Cellular immune findings in Lyme disease. Correlation with serum IgM and disease activity.

Cellular immune findings were studied in 48 patients with various stages of Lyme disease. At each stage, some patients, particularly those with neuritis or carditis, had elevated serum IgM levels and lymphopenia. During early disease, mononuclear cells tended to respond normally to phytohemagglutinin, and spontaneous suppressor cell activity was greater than normal. Later, during active neuritis, carditis, or arthritis, the trend was toward heightened phytohemagglutinin responsiveness and less suppression than normal. By multiple regression analysis, serum IgM levels correlated directly with disease activity (p = 0.025) and inversely with the number of T cells (p = 0.02); during acute disease only, elevated IgM levels correlated with increased phytohemagglutinin responsiveness (p = 0.004) and decreased suppressor cell activity (p = 0.03). Decreased suppression, observed later in the disease, may permit damage to host tissues because of either autoimmune phenomena or a heightened response to the Lyme spirochete.