Primary subtaler arthrodesis for the treatment of comminuted calcaneal fractures

We retrospectively evaluated the results of primary subtalar arthrodesis for the treatment of severely comminuted calcaneal fractures. Of 108 patients with 112 calcaneal fractures treated at our institution between 1989 and 1992, 16 (15%) underwent primary subtalar arthrodesis through an extensile lateral approach. The calcaneal height and width were restored with standard fixation techniques and then arthrodesis was performed with bone graft and fixation by 7.0-mm cannulated cancellous screws. Fourteen patients (12 males and 2 females; mean age, 40 years) were available for examination at a mean time of 26 months (range, 12-54 months) after surgery. Arthrodesis, evidenced by radiographic bony bridging across the arthrodesis site, was present in all patients between 8 and 12 weeks. Minor wound complications occurred in three patients. Of the 12 patients employed before the injury, 11 returned to their original occupations at a mean time of 8.8 months after injury (range, 1 month to 3 years). The mean AOFAS 100-point clinical rating scale score, evaluating pain, function, and alignment, was 72.4 points (range, 48-88 points). We conclude that primary subtalar arthrodesis is indicated as part of the management of comminuted displaced articular calcaneal fractures, yielding results that allowed 11 of 12 formerly employed patients to return to work.

Myelin antigen-coupled splenocytes suppress experimental autoimmune encephalomyelitis in Lewis rats through a partially reversible anergy mechanism

Mechanisms of adult tolerance induced by injecting myelin Ag/ECDI (ethyl carbodiimide)-coupled splenocytes (Ag-SPL) were evaluated in Lewis rat experimental autoimmune encephalomyelitis (EAE). Rats could be tolerized against the major encephalitogenic epitope of guinea pig basic protein (Gp-BP), residues 72-89, using either S72-89-SPL or crude spinal cord homogenate (SCH)-SPL. In contrast to lymph node responses that were not affected significantly, the proliferation responses of blood T cells were markedly inhibited at the peak of EAE and during the recovery period to both Gp-BP and S72-89, but not to purified protein derivative (PPD), demonstrating Ag-specific tolerance. Tolerance induction reduced the number of infiltrating spinal cord (SC) cells, especially recruited CD45RC+ cells, as well as SC proliferation responses to S72-89 throughout the course of EAE. In contrast, SC response to PPD was increased at onset of EAE, but later during recovery the PPD response was also decreased compared with control rats. Tolerance induced by S72-89-SPL in blood and SC T cells could be reversed by incubation in IL-2, in accordance with an anergy model. BP-specific T cells preincubated in vitro with Gp-BP-SPL were rendered unresponsive to Gp-BP or S72-89, compared with the same T cells preincubated with histone (Hist)-SPL that remained Ag responsive. Consistent with an anergy model, preincubation with BP-SPL+IL-2 partially prevented tolerance induction to BP. T cells tolerized in vitro to BP-SPL induced milder EAE with delayed onset compared with control-tolerized T cells that produced lethal disease. These results demonstrate the efficacy of myelin Ag-coupled SPL in preventing EAE by selective tolerization of encephalitogenic T cells through a partially reversible anergy-induction mechanism.

Myelin antigen-coupled splenocytes suppress experimental autoimmune encephalomyelitis in Lewis rats through a partially reversible anergy mechanism

Mechanisms of adult tolerance induced by injecting myelin Ag/ECDI (ethyl carbodiimide)-coupled splenocytes (Ag-SPL) were evaluated in Lewis rat experimental autoimmune encephalomyelitis (EAE). Rats could be tolerized against the major encephalitogenic epitope of guinea pig basic protein (Gp-BP), residues 72-89, using either S72-89-SPL or crude spinal cord homogenate (SCH)-SPL. In contrast to lymph node responses that were not affected significantly, the proliferation responses of blood T cells were markedly inhibited at the peak of EAE and during the recovery period to both Gp-BP and S72-89, but not to purified protein derivative (PPD), demonstrating Ag-specific tolerance. Tolerance induction reduced the number of infiltrating spinal cord (SC) cells, especially recruited CD45RC+ cells, as well as SC proliferation responses to S72-89 throughout the course of EAE. In contrast, SC response to PPD was increased at onset of EAE, but later during recovery the PPD response was also decreased compared with control rats. Tolerance induced by S72-89-SPL in blood and SC T cells could be reversed by incubation in IL-2, in accordance with an anergy model. BP-specific T cells preincubated in vitro with Gp-BP-SPL were rendered unresponsive to Gp-BP or S72-89, compared with the same T cells preincubated with histone (Hist)-SPL that remained Ag responsive. Consistent with an anergy model, preincubation with BP-SPL+IL-2 partially prevented tolerance induction to BP. T cells tolerized in vitro to BP-SPL induced milder EAE with delayed onset compared with control-tolerized T cells that produced lethal disease. These results demonstrate the efficacy of myelin Ag-coupled SPL in preventing EAE by selective tolerization of encephalitogenic T cells through a partially reversible anergy-induction mechanism.

p53 inhibits DNA replication in vitro in a DNA-binding-dependent manner

The p53 tumor suppressor gene product is a sequence-specific DNA-binding protein that is necessary for the G1 arrest of many cell types. Consistent with its role as a cell cycle checkpoint factor, p53 has been shown to be capable of both transcriptional activation and repression. Here we show a new potential role for p53 as a DNA-binding-dependent regulator of DNA replication. Constructs containing multiple copies of the ribosomal gene cluster (RGC) p53 binding site cloned on the late side of the polyomavirus origin were used in in vitro replication assays. In the presence of p53, the replication of these constructs was strongly inhibited, while the replication of constructs containing a mutant version of the RGC site was not affected by p53. Several tumor-derived mutant p53 proteins were unable to inhibit replication of the construct with wild-type RGC sites. Additionally, the transactivator GAL4-VP16 was unable to inhibit replication of a construct containing GAL4 binding sites adjacent to the polyomavirus origin. We also show that the inhibition by p53 can occur from sites cloned as far as 600 bp from the origin. Preincubation experiments suggest that p53 inhibits replication at a step mediated by ATP, possibly by inhibiting the binding of polyomavirus T antigen to the core origin. The presence of an endogenous p53 binding site in the polyomavirus origin suggests potential mechanisms for the observed inhibition.

Blockade of CD28/B7-1 interaction prevents epitope spreading and clinical relapses of murine EAE

Relapsing experimental autoimmune encephalomyelitis (R-EAE) induced with the immunodominant epitope from proteolipid protein, PLP139-151, is characterized by the development of recurrent relapses with recruitment of T cells reactive to additional myelin peptides, including PLP178-191 (epitope spreading). In this study, we have determined that the CD28/B7 costimulatory pathway is involved in this process. We found preferential up-regulation of B7-1 during the course of R-EAE and a selective increase in its functional costimulatory activity, relative to B7-2. Anti B7-1 F(ab) fragment therapy, but not anti B7-2 MAb therapy, blocked clinical relapses, ameliorated CNS pathology, and blocked epitope spreading. These results suggest that the maintenance of autoimmune reactivity in EAE depends on CD28/B7-1-dependent costimulation of newly recruited T cells responsible for epitope spreading. These studies have important implications for the role of epitope spreading in disease progression and the clinical application of costimulatory antagonists in autoimmune diseases.

An important role for the chemokine macrophage inflammatory protein-1 alpha in the pathogenesis of the T cell-mediated autoimmune disease, experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is a CD4+ T cell-mediated, inflammatory demyelinating disease of the central nervous system (CNS) that serves as a model for the human demyelinating disease, multiple sclerosis. A critical event in the pathogenesis of EAE is the entry of both Ag-specific T lymphocytes and Ag-nonspecific mononuclear cells into the CNS. In the present report we investigated the role of two C-C chemokines (macrophage inflammatory protein-1 alpha (MIP-1 alpha) and monocyte chemotactic protein-1) and a C-x-C chemokine (MIP-2) in the pathogenesis of EAE. Production in the CNS of MIP-1 alpha, but not that of MIP-2, a rodent homologue of IL-8, or monocyte chemotactic protein-1, correlated with development of severe clinical disease. Administration of anti-MIP-1 alpha, but not that of anti-monocyte chemotactic protein-1, prevented the development of both acute and relapsing paralytic disease as well as infiltration of mononuclear cells into the CNS initiated by the transfer of neuroantigen peptide-activated T cells. Ab therapy could also be used to ameliorate the severity of ongoing clinical disease. Anti-MIP-1 alpha did not affect the activation of encepahlitogenic T cells as measured by cytokine secretion, surface marker expression, and ability to adoptively transfer EAE. These results demonstrate that MIP-1 alpha plays an important role in directing the chemoattraction of mononuclear inflammatory cells in the T cell-mediated autoimmune disease, EAE.

