Background: The incidence of patients with serious adverse effects after Bacille Calmette-Guerin (BCG) instillation for bladder cancer is approximately 0.5%. We report a patient with bladder cancer treated with BCG who subsequently developed rheumatoid arthritis associated with polyneuropathy and vasculitis.
Case: A 55-year-old white man with bladder cancer was treated with instillation of BCG. After the third treatment, the patient developed symmetrical arthralgias and arthritis in the hands, feet, elbows, and knees associated with a burning sensation of the hands and soles bilaterally. An electromyogram nerve conduction study showed severe polyneuropathy. A muscle biopsy was compatible with vasculitis. Bacille Calmette-Guerin was discontinued, and the patient was started on isoniazid/vitamin B6, prednisone, and methotrexate. His symptoms resolved within 6 weeks of therapy.
Discussion: Bacille Calmette-Guerin is able to induce an autoimmune phenomenon through a mechanism of molecular mimicry. This hypothesis could explain the clinical manifestations and the presence of markers of autoimmunity seen in our patient. Monoclonal antibodies and clones of T cells derived from Mycobacterium tuberculosis against several human tissues have been found. We postulate that our patient’s positive rifampin, antinuclear antibodies and anti-cyclic citrullinated peptide antibodies by molecular mimicry to as well as the inflammatory response directed against BCG.
Conclusion: Bacille Calmette-Guerin immunotherapy for bladder cancer can induce a clinical picture of rheumatoid arthritis associated with polyneuritis multiples and vasculitis.