Immune response genes in the post-Q-fever fatigue syndrome, Q fever endocarditis and uncomplicated acute primary Q fever.

BACKGROUND: The influence of immune response gene variations on the development of chronic complications of Q fever is presently unclear. AIM: To compare the frequencies of allelic polymorphisms in immune response genes in different Q fever patient groups. DESIGN: Genetic association study. METHODS: We measured the frequencies of immune response gene variants in: (i) an expanded group of 31 post-Q-fever fatigue patients (QFS); (ii) 22 Q fever endocarditis patients (QFE); and (iii) 22 patients who made an uncomplicated recovery from their initial attack of primary acute Q fever, comparing them with various standard control panels from the general population. RESULTS: There were significant differences between the three Q fever groups. QFS patients differed from both QFE and uncomplicated patients and controls in the frequency of carriage of HLA-DRB1*11 and of the 2/2 genotype of the interferon-gamma intron1 microsatellite. Carriage of the HLA DRB1*11 allele was associated with reduced interferon-gamma and IL-2 responses from PBMC stimulated with ligand in short-term culture. QFE showed differences in the IL-10 promoter microsatellites R and G and had higher frequencies of the TNF-alpha receptor II 196R polymorphism. Q fever patients who had made an uncomplicated recovery differed from those with QFS or QFE, but were not significantly different in allelic frequencies to the control panels. DISCUSSION: These immunogenetic differences support the concept of different immune states in chronic Q fever, determined by genetic variations in host immune responses, rather than by solely properties of Coxiella burnetii.

Long-term persistence of Coxiella burnetii after acute primary Q fever.

BACKGROUND: Long-term persistence of C. burnetii in infected animals was established in the 1950s and 60s, but the implications for human Q fever are not fully explored. AIM: To compare the prevalence of markers of infection in a cohort of Q fever patients in Australia (up to 5 years after infection) with those in the 1989 Birmingham cohort (12 years after infection). DESIGN: Case follow-up study. METHODS: C. burnetii was tested for by: (i) antibodies to Phase 1 and 2 antigens in the three immunoglobulin classes; (ii) detection of DNA in bone marrow and peripheral blood mononuclear cells by PCR assays directed against several different targets in the genome; and (iii) attempts to isolate coxiellas in cell culture or mice from PCR-positive samples. Amplicon specificity was verified by fluorometric probing and by sequencing. Cross-contamination was excluded by extensive use of non-template controls, and in particular by the use of certain IS1111a target sequences. RESULTS: Irrespective of clinical state, both groups remained seropositive, principally exhibiting medium levels of IgG antibody against C. burnetii Phase 2 antigen. C. burnetii genomic DNA was detected by PCR in 65% of bone marrow aspirates from Australian patients and approximately 88% of Birmingham patients. No coxiella were isolated from PCR positive samples. DISCUSSION: We propose a provisional model for persistence. In Q fever without sequelae, the process is largely confined to the bone marrow. In Q fever fatigue syndrome (QFS), it is modulated by the patient's immunogenetic background to give higher levels of coxiella genomes in bone marrow and increased shedding into the peripheral blood. In Q fever endocarditis, late pregnancy, or during iatrogenic or other immunosuppression, the multiplication cycle is prolonged, and a potential source of live organisms.

Cytokine dysregulation in the post-Q-fever fatigue syndrome.

The post-Q-fever fatigue syndrome (QFS) (inappropriate fatigue, myalgia and arthralgia, night sweats, changes in mood and sleep patterns) follows about 20% of laboratory-proven, acute primary Q-fever cases. Cytokine dysregulation resulting from chronic immune stimulation and modulation by persistence of Coxiella burnetii cells or their antigens is hypothesized. We studied cytokine release patterns of peripheral blood mononuclear cells (PBMC) stimulated with various ligands in short-term culture, from 18 patients with active QFS, and 27 controls: six with resolving QFS, five who had had acute primary Q-fever without subsequent QFS, eight healthy Q-fever vaccinees and eight healthy subjects without Q-fever antibody. Conditioned media (CM) from PBMC stimulated in short-term culture with Q-fever antigens, PHA or measles antigen (as an unrelated antigen) were assayed for IL-2, IL-4, IL-5, IL-6, IL-10 and IFN gamma by AgEIA, and for IL-1 and TNF alpha/beta by bioassay. Aberrant cytokine release patterns were observed with PBMC from QFS patients when stimulated with Q-fever antigens: an accentuated release of IL-6 which was significantly [p = 0.01, non-parametric one-way analysis of variance (ANOVA)] in excess of medians for all four control groups. With IL-2, the number of responders in the active QFS group was decreased relative to control groups (Fisher's exact test, p = 0.01) whereas the number of IFN gamma responders was increased (Fisher's exact test, p = 0.0008). Significant correlations were observed between concentrations of IL-6 in CM, total symptom scores, and scores for other key symptoms.

