RESUMO
BACKGROUND: Endoscopic mucosal healing is an established treatment target for UC, yet the value of achieving histological remission remains unclear. AIMS: To evaluate histological remission compared to endoscopic mucosal healing for predicting patient outcomes in UC. METHODS: Blinded assessment of endoscopic and histological measures of disease activity was performed on patients with established UC at baseline. Concordance and prognostic values of endoscopic mucosal healing (defined by Baron score ≤1) and histological remission (defined by Truelove and Richards' index) for predicting outcomes of corticosteroid use, hospitalisation and colectomy were determined over a median 6â years follow-up, including κ statistics and Cox regression multivariate analysis. RESULTS: 91 patients with UC were followed up for a median 72â months (IQR 54-75â months). Overall, concordance between endoscopic and histological remission was moderate (κ=0.56, 95% CI 0.36 to 0.77); 24% patients had persistent inflammation despite endoscopic remission. Histological remission predicted corticosteroid use and acute severe colitis requiring hospitalisation over the follow-up period (HR 0.42 (0.2 to 0.9), p=0.02; HR 0.21 (0.1 to 0.7), p=0.02; respectively), whereas endoscopic mucosal healing did not (HR 0.86, 95% CI 0.5 to 1.7, p0.65; HR 0.83 95% CI 0.3 to 2.4, p0.74; respectively). CONCLUSIONS: Histological remission is a target distinct from endoscopic mucosal healing in UC and better predicts lower rates of corticosteroid use and acute severe colitis requiring hospitalisation, over a median of 6â years of follow-up. Our findings support the inclusion of histological indices in both UC clinical trials and practice, towards a target of 'complete remission'.
Assuntos
Corticosteroides/uso terapêutico , Anti-Inflamatórios/uso terapêutico , Colite Ulcerativa/patologia , Colo/patologia , Colonoscopia , Hospitalização/estatística & dados numéricos , Mucosa Intestinal/patologia , Adulto , Idoso , Colectomia/estatística & dados numéricos , Colite Ulcerativa/tratamento farmacológico , Colite Ulcerativa/cirurgia , Colo/cirurgia , Terapia Combinada , Progressão da Doença , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Estudos Prospectivos , Indução de Remissão , Índice de Gravidade de Doença , Método Simples-Cego , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Esophageal full-thickness wall repair is an important but unsolved issue in endoscopy. It is unknown how well endoscopic clip closure (ECC) and endoscopic closure with suturing (ECS) perform compared with the criterion standard of thoracoscopic closure (TC). OBJECTIVE: Comparison of technical success, feasibility, long-term patency, complications, and histological quality of the different closure techniques (ECC, ECS, TC) for esophageal perforations. DESIGN: Comparative animal study. SETTING: Approved animal facility. SUBJECTS: Eighteen pigs. INTERVENTIONS: Eighteen pigs were randomized, 6 each into 3 groups (ECC, ECS, TC). After endoscopic wall incision and mediastinoscopy, closure was performed by using 1 of the 3 techniques. After 8 to 12 weeks, pre-euthanasia endoscopic, necropsy, histological, and morphometric analyses were performed. MAIN OUTCOME MEASUREMENT: Long-term survival and histological quality of the repair. RESULTS: The closure of the esophageal incisions was successful in all pigs. On days 2 and 6, 1 animal died of mediastinitis, 1 in the ECS group because of reflux of gastric contents into the mediastinum before the repair and 1 in the TC group because of leakage of the sutured closure (P = 1.0). No strictures were seen on prenecropsy endoscopy. At necropsy, 1 mediastinal abscess was found in an ECS animal (P = 1.0). Minor complications included periesophageal adhesions and reactive lymph nodes in 3 of 6 (ECC group) and 5 of 6 (TC and ECS groups). Histology showed muscle layer defects up to 12 mm in width and 21 mm in length, with a trend toward smaller defect size of width and length in the ECS group of animals. LIMITATIONS: Animal study of limited size. CONCLUSIONS: Overall, ECS and ECC performed similarly to TC. ECS showed the smallest histological defects in the long-term repair.
