Stephanie Weinreich

Germ-free mice do not develop ankylosing enthesopathy, a spontaneous joint disease

Ankylosing enthesopathy (ANKENT) is a naturally occurring joint disease in mice with numerous parallels to human ankylosing spondylitis (AS). Similarities between AS and ANKENT include not only affected tissue (joint entheses) but also association of the disease with genetic background, including MHC genes, gender, and age. Young males with the C57Bl/10 background have been described to suffer from ANKENT and, among H-2 congenic strains, high frequency of afflicted joints has been recorded in B10.BR (H-2(k)) males. Interestingly, the incidence of ANKENT is higher in conventional (CV) males that in their specific-pathogen-free (SPF) counterparts. The latter finding suggests that microbes could play a role as an ANKENT-triggering agent. To further examine this hypothesis we have established a germ-free (GF) colony of B10.BR mice and observed ANKENT incidence in both GF males and their conventionalized (ex-GF) male littermates; 20% of ex-GF males developed ANKENT before 1 year of age. In contrast, no joint disease was observed under GF conditions (p < 0.0001). Our results show that live microflora is required in ANKENT pathogenesis.

The influence of prednisolone on the recirculation of peripheral blood lymphocytes in vivo.

In humans and in laboratory animals, administration of a single dose of glucocorticosteroids induces a rapid and transient decrease in the numbers of peripheral blood lymphocytes through a redistribution of circulating lymphocytes. This lymphocytopenic effect is an important factor in the immunosuppressive capacity of corticosteroids. We have investigated whether the redistribution is due to an increased influx of circulating lymphocytes from the blood into the lymphoid organs or to a decreased efflux from the organs. Fluoresceinated lymphocytes were injected intravenously in unrestrained normal and prednisolone‐treated rabbits and the distribution curves in the peripheral blood were analysed on the basis of a two‐compartment model (known from pharmacokinetic studies). In this way. it is shown that the rapid fall in peripheral blood lymphocyte numbers induced by prednisolone is due to a decreased efflux of circulating lymphocytes from the lymphoid organs. In addition, it is demonstrated that prolonged infusion of prednisolone leads to an altered distribution pattern of the circulating lymphocytes among the organs.

Prednisolone and cyclosporin a exert differential inhibitory effects on T-cell proliferation in vitro

To elucidate the mechanisms of action of prednisolone (pred) and cyclosporin A (CyA), we have investigated the effects of these immunosuppressive drugs on the proliferative response of human peripheral blood lymphocytes (PBMN) induced by various stimulants, well defined with regard to their monocyte dependence. We found that pred-induced inhibition of monocyte-dependent proliferative responses could be reversed by the addition of exogenous interleukin 2 (IL-2). Monocyte-independent proliferative responses were not affected by pred. These findings suggest that pred inhibits IL-2 production and subsequent lymphocyte proliferation at the level of the signal derived from the monocyte. In contrast, CyA inhibited monocyte-dependent as well as monocyte-independent proliferative responses of human PBMN. This inhibition could not be reversed by the addition of exogenous IL-2. We have previously demonstrated that CyA does not affect the expression of receptors for IL-2. Taken together, these data indicate that CyA-mediated inhibition does not primarily occur at the level of the IL-2 system, but rather affects the proliferative mechanism of the T cell itself. These data clearly demonstrate that pred and CyA act at distinct sites of the triggering process.