Neuroantigen-specific Th2 cells are inefficient suppressors of experimental autoimmune encephalomyelitis induced by effector Th1 cells

We have identified a method of polarizing polyclonal populations of activated T helper cells toward either the Th1 or Th2 phenotype using different short-term in vitro culture conditions. Since the Ag used was an encephalitogenic peptide for SJL/J mice, the pathogenic potential of these cell populations was tested in an adoptive transfer model of experimental autoimmune encephalomyelitis (EAE). Th1 cells reproducibly caused severe EAE, whereas highly polarized Th2 cells did not. Furthermore, highly polarized Th2 cells did not suppress EAE caused by Th1 cells. The anti-inflammatory cytokines made by Th2 cells may simply fail to inhibit tissue destruction mediated by differentiated Th1 cells at the effector phase of the disease. It is also possible that highly polarized Th2 cells may be inefficient at crossing the blood-brain barrier, which may limit their suppressive potential. In contrast, incompletely skewed T cell populations that produced high levels of both Th1 and Th2 cytokines were consistently only weakly encephalitogenic. Therefore, disease inhibition by Th2 cytokines may best be accomplished by intervention at earlier points preceding development of differentiated Th1 cells.

An important role for the chemokine macrophage inflammatory protein-1 alpha in the pathogenesis of the T cell-mediated autoimmune disease, experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is a CD4+ T cell-mediated, inflammatory demyelinating disease of the central nervous system (CNS) that serves as a model for the human demyelinating disease, multiple sclerosis. A critical event in the pathogenesis of EAE is the entry of both Ag-specific T lymphocytes and Ag-nonspecific mononuclear cells into the CNS. In the present report we investigated the role of two C-C chemokines (macrophage inflammatory protein-1 alpha (MIP-1 alpha) and monocyte chemotactic protein-1) and a C-x-C chemokine (MIP-2) in the pathogenesis of EAE. Production in the CNS of MIP-1 alpha, but not that of MIP-2, a rodent homologue of IL-8, or monocyte chemotactic protein-1, correlated with development of severe clinical disease. Administration of anti-MIP-1 alpha, but not that of anti-monocyte chemotactic protein-1, prevented the development of both acute and relapsing paralytic disease as well as infiltration of mononuclear cells into the CNS initiated by the transfer of neuroantigen peptide-activated T cells. Ab therapy could also be used to ameliorate the severity of ongoing clinical disease. Anti-MIP-1 alpha did not affect the activation of encepahlitogenic T cells as measured by cytokine secretion, surface marker expression, and ability to adoptively transfer EAE. These results demonstrate that MIP-1 alpha plays an important role in directing the chemoattraction of mononuclear inflammatory cells in the T cell-mediated autoimmune disease, EAE.

Neuroantigen-specific Th2 cells are inefficient suppressors of experimental autoimmune encephalomyelitis induced by effector Th1 cells

We have identified a method of polarizing polyclonal populations of activated T helper cells toward either the Th1 or Th2 phenotype using different short-term in vitro culture conditions. Since the Ag used was an encephalitogenic peptide for SJL/J mice, the pathogenic potential of these cell populations was tested in an adoptive transfer model of experimental autoimmune encephalomyelitis (EAE). Th1 cells reproducibly caused severe EAE, whereas highly polarized Th2 cells did not. Furthermore, highly polarized Th2 cells did not suppress EAE caused by Th1 cells. The anti-inflammatory cytokines made by Th2 cells may simply fail to inhibit tissue destruction mediated by differentiated Th1 cells at the effector phase of the disease. It is also possible that highly polarized Th2 cells may be inefficient at crossing the blood-brain barrier, which may limit their suppressive potential. In contrast, incompletely skewed T cell populations that produced high levels of both Th1 and Th2 cytokines were consistently only weakly encephalitogenic. Therefore, disease inhibition by Th2 cytokines may best be accomplished by intervention at earlier points preceding development of differentiated Th1 cells.

Treatment with bacterial LPS renders genetically resistant C57BL/6 mice susceptible to Theiler's virus-induced demyelinating disease

Theiler's murine encephalomyelitis virus (TMEV) induces a demyelinating disease in susceptible strains, which clinically and histopathologically resembles human multiple sclerosis. Since bacterial LPS produced by Gram-negative bacteria is known to potentiate an immune response and trigger resident central nervous system cells to produce various inflammatory cytokines, we examined the ability of LPS to affect resistance to TMEV-induced demyelinating disease (TMEV-IDD). Intraperitoneal injection of LPS, concomitant with intracerebral of genetically resistant C57BL/6 mice with TMEV, resulted in clinical symptoms in approximately 50% of the group. The increase in susceptibility following LPS treatment correlated with the enhanced levels of TMEV-specific delayed-type hypersensitivity and T cell proliferative responses. Similar treatment with LPS, however, did not accelerate the clinical course of susceptible (SJL/J) or intermediately susceptible (C3H) mice. The LPS-treated C57BL/6 mice displayed an increased viral persistence in the central nervous system when compared with nontreated control mice. Intraperitoneal administration of IL-1 beta could mimic the LPS effect in C57BL/6 mice, suggesting that the increase in susceptibility to TMEV-IDD may function via IL-1 produced following LPS stimulation.

Treatment with bacterial LPS renders genetically resistant C57BL/6 mice susceptible to Theiler's virus-induced demyelinating disease

Theiler's murine encephalomyelitis virus (TMEV) induces a demyelinating disease in susceptible strains, which clinically and histopathologically resembles human multiple sclerosis. Since bacterial LPS produced by Gram-negative bacteria is known to potentiate an immune response and trigger resident central nervous system cells to produce various inflammatory cytokines, we examined the ability of LPS to affect resistance to TMEV-induced demyelinating disease (TMEV-IDD). Intraperitoneal injection of LPS, concomitant with intracerebral of genetically resistant C57BL/6 mice with TMEV, resulted in clinical symptoms in approximately 50% of the group. The increase in susceptibility following LPS treatment correlated with the enhanced levels of TMEV-specific delayed-type hypersensitivity and T cell proliferative responses. Similar treatment with LPS, however, did not accelerate the clinical course of susceptible (SJL/J) or intermediately susceptible (C3H) mice. The LPS-treated C57BL/6 mice displayed an increased viral persistence in the central nervous system when compared with nontreated control mice. Intraperitoneal administration of IL-1 beta could mimic the LPS effect in C57BL/6 mice, suggesting that the increase in susceptibility to TMEV-IDD may function via IL-1 produced following LPS stimulation.

Two models of multiple sclerosis: experimental allergic encephalomyelitis (EAE) and Theiler's murine encephalomyelitis virus (TMEV) infection. A pathological and immunological comparison

Theiler's murine encephalomyelitis virus (TMEV) infection and experimental allergic encephalomyelitis (EAE) are considered among the best models of human multiple sclerosis (MS). In both models, clinical disease is characterized by paralysis, while pathological changes consist of inflammatory demyelination. In both models there is a genetic influence on susceptibility/resistance to the development of disease. This has been thoroughly studied in TMEV infection, and it has been found to depend on both major histocompatibility complex (MHC) and non-MHC genes. At least four genes have been so far identified. Because of this genetic influence, some strains of mice are more susceptible to both clinical and pathological changes than others, and susceptibility appears to best correlate with the ability of a certain murine strain to develop a delayed-type hypersensitivity (DTH) response to viral antigens. We have also observed that even among mice which are equally susceptible clinically, striking differences may be seen under pathological examination. These consist of different gradients of severity of inflammation, particularly in regards to the macrophage component. There is an inverse relationship between the number of macrophages, and their length of stay in the CNS, and the ability of mice to remyelinate their lesions. The most severe lesions are in SJL/J mice, and remyelination in this strain is extremely poor. The least severe lesions in terms of macrophage invasion are in strains such as NZW and RIIIS/J, and these are able to remyelinate lesions very successfully. Murine chronic relapsing EAE (CR-EAE) shows pathological changes in many ways similar to those in TMEV-infected SJL/J mice, although less severe in terms of degrees of macrophage infiltration and tissue destruction. Mice with CR-EAE have a correspondingly limited ability to remyelinate their lesions. In both models the pathology appears to be mediated through a DTH response. However, while in EAE the DTH response is clearly against neuroantigens, the response in TMEV infection is against the virus itself. The end result in both models would be that of myelin destruction through a lymphotoxin-cytokine-mediated mechanism. The importance of the DTH response in both models is well illustrated by the effects of tolerance induction in EAE and TMEV infection to neuroantigens and virus, respectively. These are important models of human MS, since the current hypothesis is that a viral infection early in life, on the appropriate genetic background, may trigger a secondary misdirected immune response which could be directed either against myelin antigens and/or possible persistent virus(es).