Assuntos
Perfuração Esofágica/cirurgia , Técnicas de Sutura/instrumentação , Suturas , Toracoscopia , Animais , Modelos Animais de Doenças , Perfuração Esofágica/etiologia , Perfuração Esofágica/patologia , Estudos de Viabilidade , Feminino , Doença Iatrogênica , Técnicas de Sutura/efeitos adversos , Suínos , CicatrizaçãoRESUMO
BACKGROUND: The first experiences with endoscopic closure of esophageal perforations in animal survival studies encouraged us to extend these procedures to full-thickness resections of pieces of the esophageal wall (FTEW). OBJECTIVE: To learn the feasibility, safety, and long-term effects of FTEW removal and defect closure. DESIGN: Feasibility animal study. SETTING: Approved animal facility. INTERVENTIONS: Twelve pigs were used for 3-month survival studies, autopsy, and histologic examination. Resection of a 2-cm piece of wall was performed with needle-knife and forceps/snare. Closure was performed by using prototype endoscopic suturing. MAIN OUTCOME MEASUREMENTS: Feasibility and complication assessment of this new endoscopic method. RESULTS: There were no complications relating to incision, resection, or closure. All pigs recovered quickly. In 2 animals a larger piece of wall causing a larger defect was removed, resulting in much air penetrating into the mediastinum, causing difficult ventilation. This was resolved with thoracic drain. In 3 of 12 animals a toxic substance slipped into the mediastinum, resulting in an abscess in 1 pig and misfire of an anchor as a result of obscured vision. This caused temporary illness of the animal but not death. Autopsy and histologic study confirmed no mediastinitis and well-healed scars in all but one. LIMITATION: Animal study. CONCLUSION: FTEW has proven to be feasible. Long-term survival demonstrated no mediastinitis and only 1 abscess after contamination of the mediastinum. These first experiences encourage further animal studies because the prospect of endoscopic full-thickness removal of esophageal lesions in patients might be very advantageous.
Assuntos
Esofagectomia/métodos , Esofagoscopia , Animais , Esofagoscopia/efeitos adversos , Estudos de Viabilidade , Modelos Animais , Estudos Prospectivos , Técnicas de Sutura , Suínos , Resultado do TratamentoRESUMO
CDC4/FBXW7 is part of a ubiquitin ligase complex which targets molecules such as cyclin E, c-myc, and c-jun for destruction. CDC4 mutations occur in several cancer types and are best described in colorectal tumors. Knockout of CDC4 in vitro in colorectal cancer cells causes changes suggestive of chromosomal instability (CIN). In p53(+/-) mice, radiation-induced lymphomas show deletion or mutation of one copy of CDC4 and knockdown of CDC4 leads to increased aneuploidy in mouse fibroblasts. We screened 244 colorectal tumors and 40 cell lines for CDC4 mutations and allelic loss. Six percent (18 of 284) of tumors, including near-diploid (CIN-) lesions, harbored CDC4 mutations and there was no association between mutation and CIN (polyploidy). The CDC4 mutation spectrum in colorectal tumors was heavily biased towards C:G > T:A changes, either missense mutations at critical arginine residues or nonsense changes in the 5' half of the gene. The reasons for this odd mutation spectrum were unclear but C:G > T:A changes were not found more often than expected at APC, K-ras, or p53 in the same tumors and we found no specific defects in DNA repair to account for the observations. No colorectal tumor was found to carry two CDC4 mutations predicted to abolish protein function; partial loss of CDC4 function may therefore cause tumorigenesis. The in vitro studies, therefore, did not assess the functional effects of mutant alleles which are found in vivo. CDC4 mutations may be selected primarily to drive progression through the cell cycle although CIN might be an important secondary effect in some cancers.