Post-infection fatigue syndrome following Q fever.

In 1989, 147 individuals in the West Midlands, UK, were infected with Q fever. Five years later, following anecdotal reports of fatigue, we used a questionnaire-based case-control study to determine the prevalence of chronic fatigue syndrome symptoms in this group. Replies from 71 patients were compared with those from 142 age- and sex-matched controls. Increased sweating (52.9% vs. 31.6%, p = 0.006), breathlessness (50.7% vs. 30.6%, p = 0.006), blurred vision (34.3% vs. 17.8%, p = 0.016) and undue tiredness (68.7% vs. 51.5%, p = 0.03) were found in controls compared to cases. These findings were similar to those in Australian abbatoir workers occupationally exposed to Q fever. CDC criteria for chronic fatigue syndrome were fulfilled by 42.3% of cases and 26% of controls. Using visual analogue scores, symptoms were more severe in cases than in controls. Our findings support the existence of a chronic fatigue state following acute Q fever, in a group of patients exposed just once to the organism, and in circumstances free of such confounding factors as lawsuits over compensation.

Antibody responses in acute and chronic Q fever and in subjects vaccinated against Q fever.

An analysis is made of the antibody response to Coxiella burnettii Phase-1 and Phase-2 antigens, as measured by immunofluorescence in the IgM, IgG or IgA immunoglobulin classes, or by complement-fixation, in patients with acute and chronic Q fever and in vaccinated or skin-tested subjects. In acute (primary) Q fever, IgM specific antibodies to Phase-1 antigen are present in early convalescence together with IgM, IgG, IgA and CF antibodies to Phase-2 antigen. IgM specific antibody may persist for at least 678 days after onset of the acute illness. Patients with chronic Q fever have no IgM specific antibody to Phase-1 or -2 antigens, or only at very low levels; high levels of specific antibody in the IgG and IgA classes, together with CF antibody to both antigenic phases, appear to be characteristic. The serological response in initially seronegative, vaccinated subjects is mainly to Phase-1 antigen in the IgM fraction, and to a lesser degree to Phase-2 antigen by CF and in IgM and IgG classes. Subjects who were equivocally seropositive before vaccination showed IgA and IgG specific antibody responses to Phase-1 antigen and CF and IgG class responses to Phase-2 antigen. Similar antibody profiles were observed in patients who seroconverted after a positive skin-test. Data are also presented on the suitability of C. burnettii antigens for use in immunofluorescence and on the binding of IgM specific antibody by Phase-1 antigen but its failure to fix complement.

Co-cultivation of human cell lines with synovial fluids of patients with rheumatoid arthritis.

We have interpreted the above findings as implying that the changes seen may have arisen as a result of co-cultivation, albeit accidental, of Chang cells and cells derived from RA synovial tissue or fluid. A further obvious approach to this problem is to attempt deliberately to repeat the co-cultivation of Chang cells with RA synovial fluids.

Long-term persistence after acute Q fever of non-infective Coxiella burnetii cell components, including antigens.