Inhibition of Theiler's virus-mediated demyelination by peripheral immune tolerance induction

Theiler's murine encephalomyelitis virus (TMEV), a member of the cardiovirus subfamily of the Picornaviridae, is a natural pathogen of mice. Thirty to 60 days following intracerebral infection with TMEV, susceptible inbred mouse strains develop a chronic, progressive, T cell-mediated inflammatory demyelinating disease of the central nervous system (CNS) characterized by spastic hind limb paralysis and a lifelong persistent CNS virus infection. We have examined the effect of peripheral virus-specific tolerance on the development of demyelinating disease. Treatment of SJL/J mice with TMEV-coupled, ethyl carbodiimide-treated splenocytes either before or after infection with live TMEV prevented the development of clinical disease, including inflammation and demyelination in the CNS. Prevention of clinical disease was paralleled by significant reductions in virus-specific immune responses, including delayed type hypersensitivity and T cell proliferative responses. Tolerance induction resulted in a significant reduction in the absolute numbers of mononuclear cells infiltrating the CNS, particularly the CD4+IL-2R+ T cell subset, 3, 5, and 8 wk postinfection. In contrast, tolerance induction had no effect on the numbers of CD8+IL-2R+ T cells infiltrating the CNS. Treatment with TMEV-coupled splenocytes failed to prevent the development of relapsing experimental autoimmune encephalomyelitis, demonstrating the specificity of in vivo tolerance induction. Prevention of demyelinating disease did not correlate with the increased TMEV-specific Ab responses observed in tolerized mice. These results indicate that induction of immune tolerance to TMEV can down-regulate a chronic immunopathogenic disease directed against virus Ag persisting in the CNS that normally results in a progressive demyelinating disease similar to multiple sclerosis.

Inhibition of Theiler's virus-mediated demyelination by peripheral immune tolerance induction

Theiler's murine encephalomyelitis virus (TMEV), a member of the cardiovirus subfamily of the Picornaviridae, is a natural pathogen of mice. Thirty to 60 days following intracerebral infection with TMEV, susceptible inbred mouse strains develop a chronic, progressive, T cell-mediated inflammatory demyelinating disease of the central nervous system (CNS) characterized by spastic hind limb paralysis and a lifelong persistent CNS virus infection. We have examined the effect of peripheral virus-specific tolerance on the development of demyelinating disease. Treatment of SJL/J mice with TMEV-coupled, ethyl carbodiimide-treated splenocytes either before or after infection with live TMEV prevented the development of clinical disease, including inflammation and demyelination in the CNS. Prevention of clinical disease was paralleled by significant reductions in virus-specific immune responses, including delayed type hypersensitivity and T cell proliferative responses. Tolerance induction resulted in a significant reduction in the absolute numbers of mononuclear cells infiltrating the CNS, particularly the CD4+IL-2R+ T cell subset, 3, 5, and 8 wk postinfection. In contrast, tolerance induction had no effect on the numbers of CD8+IL-2R+ T cells infiltrating the CNS. Treatment with TMEV-coupled splenocytes failed to prevent the development of relapsing experimental autoimmune encephalomyelitis, demonstrating the specificity of in vivo tolerance induction. Prevention of demyelinating disease did not correlate with the increased TMEV-specific Ab responses observed in tolerized mice. These results indicate that induction of immune tolerance to TMEV can down-regulate a chronic immunopathogenic disease directed against virus Ag persisting in the CNS that normally results in a progressive demyelinating disease similar to multiple sclerosis.

Functional evidence for epitope spreading in the relapsing pathology of experimental autoimmune encephalomyelitis

The role of epitope spreading in the pathology of relapsing-remitting experimental autoimmune encephalomyelitis (R-EAE) was examined. Using peripherally induced immunologic tolerance as a probe to analyze the neuropathologic T cell repertoire, we show that the majority of the immunopathologic reactivity during the acute phase of R-EAE in SJL/J mice induced by active immunization with the intact proteolipid (PLP) molecule is directed at the PLP139-151 epitope and that responses to secondary encephalitogenic PLP epitopes may contribute to the later relapsing phases of disease. Intermolecular epitope spreading was demonstrated by showing the development of T cell responses to PLP139-151 after acute disease in mice in which R-EAE was initiated by the transfer of T cells specific for the non-cross-reactive MBP84-104 determinant. Intramolecular epitope spreading was demonstrated by showing that endogenous host T cells specific for a secondary encephalitogenic PLP epitope (PLP178-191) are demonstrable by both splenic T cell proliferative and in vivo delayed-type hypersensitivity responses in mice in which acute central nervous system damage was initiated by T cells reactive with the immunodominant, non-cross-reactive PLP139-151 sequence. The PLP178-191-specific responses are activated as a result of and correlate with the degree of acute tissue damage, since they do not develop in mice tolerized to the initiating epitope before expression of acute disease. Most importantly, we show that the PLP178-191-specific responses are capable of mediating R-EAE upon adoptive secondary transfer to naive recipient mice. Furthermore, induction of tolerance to intact PLP (which inhibits responses to both the initiating PLP139-151 epitope and to the PLP178-191 epitope) after the acute disease episode is sufficient to prevent relapsing disease. These results strongly support a contributory role of T cell responses to epitopes released as a result of acute tissue damage to the immunopathogenesis of relapsing clinical episodes and have important implications for the design of antigen-specific immunotherapies for the treatment of chronic autoimmune disorders in humans.

The use of a future time frame in psychotherapy with and without hypnosis

Developments from various theorists and practitioners suggest an increasing interest in the use of future time frames in hypnosis and psychotherapy. We will present the development of a position focusing on the use of the future time frame without the necessary use of formal hypnosis. This position supposes an active, as opposed to a passive client role in the clinical interaction, and the techniques are applicable to a broader range of client population than other future oriented techniques. Thereafter, the use of this future time frame position is illustrated with case material, and potential interpretations of the case material are suggested.

Differential recognition of peptide analogs by naive verses activated PLP 139-151-specific CD4+ T cells

CD4+ T cells specific for PLP 139-151 induce a relapsing-remitting form of EAE which is similar to the human demyelinating disease multiple sclerosis (MS) in both clinical course and histopathology. Conservative and nonconservative amino acid substitutions were introduced at three TcR or MHC contact residues within PLP 139-151 to identify fine specificity requirements, at the polyclonal level, for stimulating naive encephalitogenic T cells and for reactivating pre-primed autoreactive T cells as measured by T cell proliferation, cytokine induction, and functional encephalitogenic potential. The results indicate that peptides with substitutions at position 145 exhibited a significantly diminished ability to induce active disease, but these substitutions had little or no effect on the ability to activate PLP 139-151-primed T cells for proliferation or disease transfer. A conservative or a nonconservative substitution at position 144 ablated both encephalitogenic potential in active and adoptive EAE models and the ability to induce proliferative responses in T cells primed to the native peptide. A nonconservative lysine for glycine, but not a conservative serine substitution, at position 146 had similar effects. In contrast to their inability to induce active EAE and stimulate in vitro proliferation of PLP 139-151-primed T cells, the Y144 and the 146 analog peptides were able to suboptimally reactivate these cells for transfer of adoptive EAE. Furthermore, the nonencephalitogenic K146 peptide was found to exacerbate in vivo induction of EAE induced by priming with a suboptimal dose of PLP 139-151. These data support the hypothesis that naive neuroantigen-specific CD4+ T cells have more stringent activation requirements than do PLP 139-151-specific T cells which have previously encountered antigen. The finding that the analog peptides induced differential patterns of cytokine production, with LT/TNF-alpha production but not IFN-gamma production correlating with full encephalitogenic potential, suggests different functional outcomes may result from differential levels of signal transduction triggered by the substituted peptides. The significance of these results to the potential development of autoimmune disease via molecular mimicry and for the development of new strategies for preventing and treating T cell-mediated autoimmune diseases is discussed.

