise for some conditions. However, she emphasizes the need for larger, comprehensive trials for various diseases to confirm these effects and to better understand the underlying mechanisms, including how UV light affects antigen-specific cell-mediated immunity.

Confirming these effects could also solve an old puzzle regarding disease prevalence. Specifically, why do populations in geographical areas with less sunlight exposure often exhibit higher rates of certain diseases, including some autoimmune disorders and skin conditions?

A Historical Puzzle: The Latitude Connection

The investigation into UV light's benefits began, paradoxically, with an understanding of its dangers. In 1974, researcher Margaret L. Kripke discovered she could induce skin tumors in mice using UV light. Interestingly, these tumors did not grow if transplanted to another mouse, as the new host's immune system destroyed them, demonstrating an active cell-mediated immunity.

This phenomenon occurred repeatedly. However, if she suppressed the new host's immune system with drugs, the tumors thrived. This was a critical insight. It raised the question: why did the tumor grow in the first mouse? Was UV light itself suppressing its immune response, perhaps through mechanisms involving dendritic cells?

Kripke's work revealed that UV radiation posed a dual threat. It caused DNA damage, potentially leading to cancer through mutations in skin cells. Concurrently, it suppressed the immune system's surveillance in the skin, allowing nascent cancers to evade detection and leading to an increased risk of skin cancer.

This was a significant advancement in understanding skin cancer. However, it seemed counterintuitive from an evolutionary perspective. Why would our immune system relax its guard near a common cancer-causing agent like solar radiation?

It appears that immune cells within our skin must maintain a delicate balance. Our skin is the primary interface with the external world, constantly exposed to heat, cold, injuries, bites, and a myriad of microbes. For early humans living under tropical skies, solar radiation from sunlight exposure was the most frequent environmental stressor.

Prue Hart elaborates, "It's a challenge to the body. It's the most important environmental insult we have. We evolved to cope with it." If the immune system launched an aggressive attack with every touch of sunlight, chronic skin inflammation would be rampant, leading to constant rashes and skin autoimmune issues. Instead, the system adapted to exhibit a degree of tolerance, a form of UVB-mediated immunosuppression.

In ancient times, this adaptive response was generally beneficial. Damage induced by typical UV exposure was usually minor, the skin repaired itself, and life continued. The trade-off, particularly evident now as people live longer, is that sometimes skin cancer can develop. An interesting illustration is polymorphic light eruption (PLE); individuals with PLE have immune systems that do not get suppressed by sunlight, resulting in itchy rashes after sun exposure but a potentially lower likelihood of skin cancer.

The discovery of UV light's potent impact on immune responses, including its ability to trigger cell death in certain immune cells or promote the formation of apoptotic cells, founded the field of photoimmunology. Initially, scientists focused on the negative aspects of this immunosuppression. However, they soon identified positive applications. For instance, it explained why sunlight or specific light treatment often soothed psoriasis, an autoimmune disease where the immune system attacks skin cells. UVB exposure, from the sun or a lamp, helped by reducing skin inflammation.

Furthermore, this effect was not merely localized. Light applied to one patch of skin could lessen symptoms of inflammatory skin conditions elsewhere on the body. People with psoriasis frequently have other autoimmune conditions as well, and sometimes phototherapy improved these associated symptoms, hinting at systemic effects beyond the treated area of human skin. Understanding these mechanisms driving UVB-mediated is crucial for developing safer therapies.

Beyond Vitamin D: Unraveling the Real Mechanisms

For over a century, scientists have observed that many diseases, especially autoimmune and heart conditions, follow a distinct latitude pattern. After controlling for variables such as diet, exercise, and socioeconomic factors, disease rates tend to increase with greater distance from the equator. Numerous explanations were proposed, including climate, diet, and even cosmic rays, but none fully accounted for the phenomenon.

Studies, including research published in sources like the Journal of Neurology, Neurosurgery & Psychiatry, consistently show this trend. Multiple sclerosis prevalence, for example, often increases with distance from the equator. This pattern has been observed in numerous studies analyzing data collected over many decades, looking at the impact of reduced natural sunlight.

In 1940, Frank Apperly demonstrated that states with more sunshine had higher rates of skin cancer deaths but, paradoxically, fewer cancer deaths overall. He theorized that something in the sun protected against internal cancers. Later, in 1980, epidemiologists Frank and Cedric Garland identified a strong north-south pattern for colon cancer, suggesting vitamin D, synthesized in human skin through UVB exposure, was the protective factor.

At that time, vitamin D was primarily known for preventing rickets. The Garlands proposed it had a much broader role in health. Subsequently, scientists found associations between low vitamin D levels and a host of diseases, including breast cancer, diabetes, heart problems, and various autoimmune disorders. This period marked the beginning of the vitamin D era, with doctors worldwide recommending supplements.

However, as more research emerged, many rigorous trials indicated that extra vitamin D supplementation did not significantly help treat these diseases for most individuals. Most people obtain sufficient vitamin D from incidental sun exposure or their diet, with fortified dairy products and fatty fish being good sources. Whatever beneficial effects sunshine imparts to prevent diseases, it involves more than just vitamin D production; the mechanisms driving UVB-mediated immunosuppression are clearly more complex and involve other photochemical reactions in human keratinocytes.

