Autoimmune Diseases in Women: Why They Suffer Most and How Innovation Is Fighting Back

Autoimmune disease is not just a clinical problem; it is one of the largest and most overlooked opportunities in women's health investing. Women make up the majority of autoimmune patients, yet innovation, funding, and care models have lagged far behind the scale of the need.

This article does not offer medical advice. Instead, it looks at autoimmune diseases in women through an investing lens: why women are disproportionately affected, where new diagnostics and therapies are emerging, and how investors can back companies improving outcomes for women. Throughout, we highlight how platforms like Portfolia’s women’s health funds are helping direct capital into autoimmune innovation with both impact and return in mind.

What is an Autoimmune Disease?

Autoimmune diseases occur when the body's immune system malfunctions and mistakenly attacks healthy cells, tissues, and organs. Unlike other chronic conditions where external factors or genetic mutations drive disease progression, autoimmune disorders represent a fundamental breakdown in the body's ability to distinguish self from foreign invaders.

The immune system, which is designed to protect against bacteria, viruses, and other pathogens, starts turning against the very tissues it should defend.

The statistics reveal a striking gender disparity: women account for approximately 78 percent of all autoimmune disease patients. Women are affected two to three times more often than men across most autoimmune conditions, with some diseases showing even more dramatic imbalances.

• Sjögren's syndrome affects women at a ratio of 19 to 1 compared to men
• Lupus shows a 9 to 1 female predominance

Common autoimmune conditions that disproportionately affect women include:

• Systemic lupus erythematosus
• Rheumatoid arthritis
• Multiple sclerosis
• Hashimoto's thyroiditis
• Graves' disease
• Inflammatory bowel disease
• Sjögren's syndrome
• Psoriasis

Collectively, autoimmune diseases represent the third most common disease category in the United States after cancer and cardiovascular disease, affecting approximately 5 to 8 percent of the population, or 14 to 22 million Americans.

Given this burden, autoimmune conditions should be viewed as a core women's health category rather than a specialty niche. The NIH even established the Office of Autoimmune Disease Research within the Office of Research on Women's Health to reflect this reality and to acknowledge that understanding autoimmune disease is inseparable from understanding women's health.

Why are Autoimmune Diseases more Common in Women?

A landmark 2024 study from Stanford University may have finally cracked the code on why women face dramatically higher autoimmune risk. The research, published in Cell, identified a molecule called Xist as a major driver of sex biased autoimmunity.

Xist is produced only in female cells to inactivate one of the two X chromosomes, which prevents a toxic double dose of X chromosome genes. However, the proteins that associate with Xist can trigger autoantibodies, the immune system proteins that mistakenly attack the body's own tissues.

When researchers engineered male mice to produce Xist, these males developed autoimmune symptoms at rates approaching those of females. This showed that Xist itself, not only female hormones or having two X chromosomes, plays a causal role in autoimmunity. As Dr. Howard Chang, the study's senior author, explained:

"This is like a completely different and novel explanation for female bias in immune disease."

Beyond genetics, several factors elevate autoimmune disease risk for women:

• Hormonal influences
  • Estrogen enhances immune function
  • This boosts infection defense but may also increase susceptibility to autoimmune reactions
    ‍
• Hormonal transition windows
  • Puberty
  • Pregnancy
  • Postpartum period
  • Menopause
    Many autoimmune diseases emerge or flare during these transitions.
    ‍
• Pregnancy and immune shifts
  • The immune system adapts to tolerate the fetus, which is genetically half foreign
  • Many women experience remission of autoimmune disease during pregnancy
  • Intense flare ups are common after childbirth when the immune system rebounds
  • Approximately 1 in 12 women will develop an autoimmune thyroid condition after giving birth
    ‍
• Social and environmental stressors
  • Chronic stress disrupts hormonal balance and weakens immune regulation
  • Emotional stress is a well documented trigger for autoimmune onset and flares

Research gaps and the historical exclusion of women from clinical studies have left us with incomplete understanding of how autoimmune mechanisms differ between sexes. That is now starting to change, but the evidence is already clear: autoimmune disease in women is driven by a powerful combination of biology, hormones, and environment.

Where are the Biggest Gaps in Autoimmune Diagnosis and Care for Women?

The average person with an autoimmune disease sees four different doctors over nearly four years before receiving a correct diagnosis. For many women, this journey is even longer and more frustrating.

Symptoms like fatigue, joint pain, and mood changes are frequently dismissed as:

• Stress
• Anxiety
• Depression
• Hormonal fluctuations

rather than investigated as potential signs of autoimmune disease.

A 2025 study found that patients whose autoimmune disease was misdiagnosed as psychosomatic or psychiatric reported lasting psychological harm:

• Over 80 percent said it damaged their self worth
• 72 percent reported the misdiagnosis still upset them even decades later

As one patient described:

"One doctor told me I was making myself feel pain and I still can't forget those words."

