The usefulness of combined measurements of squamous cell carcinoma antigens 1 and 2 in diagnosing atopic dermatitis.

BACKGROUND

The squamous cell carcinoma antigen (SCCA) is widely used as a serological biomarker for various cancers. There are two known SCCA molecules, SCCA1 and SCCA2. We previously found that interleukin-4 or interleukin-13, two related Th2-type cytokines that play an important role in allergic diseases, induce expression of SCCA1 and SCCA2. In this study, we examined whether combined measurements of SCCA1 and SCCA2 are useful for diagnosing atopic dermatitis (AD).

METHODS

We established new enzyme-linked immunosorbent assays (ELISAs) to specifically detect SCCA1 or SCCA2. We applied serum samples from AD patients with food allergies and from cervical cancer patients to these ELISAs. We performed receiver operating characteristic analyses to diagnose AD and to distinguish AD from cervical cancer.

RESULTS

Serum concentrations of both SCCA1 and SCCA2 were elevated in AD patients. The serum concentrations of SCCA1 and SCCA2 positively correlated with the clinical severity of AD, showing high specificity (0.86-0.88) and sensitivity (0.86) against control donors. The serum concentrations of SCCA1 and SCCA2 were elevated in cervical cancer patients; however, the SCCA2/SCCA1 ratios clearly distinguished AD patients from cervical cancer patients with high specificity (0.87) and sensitivity (0.87). Expression of SCCA2 was predominant in AD patients, whereas cervical cancer patients showed a predominance of SCCA1.

CONCLUSIONS

Combined measurements of SCCA1 and SCCA2 are very useful in estimating the severity of allergic diseases, making it possible to distinguish allergic diseases from cancers.