Assuntos
Proteínas de Ciclo Celular/genética , Instabilidade Cromossômica , Neoplasias Colorretais/genética , Proteínas F-Box/genética , Perda de Heterozigosidade , Mutação/genética , Ubiquitina-Proteína Ligases/genética , Adenocarcinoma/genética , Adenocarcinoma/secundário , Adenoma/genética , Adenoma/patologia , Proteína da Polipose Adenomatosa do Colo/genética , Neoplasias Colorretais/patologia , Análise Mutacional de DNA , DNA de Neoplasias , Proteína 7 com Repetições F-Box-WD , Genes ras/genética , Humanos , Repetições de Microssatélites , Ploidias , Polimorfismo Conformacional de Fita Simples , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/genéticaRESUMO
The International Registry of Werner syndrome (www.wernersyndrome.org) has been providing molecular diagnosis of the Werner syndrome (WS) for the past decade. The present communication summarizes, from among 99 WS subjects, the spectrum of 50 distinct mutations discovered by our group and by others since the WRN gene (also called RECQL2 or REQ3) was first cloned in 1996; 25 of these have not previously been published. All WRN mutations reported thus far have resulted in the elimination of the nuclear localization signal at the C-terminus of the protein, precluding functional interactions in the nucleus; thus, all could be classified as null mutations. We now report two new mutations in the N-terminus that result in instability of the WRN protein. Clinical data confirm that the most penetrant phenotype is bilateral ocular cataracts. Other cardinal signs were seen in more than 95% of the cases. The median age of death, previously reported to be in the range of 46-48 years, is 54 years. Lymphoblastoid cell lines (LCLs) have been cryopreserved from the majority of our index cases, including material from nuclear pedigrees. These, as well as inducible and complemented hTERT (catalytic subunit of human telomerase) immortalized skin fibroblast cell lines are available to qualified investigators.
Assuntos
DNA Helicases/genética , Síndrome de Werner/diagnóstico , Síndrome de Werner/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Sequência de Aminoácidos , DNA Helicases/química , Análise Mutacional de DNA , Exodesoxirribonucleases , Humanos , Pessoa de Meia-Idade , Modelos Moleculares , Dados de Sequência Molecular , Linhagem , RecQ Helicases , Sistema de Registros , Alinhamento de Sequência , Síndrome de Werner/mortalidade , Helicase da Síndrome de WernerRESUMO
The small intestinal mucosa makes up about 90% of the total surface of the gastrointestinal tract. However, adenocarcinomas arise rarely in this location. To elucidate genetic alterations underlying tumour development in the small intestine we investigated 17 sporadic adenocarcinomas. By comparative genomic hybridization recurrent gains of chromosomal material were found at chromosomes 7, 8, 13q, and 20 (5/17, each), while non-random losses were seen at 8p, 17p (4/17, each), and 18 (8/17 cases). Deletions at 5q, the location of the APC tumour suppressor gene, were seen in three cases. Microsatellite analysis with markers on chromosomal arms 1p, 5q, 8p, 17p, 18q, 19p, and 22q revealed a microsatellite instable phenotype in two cases and a high frequency of loss at 18q21-q22 (80%). Given the high incidence of 18q21-q22 deletions, we performed sequencing analysis of SMAD4, a downstream component of the TGFbeta-pathway, located at 18q21. Four tumours displayed mutations in highly conserved domains of the gene indicating disruption of TGFbeta-signalling. Our data reveal complex genetic alterations in sporadic small intestinal carcinomas. However, most tumours share deletions of 18q21-q22, which frequently target SMAD4. This indicates that disruption of TGFbeta-signalling plays a critical role in small intestinal tumorigenesis.