The multi organ nature of many autoimmune conditions creates additional diagnostic challenges. Symptoms that fluctuate and affect different body systems at different times confound standard clinical workflows that are designed around single organ specialty care.

Women with complex autoimmune conditions often need coordinated care across:

• Rheumatology
• Neurology
• Gynecology
• Mental health
• Primary care

Integrated autoimmune care for women is still the exception, not the norm.

Gaps that particularly affect women include:

• Diagnosis and referral
  • Long delays before appropriate specialist referral
  • Symptoms attributed to mental health rather than investigated as autoimmune
    ‍
• Mental health support
  • Depression, anxiety, and trauma from years of invalidation
  • Limited integrated mental health support within autoimmune care
    ‍
• Workplace and daily life
  • Limited accommodations for fatigue, pain, or flare patterns
  • Autoimmune disease as an "invisible illness" that others cannot see or easily understand

These gaps are painful for patients and costly for employers and health systems, which makes them a critical focus for autoimmune innovation.

How Big is the Autoimmune Market Opportunity and Why is it Underfunded?

The global autoimmune disease therapeutics market exceeded 120 billion dollars in 2024 and is projected to reach 215 to 250 billion dollars by 2033 or 2034, growing at a compound annual growth rate of approximately 5 to 7 percent.

The diagnostics market adds another 5 to 6 billion dollars, and is expected to exceed 10 billion dollars by 2034. These figures encompass treatments for more than 80 recognized autoimmune conditions across rheumatology, neurology, dermatology, and gastroenterology.

Yet autoimmune disease research has historically been underfunded relative to its burden. For example:

• In fiscal year 2020, NIH spent 1.1 billion dollars, only 2.6 percent of its total obligations, on autoimmune disease research
• Diseases that predominantly affect women, including migraines, endometriosis, and chronic fatigue syndrome, consistently receive a fraction of the funding allocated to conditions with similar disability burdens

Traditional venture capital has often overlooked chronic, complex, multi system conditions in favor of more straightforward targets. From an investment perspective autoimmune diseases can look challenging:

• Long term management rather than one time cures
• Heterogeneous patient populations
• Need for sophisticated diagnostics and stratification

The flip side is that these same characteristics create durable business models with:

• Recurring revenue
• High patient lifetime value
• Deep, long term patient relationships

The true autoimmune market opportunity is likely even larger than current estimates because:

• Many patients remain undiagnosed
• Fragmented care prevents optimal treatment adherence
• Better diagnostics and care coordination can dramatically expand the treated population

Where is Innovation Emerging in Autoimmune Care for Women?

Innovation in autoimmune diseases in women is accelerating across diagnostics, therapies, care models, and digital platforms.

Diagnostics and Data Tools Reshaping Autoimmune Detection

Artificial intelligence and multi omics approaches are transforming autoimmune diagnosis. Machine learning algorithms can process genomic, proteomic, and clinical data to identify biomarkers associated with disease onset and progression.

These tools can spot patterns across fragmented health records that clinicians might miss, which can reduce the years long diagnostic journey many women endure.

Key directions include:

• Advanced biomarker panels that differentiate autoimmune disease from functional symptoms
• Imaging and lab tools that detect early disease activity
• Data platforms that combine electronic health records and real world data to flag high risk patients earlier

For investors, strong diagnostic companies show:

• Clear metrics for reducing diagnostic delay
• Integration into existing clinical workflows
• Evidence they reduce misdiagnosis for women

Therapies and care models evolving for women

CAR-T cell therapy, originally developed for cancer, is now showing remarkable results in autoimmune disease. In groundbreaking research from Germany, patients with lupus, systemic sclerosis, and myositis achieved drug free remission after a single CAR T infusion.

Some lupus patients have remained disease free for over three years. As one researcher reported:

"They lose their autoantibodies which trigger the disease, and they don't have any symptoms any more."

The therapeutic pipeline now includes:

• CAR T cell trials for lupus, myasthenia gravis, and other autoimmune disorders
• Next generation biologics and targeted therapies with more precise mechanisms
• Cell based approaches that reset immune tolerance rather than only suppressing activity

At the same time, integrated care models are emerging that combine:

• Rheumatology, neurology, gynecology, mental health, and primary care
• Digital health tools and remote monitoring for flare tracking and medication adherence
• Value based care models that reward long term outcomes, not just acute interventions

These models are particularly relevant for autoimmune diseases in women, because they reflect how symptoms cross specialties over time.

Digital platforms, communities, and employer programs

Virtual clinics and condition specific platforms are creating new ways to deliver autoimmune care:

• Online care teams that understand chronic autoimmune conditions and women's lived experience
• Peer support communities that reduce isolation and improve self management
• Content and coaching tailored to women who are balancing disease management with caregiving and careers

Employers are beginning to recognize chronic autoimmune conditions as a workforce issue. Some are introducing:

• Benefits programs that cover specialists, infusion centers, and digital autoimmune care
• Flexible work and accommodations that reflect flare patterns
• Targeted support for women at high risk of burnout due to chronic illness

These models create recurring revenue and valuable data assets, which makes them compelling for women's health investing.