BACKGROUND: Previous studies of inciting factors for a prolonged post-infection fatigue syndrome after Q fever (variously termed QFS or Q fever associated CFS/ME in the literature) showed that after the acute infection a high proportion of asymptomatic and QFS patients had Q fever antibody and also low levels in PBMC and bone marrow of Coxiella burnetii (C.b.) DNA with PCR assays directed against three different target sequences in different parts of the coxiella genome. Attempts to isolate a strain of C.b. in A/J mice, and cell culture from PCR positive PBMC and bone marrow were consistently negative. The detailed composition of the persisting coxiella residues remains to be defined. AIM: To retest and provide detailed results on selected PCR positive samples from the Birmingham Q fever outbreak patients tested by a highly sensitive method to detect viable organisms and to determine the nature of the residual coxiella cell components. DESIGN: Laboratory case study. METHODS: NOD/SCID mice were inoculated with samples from the 1989 Q fever outbreak in Birmingham and followed for evidence of infection and the presence of coxiella DNA and specific antigens in spleen and liver macrophages. A significant, unexpected finding of specific antigen was followed by assessment of its ability to provoke production of inflammatory and non-inflammatory cytokines in mice, in THP-1 human macrophage cell cultures and to induce inflammatory lesions in the skin of guinea pigs hyperimmunized against Q fever vaccine. RESULTS: Culture of samples from 10 Birmingham Q fever patients in NOD/SCID mice, 12 years from infection did not yield viable Coxiella burnetii, as shown earlier. However complexes of material with coxiella antigens were found in mouse spleens in all cases but in significantly greater amounts in samples from those with post Q fever fatigue syndrome. The antigenic complexes [now designated 'immunomodulatory complexes' (IMC)] were shown to stimulate cytokine release in the mice and in the THP-1 macrophages and to provoke an inflammatory reaction on intradermal injection into the skin of Q fever hyperimmunized guinea pigs. CONCLUSION: The study identifies a non-infective complex of C.b. antigens able to survive in the host and provoke aberrant humoral and cell medicated immunity responses - a possible pathogenic link between initial infection and a subsequent long-term post Q fever fatigue syndrome.

Q fever: persistence of antigenic non-viable cell residues of Coxiella burnetii in the host--implications for post Q fever infection fatigue syndrome and other chronic sequelae.

BACKGROUND: Our previous studies of persistence of Coxiella burnetii in humans after an initial acute Q fever infection revealed raised, maintained antibody levels and low levels of coxiella genomic DNA at the age of 5 years from onset in Australian patients and at 12 years in patients in the 1989 Birmingham UK Q fever outbreak. Attempts to isolate the coxiella in standard cell culture and susceptible mice by serial passage of PCR positive PBMC and bone marrow were negative. AIM: To retest PCR positive patient samples by more sensitive methods for viable coxiellas and for the coxiella cell components of antigen and specific lipopolysaccharide (LPS). To re-interpret the previous results in the light of the new information. To review the pertinent literature for a concept of an immuno-modulatory complex generated by the current studies. DESIGN: Laboratory case study. METHODS: Stored patient samples were inoculated into SCID mice that were followed for 60 days. Mouse spleen and liver samples were then examined by PCR assay for targets in the COM1 and IS1111a sequences and for antigens by IFA with a polyclonal rabbit antiserum to C. burnetii Phase 1 and a monoclonal antiserum to Phase 1 LPS (details; O. Sukocheva et al., unpublished data). RESULTS: All specimens, including a recently excised heart valve from a Birmingham patient with late developing endocarditis, were infection negative in SCID mice. Dilutions of SCID mouse spleen and liver homogenates titrated in PCR assays were negative at dilutions attained by control mice inoculated with an endpoint dilution of a viable prototype strain of C. burnetii. Sections of the spleens from all specimens showed a complex of coxiella antigen-LPS by IFA. DISCUSSION/REVIEW: We advance a concept of long-term persistence of a non-infective, non-biodegraded complex of coxiella cell components with its antigens and specific LPS [so called Immunomodulatory complex (IMC)] associated with traces of genomic DNA that signalled its presence in our earlier studies. The IMC's survival in patients for at least 12 years, and in one patient for 70 years implies a capacity for serial passage in macrophages with effective down-regulation of their biodegrading functions. The review assesses the compatibility of the IMC concept in relation to cogent literature on C. burnetii interactions with macrophage and cell-mediated immunity. Some remaining gaps in our knowledge of the organ sites and duration of carriage of viable coxiellas after initial infection are also identified.

