Results of the IFN-γ production assay and <i>Coxiella</i> ELISPOT in chronic Q fever patients and control subjects.

<p><i>In vitro</i> IFN-γ production by whole blood in response to Henzerling and Nine Mile phase 1 antigens was measured in the IFN-γ production assay. The number of IFN-γ positive cells in response to Nine Mile phase 1 and Nine Mile phase 2 antigens was measured in the <i>Coxiella</i> ELISPOT. Individual values of patients and controls are shown separately, and the lines indicate the medians. Patients and controls were compared using the Mann-Whitney <i>U</i>-test. ***<i>P</i><0.001, **<i>P</i><0.01. Abbreviations: NMI, Nine Mile phase 1; NMII, Nine Mile phase 2; IFN-γ, interferon-gamma.