Q Fever Research

Marmion BP,Harris RJ, Penttila IA, Storm P, Stallard K, Wuttke N.

The group has continued its studies of the post Q fever debility and fatigue syndrome (QFS) on the hypotheses of cytokine dysregulation and persistence of C. Burnetii in the body after acute Q fever and, in particular, in QFS patients.

Peripheral blood mononuclear cells (PBMC) were collected under LPS-free conditions from active QFS patients (N=18), resolving QFS cases (N=6), Q fever cases with low or no QFS symptoms (N=5), Q fever vaccines (N=8) and Q fever seronegatives (N=8), stimulated in 72hr culture with PHA or C. burnetii phase 1 and 2 antigen or measles antigen (as an unrelated agent causing long-term cellular immunity); the cytokines released into the fluid phase after culture were assayed by AgEIA or bioassay.

Active QFS patients released significantly (P=0.01) more IL-6 than the controls and similar accentuation was not observed with PHA or measles antigen. As a group active QFS patients also had significantly more (P=0.0008) IFNg responders and fewer (P=0.01) IL-2 responders than controls. Response patterns for other cytokines - IL-1, TNFa , IL-4, IL-5 and IL-10- were only slightly accentuated or unchanged. These findings are being further explored in collaboration with Prof. H. Zola by flow cytometry and double staining with antibodies to cell markers and to intracellular cytokines to determine the cellular origin of the cytokines - macrophage or lymphocyte - and to quantify the proportion of activated cells as the basis for a possible diagnostic test. Thus far it has been possible to detect IL-6 and IFNg in lymphocytes after stimulation of PBMC in 4 hrs culture with panmitogens and also with C. Burnetii antigens. (paper submitted

Preliminary attempts to isolate C. burnetii from bone marrow aspirates, liver biopsies and PBMC from QFS patients in guinea pigs or cell culture are negative so far but PCR amplification of sequences in the superoxide dismutase gene of C. burnetii indicates small numbers of coxiellas in some PBMC and liver biopsies from QFS patients and their absence from seronegative control subjects.

Sequencing of the amplicon from a limited number of PCR assays shows homology with that described for C. burnetii. Further work is required (1) to expand numbers of QFS cases and controls. (2) to exclude organism or amplicon contamination by the use, as control, of a synthetic target with appropriate primer sites but with a distinctive restriction enzyme site not found in C. burnetii. (paper submitted)