An experimental model of human autoimmune arthritis is produced by the intradermal injection of native heterologous or homologous collagen in rats (1,2). The collagen, which may be emulsified in either complete or incomplete Freund's adjuvant, induces a chronic polyarthritis. Plastic surgeons have recently begun to use subcutaneous collagen injection to fill in scars from acne. We wish to report a patient who developed polyarthritis after such a course of therapy.
The patient was a 36-year-old transsexual who had no previous rheumatic history. The only medication she had received was an estrogen preparation, which she had taken for several years. While at a plastic surgery clinic in California, she was injected subcutaneously with a test dose of collagen, the exact composition of which was not disclosed. Approximately 1 week later she developed swelling and stiffness in the distal phalangeal joints of both hands. The patient failed to report these symptoms to her physician and received 2 "regular" injections, 4 and 6 weeks later. Her arthritic symptoms persisted throughout this period until 1 month after the last injection, when all symptoms resolved spontaneously. She remains asymptomatic 6 months later.
Serum obtained 2 weeks after her last injection demonstrated neither rheumatoid factor nor antinuclear antibodies. A passive hemagglutination assay for antibodies to native human collagen types I and 11, kindly performed by Dr. David Trentham, was negative (3). Two control specimens from patients with rheumatoid arthritis were positive.
Patients with rheumatoid arthritis have both a humoral and cellular sensitivity to native human collagen (43). This patient developed a short, self-limited course of arthritis after subcutaneous collagen injections. Although no collagen antibodies were demonstrated, cellular sensitization may have occurred. It is possible that this patient's arthritis represents a serum sickness reaction induced by xenogeneic protein. In view of the experimental animal model of collagen-induced arthritis and this patient's course, however, it is intriguing to speculate that there was a relationship between the patient's arthritis and the collagen injections she received.