The vitamin D status and serum eosinophilic cationic protein levels in infants with cow's milk protein allergy.

Eosinophil cationic protein (ECP) is a cytotoxic protein released from eosinophils. The level of ECP increases in some allergic diseases. Recently, vitamin D deficiency has been suggested to be a risk factor for childhood allergic disease. The first aim of the study is to measure the serum vitamin D levels and ECP in infants with cow's milk protein allergy (CMPA) and compare them with controls. The second aim of this study is to investigate whether vitamin D levels are correlated with ECP or not. Sixty-two infants with CMPA were compared to 58 healthy, similar to distribution of age and sex normal infants as controls. The serum ECP levels were detected by an immunoassay system. Serum 25(OH)D levels were measured by using an enzyme-linked immunoassay kit. Vitamin D deficiency was defined as a serum 25(OH)D level of < 10 ng/mL and sufficient 30 ng/mL. The median serum ECP level in the CMPA group was significantly higher than in the control group (51.45 and 17.55 ng/mL, respectively, P = 0.001). There were no significant differences between groups with regards to median 25(OH)D levels (29.31 ± 1.67 and 27.32 ± 1.41 ng/mL, respectively, P = 0.646). The serum 25(OH)D levels were under 30 ng/mL in 38 of infants with CMPA (61.2%) and in 32 of controls (55.1%). Correlation analysis between the serum 25(OH)D level and ECP of infants with CMPA have revealed no significant relation (P = 0.888). Our results do not support the hypothesis that vitamin D deficiency may be a risk factor for CMPA.