Immunohistochemical differentiation between histiocytic and lymphoid neoplasms

Area of Science:

• Immunohistochemistry
• Hematopathology
• Cellular Biology

Background:

• Lysozyme was the primary immunohistochemical marker for histiocytes.
• Few lymphoreticular neoplasms of histiocytic origin were identified using lysozyme.
• Alpha-1-anti-trypsin emerged as a superior marker for malignant histiocytes.

Purpose of the Study:

• To evaluate alpha-1-anti-trypsin as a marker for malignant histiocytes.
• To develop and assess a new antiserum (S22) for identifying histiocytes and neutrophils.
• To compare the efficacy of S22, lysozyme, and alpha-1-anti-trypsin in diagnosing histiocytic and T-cell neoplasms.

Main Methods:

• Immunization of rabbits with human blood monocytes to produce antiserum S22.
• Immunohistochemical staining of paraffin-embedded tissues using antisera against lysozyme, alpha-1-anti-trypsin, and S22.
• Analysis of stained tissues including reactive histiocytes, histiocytic proliferations, leukemic infiltrates, and lymphoreticular tumors.

Main Results:

• Alpha-1-anti-trypsin demonstrated the highest reliability in marking malignant histiocytes.
• Antiserum S22 specifically stained histiocytes and neutrophils in paraffin sections.
• The uncharacterized antigen recognized by S22 presents a potential alternative marker.

Conclusions:

• Alpha-1-anti-trypsin is the current gold standard for identifying malignant histiocytes.
• Antiserum S22 is a promising new tool for the immunohistochemical detection of histiocytes and neutrophils.
• Further characterization of the S22 antigen may lead to improved diagnostic markers in hematopathology.