1988: Raymond Dattwyler develops a seronegative Lyme assay.
In this report, Dattwyler states:
“We studied 17 patients who had presented with acute Lyme disease and received prompt treatment with oral antibiotics, but in whom chronic Lyme disease subsequently developed. Although these patients had clinically active disease, none had diagnostic levels of antibodies to B. burgdorferi on either a standard enzyme-linked immunosorbent assay or immunofluorescence assay. On Western blot analysis, the level of immunoglobulin reactivity against B. burgdorferi in serum from these patients was no greater than that in serum from normal controls.”
Here, knowing Lyme (especially chronic neurologic Lyme) is seronegative, they develop an assay that Steere later uses to assess "Chronic Neurologic Lyme" cases, proving he knows these cases are seronegative.