Mutation of a major histocompatibility class I locus, H-2D, leads to an increased virus burden and disease susceptibility in Theiler's virus-induced demyelinating disease

Genetic studies have demonstrated that susceptibility to Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease is multigenic with linkage to the MHC class I locus, H-2D. We have analyzed the effect of mutations (H-2bm13 and H-2bm14) in the H-2Db gene on central nervous system (CNS) virus replication, virus-specific delayed type hypersensitivity (DTH) and disease induction in mutant [bm14D2F1 and bm13D2F1] and parental B6D2F1 hybrids. The results indicate that substitutions of only a single residue (bm14D2F1) or three residues (bm13D2F1) in H-2D in the mutant leads to a sequence of events culminating in disease susceptibility. Mutation of the H-2D gene is associated with reduced or delayed virus clearance following the acute phase of exponential CNS virus growth and an increased level of virus persistence. Concomittant with the greater virus antigen burden, mutant mice respond with higher levels of virus-specific DTH and develop inflammatory demyelinating lesions.

Evolution of the T-cell repertoire during the course of experimental immune-mediated demyelinating diseases

Fig. 6 depicts a model for epitope spreading in T cell-mediated demyelination. The acute phase of disease is due to T cells specific for the initiating epitope, which can be either a determinant on the CNS target organ of the autoimmune response or a determinant on a persisting, CNS-tropic virus. The primary T cell response is responsible for the initial tissue damage by the production of proinflammatory Th1 cytokines which can affect myelination directly (Selmaj et al. 1991) and indirectly by their ability to recruit and activate macrophages to phagocytize myelin (Cammer et al. 1978). As a result of myelin damage and opening of the blood-brain-barrier during acute disease, T cells specific for endogenous epitopes on the same and/or different myelin proteins are primed and expand either in the periphery or locally in the CNS. These secondary T cells initiate an additional round of myelin destruction, leading to a clinical relapse by production of additional pro-inflammatory cytokines, similar to the bystander demyelination operative during acute disease. It will be of great interest to determine the relative contributions of local and systemic immune responses to these endogenous neuroepitopes. It is possible that local CNS presentation of endogenous neuroepitopes following acute CNS damage could be mediated by infiltrating inflammatory macrophages, activated microglial cells, endothelial cells and/or astrocytes. These tissue resident antigen presenting cells have been shown to upregulate expression of MHC class II (Sakai et al. 1986, Traugott & Lebon 1988), certain adhesion molecules (Cannella et al. 1990), and B7 costimulatory molecules (K. M. Nikcevich, J. A. Bluestone, and S. D. Miller, in preparation) in response to pro-inflammatory cytokines. The data on epitope spreading provided by the murine demyelinating disease models clearly illustrate the dynamic nature of the T cell repertoire during chronic inflammation in a specific target organ. The contribution of epitope spreading to chronic CNS demyelination could be considered to be a special case since tolerance to myelin epitopes would be expected to be inefficient due to their sequestration behind the blood-brain-barrier. However, the recent description of epitope spreading in response to pancreatic antigens in spontaneous diabetes in the NOD mouse may indicate that this phenomenon is operative in a variety of organ-specific experimental and spontaneous autoimmune diseases.(ABSTRACT TRUNCATED AT 400 WORDS)

Late reconstruction after failed treatment for ankle fractures

The ankle is a very resilient joint, but fractures in this area require accurate recognition and aggressive treatment (Fig. 7). Care must be exercised in evaluating the radiographics, and further surgical intervention often leads to satisfying results. Degenerative changes that may occur years postoperatively can turn a "fine" result into an ankle fusion.

Increased severity of experimental autoimmune encephalomyelitis in rats tolerized as adults but not neonatally to a protective TCR V beta 8 CDR2 idiotope

The ability of synthetic V region peptides to induce regulatory T cells and Abs in rodents and humans provides clear evidence that these idiotopes do not naturally induce tolerance. In this study, we investigated the ability of TCR V beta 8.2 peptides to experimentally induce specific T cell tolerance, as measured by loss of Ag-specific proliferation and delayed-type hypersensitivity responses, and by increased susceptibility to experimental autoimmune encephalomyelitis (EAE). We found that both neonatal and adult exposure to V beta 8.2-39-59 or V beta 8-44-54 peptides could induce efficient T cell tolerance, resulting in a significant inhibition of peptide-specific proliferative responses. In addition, neonatal tolerance resulted in a partial reduction in delayed-type hypersensitivity response and an inability to vaccinate against EAE after adult immunization with the tolerizing peptide. We further evaluated the contribution of naturally induced TCR-specific responses to EAE resistance induced by challenging neonatally or adult tolerized rats with myelin basic protein in adjuvant. The clinical course of EAE was not significantly altered in rats tolerized neonatally to V beta 8.2 peptides, but both the severity and incidence of mortality from EAE was increased in rats tolerized as adults with V beta 8.2 peptides conjugated to syngeneic splenocytes. These results demonstrate that V beta 8.2 peptides are tolerogenic as well as immunogenic. Moreover, the observation of different effects of neonatal vs adult tolerization on the course of EAE suggests either the emergence of additional protective idiotopes after neonatal tolerization and/or mechanistic differences in the two tolerance-inducing protocols. Most importantly, the enhancement of clinical EAE in rats tolerized as adults with V beta 8.2 peptides provides evidence for an innate regulatory role of the CDR2 idiotope in recovery from EAE.

Increased severity of experimental autoimmune encephalomyelitis in rats tolerized as adults but not neonatally to a protective TCR V beta 8 CDR2 idiotope

The ability of synthetic V region peptides to induce regulatory T cells and Abs in rodents and humans provides clear evidence that these idiotopes do not naturally induce tolerance. In this study, we investigated the ability of TCR V beta 8.2 peptides to experimentally induce specific T cell tolerance, as measured by loss of Ag-specific proliferation and delayed-type hypersensitivity responses, and by increased susceptibility to experimental autoimmune encephalomyelitis (EAE). We found that both neonatal and adult exposure to V beta 8.2-39-59 or V beta 8-44-54 peptides could induce efficient T cell tolerance, resulting in a significant inhibition of peptide-specific proliferative responses. In addition, neonatal tolerance resulted in a partial reduction in delayed-type hypersensitivity response and an inability to vaccinate against EAE after adult immunization with the tolerizing peptide. We further evaluated the contribution of naturally induced TCR-specific responses to EAE resistance induced by challenging neonatally or adult tolerized rats with myelin basic protein in adjuvant. The clinical course of EAE was not significantly altered in rats tolerized neonatally to V beta 8.2 peptides, but both the severity and incidence of mortality from EAE was increased in rats tolerized as adults with V beta 8.2 peptides conjugated to syngeneic splenocytes. These results demonstrate that V beta 8.2 peptides are tolerogenic as well as immunogenic. Moreover, the observation of different effects of neonatal vs adult tolerization on the course of EAE suggests either the emergence of additional protective idiotopes after neonatal tolerization and/or mechanistic differences in the two tolerance-inducing protocols. Most importantly, the enhancement of clinical EAE in rats tolerized as adults with V beta 8.2 peptides provides evidence for an innate regulatory role of the CDR2 idiotope in recovery from EAE.

Ectopia of the vas deferens

We present a case of bilateral ectopic vas deferens with insertion in the posterior bladder, a rare congenital anomaly related to abnormal distal Wolffian duct development. Common presentations include urinary tract infections, epididymitis or a swollen scrotum although this abnormality can be an asymptomatic, incidental finding. There is also a strong association with anorectal malformations, ureteral ectopia and vesicoureteral reflux.

Alteration in the level of interferon-gamma results in acceleration of Theiler's virus-induced demyelinating disease

Intracerebral (i.c.) inoculation of susceptible strains of mice with Theiler's murine encephalomyelitis virus (TMEV) results in immune-mediated demyelination. We examined the role of interferon (IFN)-gamma in this virally induced pathogenesis. Intraperitoneal (i.p.) injection of susceptible mice with an IFN-gamma-neutralizing monoclonal antibody (mAb), DB-1, resulted in a significantly accelerated onset of disease. The anti-IFN-gamma mAb-treated animals showed a strong delayed-type hypersensitivity (DTH) response to the virus similar to that of control mAb-treated animals. Treatment with anti-IFN-gamma mAb had no significant effect on the clinical course of disease. However, intracerebral administration of recombinant IFN-gamma significantly accelerated the onset of TMEV-induced disease, as well as enhanced TMEV-specific T cell proliferation and DTH responses. The enhancing effect of IFN-gamma was completely abrogated by simultaneous treatment with anti-IFN-gamma mAb. Collectively, our data suggest that the level of IFN-gamma plays a key role in the TMEV-induced inflammatory response and a perturbation of this balance may result in an alteration in the course of the demyelinating disease.