Assuntos
Adenocarcinoma/genética , Cromossomos Humanos Par 18/genética , DNA de Neoplasias/genética , Proteínas de Ligação a DNA/genética , Neoplasias Intestinais/genética , Intestino Delgado , Proteínas de Neoplasias/genética , Deleção de Sequência , Transativadores/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Substituição de Aminoácidos , Transformação Celular Neoplásica/genética , Aberrações Cromossômicas , Cromossomos Humanos Par 18/ultraestrutura , Cromossomos Humanos Par 5/genética , Cromossomos Humanos Par 5/ultraestrutura , Códon/genética , Análise Mutacional de DNA , Feminino , Humanos , Mucosa Intestinal/metabolismo , Intestino Delgado/metabolismo , Perda de Heterozigosidade , Masculino , Repetições de Microssatélites , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Hibridização de Ácido Nucleico , Mutação Puntual , Estudos Retrospectivos , Transdução de Sinais/genética , Proteína Smad4 , Fator de Crescimento Transformador beta/fisiologiaAssuntos
Enteropatias/diagnóstico , Transplante de Rim/efeitos adversos , Transtornos Linfoproliferativos/diagnóstico , Biópsia , Colonoscopia , Humanos , Enteropatias/etiologia , Transtornos Linfoproliferativos/etiologia , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios X , Úlcera/diagnóstico , Úlcera/etiologiaRESUMO
BACKGROUND: Pouchitis is believed to occur as a reaction to dysbiosis. In this study we assessed differences between mucosal bacterial communities cultured from noninflamed and inflamed ileal pouches. METHODS: Thirty-two ileal pouch patients, 22 with ulcerative colitis (UC) and 10 with familial adenomatous polyposis (FAP), underwent symptomatic, endoscopic, and histological assessment. The Objective Pouchitis Score (OPS) and the Pouch Disease Activity Index (PDAI) were used to diagnose pouchitis. Seven UC patients had pouchitis (UC+), 15 had a noninflamed pouch (UC-), 9 had a noninflamed pouch (FAP-), and 1 FAP patient had pouchitis (FAP+). Biopsies taken from the ileal mucosa of the pouch were cultured under aerobic and anaerobic conditions. Following standardized DNA extraction a polymerase chain reaction (PCR) was performed to generate 16S rRNA gene products. A "fingerprint" of the bacterial community within each sample was created using terminal-restriction fragment length polymorphism (T-RFLP) profiling. Species richness and evenness were determined using T-RF band lengths and relative band intensities. RESULTS: From the 64 DNA samples, 834 bands were detected, of which 179 represented different species (operational taxonomic units [OTUs]). The average species richness for the FAP-, FAP+, UC-, and UC+ groups was 26, 35, 23.9, and 29.6 per patient, with the average species diversity within the groups of 10.6, 29, 8.3, and 11.4, respectively. Similar trends were observed when the anaerobic and aerobic-derived bacterial groups were analyzed separately. CONCLUSIONS: No significant differences were found between the bacterial cultures derived from any of the clinical groups or between pouchitis and nonpouchitis patients.
Assuntos
Polipose Adenomatosa do Colo/cirurgia , Bactérias/classificação , Colite Ulcerativa/cirurgia , Bolsas Cólicas/microbiologia , Pouchite/microbiologia , Adulto , Bactérias/genética , Bactérias/isolamento & purificação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proctocolectomia RestauradoraRESUMO
We report a female patient with cytomegalovirus (CMV) terminal ileitis and CMV viraemia, associated with a metastatic goblet cell carcinoid (GCC) tumour of the appendix. She was treated with ileocaecal resection followed by ganciclovir. We highlight the importance of vigilant histopathological assessment and discuss the existing literature on gastrointestinal CMV infection in immunocompetent patients.
Assuntos
Neoplasias do Apêndice/complicações , Tumor Carcinoide/complicações , Infecções por Citomegalovirus/complicações , Citomegalovirus/isolamento & purificação , Ileíte/complicações , Ileíte/virologia , Antivirais/uso terapêutico , Neoplasias do Apêndice/patologia , Neoplasias do Apêndice/cirurgia , Tumor Carcinoide/patologia , Tumor Carcinoide/secundário , Tumor Carcinoide/cirurgia , Infecções por Citomegalovirus/tratamento farmacológico , Infecções por Citomegalovirus/cirurgia , Infecções por Citomegalovirus/virologia , Feminino , Ganciclovir/uso terapêutico , Histocitoquímica , Humanos , Pessoa de Meia-Idade , ViremiaRESUMO
A 26-year-old, HLA-B27 positive man with steroid dependent Crohn's disease presented with abdominal lymphadenopathy and multiple abscess-like masses in the spleen and liver 2 years after the initial diagnosis. A biopsy of one of the liver lesions showed epitheloid cell granuloma, no microorganisms were detected despite intensive investigations. The liver lesions and the lymphadenopathy repeatedly disappeared completely in response to prednisolone pulse therapy while the lesions in the spleen remained practically unchanged. One year later, on immunosuppressive therapy with azathioprine and low-dose prednisolone, the patient's condition exacerbated with development of fever, disseminated arthritides and enlargement of the splenic lesions. Following ineffective antimicrobial treatment, a splenectomy was carried out. Histology showed that the splenic parenchyma was filled with abacterial, rheumatoid granulomas. After a renewed flare-up of severe extraintestinal symptoms, the patient is now asymptomatic on immunosuppressive therapy with azathioprine and prednisolone. Abdominal lymphadenopathy is no longer present and the liver lesions are regressing. The intermittent course and the positive response to immunosuppressive therapy point to a further extraintestinal manifestation of Crohn's disease.
