Bilateral Rasmussen Encephalitis: Good Outcome Following Hemispherotomy.

BACKGROUND: Bilateral Rasmussen encephalitis is a rare variant of a debilitating, typically unihemispheric disease with limited treatment options. Few cases with bilateral histopathology have been reported, all with poor seizure control following surgery. Here we report a favorable outcome following hemispherotomy in a four-year-old male with biopsy-confirmed bilateral disease. CASE: The patient presented with right hemispheric focal seizures with behavioral arrest and over a year progressed to left lower extremity clonic seizures, epilepsia partialis continua, and loss of ambulation, with transient response to steroids and tacrolimus. Histopathology confirmed bilateral disease. The patient developed super-refractory status epilepticus and underwent right functional hemispherotomy 4.5 years after initial presentation. In a 2.5-year follow-up period, an Engel 1D outcome classification was observed with substantially improved quality of life. CONCLUSION: Previous reports of bilateral Rasmussen encephalitis describe universally poor outcomes, and hemispherotomy is often considered contraindicated. However, hemispherotomy in a patient with bilateral Rasmussen encephalitis may have a good outcome if seizures are unihemispheric.

Autoimmune Encephalitis: Distinguishing Features and Specific Therapies.

Autoimmune encephalitis is characterized by subacute onset of the altered mental status that can rapidly progress to autonomic instability and refractory seizures requiring intensive care. It is mediated by autoantibodies that bind to synaptic surface proteins and alter their function. In contrast to many autoimmune CNS diseases, there is often little detectable inflammatory damage to the brain making it difficult to diagnose. Early engagement of a multidisciplinary team is essential to obtaining a complete diagnostic workup and instituting definitive therapy as early as possible to optimize outcomes. Diagnosis, treatment, and monitoring for this devastating condition continue to evolve. Pathogenesis, diagnosis and both current and emerging therapies are reviewed.

T Cell Interactions in Mycobacterial Granulomas: Non-Specific T Cells Regulate Mycobacteria-Specific T Cells in Granulomatous Lesions.

Infections with pathogenic mycobacteria are controlled by the formation of a unique structure known as a granuloma. The granuloma represents a host-pathogen interface where bacteria are killed and confined by the host response, but also where bacteria persist. Previous work has demonstrated that the T cell repertoire is heterogenous even at the single granuloma level. However, further work using pigeon cytochrome C (PCC) epitope-tagged BCG (PCC-BCG) and PCC-specific 5CC7 RAG-/- TCR transgenic (Tg) mice has demonstrated that a monoclonal T cell population is able to control infection. At the chronic stage of infection, granuloma-infiltrating T cells remain highly activated in wild-type mice, while T cells in the monoclonal T cell mice are anergic. We hypothesized that addition of an acutely activated non-specific T cell to the monoclonal T cell system could recapitulate the wild-type phenotype. Here we report that activated non-specific T cells have access to the granuloma and deliver a set of cytokines and chemokines to the lesions. Strikingly, non-specific T cells rescue BCG-specific T cells from anergy and enhance the function of BCG-specific T cells in the granuloma in the chronic phase of infection when bacterial antigen load is low. In addition, we find that these same non-specific T cells have an inhibitory effect on systemic BCG-specific T cells. Taken together, these data suggest that T cells non-specific for granuloma-inducing agents can alter the function of granuloma-specific T cells and have important roles in mycobacterial immunity and other granulomatous disorders.

Lipoatrophic panniculitis in an adolescent.

Lipoatrophic panniculitis (LP) is a rare childhood panniculitis characterized by sclerotic, atrophic plaques on the extremities. We present a case of LP diagnosed during the inflammatory phase that was difficult to distinguish clinically from eosinophilic fasciitis. This report adds to the limited phenotypic spectrum of LP by differentiating the clinical features of disease activity from disease damage and highlighting the importance of biopsy in establishing a diagnosis.

Hypergammaglobulinemic purpura of Waldenström in children.

BACKGROUND: Hypergammaglobulinemic purpura of Waldenström (HGPW), a rare cutaneous eruption characterized by the triad of recurrent episodes of lower extremity petechiae, symptoms of stinging and burning, and lower extremity edema, is poorly described in children. Some children have been reported to follow a benign course, while others are eventually diagnosed with fulminant rheumatologic disease. OBJECTIVES: To determine the distinguishing features of HGPW including the spectrum of disease manifestations and clinical outcomes. METHODS: This is a multicenter, retrospective case series of six children with HGPW combined with a literature review of 45 previously published pediatric cases. RESULTS: Most children were eventually diagnosed with systemic disease (63%) or developed autoantibody accumulation suggestive of evolving disease (71%). The most common diagnoses were Sjogren's syndrome and systemic lupus erythematosus. The mean duration between onset of cutaneous eruption and diagnosis of systemic disease was 5.6 years, underscoring that HPGW patients often present with a rash that precedes the development of systemic symptoms. CONCLUSIONS: Diagnosis of HGPW should prompt initial screening for rheumatologic disease with long-term rheumatology follow-up, as the majority of patients present with evolving manifestations of systemic disease.

