Discussion: Clinical Features (Part One)

Dr. Benach questioned whether the relationship between HLA-DR2 and Lyme disease has held up. Dr. Steere responded that additional patients have been tested since the initial report in 1979. It seems mainly that patients with neurologic involvement, arthritis or chronic arthritis, have an increased frequency of HLA-DR2. As yet, HLA phenotypes have not been determined for European patients. Dr. Edelman asked whether lymphocytoma benigna cutis and acrodermatitis chronica atrophicans are clinical variants of ECM that are only seen in Europe. Dr. Weber stated that both lymphocytoma and acrodermatitis have been described in the U.S.A.; the latter lesion has been seen primarily in patients who immigrated from Europe. Lymphocytoma is probably a non-specific reaction that may have more than one etiology. Dr. Steere questioned Dr. Weber on the frequency of tick bites in patients with lymphocytoma. Dr. Weber stated that tick bites were occasionally observed; in one out of four patients, a tick was removed from an ear lobe where lymphocytoma developed. Acrodermatitis was found by Walter Hauser to have the same distribution as Ixodes ricinus in Europe. Acrodermatitis atrophicans is thus probably a sequela of spirochetal infection. Dr. Stenn added that both acrodermatitis and lymphocytoma have been seen in patients presenting to the dermatopathology department at Yale. Drs. Verardo and Shope asked about the efficacy of antibiotics in treating Lyme disease and whether antibiotic prophylaxis should be employed for individuals entering an endemic area. Dr. Steere answered that antibiotic therapy early in the course of Lyme disease is clearly effective. It seems that later therapy is also effective, but higher doses of antibiotics may be required. Therefore, Dr. Steere did not recommend the prophylactic approach. Dr. Paardenkooper mentioned that he nevertheless goes ahead and treats individuals from an endemic area with a clear history of tick bite. Dr. Bartenhagen asked if Lyme disease takes a milder course in European patients. Dr. Steere agreed that there were some differences between American and European cases of Lyme disease. The multiple secondary annular skin lesions, common in the United States, seem much less common in European patients. Although patients in Europe may develop arthralgias or arthritis, joint involvement seems to be much more prominent in patients seen in the United States. Dr. Shulman inquired about future research avenues in deciphering the pathogenesis of Lyme arthritis. Dr. Malawista suggested that one question is whether the arthritis is related to a live or a dead organism. If antibiotics cure the arthritis, then a live organism is clearly involved, although not necessarily one that resides in joints; it is possible that the organism simply contributes a poorly degradable substance that drives the inflammation. The approach here is to search for the organism and antigens related to it in tissues. It is hoped that methods developed for these purposes in Lyme disease, where an agent and its antigens are now known, will be useful for the study of other rheumatic diseases of unknown etiology.