The role of MHC class I heterodimer expression in mouse ankylosing enthesopathy

Abstractu2003Ankylosing enthesopathy (ANKENT) is a spontaneous mouse joint disease with strikingly similar pathology to human HLA-B27-associated enthesopathies such as ankylosing spondylitis. In C57Bl/10 mice, transgenic HLA-B*2702 as well as H2 genes have been shown to be relative risk factors for ANKENT. To investigate the role of major histocompatibility complex (MHC) class I expression in disease pathogenesis, ANKENT occurrence was compared among β2-microglobulin (β2m) knockout littermates with or without transgenes for HLA-B*2702 and human β2m. In the knockout phenotype lacking β2m, ANKENT occurrence is significantly reduced (P = 0.016). In the absence of β2m, B*2702 is not detected on the cell membrane, nor does it increase the risk for ANKENT. This means that the previous finding that HLA-B*2702 increases susceptibility to ANKENT in C57Bl/10 mice cannot be ascribed to a transgene insertion effect. Rather, in order to increase disease susceptibility, B*2702 must be coexpressed with mouse β2m (mo-β2m). In contrast, when HLA-B*2702 is expressed with β2m of human origin, disease susceptibility is not affected. Thus, both H2b-derived class I heterodimers and HLA-B*2702/mo-β2m heterodimers contribute to ANKENT susceptibility.

HISTOPATHOLOGY OF MURINE ANKYLOSING ENTHESOPATHY

Ankylosing enthesopathy is a spontaneously occurring progressive stiffening of the ankle and/or tarsal joints in mice of C57Black background. In C57BL/10 mice and mice of the same genetic background that had been made transgenic for HLA-B27, the start of the disease was detected by weekly testing for decreased mobility in the ankle/tarsus region. Ankylosing enthesopathy was found to begin with a short phase of proliferative inflammation of the joints and adjacent tissues, with some fibrinous exsudation, some leucocytic infiltration and slight bone erosion. This inflammation is soon accompanied and followed by proliferation of cartilaginous cells at the bone insertions of joint capsule ligaments (entheses). Ossification of the cartilage proliferations and some desmal ossification lead to large osteophytes that inhibit mobility. Fusion of osteophytes occasionally leads to marginal ankylosis. The histopathology of the successive stages of murine ankylosing enthesopathy and the preponderance in males and HLA-B27 transgenic mice are reminiscent of ankylosing spondylitis in man. The spine, however, was not affected.

Pharmacodynamic modeling of lymphocytopenia and whole blood lymphocyte cultures in prednisolone-treated individuals

In this study, we describe the time course of the influence of a single oral dose of prednisolone (10 mg) in man on the proliferative response of peripheral blood lymphocytes in whole blood. The data were fitted to an integrated pharmacokinetic-pharmacodynamic model, relating the plasma concentrations of prednisolone to its effect. The determination of prednisolone-induced lymphocytopenia and monocytopenia in vivo and the assessment of the influence of varying lymphocyte and monocyte numbers on proliferative responses in vitro enabled us to calculate the relative contributions of several prednisolone-induced effects to the diminished lymphoproliferative responses in whole blood after administration of prednisolone in vivo. We demonstrate that the decrease of the proliferative response in whole blood lymphocyte cultures stimulated with a monoclonal antibody directed against CD3 is mainly determined by the time course of the prednisolone-induced lymphocytopenia. The time course of the monocytopenia and the relative changes in the CD4+ and CD8+ T-cell subpopulations induced by prednisolone and the direct inhibitory effect of the changing plasma concentrations of the drug also contribute to the decrease of aCD3-stimulated whole blood lymphocyte cultures to some extent. The decrease of the proliferative response in whole blood lymphocyte cultures stimulated with a horse anti-human lymphocyte serum closely followed the time course of the lymphocytopenia induced by prednisolone. However, this response remained decreased for a longer period of time than could be expected on the basis of the prednisolone-induced lymphocytopenia in vivo. A possible mechanism which might explain this discrepancy between the prednisolone-induced effects in vivo and in vitro will be discussed.

