Low secretory IgA left a nurse open to every infection
This is case 8 in the book IBSyncrasy
Mary, a nurse, caught every infection going and had daily gut symptoms for 16 months. Her case shows how low secretory IgA, a weak first line of gut defense, can sit behind frequent infections and IBS, and what her plan started with.
Mary's casecase study
1DemographicsStop 1 of 8
Who Mary is
Mary was a 39-year-old nurse and mother of two when she came to the clinic where I work as a scientific collaborator. She had worked in hospitals for 18 years. She was born by C-section and was not breastfed.
- 39 years old
- Woman
- Nurse for 18 years
- Mother of two
- Born by C-section
- Tonsils removed
- Daily gut symptoms for 16 months
Statistics from the practice for similar cases
- Number of cases
- 55
- Age range
- Any
- Success rate
- >80%
- Treatment duration
- 1 to 3 months
- Most common symptom
- Frequent infections
- Most common trigger
- Removal of a lymphatic organ
Average improvement score
Figures from the practice's own records of cases like this one, not from a published study.
Her main complaints were loose stools, bloating, frequent infections, fatigue and allergies. Her full case is described in the book IBSyncrasy.
2IntroductionStop 2 of 8
What secretory IgA does
Secretory IgA (sIgA) is the most abundant antibody on the body's mucous surfaces, including the gut. It works as the first line of defense: it binds bacteria, viruses and toxins in the gut and keeps them from attaching to the gut lining, a process called immune exclusion.1 It also helps shape which bacteria live in the gut.1
Low sIgA in stool or saliva is not the same as selective IgA deficiency. Selective IgA deficiency is the most common primary immune deficiency, defined by low IgA in the blood. Most people with it have no symptoms, but some have repeated respiratory and gut infections, allergies or autoimmune conditions.2 Low sIgA in a stool test reflects the local defense of the gut, which can change with stress, infections, diet and the gut bacteria.
Several factors can affect sIgA. In animal studies, stress raised or lowered intestinal sIgA, depending on how strong and how long it was.3 In mice, sIgA from breast milk shaped the gut bacteria and the gut lining into adulthood.4 Removing the tonsils or the appendix has also been linked with lower sIgA. In a study of 160 adults, serum secretory IgA after tonsillectomy was less than half that of controls (2.19 against 4.97 mg/dl), the drop lasted more than 20 years, and it was largest in people who had both operations.5 Not every study agrees, since one study in children found similar total salivary IgA within the first year after tonsillectomy.6 Ways to support sIgA are discussed in how to increase secretory IgA naturally.
3MeetingStop 3 of 8
Meeting Mary
Despite regular vaccinations, Mary often fell ill, with low fevers, upper respiratory infections, urinary complaints and gastroenteritis. At first, she put this down to the hospital environment, but she soon noticed that her colleagues did not get sick as often as she did.
As a result, she took many antibiotic courses, and her cultures usually grew bacteria such as E. coli and Klebsiella pneumoniae. After the birth of her second daughter, her health got worse. For the 16 months before we met, she had gut symptoms every day, despite medical treatment and changes to her lifestyle.
Looking back, four factors seemed to have built on each other.
C-section birth
Mary was born by C-section, so her gut was first exposed to skin and hospital bacteria.7
No breastfeeding
She was not breastfed, so she missed the sIgA that a mother passes to her baby through breast milk.4
Tonsils removed
Tonsil removal has been linked with lower secretory IgA for more than 20 years after surgery.5
Hospital work
Years in hospitals meant daily contact with many microbes and a constant load on her defenses.
4DiagnosticsStop 4 of 8
Diagnostics: the defense, not the reaction
Mary's history pointed to a problem with the gut's first line of defense rather than with her immune system's ability to react. Her tests therefore focused on sIgA in stool and saliva, her gut bacteria and markers of immune activity.
Her fevers never went above 38 °C, so the problem did not seem to be her immune system's ability to react. More likely, her first line of defense could not keep out new microbes efficiently.
Tonsil removal has been linked with lower secretory IgA, and in one study the drop was still present more than 20 years later.5 In my practice, frequent infections of mucosal organs often come with it.
Stress can make almost any symptom worse, and it also affects sIgA directly, raising or lowering it depending on how strong and how long it is.3
Low sIgA cannot be seen on a colonoscopy, but it can be measured, in stool for the gut and in saliva for the mouth.
Other details completed her picture:
- Low-grade fevers
- Loose stools
- Fatigue
- Allergies
- Recurrent urinary infections
- Bloating and flatulence
- No breastfeeding
5ResultsStop 5 of 8
Results: no sIgA at all
Mary's stool sIgA was undetectable. Her gut bacteria were heavily imbalanced, her complement factors were high and her salivary IgA was low.