Assuntos
Doença de Crohn/patologia , Granuloma/patologia , Nódulo Reumatoide/patologia , Baço/patologia , Esplenopatias/patologia , Adulto , Doença de Crohn/complicações , Doença de Crohn/diagnóstico , Doença de Crohn/tratamento farmacológico , Granuloma/complicações , Granuloma/diagnóstico por imagem , Humanos , Imunossupressores/uso terapêutico , Fígado/diagnóstico por imagem , Fígado/patologia , Hepatopatias/complicações , Hepatopatias/diagnóstico por imagem , Hepatopatias/patologia , Masculino , Radiografia , Nódulo Reumatoide/complicações , Nódulo Reumatoide/diagnóstico por imagem , Baço/diagnóstico por imagem , Esplenopatias/complicações , Esplenopatias/diagnóstico por imagemRESUMO
Rare cases of culture-negative infective endocarditis are caused by Tropheryma whipplei, the uncommon bacterium of Whipple's disease. We evaluated an 80-year-old woman with valvular heart disease but without intestinal Whipple's disease. The diagnosis of aortic valve xenograft culture-negative infection with T. whipplei was established by multiple molecular assays and by electron microscopy. First, a PCR with broad-range primers identified the complete 16S ribosomal DNA of T. whipplei in bioprosthesis tissue. Novel real-time reverse transcription-PCR assays were developed to detect mRNAs encoding recently identified proteins determined from the T. whipplei genome, specifically Whipplei surface protein (TW113) and a DNA polymerase III subunit (TW727). The positive detection of mRNAs indicated the presence of metabolically active bacteria and suggested the viability of T. whipplei. The quantification of T. whipplei genome equivalents by real-time PCR indicated a high-density bacterial colonization of the valve tissue. Additionally, an ultrastructural examination revealed numerous rod-shaped bacteria consistent in size with T. whipplei in the extracellular collagen matrix of the bioprosthesis. We conclude that extracellular growth of T. whipplei can occur in the microenvironment of biological prosthetic valve tissue and that T. whipplei endocarditis can occur in the absence of intestinal Whipple's disease.
Assuntos
Actinomycetales/isolamento & purificação , Valva Aórtica/microbiologia , Bioprótese/microbiologia , Endocardite Bacteriana/microbiologia , Doença de Whipple/microbiologia , Actinomycetales/classificação , Actinomycetales/genética , Infecções por Actinomycetales/microbiologia , Idoso , Idoso de 80 Anos ou mais , Animais , Proteínas de Bactérias/genética , Feminino , Humanos , Microscopia Eletrônica , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Whipple disease (WD) is a systemic disorder caused by the bacterium Tropheryma whipplei. Since the recognition of a bacterial etiology in 1961, many attempts have been made to cultivate this bacterium in vitro. It was eventually isolated, in 2000, from an infected heart valve, in coculture with human fibroblasts. Here we report the isolation of 2 new strains of T. whipplei from cerebrospinal fluid (CSF) of 2 patients with intestinal WD but no neurological signs or symptoms. One culture-positive specimen was obtained before treatment; the other was obtained 12 months after discontinuation of therapy, at a time of intestinal remission. In both cases, 15 passages of the cultures were completed over 17 months. Bacterial growth was measured by quantitative polymerase chain reaction, which suggested a generation time of 4 days. Staining with YO-PRO nucleic-acid dye showed characteristic rod-shaped bacteria arranged in chains. Fluorescent in situ hybridization with a T. whipplei-specific oligonucleotide probe, a broad-range bacterial probe, and a nonspecific nucleic-acid stain indicated that all visible bacteria were T. whipplei. Scanning electron microscopy and transmission electron microscopy showed both intracellular and extracellular bacteria. This first isolation of T. whipplei from CSF provides clear evidence of viable bacteria in the central nervous system in individuals with WD, even after prolonged antibiotic therapy.
