Patient Stratification for Serum LDH Levels Reveals Distinct CLA⁺ T-Cell Cytokine Secretion in Response to HDM,...

Lactate dehydrogenase (LDH) is a serum biomarker well known to correlate with disease severity in atopic dermatitis (AD). The aim of this study was to explore the cutaneous immune responses and the clinical profile of AD patients in relation to serum LDH levels. To this end, 47 untreated, adult patients with moderate-to-severe AD were stratified by median levels of serum LDH. Circulating memory T-cell responses to house dust mite (HDM) extract, in the presence of autologous lesional epidermal cells, were compared between AD subgroups. The LDH^high group exhibited significantly higher IL-13, IL-5 and IL-9 in vitro responses confined to the cutaneous lymphocyte-associated antigen (CLA)⁺ subset compared to LDH^low patients. Clinically, LDH^high patients were younger and exhibited more severe disease, elevated eosinophil counts in their blood, increased total and specific IgE levels in their plasma, and a higher prevalence of allergic rhinitis. Our data suggests that high LDH levels identify a subgroup of AD patients with a specific immune and clinical profile, and highlight the potential of LDH as a clinical parameter that may enable patient stratification for treatment selection.