Prospects for new viral vaccines.

Animal virology has made outstanding contributions to preventive medicine by the development of vaccines for the control of infectious disease in man and animals. Cost-benefit analysis indicates substantial savings in health care costs from the control of diseases such as smallpox, poliomyelitis, yellow fever and measels. Areas for further development include vaccines for influenza (living, attenuated virus), the herpes group (varicella: cytomegalovirus), respiratory syncytial virus, rotavirus and hepatitis A, B, and non A/non B. The general options for vaccine formulation are discussed with particular emphasis on approaches with the use of viral genetics to 'tailor make' vaccine viruses with defined growth potential in laboratory systems, low pathogenicity, and defined antigens. Current progress with the development of an inactivated hepatitis B vaccine is reviewed as a case study in vaccine development. The impact of recent experiments in cloning hepatitis B virus DNA in E. coli on the production of a purified viral polypeptide vaccine is assessed.

Eaton agent--science and scientific acceptance: a historical commentary.

The three classical papers published in 1944 and 1945 by Monroe A. Eaton and colleagues deal with the etiology of primary atypical pneumonia (PAP) and with the properties of a filterable agent (subsequently and for a number of years known as Eaton agent) from the sputum or lung of patients with PAP using cotton rats, hamsters, and chick embryos as laboratory hosts. The present review is first and foremost a tribute to Monroe Eaton and his colleagues for their trail-blazing discovery of a major cause of the atypical pneumonia syndrome and their steadfast vision of its importance. The organism was finally identified and designated Mycoplasma pneumoniae some 20 years after their papers first appeared in the Journal of Experimental Medicine.

Variation in interferon-gamma responses to Coxiella burnetii antigens with lymphocytes from vaccinated or naturally infected subjects.

Previous work in our laboratory has shown that lymphocytes from persons vaccinated with a formalin-inactivated Phase I Q fever vaccine (Q-Vax CSL Ltd) show a mitogenic response to Coxiella burnetii antigens. The mitogenic response is the sum of that from various subsets of CD4+, T helper cells, CD8+ T cells and probably B cells. It does not distinguish between T helper cell responses leading to formation of interferon-gamma (IFN-gamma)--a cytokine responsible for clearing intracellular infection with C. burnetii organisms--and responses of other T cell subsets which may produce disease-enhancing cytokines. The present study analyses (i) the capacity of Q-Vax to induce T cell sensitization which leads to IFN-gamma responses on antigen stimulation, and (ii) the immunomodulatory, (down-regulatory) effects of the Phase I lipopolysaccharide (LPS) of the organism, which interacts with monocyte/macrophages to limit IL-2 production and production of IFN-gamma by sensitized T lymphocytes.

Rubella virus and rheumatoid arthritis.

A collection of synovial fibroblasts from 19 patients with rheumatoid arthritis (RA) and 12 patients with osteoarthrosis or other non-RA disease has been examined for rubella virus antigens by immunofluorescence and radioimmunoassay with negative results. Eluates of synovial membrane prepared under conditions likely to dissociate antigen-antibody complexes have shown no rubella antibody. A serological survey of RA patients and those with other forms of arthritis has shown no differences in the frequency or levels of rubella haemagglutination-inhibiting antibody. These results provide little support for various hypotheses that a persistent infection with rubella virus underlies or initiates the rheumatoid process.

Attempts to identify viruses in rheumatoid synovial cells.

Synovial fibroblast cell strains derived from the synovial membranes of 7 patients with rheumatoid arthritis were examined for the presence of viruses, in particular leucoviruses. Seven similar synovial strains derived from patients with other arthritic conditions were used as a control group. Evidence of the presence of a virus or a viral genome was looked for by several methods of induction followed by 3H-uridine labelling of the cultures. In addition, the culture supernatant, after induction and after the synovial strains had been co-cultivated with a variety of cell lines from several species, was assayed for the presence of viral RNA-dependent DNA polymerase activity. The DNA-polymerase activity of the synovial cells themselves was also determined. No evidence was found by any of these techniques to indicate the presence of virus or viral information within the synovial fibroblasts.