How Often are Pediatric Patients with Clinically Amyopathic Dermatomyositis Truly Amyopathic?

BACKGROUND: Pediatric patients can present with skin manifestations of dermatomyositis without overt weakness (clinically amyopathic juvenile dermatomyositis [JDM]), but it is unclear how often this happens and how often they have subclinical muscle inflammation. OBJECTIVE: Our goal was to determine the frequency of clinically amyopathic JDM and the frequency with which a thorough evaluation uncovers subclinical myositis at a single institution. METHODS: A retrospective review was performed of 46 patients diagnosed with JDM at Children's Hospital of Wisconsin. RESULTS: Of 46 patients presenting with skin findings consistent with dermatomyositis, 10 patients (21.7%) did not have evidence of muscle involvement on history or exam, and these tended to be the younger patients. Of these 10, only 2 (4% of all the JDM patients) were truly amyopathic upon further evaluation (all five muscle enzymes [aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, creatine kinase and aldolase], magnetic resonance imaging [MRI], muscle biopsy). In our series, muscle biopsy was not helpful in identifying subclinical myositis. In contrast, MRI did uncover subclinical muscle disease. CONCLUSION: These data suggest that truly amyopathic JDM is rare and that a thorough workup that includes all five muscle enzymes and MRI may uncover occult myositis.

Toxic Epidermal Necrolysis-Like Cutaneous Lupus in Pediatric Patients: A Case Series and Review.

Bullous eruptions in patients with underlying systemic lupus erythematosus (LE) can mimic toxic-epidermal necrolysis (TEN), a rapidly progressive mucocutaneous reaction usually associated with medication use. Differentiating between classic drug-induced TEN and TEN-like cutaneous LE is important but difficult. We report a series of 3 patients with pediatric systemic LE who were admitted with severe worsening of skin disease resembling TEN. However, the initial photo-distribution of the eruption, subacute progression, limited mucosal involvement, mild systemic symptoms, supportive biopsy and laboratory results, and lack of culprit drugs was more suggestive of a TEN-like cutaneous LE. These patients recovered with various systemic immunosuppressive medications including methylprednisolone, intravenous immunoglobulin, and plasmapheresis. Our cases are rare and demonstrate key clinical and histologic features of TEN-like cutaneous LE in young patients and the importance of differentiating this entity from drug-induced TEN.

Virally activated CD8 T cells home to Mycobacterium bovis BCG-induced granulomas but enhance antimycobacterial protection only in immunodeficient mice.

The effect of secondary infections on CD4 T-cell-regulated chronic granulomatous inflammation is not well understood. Here, we have investigated the effect of an acute viral infection on the cellular composition and bacterial protection in Mycobacterium bovis strain bacille Calmette-Guérin (BCG)-induced granulomas using an immunocompetent and a partially immunodeficient murine model. Acute lymphocytic choriomeningitis virus (LCMV) coinfection of C57BL/6 mice led to substantial accumulation of gamma interferon (IFN-gamma)-producing LCMV-specific T cells in liver granulomas and increased local IFN-gamma. Despite traffic of activated T cells that resulted in a CD8 T-cell-dominated granuloma, the BCG liver organ load was unaltered from control levels. In OT-1 T-cell-receptor (TCR) transgenic mice, ovalbumin (OVA) immunization or LCMV coinfection of BCG-infected mice induced CD8 T-cell-dominated granulomas containing large numbers of non-BCG-specific activated T cells. The higher baseline BCG organ load in this CD8 TCR transgenic animal allowed us to demonstrate that OVA immunization and LCMV coinfection increased anti-BCG protection. The bacterial load remained substantially higher than in mice with a more complete TCR repertoire. Overall, the present study suggests that peripherally activated CD8 T cells can be recruited to chronic inflammatory sites, but their contribution to protective immunity is limited to conditions of underlying immunodeficiency.

Interactions between T cells responding to concurrent mycobacterial and influenza infections.

CD4(+) T cells are central in mediating granuloma formation and limiting growth and dissemination of mycobacterial infections. To determine whether T cells responding to influenza infection can interact with T cells responding to Mycobacterium bovis bacille Calmette-Guérin (BCG) infection and disrupt granuloma formation, we infected mice containing two monoclonal T cell populations specific for the model Ags pigeon cytochrome c (PCC) and hen egg lysozyme (HEL). These mice were chronically infected with PCC epitope-tagged BCG (PCC-BCG) and acutely infected with HEL epitope-tagged influenza virus (HEL-flu). In these mice, PCC-BCG infection is much more abundant in the liver than the lung, whereas HEL-flu infection is localized to the lung. We observe that both T cells have access to both inflammatory sites, but that PCC-specific T cells dominate the PCC-BCG inflammatory site in the liver, whereas HEL-specific T cells dominate the HEL-flu inflammatory site in the lung. Influenza infection, in the absence of an influenza-specific T cell response, is able to increase the activation state and IFN-gamma secretion of PCC-BCG-specific T cells in the granuloma. Activation of HEL-specific T cells allows them to secrete IFN-gamma and contribute to protection in the granuloma. Ultimately, infection with influenza has little effect on bacterial load, and bacteria do not disseminate. In summary, these data illustrate complex interactions between T cell responses to infectious agents that can affect effector responses to pathogens.

