The relationship between serum tarc and SCCA2 levels and atopy, disease severity, therapy response and prognosis in infants with atopic dermatitis

Aim SCORAD is the most widely used scale to describe the severity and extent of the disease in atopic dermatitis. Serum TARC level is the most studied biomarker to evaluate the severity of the disease in AD patients. In a recent study, serum SCCA2 level was shown to be a more reliable biomarker than serum TARC level in determining the severity of AD. Our study aimed to study serum TARC and SCCA2 levels in infants with AD, to compare them with healthy children, and to evaluate the relationship between these biomarkers and prognosis and atopy. Materials and methods In this study, hemogram, total IgE, food sIgE, skin prick test, serum TARC and SCCA2 levels and clinical findings (SCORAD) were recorded in 42 patients aged 3 months-24 months who applied to the Pediatric Immunology and Allergy Diseases Polyclinic of Aydın Adnan Menderes University Faculty of Medicine. Forty-two volunteers in the same age group without any acute or chronic diseases were also included in the study as a control group. Hemogram, serum TARC and SCCA2 levels were recorded in the control group. Research data were evaluated using the SPSS 21.0 statistical program. Results There was no difference between the patient and control groups in terms of gender, age, height, body weight, gestational week, mode of delivery, birth weight, and duration of breastfeeding. 64.3% of the patient group and 19% of the control group were high-risk infants, and the difference was statistically significant (p<0.001). Eosinophil count was found to be statistically significantly higher in the patient group (p=0.014). Food sensitivity was present in 42.9% of the patients. The most common allergen detected by skin test was egg. There was no difference between the patient and control groups in terms of serum TARC and SCCA2 levels. There was no correlation between SCORAD index and serum TARC and SCCA2 levels. According to the SCORAD index, 54,8% of the cases were evaluated as mild-moderate and 45,2% as severe. First month and third month SCORAD indexes were statistically significantly higher in the group with severe SCORAD index at admission compared to the group with mild-moderate (p=0.001, p=0.044, respectively). In the group with severe SCORAD index, the decrease in SCORAD scores in the first and third months was higher than in the mild-moderate group (p=0.002 and p=0.000, respectively). The increase in serum TARC level in AD patients older than 6 months significantly reduced the SCORAD difference between the third month and the time of presentation. In other words, the higher the serum TARC level, the greater the improvement in the SCORAD index. Food sensitivity in cases with high total IgE was significantly higher than in the group without total IgE elevation (p=0.002). TCS use was higher in the three months of follow-up in cases with elevated total IgE and in cases with food sensitivity (p=0.002 and p=0.019, respectively). Serum TARC level was found to be higher in cases with food allergy (p=0.033). In the patient group, there was a high degree of positive correlation between sIgE value and serum TARC levels (r=0.517) (p=0.00). There was a significant positive correlation between serum TARC and SCCA2 levels in both groups. Conclusion In our study, patients with AD in the 0-2 age range were evaluated prospectively. 64.3% of our patients had a familial history of atopy, and 42.9% had food sensitivity. The most frequently sensitized food was found to be egg. The SCORAD indices of the patients at first admission were correlated with the SCORAD indices at follow-up, and a greater decrease was observed in the SCORAD index with treatment in the group with severe AD at first admission. Food sensitivity was significantly higher in patients with elevated total IgE. There was a significant positive correlation between serum TARC and SCCA2 levels in the whole group. The higher serum TARC level in patients with food allergy and the high positive correlation between sIgE value and serum TARC levels may be important for investigating the relationship between atopy and serum TARC level. Key words: Serum TARC, serum SCCA2, total IgE elevation, food sensitivity, food specific IgE, skin prick test