Eosinophil infiltration and degranulation in normal human tissue

Area of Science:

• Immunology
• Gastroenterology

Background:

• Eosinophil granule major basic protein (MBP) detection via immunofluorescence identifies eosinophil infiltration and degranulation.
• Previous studies indicated eosinophil infiltration and degranulation in diseased human tissues and normal gut.
• The current study expanded analysis to nearly all normal human organs.

Purpose of the Study:

• To investigate eosinophil infiltration and degranulation across a comprehensive range of normal human tissues.
• To determine if tissue procurement methods influence eosinophil degranulation in the normal gastrointestinal tract.

Main Methods:

• Indirect immunofluorescence was used to detect MBP in 117 normal human biopsy/autopsy specimens from various organs.
• Normal proximal jejunum samples from six patients were obtained using endoscopic forceps or a scalpel.
• Immunofluorescence analysis compared eosinophil degranulation based on procurement method.

Main Results:

• The gastrointestinal tract was the only normal organ exhibiting both significant eosinophil infiltration and degranulation.
• Spleen, lymph node, and thymus showed eosinophil infiltration but minimal degranulation.
• Eosinophil degranulation was significantly higher in jejunum specimens procured via endoscopic forceps compared to scalpel (P = 0.021).

Conclusions:

• Normal human organs consistently show both eosinophil infiltration and degranulation primarily in the gastrointestinal tract.
• Tissue procurement techniques significantly impact the observed level of eosinophil degranulation in gut tissues.
• Findings highlight the gut's unique eosinophil activity and the importance of standardized tissue handling.