UV Light Autoimmune Treatment: Exploring the Research

The disease exhibiting the most striking latitude pattern is multiple sclerosis (MS). MS rates are nearly zero at the equator. They increase by approximately 3.64 cases per 100,000 people for each degree of latitude, highlighting a strong correlation with reduced UV radiation.

In northern Europe and North America, MS rates can exceed 100 per 100,000 people. This geographic pattern is consistent worldwide and has, in fact, grown stronger over time. It is even observable within individual countries that span significant latitudes, such as the U.S. and Australia, suggesting that levels of ultraviolet irradiation play a role.

Focus on Multiple Sclerosis (MS)

Australia provides some of the most compelling data due to its wide range of latitudes, relatively uniform population, and robust health records. A 1981 study found MS rates increased from 12 per 100,000 in tropical Townsville to 76 per 100,000 in Hobart, located further south. This latitude-associated link was further substantiated in studies conducted in the early 2000s.

Robyn Lucas, an epidemiologist, mentioned that many initially attributed this disparity to a lack of vitamin D. "Vitamin D was the flavor of the day," she recalls. However, in 2010, Lucas encountered a study demonstrating that UV treatments protected mice against an MS-like condition without altering their vitamin D levels, piquing her curiosity about other mechanisms, such as those involving dendritic cell modulation or effects on IFN production.

This finding prompted her to re-examine her data, where she discovered a much stronger correlation with sun exposure itself. Since then, evidence supporting sunlight's protective effect on MS has emerged from various sources. For example, individuals with more sun damage on their hands, an indicator of cumulative UV exposure, tend to have significantly lower MS rates. Furthermore, research indicated that children who spent less than 30 minutes daily outdoors had double the MS risk compared to those outside for up to an hour, suggesting early life sunlight exposure is important.

Of course, these observational studies do not definitively prove causation; perhaps early MS symptoms limit outdoor activity. Consequently, researchers sought additional evidence. They found that MS relapse rates exhibit seasonality, being higher in winter. Incidence rates also show a connection to birth month, with the highest rates among those whose first trimester of gestation occurred during winter, a critical period for brain and immune system development, possibly influenced by maternal UVB exposure.

Prue Hart conducted a small clinical trial involving 20 patients with an early form of MS. Half the participants received eight weeks of narrowband UVB light therapy three times a week, a specific type of light treatment. The other half, the control group, received no light therapy. Within a week, levels of inflammatory proteins in the blood of the UV group dropped significantly and remained low even after the treatments concluded.

Three months later, the disease scores in the UV group fell by 13 percent, while the control group's scores rose by 14 percent. A year later, all subjects who did not receive UV therapy had developed full MS. In contrast, 30 percent of the group that received UVB light did not progress to full MS, indicating potentially lasting beneficial effects.

The long-lasting effect observed was particularly interesting. The UV light hadn't just suppressed existing immune cells; it seemed to reset the immune system to a more tolerant state. Hart believes UV radiation is part of our innate immune training. It appears to reprogram developing immune cells, such as T cells and dendritic cells, making them less inflammatory and more regulatory, a key aspect of mechanisms driving UVB-mediated immunosuppression.

Potential for Other Autoimmune Conditions

This concept is analogous to recent research on allergens, where early exposure to small amounts can prevent subsequent overreactions by the immune system. Hart suggests, "You get this rebalancing." She believes UV light's potential as a controller of body balance, including its influence on white blood cells and specific immune pathways, is not yet fully appreciated. This could extend to conditions like systemic lupus erythematosus or even specific skin conditions such as cutaneous lupus erythematosus (CLE).

The implications extend beyond MS or even the broader category of autoimmune diseases. Many chronic conditions have an inflammatory component. Heart disease, for instance, is partly caused by immune cells damaging blood vessel walls. Alzheimer's disease is linked to brain inflammation. Arthritis, asthma, allergies, and even depression may have inflammatory connections that could potentially be influenced by UV-mediated inflammation modulation. Our modern, predominantly indoor lifestyles might contribute to our immune systems losing their healthy, balanced state.

Effects of sun exposure have also been noted in type 1 diabetes, where the immune system attacks the pancreas. The rate of type 1 diabetes is threefold higher in southern Australia compared to northern Australia. In the U.S., rates are lowest in babies born in the fall, who gestated over the summer months, suggesting a prenatal influence of sunlight. Lucas notes, "There's a consistency of evidence across autoimmune diseases that have a similar immunopathology," pointing to conditions like lichen planus or mycosis fungoides where immune dysregulation in the skin is prominent.

For lupus patients, especially those with cutaneous lupus, UV exposure is often a trigger for skin lesions, known as CLE lesions. However, the immunomodulatory effects of controlled UVB light are being explored carefully due to this increased sensitivity. The goal is to find a therapeutic window where UVB exposure might reduce overall skin inflammation without exacerbating the skin condition. Research is ongoing to understand how specific ultraviolet irradiation protocols might offer beneficial effects for such autoimmune patients, possibly by influencing human keratinocytes to produce anti-inflammatory signals or by selectively inducing cell death (apoptosis) in overactive immune cells.