Staged arthrodesis for salvage of the septic hallux metatarsophalangeal joint

Failed surgery at the hallux metatarsophalangeal joint may present substantial difficulties in treatment, especially when complicated by infection. This retrospective study reviews the staged treatment of 5 patients with complications of hallux valgus surgery associated with sepsis of the metatarsophalangeal joint. The initial salvage treatment included debridement with placement of an antibiotic cement spacer and either an intramedullary Kirschner wire (4 patients) or an external fixator (1 patient). At the second stage procedure, the spacer and fixation were removed, and an autogenous tricortical iliac crest graft was inserted into the joint. All patients had clinical control of joint sepsis. Pseudoarthrosis occurred at the proximal end of the tricortical graft in 2 patients. Patients were evaluated at an average of 28 months after the fusion. Staged arthrodesis appears to be a satisfactory approach to postoperative sepsis of the hallux metatarsophalangeal joint.

Posterior transvertebral osteotomy for adult thoracolumbar kyphosis

STUDY DESIGN

A retrospective case study was performed on the single-stage posterior transvertebral closing-wedge osteotomy for treatment of adult thoracolumbar kyphosis.

SUMMARY OF BACKGROUND DATA

Forty-one consecutive cases in 38 patients available for follow-up, averaging 33 months (range 4-87 months), are included. All patients had severe pain and/or deformity; 51% of cases had previous fractures, and 49% had postlaminectomy failed back syndromes with kyphosis. A preoperative neurologic deficit was present in 34% of the cases including two with cauda equina syndrome.

METHODS

Patient examination and interviews, subjective questionnaire, chart reviews, and radiographic measurements were performed independently. Complications, risks, benefits, results, and biomechanical considerations were evaluated and discussed as compared with other techniques.

RESULTS

All cases had solid union at follow-up; 93% maintained correction averaging 35 degrees with three requiring revision for failure. Postoperatively, 19.5% of the cases had new neurologic deficits with five (12.2%) temporary or minor and three (7.3%) major, including one with unimproved paraplegia at follow-up. Eight of the 14 preoperative neurologic deficit cases improved postoperatively; 26 additional surgeries were performed on 18 patients most commonly for pain (x 11) and additional trauma (x 4). The subjective questionnaire results indicated significant patient satisfaction, with 76% stating they would repeat the surgery and 90% recommending it to another.

CONCLUSION

This technically demanding high-risk procedure provides an effective and mechanically superior correction for acute angle thoracolumbar kyphosis in selected adult patients, with high subjective satisfaction.

Fine specificity of CD4+ T cell responses to the dominant encephalitogenic PLP 139-151 peptide in SJL/J mice

PLP 139-151(S) is the major encephalitogenic epitope of PLP in the SJL/J mouse. CD4+ T cells specific for PLP 139-151(S) induce a relapsing-remitting form of EAE which is similar to the human demyelinating disease MS in both clinical course and histopathology. We are interested in events involved in activation of autoreactive T cells and how to specifically regulate these immune response to both prevent and treat ongoing demyelinating disease. In the current study, we examined the effect of both amino acid substitutions and deletions in the native PLP 139-151(S) peptide to identify which residues are critical for immunogenicity and encephalitogenicity. Conservative and nonconservative substitutions at position 145 diminished or completely destroyed the encephalitogenic potential of the peptide without affecting the ability to recall a proliferative response in lymph node T cells primed with the native PLP 139-151(S) peptide indicating an interesting dichotomy between ability to induce T cell proliferation and ability to induce active clinical disease. In addition, tryptophan at position 144 was identified as a critical TCR contact site as a peptide containing an alanine for tryptophan at this position (A144) primed a unique population of T cells which did not cross react with the native PLP 139-151(S). In addition, A144 was unable to stimulate PLP 139-151(S)-specific T cells in vitro or to induce active relapsing EAE in vivo. The significance of these results to the potential development of new strategies for preventing and treating T cell-mediated autoimmune diseases is discussed.

Familial paraganglioma

Extra-adrenal pheochromocytomas and paragangliomas are rare tumors of neural crest origin, most commonly found in the retroperitoneum. Because these tumors are so uncommon, relatively little is known about their natural history. Comparisons between adrenal pheochromocytomas and extra-adrenal pheochromocytomas have appeared in the medical literature. Like pheochromocytomas, paragangliomas may occur as functional or nonfunctional tumors. Furthermore, although the hereditary occurrence of pheochromocytomas is well documented, the familial nature of paragangliomas is unclear. We present the first report of a mother and son with nonfunctional paragangliomas occurring in the same anatomic location and describe their care and treatment.

The immunopathogenesis and regulation of T-cell-mediated demyelinating diseases

A variety of experimental approaches are currently being evaluated for controlling CD4+ T helper 1 (Th1)-mediated autoimmune pathology. Here, Stephen Miller and William Karpus compare and contrast the efficacies of various antigen-specific regulatory strategies. Particular emphasis is placed on the mechanisms of peripheral immune tolerance and how this may be used in the treatment and analysis of the pathologic T-cell repertoire in autoimmune and virus-induced demyelinating diseases.

Epitope and functional specificity of peripheral tolerance induction in experimental autoimmune encephalomyelitis in adult Lewis rats

Intravenous treatment of Lewis rats with neuroantigen-coupled splenocytes 7 days before the induction of experimental autoimmune encephalomyelitis with guinea pig myelin basic protein (GP-MBP) resulted in a significant reduction of both the incidence and severity of clinical disease. To test the epitope and functional specificities of the unresponsiveness, splenocytes (SP) coupled with the major encephalitogenic MBP determinant, GP-68-86, were compared with those coupled with intact GP-MBP for the ability to down-regulate clinical disease and Ag-specific T cell responses (proliferation, cytokine production, and delayed-type hypersensitivity) in animals primed with either intact GP-MBP/CFA or GP-68-86/CFA. GP-MBP-SP and GP-68-86-SP were equally efficient at significantly inhibiting clinical disease in animals primed with GP-68-86/CFA. In contrast, tolerization with intact GP-MBP-SP was significantly more efficient than that with GP-68-86-SP at reducing disease incidence and severity in GP-MBP/CFA-primed animals, which indicates a role for secondary (cryptic) encephalitogenic epitopes in GP-MBP-induced disease. By testing a panel of GP-68-86 peptides that contained conservative amino acid substitutions at either position 75 (A75) or 80 (P80) or at both, residues that previously had been shown to be TCR contact residues, for their ability to inhibit experimental autoimmune encephalomyelitis induction, were assessed for the fine specificity of tolerance induction. None of the substituted peptides were capable of affecting the course of paralytic disease that had been induced by sensitization with the native GP-68-86 epitope, but all significantly reduced a milder form of the disease that had been produced by priming with the (A75,P80) 68-86 substituted peptide. With regard to the functional specificity of tolerance induction, lymph node T cells derived from either GP-MBP-SP- or GP-68-86-SP-treated animals exhibited a marked reduction in both proliferation and production of Th1-derived cytokines (IL-2, IFN-gamma, and lymphotoxin/TNF-alpha) in response to either GP-MBP or GP-68-86 in culture. In contrast, no consistent significant differences in delayed-type hypersensitivity responses were observed in any of the experimental groups relative to controls. Histologic examination of central nervous system tissues from the tolerant and control groups revealed significantly reduced, but still demonstrable, levels of perivascular infiltration even in asymptomatic animals.

Epitope and functional specificity of peripheral tolerance induction in experimental autoimmune encephalomyelitis in adult Lewis rats

Intravenous treatment of Lewis rats with neuroantigen-coupled splenocytes 7 days before the induction of experimental autoimmune encephalomyelitis with guinea pig myelin basic protein (GP-MBP) resulted in a significant reduction of both the incidence and severity of clinical disease. To test the epitope and functional specificities of the unresponsiveness, splenocytes (SP) coupled with the major encephalitogenic MBP determinant, GP-68-86, were compared with those coupled with intact GP-MBP for the ability to down-regulate clinical disease and Ag-specific T cell responses (proliferation, cytokine production, and delayed-type hypersensitivity) in animals primed with either intact GP-MBP/CFA or GP-68-86/CFA. GP-MBP-SP and GP-68-86-SP were equally efficient at significantly inhibiting clinical disease in animals primed with GP-68-86/CFA. In contrast, tolerization with intact GP-MBP-SP was significantly more efficient than that with GP-68-86-SP at reducing disease incidence and severity in GP-MBP/CFA-primed animals, which indicates a role for secondary (cryptic) encephalitogenic epitopes in GP-MBP-induced disease. By testing a panel of GP-68-86 peptides that contained conservative amino acid substitutions at either position 75 (A75) or 80 (P80) or at both, residues that previously had been shown to be TCR contact residues, for their ability to inhibit experimental autoimmune encephalomyelitis induction, were assessed for the fine specificity of tolerance induction. None of the substituted peptides were capable of affecting the course of paralytic disease that had been induced by sensitization with the native GP-68-86 epitope, but all significantly reduced a milder form of the disease that had been produced by priming with the (A75,P80) 68-86 substituted peptide. With regard to the functional specificity of tolerance induction, lymph node T cells derived from either GP-MBP-SP- or GP-68-86-SP-treated animals exhibited a marked reduction in both proliferation and production of Th1-derived cytokines (IL-2, IFN-gamma, and lymphotoxin/TNF-alpha) in response to either GP-MBP or GP-68-86 in culture. In contrast, no consistent significant differences in delayed-type hypersensitivity responses were observed in any of the experimental groups relative to controls. Histologic examination of central nervous system tissues from the tolerant and control groups revealed significantly reduced, but still demonstrable, levels of perivascular infiltration even in asymptomatic animals.