Strong association of HLA-B27 heavy chain with β2-microglobulin

Monoclonal antibody TG1 recognizes specifically antigens HLA-B27, B7, B22 and B17 on cell surface in cytotoxicity and cytofluorometry tests. When cell detergent extracts were subjected to SDS PAGE under mild conditions (no heating and no reduction of the sample) followed by Western blotting, TG1 detected exclusively a complex of B27 heavy chains with beta(2)-microglobulin (as a 50 kDa band) whereas the other B-locus antigens (B7, B22, B17) were detected as free 43 kDa heavy chains under the same conditions. When the samples were boiled prior to SDS PAGE, TG1 detected again the 43 kDa free heavy chains of B7, B22 and B17 but no zone corresponding to B27 could be detected indicating that the epitope in free B27 chains is more sensitive to denaturation by SDS. Thus, our main finding is that the interaction of HLA-B27 heavy chain with beta(2)-microglobulin appears to be stronger than that of the other HLA-B chains. The resistance of the HLA-B27/beta(2)-microglobulin complex to the SDS dissociation is strikingly similar to the behavior of MHC class II molecules under similar conditions. Thus, it may be speculated that HLA-B27 complexes can be also more stable than other MHC class I molecules under more physiological dissociative conditions (e.g. in endosomal compartments). This feature might potentially influence antigen presentation by HLA-B27 and contribute to the well known disease linkage of HLA-B27.

Characterization of a human plasmacytoma line

Summary The TH line was established by bringing tumour cells from a multiple myeloma patient into suspension culture and subsequently cloning them by limiting dilution. The cultured cells show marked heterogeneity: there are ultrastructural differences between small and large TH cells, particularly with respect to the rough endoplasmatic reticulum (RER). Karyotyping revealed chromosome numbers in the triploid range, with many structural abnormalities, at the 14q32 region among others. A t(14:18) could not be demonstrated. TH was shown to have germline and a rearranged allele for kappa light chain, and only a single rearranged gene for heavy chain immunoglobulin. TH expressed PCA‐1, CD9, CD28 and CD38 antigens, HLA class II, RER and kappa light chain, but few or no other antigens associated with the B‐cell lineage. Light chain kappa and trace amounts of IgG3 were found intracellularly as well as in culture supernatant. The addition of IL‐6 to cultures of TH increased proliferation, as well as the secretion of kappa light chain and the membrane expression of CD28 and CD38 antigens. Because TH has relatively few B cell markers on its membrane, it may be useful for the induction of monoclonal antibodies specific for human plasma cells. It also provides a model for the demonstration that IL‐6 can act as a paracrine growth and differentiation factor for cells of myelomal origin.

A systematic review to investigate the measurement properties of goal attainment scaling, towards use in drug trials

BackgroundOne of the main challenges for drug evaluation in rare diseases is the often heterogeneous course of these diseases. Traditional outcome measures may not be applicable for all patients, when they are in different stages of their disease. For instance, in Duchenne Muscular Dystrophy, the Six Minute Walk Test is often used to evaluate potential new treatments, whereas this outcome is irrelevant for patients who are already in a wheelchair. A measurement instrument such as Goal Attainment Scaling (GAS) can evaluate the effect of an intervention on an individual basis, and may be able to include patients even when they are in different stages of their disease. It allows patients to set individual goals, together with their treating professional. However, the validity of GAS as a measurement instrument in drug studies has never been systematically reviewed. Therefore, we have performed a systematic review to answer two questions: 1. Has GAS been used as a measurement instrument in drug studies? 2: What is known of the validity, responsiveness and inter- and intra-rater reliability of GAS, particularly in drug trials?MethodsWe set up a sensitive search that yielded 3818 abstracts. After careful screening, data-extraction was executed for 58 selected articles.ResultsOf the 58 selected articles, 38 articles described drug studies where GAS was used as an outcome measure, and 20 articles described measurement properties of GAS in other settings. The results show that validity, responsiveness and reliability of GAS in drug studies have hardly been investigated. The quality of the reporting of validity in studies in which GAS was used to evaluate a non-drug intervention also leaves much room for improvement.ConclusionsWe conclude that there is insufficient information to assess the validity of GAS, due to the poor quality of the validity studies. Therefore, we think that GAS needs further validation in drug studies, especially since GAS can be a potential solution when a small heterogeneous patient group is all there is to test a promising new drug.Trial registrationThe protocol has been registered in the PROSPERO international prospective register for systematic reviews, with registration number CRD42014010619. http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42014010619.