Biomedical subjects

Nigel J Klein

Publications and source records attributed to Nigel J Klein.

24 records · Page 2Linked to original sources

PubMed2003

CSF and serum immune parameters in Sydenham's chorea: evidence of an autoimmune syndrome?

Previous investigations have suggested that Sydenham's chorea (SC) may be an autoantibody mediated disorder. We examined this autoimmune hypothesis by measuring Th1 (IFN-gamma, IL-12) and Th2 (IL-4, IL-10) cytokines, oligoclonal bands (OCB) and anti-basal ganglia antibodies (ABGA). CSF IL-4 was elevated in 31% of acute SC and 50% of persistent SC. CSF IL-10 was also elevated in 31% of acute SC but 0% of persistent SC. CSF IFN-gamma was undetectable in all patients. Serums IL-4, IL-10 and IL-12 were elevated in acute compared to persistent SC. OCB were found in 46% of acute SC, ABGA were in 93% of acute SC and 50% of persistent SC was of IgG(1) and IgG(3) subclass. These findings support an autoantibody pathogenesis.

Adolescent↗

PubMed2003

The nature of colitis in chronic granulomatous disease.

BACKGROUND: Patients with chronic granulomatous disease (CGD) may have gastrointestinal manifestations, commonly colitis. The etiology, prevalence, and inflammatory process of CGD colitis are unclear. OBJECTIVES: To characterize the inflammatory process of CGD colitis and to compare it with other inflammatory bowel disorders. METHODS: Colonic mucosal biopsies from 8 CGD patients were immunostained for eosinophils, neutrophils, macrophages, and adhesion molecules (ICAM; VCAM, E-selectin) and compared with normal and diseased controls (allergic colitis, ulcerative colitis, and melanosis coli). Cell types were counted and expressed as cell/mm2. RESULTS: The inflammatory infiltrate in CGD colitis differed from the normal controls by an increase in eosinophils (110; 48-176 [median and range] versus 14.5; 3-30; P < 0.005) and macrophages (291.5; 203-480 versus 38.5; 27-64; P < 0.005). There was a paucity of neutrophils compared to ulcerative colitis (10; 0-101 versus 315.5; 78-688; P < 0.005). Expression of HLA-DR was increased in the epithelium and vascular endothelium in CGD compared with normal controls. Patterns of expression of the adhesion molecules differed significantly in CGD from those in other inflammatory bowel diseases: intracellular adhesion molecule-1 was more strongly expressed in the lamina propria, vascular adhesion molecule-1 was more patchily expressed, and E-selectin was present only in the small vessels. CONCLUSIONS: The mechanism of inflammation and profile of inflammatory mediators in CGD colitis differs from that in other inflammatory bowel diseases.

Biopsy↗

PubMed2003

Processing and presentation of the islet autoantigen GAD by vascular endothelial cells promotes transmigration of autoreactive T-cells.

Type 1 diabetes is characterized by T-cell infiltration of the islets of Langerhans and abundant HLA class II molecule expression on islet endothelial cells (ECs). The specificity of infiltrating T-cells for islet autoantigens has been amply demonstrated in animal models, and is implicit in human diabetes, but the processes regulating endothelial transmigration of islet autoantigen-specific T-cells into islets are not known. We examined the ability of ECs expressing HLA class II molecules to process and present the islet autoantigen GAD65 and examined the effects of presentation on transmigration of GAD65-specific T-cells. Primary cultures of human vascular ECs expressing the DRB1*0401 (VEC1) and DRB1*0301 (VEC2) genotypes were established and de novo expression of HLA class II molecules induced with interferon-gamma. Under these conditions, VEC1 efficiently processed and presented whole GAD65 to the HLA-DR4-restricted murine T-cell hybridoma T33.1 that recognizes the 274-286 epitope of GAD65. Using a transwell system, we examined the effect of GAD65 presentation on migration of GAD65-specific T-cells across EC monolayers. Migration of T33.1 hybridoma cells and of the human T-cell clone, PM1#11 (recognizes GAD65 epitope 339-352 presented by HLA-DR3) across VEC1 and VEC2, respectively, were greatly enhanced in the presence of GAD65, commencing more rapidly and achieving a higher peak migration at 3 h. Migrated PM1#11 cells retained full proliferative capacity. These results support the hypothesis that presentation of autoantigens by islet endothelium in vivo could promote transmigration of circulating islet autoantigen-specific T-cells primed in regional lymph nodes against islet autoantigens.