Molecular cloning and characterization of the 78-kilodalton glucose-regulated protein of Trypanosoma cruzi

The protozoan Trypanosoma cruzi is the etiologic agent of Chagas' disease, an illness responsible for morbidity and death among millions of Latin Americans. Mice also develop this disease when infected with T. cruzi and are a useful model organism for the study of parasite-specific immune responses. To identify immunogenic T. cruzi antigens, serum from an infected mouse was used to isolate clones from a T. cruzi epimastigote cDNA expression library. One of these clones was found to encode the 78-kDa glucose-regulated protein (grp78), the endoplasmic reticular member of the 70-kDa heat shock protein (hsp70) family. Like the mammalian and yeast grp78s, the T. cruzi protein contains an endoplasmic reticular leader peptide and a carboxyl-terminal endoplasmic reticular retention sequence. T. cruzi grp78 is encoded by a tandemly arranged family of three genes located on a chromosome of 1.6 Mb. The effects on grp78 expression of heat shock and tunicamycin treatment, the latter of which specifically stimulates mammalian grp78, were investigated. While the level of the grp78 protein remained constant under all circumstances, grp78 mRNA was unaffected by heat shock but induced fivefold by tunicamycin. Finally, we found that grp78 is the most immunogenic of the T. cruzi heat shock proteins we have characterized, reacting strongly in immunoblots with sera from infected mice.

BALB/c substrain differences in susceptibility to Theiler's murine encephalomyelitis virus-induced demyelinating disease

We report differences among BALB/c substrains in susceptibility to Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease, an immune-mediated inflammatory demyelinating disease and experimental model for human multiple sclerosis. BALB/cJ and BALB/cAnNCr mice are susceptible, while BALB/cByJ and BALB/cCum are resistant. Hybrids between BALB/cBy and BALB/cAnNCr were intermediate, although closer to the resistant parent. Backcrosses gave results compatible with differential susceptibility being related to a single segregating locus. Exposure of resistant BALB/cByJ mice to low dose irradiation, 2 days prior to infection, rendered them susceptible to TMEV-induced demyelination. The susceptibility pattern of TMEV-induced demyelinating disease among BALB/c substrains is distinct from those of several autoimmune disorders.

Postoperative toxic shock syndrome after lumbar laminectomy in a male patient

OBJECTIVES

Postoperative toxic shock syndrome in a male patient who underwent a lumbar laminectomy has not been reported. This case report identifies a rare, and potentially fatal, postoperative complication.

RESULTS

Early diagnosis and aggressive medical management were successful in this patient and are the cornerstone of treatment in toxic shock syndrome.

CONCLUSION

Spine surgeons should consider postoperative toxic shock syndrome as a diagnosis in a patient with fever, gastrointestinal symptoms, and hypotension in the presence of a benign-appearing lumbar laminectomy wound.

Anergy in vivo: down-regulation of antigen-specific CD4+ Th1 but not Th2 cytokine responses

Efficient immunologic tolerance, defined as antigen-specific unresponsiveness, can be peripherally induced by the i.v. injection of syngeneic splenocytes coupled with antigen using ethylene carbodiimide (ECDI). We have previously reported that unresponsiveness induced via i.v. injection of syngeneic splenocytes coupled with intact, UV-inactivated Theiler's murine encephalomyelitis virus (TMEV-SP) resulted in 'split tolerance'. Both virus-specific delayed-type hypersensitivity and IgG2a levels were inhibited, whereas IgG1 levels were increased when compared with sham tolerized controls. In the present report we demonstrate that tolerance induced by i.v. injection of TMEV-coupled splenocytes resulted in antigen-specific inhibition of T cell proliferation, as well as IL-2 and IFN-gamma production in response to both whole TMEV and the immunodominant viral epitope. Additionally, tolerance induction resulted in abrogation of Th1-derived [IL-2, IFN-gamma and LT/tumor necrosis factor-beta (TNF-beta)] cytokine mRNA expression in response to in vitro stimulation with UV-inactivated TMEV as determined by reverse transcriptase polymerase chain reaction. In contrast, expression of Th2-derived (IL-4, IL-6 and IL-10) cytokine mRNA was not affected in tolerized mice. Tolerance functioned directly at the level of CD4+ Th1 cells at both the induction and effector limbs as depletion of CD8+ T cells both prior to in vivo tolerization or in vitro culture had no effect on inhibition of Th1-specific responses. The mechanism of in vivo tolerance induction appeared to be anergy of CD4+ Th1 cells since IL-2, IFN-gamma and LT/TNF-beta mRNA expression as well as virus-specific proliferative responses could be restored by addition of rIL-2 to in vitro cultures of tolerant, CD4+ Th1 populations. These results suggest that in vivo 'split tolerance' induced by i.v. injection of ECDI-fixed, antigen-coupled splenocytes involves anergy of TMEV-specific, CD4+ Th1 lymphocytes and concomitant priming of Th2 cells. The induction of antigen-specific, in vivo anergy has important implications in the design of therapeutic strategies for immunopathologic diseases mediated by Th1 lymphocytes, especially T cell-mediated autoimmune disorders.

Follow-up of hymenoptera-sensitive patients without active immunotherapy

Presently there is no definitive guideline for the treatment of adult patients suffering from generalized insect sting reactions limited to skin manifestations or purely respiratory compromise who have not been treated with immunotherapy. Previous studies in adults demonstrate that the majority of patients with insect sting anaphylaxis have a decreased reactivity to re-sting with time, suggesting the insect allergy itself may be self-limiting. In this study, we evaluated 63 patients with initial insect sting manifestations limited to the skin and the respiratory system and noted the incidence and degree of natural re-sting reactions to these patients who had not undergone venom immunotherapy. In those patients with mild systemic reactions limited to the skin, none experienced an increase in severity. A local reaction was found on repeat sting in three of five patients in this group, and two of five had an equivalent cutaneous response (i.e., urticaria/angioedema). In five patients who had an initial respiratory reaction, four of the patients had a local reaction while one patient repeated the same respiratory manifestations. None of the patients with cutaneous or respiratory symptoms demonstrated a more severe reaction upon re-sting. This demonstrates that there is a natural progression of tolerance to insect stings in the adult population.

Cardiac antigen-specific autoantibody production is associated with cardiomyopathy in Trypanosoma cruzi-infected mice

An inflammatory cardiomyopathy may develop in humans and experimental animals with chronic Trypanosoma cruzi infection (Chagas' disease). Among the possible mechanisms involved in the pathogenesis of Chagas' cardiomyopathy, induction of heart-specific autoimmune responses has recently received substantial experimental support. The goal of the current study was to determine whether cardiac Ag-specific antibodies are produced in T. cruzi-infected mice with heart disease and, if so, to determine their Ag specificities. Upon infection with the Brazil strain of T. cruzi, C57BL/6 mice develop a cardiomyopathy that is histologically similar to that observed in chronically infected humans. Antisera from these mice were found to react with three cardiac Ag, having relative molecular masses of 200, 150, and 53 kDa. p200 and p150 are specifically found in heart muscle, although p53 is found in skeletal muscle as well. C57BL/6 mice infected with the Guayas strain of T. cruzi, which do not develop cardiomyopathy, did not produce antibodies to p200, p150, or p53, indicating that these antibodies may be specific markers of cardiomyopathy. Finally, p200 and p53 were identified as the contractile protein myosin and the intermediate filament protein desmin, respectively. This last finding is of special interest, because antibodies specific for myosin or desmin have been detected in humans and experimental animals with other natural and experimental cardiomyopathies. This suggests that infection with particular strains of T. cruzi may lead to the development of a cardiac Ag-specific autoimmune disease, possibly involving one or more of the Ag identified in this study.