Viruses and lymphocytes in rheumatoid arthritis. I. Studies on cultured rheumatoid lymphocytes.

Synovial fluid lymphocytes from patients with rheumatoid arthritis have been examined for evidence of a productive infection with retroviruses by electron microscopy, labelling with 3H-uredine, growth in soft agar, and culturing in conditioned medium. No such viruses were detected. In addition, the synovial lymphocytes were activated before fusion and cocultivation with several cell lines which have proved permissive for primate retroviruses. Monitoring these cultures subsequently by reverse transcriptase assay, labelling with 3H-uridine, and membrane immunofluorescence gave no indication that retroviruses were present.

Analysis of the cells involved in the lymphoproliferative response to Coxiella burnetii antigens.

Vaccination with an inactivated, whole cell, Q fever vaccine (Q-vax) induces lasting antibody conversion and a positive delayed-type hypersensitivity (DTH) skin reaction in about 60% of recipients but a long-lasting positive lymphoproliferative or mitogenic response to C. burnetii antigens with peripheral blood mononuclear cells (PBMC) in 85-95% of subjects. Analysis of the lymphoproliferative response to C. burnetii antigens has now been made by fractionation-reconstitution experiments with PBMC from vaccines, from past infections, and from healthy controls. The major contributor to the response in immune subjects proved to be the T lymphocyte. T cells were stimulated by both the phase I and phase II antigens of two prototype strains of C. burnetii and responses were greatly amplified by addition of IL-2. Similar T lymphocyte stimulation profiles were obtained with the 'Priscilla' strain of C. burnetii which represents a different biotype of Coxiella isolated from Q fever endocarditis; Q-vax is therefore likely to protect against endocarditis strains. Fractionation-reconstitution experiments with T and B cells from vaccines and subjects infected in the past, using various antigenic or haptenic fractions from C. burnetii indicate that protein, non-lipopolysaccharide components of the organism are responsible for the mitogenic response of immune T cells. However, the role of the lipopolysaccharide in the protective immunogen has still to be defined.

Markers of cell-mediated immunity after vaccination with an inactivated, whole-cell Q fever vaccine.

A clinical trial of Q fever vaccine in four South Australian abattoirs showed apparently complete protection against natural infection; however, only 50%-60% of vaccinees developed complement-fixing or immunofluorescent antibody after vaccination. Cell-mediated immunity to Coxiella burnetii antigens, as measured by an index of lymphoproliferative responses (LSI) of peripheral blood mononuclear cells, was therefore assessed. Eighty-five percent of 13 subjects with "low risk" of exposure to Q fever and with an initially negative LSI converted to a positive LSI after vaccination; conversion was noted nine to 13 days after vaccination, and positive values were obtained for at least 96 d. Only 35% of this group seroconverted. In a "high-risk" group (abattoir workers), higher rates of positive LSI (greater than 95%) and of antibody (50%-70%) were observed after vaccination; greater than 95% of vaccinees in this group, who had been vaccinated five years previously, had positive LSI values.

Vaccine prophylaxis of Q fever. A follow-up study of the efficacy of Q-Vax (CSL) 1985-1990.

OBJECTIVES: To examine the efficacy of various batches of a formalin-inactivated whole cell Coxiella burnetti vaccine (Henzerling strain, Phase 1 [Q-Vax, CSL]) in the prevention of Q fever among abattoir workers. DESIGN AND SETTING: The study was a retrospective cohort survey of all employees at three South Australian abattoirs to determine the incidence of Q fever among vaccinated and unvaccinated employees during the period 1985 to 1990. RESULTS: There were two cases of Q fever among 2555 vaccinated employees of the three abattoirs, compared with 55 cases among 1365 unvaccinated employees. The two Q fever cases in vaccinated employees were within a few days of vaccination, before immunity had developed, and represented a coincidence of natural infection and vaccination. Protective efficacy was 100%, even with a batch of Q-Vax containing 20 micrograms/dose rather than the standard dose of 30 micrograms/dose. CONCLUSIONS: Vaccination was effective for at least five years, although it was uncertain whether this was due to the vaccine per se or to a combination of vaccine immunity reinforced by periodic natural exposure.