What Is the Microbiota and How Does It Affect My APS?

What Is the Microbiota and How Does It Affect My APS?

APS Program Community Q&A Series

Yu (Ray) Zuo, MD, MSCS
Yu (Ray) Zuo, MD, MSCS

Our bodies are home to trillions of tiny microorganisms such as bacteria and fungi. We call this community of microorganisms our "microbiota." One of the most discussed examples of microbiota is those microorganisms living in our gut. There, billions of tiny, invisible critters help us digest food, protect against bad bacteria that cause disease, and produce vitamins. Recent research has suggested that these microorganisms also play a big role in regulating how our immune system works. In this edition of the APS Program Community Q&A Series, Dr. Yu (Ray) Zuo discusses the microbiota and how it affects APS.

As we all know, antiphospholipid syndrome (APS) is a condition where the immune system goes a bit haywire. It starts making antiphospholipid antibodies that can cause problems, like forming clots in our blood vessels and promoting inflammation in various organs. There is growing evidence that the microbiota also plays a role in APS:

  • For instance, when researchers injected certain proteins from bad bacteria such as H. influenzae, N. gonorrhoeae, or T. toxoid into mice, the mice developed antiphospholipid antibodies (1).
  • In another study with mice, altering their gut bacteria prevented serious blood clotting issues (2).
  • In a more recent study, a specific type of bacteria in the human gut, called R. intestinalis, was linked to the development of APS (3). This type of bacteria seems to mimic certain parts of a protein called beta-2 glycoprotein I (β2GPI) that is related to APS, and therefore antibodies produced against R. intestinalis can also recognize the human β2GPI protein.

Studies of other autoimmune diseases, such as lupus, have also revealed that when our gut's microorganisms are not in the right balance, the body experiences more inflammation (4). In APS, chronic inflammation is part of the problem. Taken together, these findings suggest that gut bacteria might trigger or sustain immune reactions related to APS and contribute to disease features.

While more research in this area is needed for APS, maintaining a healthy microbiota is crucial for our overall well-being. Here are some lifestyle practices that can help promote a healthy microbiota:

  • Eat a variety of healthy foods: Consume various fruits, vegetables, whole grains, and legumes. Different types of fiber found in these foods nourish different strains of helpful bacteria in the gut.
  • Incorporate fermented foods into your diet: Yogurt, sauerkraut, and miso contain beneficial probiotics that support a healthy gut microbiota.
  • Limit your intake of artificial sweeteners: Some studies suggest that artificial sweeteners negatively impact the gut microbiota.
  • Exercise regularly: Physical activity has been associated with a more diverse and overall healthier gut microbiota.
  • Limit refined sugars and processed foods: Diets high in refined sugars and processed foods negatively impact the diversity of gut bacteria.
  • Get adequate sleep: Poor sleep patterns may affect the gut microbiota. Aim for 7-9 hours of quality sleep per night to support overall health.

In summary, our gut microorganisms affect how our immune system behaves, and when things go off track, it can contribute to disease, including APS. Researchers are still figuring out the details, but it seems likely that we will be able to offer treatments related to the microbiota down the road. In the meantime, following the above steps to maintain a healthy microbiota is crucial for our overall health.


  1. Blank M, Krause I, Fridkin M, Keller N, Kopolovic J, Goldberg I, et al. Bacterial induction of autoantibodies to beta2-glycoprotein-I accounts for the infectious etiology of antiphospholipid syndrome. J Clin Invest. 2002;109(6):797-804.
  2. Abstracts of the 2013 Annual Meeting of the American College of Rheumatology. October 25-30, 2013. San Diego, California, USA. Arthritis Rheum. 2013;65(10 Suppl):S1-1331.
  3. Ruff WE, Dehner C, Kim WJ, Pagovich O, Aguiar CL, Yu AT, et al. Pathogenic Autoreactive T and B Cells Cross-React with Mimotopes Expressed by a Common Human Gut Commensal to Trigger Autoimmunity. Cell Host Microbe. 2019;26(1):100-13 e8.
  4. Pan Q, Guo F, Huang Y, Li A, Chen S, Chen J, et al. Gut Microbiota Dysbiosis in Systemic Lupus Erythematosus: Novel Insights into Mechanisms and Promising Therapeutic Strategies. Front Immunol. 2021;12:799788.

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