Cardiac antigen-specific autoantibody production is associated with cardiomyopathy in Trypanosoma cruzi-infected mice

An inflammatory cardiomyopathy may develop in humans and experimental animals with chronic Trypanosoma cruzi infection (Chagas' disease). Among the possible mechanisms involved in the pathogenesis of Chagas' cardiomyopathy, induction of heart-specific autoimmune responses has recently received substantial experimental support. The goal of the current study was to determine whether cardiac Ag-specific antibodies are produced in T. cruzi-infected mice with heart disease and, if so, to determine their Ag specificities. Upon infection with the Brazil strain of T. cruzi, C57BL/6 mice develop a cardiomyopathy that is histologically similar to that observed in chronically infected humans. Antisera from these mice were found to react with three cardiac Ag, having relative molecular masses of 200, 150, and 53 kDa. p200 and p150 are specifically found in heart muscle, although p53 is found in skeletal muscle as well. C57BL/6 mice infected with the Guayas strain of T. cruzi, which do not develop cardiomyopathy, did not produce antibodies to p200, p150, or p53, indicating that these antibodies may be specific markers of cardiomyopathy. Finally, p200 and p53 were identified as the contractile protein myosin and the intermediate filament protein desmin, respectively. This last finding is of special interest, because antibodies specific for myosin or desmin have been detected in humans and experimental animals with other natural and experimental cardiomyopathies. This suggests that infection with particular strains of T. cruzi may lead to the development of a cardiac Ag-specific autoimmune disease, possibly involving one or more of the Ag identified in this study.

Class II-restricted T cell responses in Theiler's murine encephalomyelitis virus-induced demyelinating disease. VI. Potentiation of demyelination with and characterization of an immunopathologic CD4+ T cell line specific for an immunodominant VP2 epitope

Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease is a relevant mouse model of multiple sclerosis. Demyelination is linked to persistent TMEV infection of the central nervous system and characterized by perivascular inflammatory mononuclear infiltrates and primary demyelination. Our previous results have shown that susceptibility correlates with the temporal development of chronic virus-specific delayed-type hypersensitivity (DTH) responses and suggest that inflammatory processes mediated by T cells specific for an immunodominant determinant on virus capsid protein 2 (VP2(74-86)) play a major immunopathologic role in SJL/J mice. In this study we have further defined the T cell-dependent nature and specificity of the demyelinating process in susceptible SJL/J mice by showing that thymectomized irradiated bone marrow-restored mice fail to develop chronic demyelination and that i.v. adoptive transfer of polyclonal TMEV-specific T cells before intracerebral infection with a suboptimal dose of the BeAn strain of TMEV led to increased incidence and accelerated onset of clinical disease. The data also show that demyelination is dependent on the activity of virus-specific CD4+ T cells because in vivo depletion with anti-CD4, but not anti-CD8, mAb led to significantly diminished incidence and severity of demyelination concomitant with a decrease in TMEV-specific DTH reactivity. In addition, the adoptive transfer of a TMEV-specific, DTH-mediating CD4+ I-A(s)-restricted Th1 line (sTV1) specific for the immunodominant VP2(74-86) epitope also led to increased incidence and accelerated onset of clinical disease only in TMEV-infected recipients. Collectively, the results of this and the companion paper demonstrate the highly significant immunopathologic contribution of CD4+ T cell responses specific for an immunodominant viral epitope to the chronic central nervous system demyelination observed in TMEV-infected SJL/J mice.

Class II-restricted T cell responses in Theiler's murine encephalomyelitis virus-induced demyelinating disease. VI. Potentiation of demyelination with and characterization of an immunopathologic CD4+ T cell line specific for an immunodominant VP2 epitope

Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease is a relevant mouse model of multiple sclerosis. Demyelination is linked to persistent TMEV infection of the central nervous system and characterized by perivascular inflammatory mononuclear infiltrates and primary demyelination. Our previous results have shown that susceptibility correlates with the temporal development of chronic virus-specific delayed-type hypersensitivity (DTH) responses and suggest that inflammatory processes mediated by T cells specific for an immunodominant determinant on virus capsid protein 2 (VP2(74-86)) play a major immunopathologic role in SJL/J mice. In this study we have further defined the T cell-dependent nature and specificity of the demyelinating process in susceptible SJL/J mice by showing that thymectomized irradiated bone marrow-restored mice fail to develop chronic demyelination and that i.v. adoptive transfer of polyclonal TMEV-specific T cells before intracerebral infection with a suboptimal dose of the BeAn strain of TMEV led to increased incidence and accelerated onset of clinical disease. The data also show that demyelination is dependent on the activity of virus-specific CD4+ T cells because in vivo depletion with anti-CD4, but not anti-CD8, mAb led to significantly diminished incidence and severity of demyelination concomitant with a decrease in TMEV-specific DTH reactivity. In addition, the adoptive transfer of a TMEV-specific, DTH-mediating CD4+ I-A(s)-restricted Th1 line (sTV1) specific for the immunodominant VP2(74-86) epitope also led to increased incidence and accelerated onset of clinical disease only in TMEV-infected recipients. Collectively, the results of this and the companion paper demonstrate the highly significant immunopathologic contribution of CD4+ T cell responses specific for an immunodominant viral epitope to the chronic central nervous system demyelination observed in TMEV-infected SJL/J mice.

Class II-restricted T cell responses in Theiler's murine encephalomyelitis virus-induced demyelinating disease. V. Mapping of a dominant immunopathologic VP2 T cell epitope in susceptible SJL/J mice

Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease is a relevant mouse model of multiple sclerosis. Demyelination is linked to persistent TMEV infection of the central nervous system and characterized by perivascular inflammatory mononuclear infiltrates and primary demyelination. Myelin damage is a T cell-dependent process and susceptibility correlates with the temporal development of chronic virus-specific delayed-type hypersensitivity (DTH) responses. Our previous results have shown that inflammatory processes mediated by Th1 cells specific for a determinant(s) on virus capsid protein 2 (VP2) play a major immunopathologic role in SJL/J mice. This study identifies a 13 amino acid peptide on VP2 (VP2(74-86)) as the immunodominant T cell epitope in TMEV-infected and -immunized SJL/J mice, and demonstrates the ability of that sequence to prime for the majority of the SJL/J DTH T cell response to intact TMEV. The importance of T cell responses to this epitope in the demyelinating process was illustrated by experiments in which SJL/J mice displayed an increased incidence and accelerated onset of clinical disease after peripheral immunization with a fusion protein containing VP2(74-84) before intracerebral infection with a suboptimal dose of the BeAn strain of TMEV. Identification of this immunopathologic TMEV T cell epitope will be critically important for delineation of the mechanisms of T cell-mediated myelin damage and for potential use to prevent and/or treat TMEV-induced demyelinating disease via the induction of epitope-specific tolerance.

Class II-restricted T cell responses in Theiler's murine encephalomyelitis virus-induced demyelinating disease. V. Mapping of a dominant immunopathologic VP2 T cell epitope in susceptible SJL/J mice

Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease is a relevant mouse model of multiple sclerosis. Demyelination is linked to persistent TMEV infection of the central nervous system and characterized by perivascular inflammatory mononuclear infiltrates and primary demyelination. Myelin damage is a T cell-dependent process and susceptibility correlates with the temporal development of chronic virus-specific delayed-type hypersensitivity (DTH) responses. Our previous results have shown that inflammatory processes mediated by Th1 cells specific for a determinant(s) on virus capsid protein 2 (VP2) play a major immunopathologic role in SJL/J mice. This study identifies a 13 amino acid peptide on VP2 (VP2(74-86)) as the immunodominant T cell epitope in TMEV-infected and -immunized SJL/J mice, and demonstrates the ability of that sequence to prime for the majority of the SJL/J DTH T cell response to intact TMEV. The importance of T cell responses to this epitope in the demyelinating process was illustrated by experiments in which SJL/J mice displayed an increased incidence and accelerated onset of clinical disease after peripheral immunization with a fusion protein containing VP2(74-84) before intracerebral infection with a suboptimal dose of the BeAn strain of TMEV. Identification of this immunopathologic TMEV T cell epitope will be critically important for delineation of the mechanisms of T cell-mediated myelin damage and for potential use to prevent and/or treat TMEV-induced demyelinating disease via the induction of epitope-specific tolerance.

