Prolactin-Linked Plasma Cell-Macrophage Immune Phenotype in Synchronous Bilateral Plasma Cell Mastitis: A Two-Center...

Area of Science:

• Breast disease research
• Immunology
• Endocrinology

Background:

• Plasma cell mastitis (PCM) is a chronic inflammatory breast condition.
• Bilateral PCM occurs in about 20% of cases, but its underlying cause (local vs. systemic) is unclear.

Purpose of the Study:

• Investigate if bilateral PCM is associated with a specific immune profile centered around prolactin (PRL).
• Develop a biomarker model to identify patients with bilateral PCM.

Main Methods:

• Retrospective study of 330 PCM patients (300 for development, 40 for external validation).
• Used LASSO and logistic regression to select predictors, comparing five machine learning algorithms.
• Performed immunohistochemistry for CD38, CD138, and CD68 on breast tissue.

Main Results:

• A five-variable model (including PRL) achieved high discrimination (AUCs 0.838 and 0.805).
• Prolactin (PRL) was the key predictor, showing a non-linear contribution.
• Bilateral PCM cases had higher tissue immune cell markers (CD38, CD138, CD68) and PRL levels correlated with these markers.

Conclusions:

• Synchronous bilateral PCM is linked to a dual immune pattern involving circulating PRL and local immune cells.
• This suggests bilateral PCM may represent a systemic immune issue, not just extensive local disease.
• Further validation and mechanistic studies are recommended.