[Comparison of two different tissue decalcification methods for immunohistochemistry].

Area of Science:

• Histopathology and Immunohistochemistry
• Biomedical Research
• Tissue Processing

Background:

• Decalcification is essential for analyzing calcified tissues.
• Standard decalcification methods can impact antigen detection in immunohistochemistry (IHC).
• Understanding the effects of different decalcifying agents on various antigens is critical for reliable IHC results.

Purpose of the Study:

• To evaluate the impact of 1% hydrochloric acid and 10% nitric acid on immunohistochemical staining.
• To compare the sensitivity of different antigens to acid decalcification.
• To determine optimal decalcification protocols for various tissue types.

Main Methods:

• Tissue samples (soft tumors and bone/marrow) were treated with 1% HCl or 10% HNO3 for varying durations or left untreated (control).
• Immunohistochemical staining was performed for multiple antigens (e.g., ER, PR, Ki-67, TTF-1, AE1/AE3, CD3, CD20) on treated and control samples.
• Effects were assessed based on the number of positive cells and staining intensity.

Main Results:

• Both acids decreased staining sensitivity and intensity, with effects increasing proportionally to treatment time.
• Bone tissue was less affected than calcified soft tissues.
• Antigen sensitivity varied: TTF-1 and Ki-67 were most vulnerable, while ER, CD3, and CD20 were least affected.

Conclusions:

• Hydrochloric acid and nitric acid decalcification generally reduce IHC sensitivity, with differential impacts on antigens.
• 10% nitric acid is recommended for larger bone tissues; 1% hydrochloric acid is preferred for bone marrow and soft tissue-rich bone samples.
• Careful selection of decalcifying agent and protocol is necessary to preserve antigenicity for accurate IHC diagnosis.