Complement split products C3a and C4a are reportedly elevated in patients with acute Lyme disease. We have now examined these immunologic markers in patients with chronic Lyme disease compared to appropriate disease controls. The study population consisted of 29 healthy controls, 445 patients with chronic Lyme disease, 11 patients with systemic lupus erythematosus (SLE) and six patients with AIDS.
The Lyme disease patients were divided according to predominant musculoskeletal symptoms (324 patients) or predominant neurologic symptoms (121 patients). C3a and C4a levels were measured by radioimmunoassay. All patients with chronic Lyme disease and AIDS had normal C3a levels compared to controls, whereas patients with SLE had significantly increased levels of this marker.