10 questions about immune system

In the past, every physician personally embraced the entirety of medicine as a single, unified science. It was also common for doctors to be scholars, writers, and philosophers at the same time. This remained true up until the late 19th and early 20th centuries. As medicine advanced, the sheer volume of knowledge and skills became too great for any one person to master, leading to the emergence of increasingly narrow specialties. Pediatric immunology is one such specialty, and it is still a relatively young field.

In May 2016, a medical symposium with international participation took place under the title “Diagnosis of Primary Immunodeficiencies at Different Levels of Pediatric Healthcare” as part of the Central and Eastern European J Project initiative. This annual event is organized by the Department of Pediatric Infectious Diseases and Pediatric Immunology at the Shupyk National Medical Academy of Postgraduate Education together with the Ukrainian Association of Pediatric Immunology. Each year, the conference is held in different cities across Ukraine, aiming to raise awareness about primary immunodeficiencies among pediatricians, family doctors, and neonatologists. That year, the symposium, which was the 12th of its kind in Ukraine, was held in Chernivtsi.

Back in Kyiv, the organizing doctors were carefully planning the conference program. We decided to open the event by asking the attending physicians 10 questions about primary immunodeficiencies and basic immunology. A few months later, after creating this website, I came across the analysis of those questions on my laptop and thought it would be worth sharing.

Over 100 physicians participated in the survey. Responses from pediatric immunologists were intentionally excluded, as we wanted to see how well non-immunologist doctors who work with children understood key immunology concepts. We also wanted to assess whether the conference itself had value as an educational initiative. To minimize guessing, each question included an option for “I don’t know.”

Sample size: 62 completed questionnaires. About 50% were pediatricians, around 30% were family physicians, along with several pediatric infectious disease specialists, a pediatric cardiologist, and a pediatric surgeon.

1. Which of the following organs of the immune system is considered a central (primary) organ?
Bone marrow
Lymph node
Spleen
Peyer’s patches

The correct answer was marked in green, incorrect answers in various shades of red, and “unable to answer” was shown in gray.

The first question was answered quite well.

2. Which class of immunoglobulins indicates an acute infectious process?
IgA
IgG
IgM
IgD

Nearly half of the physicians did not know the correct answer regarding immunoglobulins. Doctors in Chernivtsi were no different from their colleagues in Chernihiv, Kyiv, or other cities. It is reasonable to assume that the same situation exists across the country, and likely in neighboring countries as well.

This helps explain why diagnoses of “chronic Epstein-Barr infection” or “chronic cytomegalovirus infection” are still being made based solely on positive IgG results, leading to the treatment of a non-existent illness for months or even years.

3. What is a primary immunodeficiency?
A condition that develops due to poor nutrition
Genetically determined abnormalities of the immune system
An immune condition resulting from frequent acute respiratory infections
A condition caused by thymomegaly

This question was no longer general but specifically about primary immunodeficiencies. It was encouraging to see that many pediatric doctors correctly identified these as genetic abnormalities. However, there was still a downside: among the three incorrect answers, the most common choice was “frequent respiratory infections.” In other words, many physicians mistakenly believe that frequent colds and bronchitis mean “immunity has dropped.” Dropped and shattered, apparently. So now the question becomes, “How do we boost immunity?” And then we wonder why every grandmother in the courtyard insists that her grandchild’s runny nose means their immunity needs to be “boosted” again.

In reality, the immune system is trained by respiratory infections. If a child catches a cold ten times and recovers within a week each time, is that really an immunodeficiency?

4. Which primary immunodeficiencies are the most common?
Antibody deficiencies
Combined immunodeficiencies
Autoinflammatory diseases
Phagocytic defects

This was an even more challenging question, one that typically only immunologists can answer accurately. The responses were as expected, so nothing surprising here. Let’s continue.

Is an enlarged thymus (thymomegaly) a sign of immunodeficiency?
Yes, it is associated with congenital immunodeficiency
No

Only about half answered this one correctly. I’ve often seen medical records from different cities where “thymomegaly of such-and-such degree” is casually added as a comorbidity to the primary diagnosis.

A large thymus is normal for children, especially infants. The thymus naturally decreases in size with age. While true thymomegaly is possible, it is extremely rare. Yet many pediatricians in infant wards end up diagnosing “thymomegaly” in nearly every baby they see.

6. Which immunodeficiency is associated with the so-called “Slavic mutation”?
DiGeorge syndrome
Netherton syndrome
Nijmegen breakage syndrome
Bruton’s disease

The physicians surveyed honestly admitted they did not know the answer. These were exactly the kinds of questions discussed at the conference. Children with such conditions could very well be among their patients.

7. Which of the following microorganisms causes disease only in immunocompromised patients?
Pneumococcus
Enterovirus
Influenza virus
Pneumocystis

Well, that’s all correct. Maybe all this criticism is unnecessary. But the idea of “immunity that periodically drops” and the confusion around immunoglobulins—that’s a bit troubling. On the bright side, knowledge about pneumocystis pneumonia is solid, and that’s good news for children.

8. In which of the following conditions should immunodeficiency be suspected?
Cerebral aspergillosis
Acute intestinal infection
Kawasaki syndrome
Frequent obstructive bronchitis

The next question was quite specific. The correct answer wasn’t expected to be among the top choices. Yet again, frequent bronchitis was the most popular response. There seems to be a common misconception that frequent bronchitis and colds mean immunity is “dropping.” This is simply not true.

9. Which of the following treatments is not used in patients with immunodeficiency?
Bone marrow transplantation
Intravenous immunoglobulin infusion
Immunostimulatory therapy
Antibiotic therapy

This is a highly specialized, professional question, reinforcing the need for ongoing educational efforts.

10. Which of these symptoms most likely indicate immunodeficiency?
Diaper dermatitis
Thrush during breastfeeding in the first months of life
Repeated presence of Candida albicans in stool samples
Recurrent thrush in infants

The response rates to this question were quite good.

This was the final question. Thanks to all the doctors who attended the conference. Unfortunately, it wasn’t possible to conduct the same survey after the presentations and lectures, which would likely have shown improved results. The conclusions are yours to draw.

Questions prepared by: Maria Teslenko.
Edited under the guidance of Prof. Lyudmyla Chernyshova: Fedir Lapiy, Anastasia Bondarenko, Yurii Stepanovsky, Anna Gilfanova.
Analysis by: Stepan Beglaryan.