Differential recognition of sequences within the encephalitogenic region of myelin basic protein capable of eliciting cell-mediated immune responses in experimental autoimmune encephalomyelitis

The fine specificity of myelin basic protein (MBP) epitopes capable of eliciting in vivo delayed-type hypersensitivity responses in Lewis rats with experimental autoimmune encephalomyelitis (EAE) was compared to those eliciting in vitro antigen-specific T cell proliferation and augmentation of disease transfer. Utilizing a panel of synthetic peptides with sequences representing the 68-86 region of guinea pig (GP-) or bovine myelin basic protein (B-MBP), animals were primed with one species of peptide and subsequently challenged with either the same peptide or peptides with truncations or substitutions representative of the other species of MBP. In regard to minimal length sequences capable of eliciting delayed-type hypersensitivity (DTH), rats primed with GP-MBP and complete Freund's adjuvant (CFA) exhibited a hierarchical pattern of responsiveness to challenge with a series of truncated peptides, ranking as follows: GP-68-86 > GP-72-86 > GP-68-84 > > GP-75-86 = no activity. This response pattern corresponds to that previously reported for T cell proliferation and activation for disease transfer. Furthermore, a comparison of these T cell-mediated immune parameters, as elicited by the substituted peptides, revealed the response patterns of DTH reactivity to be similar to that previously described for in vitro T cell proliferation with significant DTH responses generated only by the peptide species for which the animal was primed. In contrast, a cross-reactive pattern of recognition was observed in cells mediating disease transfer, with all four 68-86 sequences capable of augmenting activation for adoptive transfer of disease, regardless of the peptide species for which the animal was primed.(ABSTRACT TRUNCATED AT 250 WORDS)

Class I-deficient resistant mice intracerebrally inoculated with Theiler's virus show an increased T cell response to viral antigens and susceptibility to demyelination

Intracerebral inoculation of Theiler's murine encephalomyelitis virus (TMEV) results in immune-mediated demyelination in susceptible mouse strains. The histology of TMEV-induced demyelination is similar to that seen in patients suffering from multiple sclerosis. It was previously shown that the susceptibility of mice to TMEV-induced demyelination in certain strain combinations is closely associated with the major histocompatibility complex (MHC) class I locus. Here we examine disease susceptibility of beta 2-microglobulin (beta 2M)-deficient transgenic mice lacking class I expression and functional CD8+ T cells. In contrast to TMEV-infected parental C57BL/6 mice, the transgenics develop high levels of virus-specific DTH and T cell proliferation accompanied by an increased frequency of central nervous system (CNS) demyelinating lesions. However, clinical signs of demyelination were not noted. Neither antibody titer nor viral persistence were significantly affected in the beta 2M-deficient mice. These results suggest that in the absence of functional class I/CD8+ cells, the class II-restricted T cell response to TMEV is enhanced and CNS pathogenesis is heightened, although the level is not severe enough to result in clinical disease. When the TMEV-infected mice were subcutaneously immunized with virus, however, the beta 2M-deficient mice displayed clinical symptoms. Therefore, our results strongly suggest that CD8+ T cells do not directly contribute to CNS demyelination. In contrast, such T cells appear to be primarily involved in down-regulation of a potentially damaging CD4+ T cell response in resistant animals, although some of the T cells may play a role in clearing viral persistence in the CNS, resulting in the protection of the host from viral demyelination.

Clostridium perfringens infection of an anterior iliac crest bone graft donor site. A case report

Postoperative infection of elective surgical wounds with Clostridium species has been linked to gastrointestinal tract lesions. A 55-year-old man with a history of peptic ulcer disease was treated by open reduction and internal fixation with autogeneic cancellous bone grafting from an anterior iliac crest donor site for nonunion of the clavicle. A mild serosanguinous drainage from the Penrose drain site at the iliac crest had ceased on postoperative Day 11; the patient complained of pain and a brownish drainage on postoperative Day 15. The infection was documented with cultures positive for Clostridium perfringens. Aggressive emergent surgical and antibiotic therapy resulted in complete clinical recovery. The wound infection did not advance to severe tissue damage and myonecrosis. This case represents the first reported infection of an iliac crest bone graft site with C. perfringens.

Elevated levels of serum immunoglobulins in asymptomatic carriers of Clostridium difficile

Serum levels of IgA, IgM, and polyvalent immunoglobulins reactive with Clostridium difficile were determined by ELISA for asymptomatic carriers (n = 5), symptomatic individuals (n = 21), and a pool of 30 "normal" individuals. Mean IgA concentrations expressed as optical density (OD +/- SD) were significantly higher (P < .001) for asymptomatic carriers (1.252 +/- 0.516) than for symptomatic patients (0.374 +/- 0.145). Mean serum IgM levels also were significantly higher (P < .001) for carriers (1.456 +/- 0.582) than for symptomatic patients (0.727 +/- 0.331), as were mean values for polyvalent immunoglobulins (2.25 +/- 0.718 for carriers vs. 1.457 +/- 0.574 for symptomatic patients; P < .05). Although the patient populations were small, the levels of immunoglobulins reactive with C. difficile antigens differed significantly. This difference might reflect the ability of the host to mount an immune response and might be a factor influencing whether a patient develops disease due to this organism. The ability to detect differences in immunoglobulin levels might also help differentiate infection from colonization.

Transverse myelitis complicating systemic lupus erythematosus: treatment including hydroxychloroquine. Case report

Transverse myelitis has been cited as a rare and unusual complication of systemic lupus erythematosus (SLE). A review of the literature reveals only 10 cases of transverse myelitis as the initial presentation of SLE, and only one with reported benefits from antimalarial therapy. The case of a 30-year-old woman is reviewed. She presented to the emergency room with complaints of hypogastric and low back pain. The ensuing course was one of frank urinary retention and rapidly progressing quadriparesis. Magnetic resonance imaging of the spine revealed marked edema of the cervical and thoracic spine. A diagnosis of SLE was based on positive antinuclear antibodies and leukopenia. The patient was treated with high dose methylprednisolone, plasmapheresis and pulse cyclophosphamide for 3 months. Subsequently, treatment was begun with hydroxychloroquine, and significant improvement in her neurologic and functional status was achieved after 1 month of therapy. Ten months after her onset of symptoms, the patient suffered an acute exacerbation of paraparesis and urinary retention. Again, she improved clinically after high dose methylprednisolone and pulse cyclophosphamide for 1 month. Hydroxychloroquine was continued throughout the duration of therapy.

Endopeptidase inhibition and intestinal antigen processing in mice

The role of gastrointestinal digestive processes in the systemic availability of ingested protein antigens was examined by feeding the trypsin inhibitor aprotinin intragastrically to mice and measuring uptake of ovalbumin and 14C-polyethylene glycol (MW 4000) from the gastrointestinal tract. Trypsin and chymotrypsin activities in the intestinal lumen were significantly reduced by aprotinin feeding. Aprotinin slowed stomach emptying, but radioimmunoassays for immunoreactive ovalbumin in the serum of mice prefed aprotinin showed 12-fold elevations within 1 hr after ovalbumin feeding. Uptake of a nonmetabolized macromolecular probe, 14C-polyethylene glycol-4000, increased less than two-fold when fed with aprotinin under the same conditions, indicating that the increased uptake of immunoreactive ovalbumin was not due to changes in intestinal permeability. The results show that inhibition of luminal proteolysis caused significant increases in the serum concentration of immunoreactive ovalbumin, indicating that acute inhibition of luminal proteases permits larger quantities of relatively intact protein to interact with mucosal absorptive surfaces. These results support the hypothesis that pancreatic proteases modulate antigen absorption from the lumen in adult animals.

Inhibition of orally-induced immune tolerance in mice by prefeeding an endopeptidase inhibitor

Intragastric feeding of T-dependent protein antigens to mice induces substantial systemic tolerance in specific antibody and cell-mediated immune responses. To evaluate the role of gastrointestinal digestion in this phenomenon, the trypsin inhibitor aprotinin was fed to adult BDF1 mice prior to tolerogenic feedings of ovalbumin or human gamma globulin. As assessed by measurement of protein-specific antibody responses, aprotinin significantly reduced tolerance induced by feeding carrier protein, but not tolerance induced by parenteral antigen injection. Aprotinin also reduced oral tolerance to ovalbumin as measured by delayed-type hypersensitivity and T cell proliferative responses. However, aprotinin did not alter antibody tolerance to a carrier-associated hapten in the same animals. Feeding of human gamma globulin concomitantly with aprotinin induced specific antibody responses without further immunization, and reduced subsequent tolerance. Aprotinin also increased the level of immunologically detectable ovalbumin found in the serum following antigen feeding. The data support the hypothesis that aprotinin indirectly mediated changes in specific stimuli available to the lymphoid system as a result of alterations in gastrointestinal processing of fed antigens rather than to direct effects of aprotinin upon systemic immune responses.