Mycobacterial granulomas: keys to a long-lasting host-pathogen relationship.

Chronic infection with mycobacteria is controlled by the formation of granulomas. The failure of granuloma maintenance results in reactivation of disease. Macrophages are the dominant cell type in granulomas, but CD4+ T cells are the master organizers of granuloma structure and function. Recent work points to an unrecognized role for nonspecific T cells in maintaining granuloma function in the chronic phase of infection. In addition, it has become clear that mycobacteria and host T cells collaborate in formation of granulomas. Further understanding of how nonspecific T cells contribute to granuloma formation, as well as how bacteria and T cells maintain a harmonious relationship over the life of the host, will facilitate the development of new strategies to treat mycobacterial disease.

T cell contributions to the different phases of granuloma formation.

Granulomatous inflammation is a form of delayed type hypersensitivity reaction that is involved in protection against chronic infections. Granulomatous inflammation can also occur without any clear inciting stimulus such as in sarcoidosis. An in depth knowledge of granuloma formation is essential to our understanding of protection against chronic infection as well as the dysregulation which occurs in granulomatous diseases of unknown origin. Granuloma formation is a complex and dynamic process involving the recruitment and coordination of diverse cell types. This review is focused on the important roles that T cells play in initiating and building the granuloma as well as in mediating effector functions and eventually resolving granulomatous inflammation. CD4(+) T cells emerge as the central mediators of this process, with T cells from other subsets also participating in the later phases of granuloma formation.

Infection with Mycobacterium bovis BCG diverts traffic of myelin oligodendroglial glycoprotein autoantigen-specific T cells away from the central nervous system and ameliorates experimental autoimmune encephalomyelitis.

Infectious agents have been proposed to influence susceptibility to autoimmune diseases such as multiple sclerosis. We induced a Th1-mediated central nervous system (CNS) autoimmune disease, experimental autoimmune encephalomyelitis (EAE) in mice with an ongoing infection with Mycobacterium bovis strain bacillus Calmette-Guérin (BCG) to study this possibility. C57BL/6 mice infected with live BCG for 6 weeks were immunized with myelin oligodendroglial glycoprotein peptide (MOG(35-55)) to induce EAE. The clinical severity of EAE was reduced in BCG-infected mice in a BCG dose-dependent manner. Inflammatory-cell infiltration and demyelination of the spinal cord were significantly lessened in BCG-infected animals compared with uninfected EAE controls. ELISPOT and gamma interferon intracellular cytokine analysis of the frequency of antigen-specific CD4(+) T cells in the CNS and in BCG-induced granulomas and adoptive transfer of MOG(35-55)-specific green fluorescent protein-expressing cells into BCG-infected animals indicated that nervous tissue-specific (MOG(35-55)) CD4(+) T cells accumulate in the BCG-induced granuloma sites. These data suggest a novel mechanism for infection-mediated modulation of autoimmunity. We demonstrate that redirected trafficking of activated CNS antigen-specific CD4(+) T cells to local inflammatory sites induced by BCG infection modulates the initiation and progression of a Th1-mediated CNS autoimmune disease.

CD4+ TCR repertoire heterogeneity in Schistosoma mansoni-induced granulomas.

The hallmark of Schistosoma mansoni infection is the formation of liver granulomas around deposited ova. The initiation of granuloma formation is T cell-dependent since granulomas are not formed in their absence. We investigated whether a few T cells arrive to initiate the inflammatory lesion and subsequently expand locally, or whether a large repertoire of systemically activated T cells home to the delayed type hypersensitivity reaction induced by the ova. The TCR repertoire of single granulomas from the same liver were analyzed by PCR using Vbeta-specific primers and CDR3 analysis. Each granuloma has a very diverse TCR repertoire indicating that most of the T cells recruited to these lesions are activated systemically. At the same time, sequence analysis of individually sized CDR3 products from single granuloma indicate that a fraction of T cells expand locally at the lesion site. Using TCR transgenic mice containing a pigeon cytochrome c-specific T cell population or lymphocytic choriomeningitis virus infection tracked with lymphocytic choriomeningitis virus-specific tetramers, we demonstrated that nonspecific T cells home to the granuloma if they are activated. However, recombinase-activating gene 2(-/-) pigeon cytochrome c-specific TCR transgenic mice fail to form granulomas in response to S. mansoni ova even after T cell activation, suggesting a requirement for egg-specific T cells in the initiation of these inflammatory lesions. Understanding the mechanism of T cell recruitment into granulomas has important implications for the rational design of immunotherapies for granulomatous diseases.