D1.431 - Distinct Immunophenotypic Signatures in Pediatric Allergic Disease: Clinical Utility of Methylation qPCR–Based Epigenetic TBNK Profiling

Lymphocyte subset quantification is essential in pediatric immunology, yet flow cytometry is limited by logistics and blood volume. Methylation qPCR enables DNA-based immune cell counting.

Retrospective study of 206 patients evaluated for allergic diseases. Methylation qPCR measured proportions of CD3, CD4, CD8, CD19 and CD16/56; absolute counts (cells/µL) were calculated as proportion × absolute lymphocyte count (complete blood count). Total IgE was log-transformed. Mann–Whitney U tests with effect sizes (Cohen’s d) were used for group comparisons (Benjamini–Hochberg FDR-controlled); Firth penalized logistic regression identified independent predictors; ROC assessed diagnostic performance.

57.8% (n=119) were male; median age 5.0 years (IQR 3–8). Diagnoses overlapped: allergic rhinitis (AR) 58.3%, asthma 45.6%, food allergy 29.1%, atopic dermatitis (AD) 28.6%. In age-adjusted models, lower CD4 counts remained independently associated with AR. AR was associated with lower CD3+ (p<0.001), CD3+CD4+ (p<0.001), and CD19+ cells (p<0.001). Food allergy was associated with higher T- and B-cell counts (all p≤0.003) and higher total lymphocyte counts (p=0.0076) Asthma was associated with lower CD3+ and CD3+CD4+ T cells (p<0.05), but preserved B cell counts.   AD was associated with higher CD4+, CD3+, CD19+ and total lymphocyte counts (p≤0.0103) and was independently predicted by higher log IgE (adjusted OR 1.48; p=0.0009).  Lower absolute CD4 count was the strongest independent predictor for AR (AUC 0.711; sensitivity 77.5%). Increasing age was associated with decreasing lymphocyte subset counts.

Methylation qPCR-based epigenetic TBNK profiling may aid in identifying age-adjusted immunophenotypes in pediatric allergic diseases. Allergic rhinitis showed a lymphopenic signature (lower CD4/CD3/CD19 and total lymphocytes), while atopic dermatitis and food allergy showed higher lymphocyte counts; high IgE values ​​remained an independent predictor for AD. Decreased CD4+ counts in AR patients warrant prospective evaluation for infection-related exacerbations, and this minimally invasive DNA-based approach can complement flow cytometry for scalable immune monitoring.