An ELISA containing a purified flagellar antigen from Borrelia burgdorferi (FLA-ELISA) was evaluated. The FLA-ELISA, detecting IgM and IgG together, did not have adequate specificity by itself. Good accuracy was obtained, however, when the FLA-ELISA was the first step in a two-step protocol that used immunoblotting as a conditional second test. Samples that scored positive or equivocal by the FLA-ELISA were evaluated with separate IgM and IgG immunoblots. The sensitivity of the two-step process for patients with erythema migrans or with later manifestations of Lyme disease was 64% and 100%, respectively. The specificity for health blood donors was 100% and was 90% for the aggregate of all persons with illness that may cause serologic cross-reactivity (98% if the samples from relapsing fever patients were excluded). Test precision was 96% overall, 99% for Lyme disease case serum samples, 100% for specimens from blood donors, and 88% for samples from persons with other illness.

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Recently, a strong correlation between high concentration of tumor necrosis factor (TNF alpha) in blood and severity of dengue hemorrhagic fever/dengue shock syndrome has been reported from Asia and the Pacific. We wished to determine if a similar relationship could be found in dengue patients in the Americas where adult patients with severe syndromes have been observed more frequently than in Asia where severe cases have been observed mostly among children. The concentrations of interleukin-1 (IL-1 beta) in hospitalized adult groups were significantly lower than that in outpatient adults. In contrast, the levels of interleukin 6 (IL-6) were significantly higher in hospitalized adults and children than in the corresponding outpatients. Levels of TNF alpha were higher in hospitalized children than in outpatient children or hospitalized adults. There was no significant difference in the levels of these three cytokines among hospitalized patients with or without hemorrhagic manifestations. Thus, an elevated IL-6 level was positively associated with severity of dengue infection in both children and adults, but IL-1 beta level was negatively associated with severity in adults.