Of the 11 results we reviewed, four guided the care plan.
Undetectable secretory IgA
With no sIgA, opportunistic bacteria can keep the gut lining inflamed, which fits her core symptoms.1
Heavy dysbiosis
An imbalance this strong harms the immune defense of the gut lining, and restoring the gut bacteria comes before sIgA can recover.
High complement factors
Complement factors that stay high mean her immune system was always switched on, which may explain her fatigue.
Low salivary IgA
Salivary IgA helps prevent infections that enter through food and air, so the mouth's defense matters too.
6Care planStop 6 of 8
Care plan: one more antibiotic, then rebuilding
It may sound like a paradox, but in Mary's case the plan started with one more antibiotic course. The total bacterial load had to come down before new beneficial bacteria could be introduced and steps to raise sIgA production could work.
Every case is different, so Mary's plan describes her care and is not a plan for anyone else. Frequent infections always need a doctor's assessment, including a blood test for IgA when a genetic deficiency is possible.2
7Follow-upStop 7 of 8
Follow-up: better, except after night shifts
On day 33, Mary came back to my office. She was optimistic, because her symptoms had not returned, but she had noticed that bloating and several bowel movements a day came back after night shifts. Overall, her bloating, the mucus in her stools and her respiratory symptoms had all eased. We set the next appointment for 45 days later.
8ConclusionStop 8 of 8
Conclusion: an overlooked defense
In my experience, low sIgA is often missed when IBS is diagnosed, because most research on it has looked at more serious conditions, such as immune deficiency, autoimmune disease and cancer. Without enough sIgA, bacteria that are not normally harmful can cause more trouble, and infections of the gut become more frequent.1
Rebuilding sIgA takes time. In some people, it rises only to the low end of normal, and genetic factors may prevent higher values. In Mary's case, her night shifts were the clearest limit, since sleep and regular rest periods support recovery.
What Mary's case shows
- Low sIgA is often overlooked in IBS, in my experience.
- Without enough sIgA, bacteria that are normally harmless can cause more gut infections.1
- Bloating, loose stools and frequent diarrhea are the most common symptoms, and nausea and vomiting can also occur.
- Rebuilding sIgA takes time, and in some people it reaches only the low end of normal.
- Daily habits matter for sIgA, and rest periods such as sleep and overnight fasting help.
Frequently asked questions
Secretory IgA is the main antibody on the body's mucous surfaces, such as the gut, mouth and airways. It binds microbes and toxins and keeps them from attaching to the lining.1
High stool secretory IgA usually points to an active immune response in the gut, for example to an infection or an overgrowth of harmful bacteria. It is read together with the rest of the stool test.
Most people with low blood IgA have no symptoms.2 Frequent infections, ongoing diarrhea or autoimmune symptoms, though, are worth checking with a doctor.
The first step is finding the cause. In Mary's case, the plan first lowered the bacterial load, then rebuilt the gut bacteria. Sleep and stress also matter, since stress affects sIgA.3
References
7 studies
- Mantis NJ, Rol N, Corthésy B. Secretory IgA's complex roles in immunity and mucosal homeostasis in the gut. Mucosal Immunol. 2011.
- Yel L. Selective IgA deficiency. J Clin Immunol. 2010.
- Campos-Rodríguez R, Godínez-Victoria M, Abarca-Rojano E, et al. Stress modulates intestinal secretory immunoglobulin A. Front Integr Neurosci. 2013.
- Rogier EW, Frantz AL, Bruno ME, et al. Secretory antibodies in breast milk promote long-term intestinal homeostasis by regulating the gut microbiota and host gene expression. Proc Natl Acad Sci U S A. 2014.
- Andreu-Ballester JC, Pérez-Griera J, Ballester F, et al. Secretory immunoglobulin A (sIgA) deficiency in serum of patients with GALTectomy (appendectomy and tonsillectomy). Clin Immunol. 2007.
- Childers NK, Powell WD, Tong G, et al. Human salivary immunoglobulin and antigen-specific antibody activity after tonsillectomy. Oral Microbiol Immunol. 2001.
- Shao Y, Forster SC, Tsaliki E, et al. Stunted microbiota and opportunistic pathogen colonization in caesarean-section birth. Nature. 2019.
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Cite this article
Prevedoros, T. (2022, September 17). Low secretory IgA left a nurse open to every infection. Gut Pathways. https://gutpathways.com/case-studies/secretory-iga-ibs/