How does Autoimmune Disease fit Portfolia's Women's Health Investing Thesis?

Portfolia defines women's health broadly. It includes:

• Conditions that affect women exclusively
• Conditions that affect women differently
• Conditions that affect women disproportionately

With 78 percent of autoimmune patients being women, autoimmune disease is one of the clearest examples of a condition that affects women disproportionately and differently.

Autoimmune disease is a core focus area for Portfolia Women's Health Fund IV, alongside cardiovascular disease, osteoporosis, menopause, and mental health. These conditions share several characteristics:

• They have been historically underfunded
• They predominantly or disproportionately affect women
• They represent significant market opportunities as innovation and awareness grow

Autoimmune pathways also intersect with other Portfolia themes:

• Hormonal transitions during reproductive years, pregnancy, and menopause trigger autoimmune onset and flares, connecting to fertility and menopause investments
• Chronic inflammation drives both autoimmune disease and cardiovascular risk, linking to heart health focus areas
• Data infrastructure companies that aggregate health records and identify disease patterns can serve autoimmune, cardiovascular, fertility, and mental health markets at the same time

This is why autoimmune innovation is not a side note in Portfolia's strategy. It is a central pillar of how the fund views the future of women's health.

What should Investors ask before backing Autoimmune-Focused Companies?

1. Diagnosis and flare prediction

Investors should seek clear metrics for reducing diagnostic delay and improving early detection. Helpful questions include:

• Does this solution help identify high risk women sooner or flag flares earlier?
• How does it integrate with existing clinical workflows and health data systems?
• Does it shorten the diagnostic journey that currently spans four years and four doctors on average?

Even modest improvements in time to diagnosis can create meaningful value in autoimmune diseases in women.

2. Path to value for patients, payers, and employers

Strong autoimmune investments define outcomes for:

• Symptom control and flare reduction
• Quality of life and daily function
• Work participation and productivity

They also show:

• Cost impact for health plans and employers, including reduced hospitalizations and disability
• Clear reimbursement pathways or benefits strategies that support adoption at scale

Because autoimmune disease is chronic, these companies can build durable business models, but only if value is clearly demonstrated to those who pay.

3. Women's lived experience in product design

The best autoimmune companies center women's lived experience. Investors can look for:

• Patient involvement in research, design, and feedback loops
• Clinical studies that reflect diversity in age, race, ethnicity, and life stage
• Messaging and access strategies that reflect how women actually navigate autoimmune care, including the skepticism that comes after years of dismissal or misdiagnosis

This is not only the right thing to do, it is also a competitive advantage.

Why is Now the Right Moment to Invest in Autoimmune Innovation for Women?

Multiple forces are converging to create an unprecedented window for autoimmune innovation.

Key dynamics include:

• Rising incidence and awareness
  • Long COVID and post infection immune complications have renewed attention on immune mediated conditions
  • Research shows that COVID infection increases the risk of developing new autoimmune diseases, which may expand the patient population
    ‍
• Policy and research momentum
  • The NIH created a dedicated Office of Autoimmune Disease Research
  • In January 2025, NIH released its first strategic plan for autoimmune disease research
  • Public private partnerships are working to identify new therapeutic targets
    ‍
• Enabling technologies
  • Artificial intelligence can analyze complex multi omics data to identify disease signatures and predict responses
  • Home diagnostics and remote monitoring can track disease activity between clinic visits
  • CAR T and other cell therapies are demonstrating that drug free remission may be possible for some patients

Investors who move now can help shape standards of care and capture early leadership in a category that is finally receiving the attention it deserves, especially for women.

How can Investors Partner with Portfolia to Advance Autoimmune Innovation?

Portfolia pioneered women's health investing and has built the most active investment platform in this space, with over 100 investments across more than 46 health companies.

The Portfolia model brings together:

• A network of over 2,000 members who contribute industry expertise, clinical perspective, and lived experience
• A focus on conditions that affect women exclusively, differently, or disproportionately
• Deep experience in diligencing complex women's health markets, including autoimmune disease

Women's Health Fund IV provides diversified exposure across autoimmune disease, cardiovascular health, menopause, mental health, osteoporosis, fertility, and more. The fund supports founders who understand both the science and the realities of being a woman living with chronic disease.

If you are an accredited investor interested in women's health venture capital and in backing companies that are changing the future of autoimmune care for women, you can connect with the Portfolia team to explore current women's health funds and opportunities.

Disclaimer: This material is provided for informational purposes only and does not constitute an offer to sell or a solicitation of an offer to buy securities. Investment decisions should be made after reviewing complete fund documentation and consulting with appropriate advisors.

‍