Human peripheral eosinophils have a specific mechanism to express gp91-phox, the large subunit of cytochrome b558.

Eosinophils as well as neutrophils, monocytes and B lymphocytes are noted for lacking normal cytochrome b558 in patients with X-linked chronic granulomatous disease. The eosinophils of an X-linked male patient, however, fully expressed surface cytochrome b558, generated superoxide anion to a normal extent and definitely expressed the large subunit of cytochrome b558 (gp91-phox). His mononuclear leukocytes contained a diminished amount of gp91-phox mRNA with normal coding sequences. All the coding sequences and a putative poly (A) signal of his gp91-phox gene were normal. These results indicate that eosinophils have a specific mechanism to express gp91-phox and suggest that the mechanism lies at the transcriptional step of the gene.