Giant Multinucleated Cells Are Associated with Mastocytic Inflammatory Signature Equine Asthma.
Authors: Basano Ilaria, Romolo Alessandra, Iamone Giulia, Memoli Giulia, Riccio Barbara, Lavoie Jean-Pierre, Miniscalco Barbara, Bullone Michela
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Giant Multinucleated Cells and Equine Asthma Current equine asthma diagnosis relies on differential cell counts from bronchoalveolar lavage fluid (BALF)—specifically elevated neutrophils (>5%), mast cells (>2%), and eosinophils (>1%)—but little attention has been paid to activated or fused macrophages, known as giant multinucleated cells (GMC), despite their potential inflammatory significance. Basano and colleagues examined BALF samples from 34 asthmatic and 10 control horses, quantifying GMC prevalence and calculating a GMC:single macrophage ratio across 15 high-magnification fields per slide to explore whether GMC formation correlates with disease severity and specific inflammatory patterns. Both asthmatic and control horses showed GMC, yet asthmatic horses demonstrated significantly higher prevalence (p = 0.01), with the GMC:M ratio proving substantially elevated in severe cases compared to mild-to-moderate disease and controls; critically, increased GMC:M ratios in asthmatic horses were significantly associated with mastocytosis after adjusting for age and clinical signs (p = 0.01), suggesting shared molecular mechanisms drive both GMC formation and mast cell recruitment. Tachypnoea showed a trend towards positive association with GMC:M ratio, implying these fused macrophages may influence respiratory rate independent of overt respiratory effort. Including GMC enumeration in routine BALF cytology could refine phenotyping of equine asthma and provide practitioners with additional markers to assess disease severity and underlying inflammatory mechanisms.
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Practical Takeaways
- •When performing BALF cytology on asthmatic horses, include GMC counts in the routine assessment—this simple addition may help distinguish disease severity and identify horses with concurrent mastocytosis
- •The presence of increased GMC appears linked to mast cell recruitment in the lung; this shared mechanism may explain some respiratory signs and could guide targeted treatment strategies
- •Tachypnea in asthmatic horses may correlate with GMC and mastocyte activity even without obvious respiratory effort at rest, helping clinicians recognize subtle disease progression
Key Findings
- •Giant multinucleated cells (GMC) were more prevalent in asthmatic horses compared to controls (p = 0.01)
- •GMC:single macrophage ratio was significantly higher in severe versus mild to moderate asthmatic and control horses
- •Increased GMC:M ratio was significantly associated with BALF mastocytosis in asthmatic horses (p = 0.01) after adjusting for age and clinical signs
- •Tachypnea showed a positive trend with GMC:M ratio (p = 0.08), suggesting a relationship between GMC formation and respiratory clinical signs