Remission of paroxysmal atrial fibrillation with iron reduction in haemophilia A.

SUMMARY: Two male first cousins with mild haemophilia A had baseline factor VIII levels of 12-15% and experienced bleeding requiring coagulation factor infusion therapy with trauma and surgical procedures. Both the patients with haemophilia A also had electrocardiographically documented symptomatic paroxysmal atrial fibrillation (PAF) for several years that had become resistant to pharmacological suppression. Radiofrequency ablation was considered in both the cases but deferred considering refusal of consent by the patients to undergo the procedure. Remission of arrhythmias has been reported in patients with iron-overload syndromes. Body iron stores assessed by serum ferritin levels were elevated in both men but neither had the C282Y or H63D genes for haemochromatosis. Calibrated reduction of iron stores by serial phlebotomy, avoiding iron deficiency, was followed by remission of symptomatic PAF in both cases. Iron reduction may be an effective treatment for arrhythmias apart from the classic iron-overload syndromes and deserves further study particularly in patients with bleeding disorders who might be at risk for arrhythmias and other diseases of ageing.

Developing theory-based risk-reduction interventions for HIV-positive young people with haemophilia.

Eleven haemophilia treatment centres in the United States collaborated in the Hemophilia Behavioural Intervention Evaluation Projects (HBIEP) to develop theory-based interventions to reduce the risk of HIV transmission from seropositive adolescents and young adults with haemophilia. While the Transtheoretical Model of Behaviour Change and the Theory of Reasoned Action provided the theoretical underpinnings, the exact form in which these theories would be applied depended on developmental research. This paper presents the various phases of the process to develop the theory based interventions: literature review, qualitative interviews, quantitative surveys, a provider survey, a materials review, and the actual planning. All or portions of this process could be applied to the development of interventions for many behaviour-change projects. A description of the HBIEP interventions is also provided.

Inhibition of macrophage-induced antigen-specific T-cell proliferation by interferon-gamma.

The effects of IFN-gamma on macrophage (M phi)-mediated antigen-specific T-cell proliferation was investigated. A well-defined assay system using purified resident populations of antigen-pulsed peritoneal M phi and immune T cells was used to measure M phi-induced antigen-specific T-cell proliferation. Antibody affinity purified or recombinant IFN-gamma inhibited M phi-induced T-cell proliferation when KLH-pulsed M phi from mice given IFN-gamma prior to KLH were cultured with KLH immune T cells from normal mice. Monoclonal rat anti-IFN-gamma antibody neutralized the inhibitory effect of IFN-gamma. This inhibition of T-cell proliferation occurred despite the fact that these M phi appeared to be activated by IFN-gamma treatment as measured by increased tumoricidal activity. The mechanism for the inhibition was unrelated to class II (Ia) expression, IL-1 secretion, and prostaglandin secretion. These results demonstrate the complex and sensitive role IFN-gamma has in regulating the immune response.

Differential protein synthesis by murine peritoneal macrophages elicited by various stimuli.

Protein synthetic patterns of murine peritoneal macrophages were analyzed by two-dimensional polyacrylamide gel electrophoresis (2D PAGE) of 35S methionine-labeled proteins. While the protein synthetic patterns exhibited by resident, inflammatory, and activated macrophages had numerous common features that distinguished them from the other normal non-macrophage cell types examined, unique proteins also characterized each macrophage population from the others. The accumulation by resident macrophages of proteins 23, 25, and 37 distinguished them from elicited cells, as did the former's more abundant synthesis of proteins 54 and 52. The protein synthetic patterns of inflammatory thioglycollate- and proteose peptone-elicited macrophages were strikingly similar, save for the former's greater levels of accumulation of proteins 14 and 28, and the latter's more pronounced expression of p23.5. Peritoneal macrophages elicited by treatment with heat-killed Propionibacterium acnes, the live, attenuated Mycobacterium bovis strain BCG, Listeria monocytogenes, and the protozoan flagellate Trypanosoma rhodesiense, all exhibited tumoricidal activity in 16-h or 72-h functional assays. They shared a common protein synthetic profile that differentiated them from the synthetic patterns characteristic of the non-tumoricidal resident and inflammatory macrophages. These tumoricidal macrophages were unique in synthesizing a protein(s) of approximate molecular weight 26,000 daltons. A time-course study employing P. acnes-activated peritoneal macrophages indicated that p26 accumulation decayed with tumoricidal capacity as a function of time in culture, although no direct correlation between lytic activity and p26 expression could be definitively established. Peritoneal macrophages elicited with proteose peptone were not directly tumoricidal but were rendered so upon in vitro treatment with nanogram amounts of bacterial lipopolysaccharide. The accumulation of low levels of p26 by the newly explanted proteose peptone-elicited macrophages suggests the possibility that this protein characterizes macrophage populations primed as well as triggered for tumoricidal activity.

