FIBROGENIC GROWTH-FACTORS IN THE EOSINOPHILIA-MYALGIA-SYNDROME AND THE TOXIC OIL SYNDROME

Background and Design: We sought to determine if growth factors of potential pathogenetic significance are deposited in the skin, muscle, and peripheral nerve lesions of eosinophilia-myalgia (EMS) and toxic oil syndrome. Immunohistochemical studies using affinity-purified peroxidase-conjugated antibodies to detect transforming growth factor-beta, platelet-derived growth factor(AA) and growth factor(BB), fibroblast growth factor, epidermal growth factor, and interleukin 4 were performed on formalin-fixed, paraffin-embedded specimens. Seven skin biopsy specimens from EMS, six skin biopsy specimens from toxic oil syndrome, nine muscle biopsy specimens from EMS, and one sural nerve biopsy specimen from EMS were studied. Results: Growth factor staining was noted primarily in the epidermis and periappendageal locations of the dermis. The presence of TGF-beta and platelet-derived growth factor(AA) in the periappendageal dermis was significantly more prevalent in EMS than toxic oil syndrome (57% vs 0%). Prominent staining of transforming growth factor-beta was also present in the perimysial connective tissue of five (63%) of eight EMS muscle biopsy specimens and one sural nerve biopsy specimen. Conclusions: These studies implicate transforming growth factor-beta and platelet-derived growth factor(AA) as potentially important cytokines in EMS and suggest that the pathogenesis of tissue fibrosis in EMS and toxic oil syndrome may be dependent on different growth factors.