⚠️ Paxillus Toxin — The Deadly Immune Reaction of the Brown Roll-Rim

Summary: The so‑called “Paxillus syndrome” is caused by repeated consumption of the Brown Roll‑Rim (Paxillus involutus). Unlike classic mushroom poisons, this is not a single toxin but an antigen–antibody reaction that triggers life‑threatening hemolysis (destruction of red blood cells). This article explains the biochemistry, occurrence, immune mechanism, symptoms, severity, diagnosis, treatment, and prevention.

1. Introduction

For many years, the Brown Roll‑Rim was considered edible or at least conditionally edible in parts of Europe. Only in the 20th century did it become clear that repeated consumption could lead to severe and often fatal poisoning. Today, it is classified as deadly poisonous. The reaction is immunologically mediated and unique among mushroom poisonings.

2. Biochemistry & Toxicology

• The Brown Roll‑Rim contains not a single isolated toxin but antigenic structures that trigger an immune response.

• The immune system forms antibodies against mushroom antigens, which interact with red blood cells.

• Result: immune‑mediated hemolysis (red blood cell destruction), hemoglobin release, and massive cell breakdown.

3. Which Mushroom Contains Paxillus Toxin?

• Brown Roll‑Rim — Paxillus involutus

This mushroom is widespread in central Europe, commonly found in both deciduous and coniferous forests, forming mycorrhiza with birch, spruce, and pine. For decades, it was collected for mushroom dishes — until fatal cases proved otherwise.

4. Mechanism of Action (Antigen–Antibody Reaction)

• Initial ingestion sensitizes the immune system to mushroom antigens.

• With repeated ingestion, a secondary immune response occurs.

• Antigen–antibody complexes cause massive hemolysis, leading to:

  • Severe anemia

  • Hemoglobinuria (dark, reddish urine)

  • Acute kidney failure

  • Multi‑organ failure

5. Symptoms

Latency: typically hours after re‑exposure.

• Nausea, vomiting, abdominal pain, diarrhea

• Fever, chills

• Rapid onset of jaundice (icterus)

• Dark urine due to hemoglobin release

• Shock symptoms: hypotension, tachycardia

• In severe cases: kidney failure, circulatory collapse, death

Unique feature: Some individuals may eat the mushroom for years without symptoms before suddenly developing a fatal reaction.

6. Severity & Lethality

• Paxillus syndrome is considered extremely dangerous.

• Mortality is high, especially without immediate medical intervention.

• Even small amounts consumed repeatedly over years can sensitize the body and trigger deadly crises.

7. Diagnosis

• History: repeated consumption of Brown Roll‑Rims.

• Lab findings: hemolysis (low hemoglobin, high LDH, bilirubin), hemoglobinuria, impaired kidney function.

• Special tests: detection of antibodies against mushroom antigens (specialized labs).

8. Treatment

• No specific antidote available.

• Immediate intensive care required.

• Measures include:

  • Stabilization of circulation and breathing

  • Blood transfusions

  • Exchange transfusion or plasmapheresis to remove antibodies and toxins

  • Dialysis in kidney failure

  • Supportive therapy for multi‑organ dysfunction

9. Prognosis

• Very serious — high lethality even with treatment.

• Survivors may suffer permanent kidney damage.

10. Prevention

• Never eat Brown Roll‑Rim (Paxillus involutus)!

• Education is critical, as older field guides may still list it as edible.

• Mushroom advisory centers warn explicitly against this species.

11. Historical Cases

• Most famous: death of mycologist Julius Schäffer (1944) after eating Brown Roll‑Rims; he documented his own poisoning.

• Since then, numerous fatal cases have been reported across Europe.

12. Conclusion

“Paxillus toxin” is not a classic chemical poison but the trigger of a fatal antigen–antibody reaction. The Brown Roll‑Rim (Paxillus involutus) is now recognized as deadly poisonous. Repeated ingestion can suddenly provoke a catastrophic immune response. Prevention is the only safe measure.

Disclaimer: This article is for informational purposes only and not a substitute for medical advice. In suspected mushroom poisoning, call emergency services or poison control immediately.