Is UV Light Therapy the Future? Hopes and Hurdles

Considering this accumulating evidence, what practical steps should be taken? Some scientists might suggest increased sun exposure for individuals at high risk of autoimmune disease. However, few doctors would broadly recommend a known carcinogen like excessive ultraviolet radiation without careful consideration of the increased risk of DNA damage and skin cancer.

The ideal solution would involve identifying the precise molecular pathway through which skin communicates with the immune system to induce relaxation or tolerance. This knowledge could then be translated into a targeted medication. The research into these mechanisms driving UVB-mediated immunosuppression is therefore critical.

John MacMahon of Cytokind poses the question, "What is the Ozempic for autoimmunity?" He speculates whether a key component within the photoimmune cascade can be identified and harnessed. He believes a pill would be preferable to a light box, as patients often prefer oral medications, doctors are more accustomed to prescribing them, and pharmaceutical companies are geared towards their production.

The Quest for a "Golden Molecule"

Prue Hart notes the "golden molecule" remains elusive, though it's evident it isn't solely vitamin D. Thus, administering UV light allows the skin to synthesize whatever this crucial substance, or substances, might be. However, pinpointing that "whatever" is a complex task, as shining UV light on human skin generates a diverse array of compounds.

Besides vitamin D, skin produces melatonin, serotonin, endorphins, and numerous other molecules, many of which are hormones or neurotransmitters. This is not surprising given the skin's role. The skin is our largest organ and an important part of the neuroendocrine system, constantly communicating with the body and brain about overall health status.

It is also a major operational site for the immune system, teeming with T cells, macrophages, dendritic cells, and other key players. The manner in which UV light interacts with this intricate mix is multifaceted. For example, a precursor to vitamin D, when energized by UV light, can form vitamin D; however, with additional UV energy, it can transform into lumisterol, a compound known for its anti-inflammatory and antitumor effects.

Scott Byrne at the University of Sydney discovered six new lipids produced by the skin following UV exposure. These lipids travel to lymph nodes, where they instruct T cells to cease proliferation. This pathway appears distinct from the one that suppresses cancer surveillance in the skin, offering hope for harnessing UV's beneficial effects, like modulating IFN production, without incurring its detrimental consequences, like excessive cell death in healthy tissue. However, the search for a single "golden molecule" will likely take considerable time. Hart suggests, "Isn't it naive to think one molecule is going to solve all the health conditions controlled by UV? It's probably multiple," reflecting the complexity of mechanisms driving UVB-mediated responses.

Practicalities and Patient Perspectives

Phototherapy itself, using devices like an excimer laser or broader UV light boxes, might not replicate all the benefits of natural sunlight. However, it doesn't necessarily need to. Its established safety profile for certain conditions, simplicity of use, and affordability mean it only needs to offer some discernible benefit to be valuable. Hart emphasizes that phototherapy is inexpensive compared to biologic drugs. She views it as a sensible supplementary treatment for inflammatory autoimmune diseases, including some inflammatory skin conditions like psoriasis.

This cost-effectiveness has attracted the attention of insurance companies. A UV light box typically costs around $2,000, whereas a leading biologic drug can cost $80,000 annually for lifelong treatment. Kaiser Permanente provided 2,200 psoriasis patients with free home UV light boxes; subsequently, fewer than a third of these patients later used biologics. Kaiser Permanente now lists at-home UV therapy as a recommended treatment for psoriasis.

However, Annette Langer Gould, the MS expert, cautions that it is premature to widely adopt this for MS. While Hart's data are encouraging, further study is essential. A large-scale clinical trial is necessary to demonstrate significant improvement and fully understand the mechanisms driving UVB-mediated immunosuppression in MS patients. Cytokind is working on such a study, but results are likely several years away.

In the meantime, phototherapy's flexibility allows individuals like Kathy Young to actively participate in their healing journey. This sense of independence is invaluable when dealing with a debilitating disease. Kathy remarks, "MS robs you of so much." For now, she has exchanged that limitation for busy, active days. She engages in weight training, yoga, charity work, and faithfully uses her UV light each morning. "It's just so empowering," she reflects. "To find a treatment that lets you actually take care of yourself is kind of amazing."

Conclusion

The journey to fully understand UV light autoimmune treatment and its effects on conditions from MS to lupus skin manifestations is still progressing. For individuals like Kathy, this approach offers a tangible sense of control and a significant improvement in well-being. While more extensive research is crucial for its widespread application and to clarify the balance between beneficial effects and risks like increased sensitivity or long-term DNA damage, the potential of using controlled UV light for autoimmune treatment continues to inspire scientists and patients alike.

The exploration of how different forms of ultraviolet radiation, including UVB light and UVA light, impact the inflammatory response, cell death, and the intricate workings of the body's immune system holds considerable promise. Further investigation into the specific mechanisms driving UVB-mediated immunosuppression may pave the way for novel therapies for a range of challenging autoimmune diseases.

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