Amino Acid Sequence↗

PubMed2002

Enhancement of complement activation and opsonophagocytosis by complexes of mannose-binding lectin with mannose-binding lectin-associated serine protease after binding to Staphylococcus aureus.

Human mannose-binding lectin (MBL) is a serum protein of the innate immune system that circulates as a complex with a group of so-called MBL-associated serine proteases (MASP-1, MASP-2, and MASP-3). Complexes of MBL-MASP2 are able to activate the complement system in an Ab and C1-independent fashion after binding of the lectin to appropriate microbial sugar arrays. We have evaluated the additive effect of the lectin pathway relative to other complement activation pathways and the subsequent effect on neutrophil phagocytosis. Complement activation in the sera of MBL-deficient individuals was studied with and without the addition of exogenous MBL-MASP. Flow cytometry was used to measure the deposition of C4, factor B, C3b, and iC3b on Staphylococcus aureus. Deposition of the first cleavage product of the lectin pathway, C4b, was increased using the sera of three different MBL-deficient individuals when exogenous MBL-MASP was added. Factor B was deposited in association with C4, but there was no evidence of independent alternative pathway activation. Similar enhancement of C3b deposition was also observed, with evidence of elevated amounts of C3b processed to iC3b. The increase in opsonic C3 fragments mediated by MBL was associated with a significant increase in the uptake of organisms by neutrophils. We also observed significant increases in phagocytosis with MBL-MASPs that were independent of complement activation. We conclude that MBL-MASP makes a major contribution to complement-mediated host defense mechanisms.

Adjuvants, Immunologic↗

PubMed2002

Early postoperative monocyte deactivation predicts systemic inflammation and prolonged stay in pediatric cardiac intensive care.

OBJECTIVE: Sepsis and systemic inflammatory response syndrome (SIRS) are major causes of morbidity and mortality after cardiopulmonary bypass. Attempts to suppress proinflammatory mediators have failed to improve outcomes in sepsis or in patients undergoing cardiopulmonary bypass. Recent work in adult patients has suggested that the balance between pro- and anti-inflammatory mediators is more important than the level of proinflammatory response alone. This balance may be reflected by the expression of monocyte human lymphocyte antigen (HLA)-DR, with low concentrations indicating an excess of anti-inflammatory stimuli and relative immunodeficiency. We investigated the relationship between monocyte HLA-DR expression and the subsequent development of sepsis/SIRS in children undergoing cardiopulmonary bypass. DESIGN: A prospective, observational, clinical study. SETTING: A tertiary pediatric cardiac center. PATIENTS: Eighty-two infants and children undergoing elective cardiac surgery between March and December 1999. MEASUREMENTS AND MAIN RESULTS: Monocyte HLA-DR expression was assessed before and after surgery and was found to be related to the length of hospital stay and the development of complications including sepsis/SIRS. The inflammatory insult of cardiopulmonary bypass decreased monocyte HLA-DR expression in all children. Lowest concentrations were seen within 72 hrs of surgery and were significantly lower in cases that subsequently required prolonged intensive care support (p <.0001, Mann-Whitney). HLA-DR expression on <60% of circulating monocytes was associated with a greatly increased risk of later (minimum 4 days) development of sepsis/SIRS (odds ratio, 12.9; 95% confidence interval, 3.4-47.5). Low HLA-DR was an independent predictor for the development of sepsis/SIRS after correction for age, bypass time, complexity of surgery, Paediatric Index of Mortality, and surgeon on multiple logistic regression analysis. CONCLUSIONS: Patients with decreased HLA-DR in the early postoperative period represent a subpopulation at greatly increased risk of later sepsis/SIRS. Such patients may benefit from strategies aimed to reduce this risk.

Adolescent↗

PubMed2002

Unique case of Helicobacter sp. osteomyelitis in an immunocompetent child diagnosed by broad-range 16S PCR.

We report the first case of Helicobacter sp. osteomyelitis in an immunocompetent child. The infection was diagnosed by broad-range 16S PCR followed by sequencing of the resulting amplicon. All other microbiological investigations proved negative. This case highlights the importance of molecular methods in the diagnosis of unsuspected etiological agents and the potential role of Helicobacter sp. in human infection.

Bacterial Typing Techniques↗