Poly I:C or IFN-alpha/beta treatment inhibits macrophage induced T cell proliferation.

IFN-alpha/beta has been previously shown to cause the suppression of various immune responses. The reason for this immunosuppression, however, remains unknown. The studies described in this report demonstrate that treatment of mice with poly I:C or partially purified IFN alpha/beta inhibited the ability of KLH pulsed macrophages to induce proliferation of KLH immune T cells. This failure to generate antigen induced proliferation was not caused by the production of prostaglandins or other suppressive molecules by IFN treated macrophages, nor did this treatment induce suppressor macrophages.

Thymocyte differentiation activity from the cloned monocyte/macrophage cell line RAW 264.7. Alterations in the expression of immature thymocyte surface antigens.

The cloned monocyte/macrophage cell line RAW 264.7 was previously shown to produce thymocyte mitogenic and co-mitogenic activity that eluted from a Sephadex G-75 column not only at approximately 16,000 daltons, the m.w. described for interleukin 1 (IL 1), but also at 30,000 to 40,000 daltons. The studies reported here indicate that the 30,000 to 40,000 dalton molecule has thymic differentiating activity. Thymocytes from A/J mice were fractionated on discontinuous BSA gradients, which yielded populations of cells enriched for immature and mature cells. The cells found at the interface between 35 and 29% BSA (band 1 cells), which are the most immature, were cultured for 48 hr with highly purified IL 1, with the 30,000 to 40,000 dalton form of thymocyte co-mitogenic activity obtained after Sephadex G-75 chromatography and chromatofocusing chromatography, or with media alone. The surface antigens TL-3, H-2Kk, Thy-1.2, Lyt-1, and Lyt-2 were examined by immunofluorescence. It was found that the highly purified 30,000 to 40,000 dalton species of co-mitogenic activity induced a significant increase in the content of surface H-2Kk, a decrease in TL-3, and a very small decrease in Thy-1.2 on the cell surface, whereas IL 1 was not capable of inducing a change in these surface antigens. There was no change in Lyt-1 on the surface of band 1 thymocytes after incubation with either IL 1 or the 30,000 to 40,000 dalton species. The 30,000 to 40,000 dalton species caused a significant decrease in the percentage of cells staining positive for Lyt-2, whereas IL 1 caused a smaller but significant decrease in Lyt-2. These changes in the surface markers TL-3, H-2Kk, and Thy-1.2 are consistent with changes that occur during thymocyte differentiation. It was also observed that the proliferative response to the 30,000 to 40,000 dalton form and IL 1 increased with increasing functional maturity of each band of thymocytes when used in the thymocyte mitogenic assay. However, only the 30,000 to 40,000 dalton form was capable of inducing a proliferative response in the immature band 1 thymocytes in the thymocyte co-mitogenic assay. These results indicate that the RAW 264.7 cells produce a factor that has, in addition to thymocyte co-mitogenic activity, thymocyte differentiation activity, and this factor is distinct from IL 1.

Identification of multiple-molecular-weight forms of thymocyte comitogenic activity from the monocyte/macrophage cell line RAW 264.7.

The cloned monocyte/macrophage cell line RAW 264.7 was investigated for interleukin 1 (IL-1) production. Of the inducers tested, bacterial lipopolysaccharide was found to be the most effective. The cyclic nucleotide analogs 8-BrcAMP and 8-BrcGMP were also tested, with only 8-BrcGMP being capable of inducing a small amount of IL-1 activity. Gel filtration studies revealed thymocyte mitogenic and comitogenic activity in three molecular-weight peaks: greater than 70,000, 30,000 to 40,000, and 12,000 to 18,000 Da. The multiple-molecular-weight forms were present when samples were prepared under serum-free conditions and also when samples were prepared and chromatographed in high ionic strength NaCl or under disulfide reducing conditions. Molecular charge heterogeneity was observed when proteins were chromatographed using column chromatofocusing (PBE 94). The intermediate-molecular-weight form eluted from the column over a pH range of 5.0 to 5.4; while the low-molecular-weight form eluted at three separate pH's: greater than or equal to 7.4 (unbound material), 5.2, and 4.8. The low-molecular-weight and intermediate-molecular-weight forms exhibited different dose-response curves when assayed under conditions used by other investigators (1 X 10(7) cells/ml; phytohemagglutinin, 1 microgram/ml), but very similar dose-response curves when assayed under conditions used by our laboratory (2 X 10(6) cells/ml; concanavalin A, 0.25 microgram/ml) in a thymocyte comitogen assay. The possible relationship of these multiple-molecular-weight species of thymocyte comitogenic activity from RAW 264.7 to other biological activities from cloned and noncloned cellular sources is discussed.