Assuntos
Actinomycetales/crescimento & desenvolvimento , Actinomycetales/isolamento & purificação , Líquido Cefalorraquidiano/microbiologia , Fibroblastos/microbiologia , Doença de Whipple/microbiologia , Actinomycetales/genética , Infecções por Actinomycetales/microbiologia , Idoso , Benzoxazóis , Células Cultivadas , Infecções Bacterianas do Sistema Nervoso Central/microbiologia , DNA Bacteriano/análise , Feminino , Corantes Fluorescentes/metabolismo , Humanos , Hibridização in Situ Fluorescente , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Compostos de Quinolínio , Inoculações Seriadas , Coloração e Rotulagem/métodosRESUMO
A case with transient, almost complete sleep loss caused by cerebral manifestation of Whipple's disease (WD) is presented. Cerebral WD is rare and in most cases occurs after gastrointestinal infection. In our case, a progressive and finally almost complete sleep loss was the initial and predominant symptom. Polysomnographic studies in several consecutive nights and over 24 h showed a total abolition of the sleep-wake cycle with nocturnal sleep duration of less than 15 min. Endocrine tests revealed hypothalamic dysfunction with flattening of circadian rhythmicity of cortisol, TSH, growth hormone and melatonin. Cerebrospinal fluid (CSF) hypocretin was reduced. [18F]Deoxyglucose positron emission tomography (FDG-PET) revealed hypermetabolic areas in cortical and subcortical areas including the brainstem, which might explain sleep pathology and vertical gaze palsy. In the course of treatment with antibiotics and additional carbamazepine for 1 year, insomnia slowly and gradually improved. Endocrine investigations at 1-year follow-up showed persistent flattening of circadian rhythmicity. The FDG-PET indicated normalized metabolism in distinct regions of the brain stem which paralleled restoration of sleep length. The extent of sleep disruption in this case of organic insomnia was similar to cases of familial fatal insomnia, but was at least partially reversible with treatment.
Assuntos
Encéfalo/fisiopatologia , Peptídeos e Proteínas de Sinalização Intracelular , Privação do Sono/fisiopatologia , Doença de Whipple/fisiopatologia , Adulto , Encéfalo/metabolismo , Proteínas de Transporte/líquido cefalorraquidiano , Proteínas de Transporte/metabolismo , Ritmo Circadiano/fisiologia , Eletroencefalografia , Fixação Ocular/fisiologia , Fluordesoxiglucose F18 , Seguimentos , Humanos , Hidrocortisona/metabolismo , Hipotálamo/metabolismo , Hipotálamo/fisiopatologia , Masculino , Melatonina/metabolismo , Neuropeptídeos/líquido cefalorraquidiano , Neuropeptídeos/metabolismo , Testes Neuropsicológicos , Orexinas , Polissonografia , Compostos Radiofarmacêuticos , Privação do Sono/complicações , Privação do Sono/metabolismo , Transtornos do Sono do Ritmo Circadiano/etiologia , Transtornos do Sono do Ritmo Circadiano/metabolismo , Tireotropina/metabolismo , Tomografia Computadorizada de Emissão , Doença de Whipple/metabolismoRESUMO
BACKGROUND: Whipple's disease is a rare multisystem chronic infection, involving the intestinal tract as well as various other organs. The causative agent, Tropheryma whipplei, is a Gram-positive bacterium about which little is known. Our aim was to investigate the biology of this organism by generating and analysing the complete DNA sequence of its genome. METHODS: We isolated and propagated T whipplei strain TW08/27 from the cerebrospinal fluid of a patient diagnosed with Whipple's disease. We generated the complete sequence of the genome by the whole genome shotgun method, and analysed it with a combination of automatic and manual bioinformatic techniques. FINDINGS: Sequencing revealed a condensed 925938 bp genome with a lack of key biosynthetic pathways and a reduced capacity for energy metabolism. A family of large surface proteins was identified, some associated with large amounts of non-coding repetitive DNA, and an unexpected degree of sequence variation. INTERPRETATION: The genome reduction and lack of metabolic capabilities point to a host-restricted lifestyle for the organism. The sequence variation indicates both known and novel mechanisms for the elaboration and variation of surface structures, and suggests that immune evasion and host interaction play an important part in the lifestyle of this persistent bacterial pathogen.