Clinical Studies

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Last updated: 13th August 2010

Clinical Studies
Increased alpha-defensins as a blood marker for schizophrenia susceptibility
Mol Cell Proteomics. 2008 Jul;7(7):1204-13
Schizophrenia is a severe psychotic illness affecting 1% of the general population. There are no consistent pathological features, and the disorder is defined by a complex symptomatology, which overlaps with other psychiatric illnesses. Diagnosis is based on a clinical interview, relying on the patient meeting criteria according to diagnosis manuals, including Diagnostic and Statistical Manual of Mental Disorders, 4th Ed. and International Statistical Classification of Diseases, 10th Revision. Because of the ambiguous symptoms, the diagnostic process can take many months and often years. Rapid and effective treatment has been shown to impact positively on disease progression and outcome, and it is therefore important to identify disease-associated biomarkers allowing early diagnosis. Reliable biomarkers can be used for the development of diagnostic tests and may also help us understand the underlying pathology of this disorder. In the present study, proteins from anti-CD3 stimulated and unstimulated peripheral blood T cell lysates from 15 minimally medicated and unmedicated patients and 15 age-, sex-, race-, and smoking-matched controls were profiled on cation exchange (CM10) chips using SELDI-TOF. Partial least squares discriminate analysis was used to separate patient and control groups according to the expression of 108 detected peaks, and two peaks of 3,374 and 3,450 Da, corresponding to alpha-defensins based on masses and cationic properties, were found to contribute significantly to the separation of patient and control groups. Reduction of T cell lysates with DTT resulted in a 6-Da shift in the mass of these peaks consistent with the presence of three cysteine bonds in the structure, confirming them as alpha-defensins. Quantification of alpha-defensins in T cell lysates from six patients and 18 healthy controls was carried out by ELISA, which also showed that alpha-defensin levels were significantly increased in patient lysates when compared with matched controls (p = 0.0197). Plasma from 21 monozygotic twins discordant for schizophrenia and eight healthy unaffected twin pairs was also analyzed for the expression of alpha-defensins by ELISA. Notably both affected and unaffected twins were found to have significantly elevated alpha-defensin levels compared with healthy control twin pairs (p = 0.0014 and p = 0.0115, respectively). Increased expression of alpha-defensins in unaffected as well as affected discordant monozygotic twins is of particular interest as monozygotic twins share genes and usually environmental upbringing. The unaffected twin therefore represents the biological and environmental risk of developing schizophrenia in the absence of overt symptomatology and therapeutic medication. These findings suggest that alpha-defensins could be an important early indicator of the risk of schizophrenia.

Plasma {alpha}-defensin is associated with cardiovascular morbidity and mortality in type 1 diabetic patients.
J Clin Endocrinol Metab. 2008 Apr;93(4):1470-5
CONTEXT: alpha-Defensins are antimicrobial peptides of the innate immune system. In addition, experimental evidence suggests that alpha-defensins are pro-atherogenic. OBJECTIVE: To examine the predictive value of plasma alpha-defensin as a clinical marker of cardiovascular disease (CVD) in patients with type 1 diabetes. METHODS: In an observational, prospective design, 389 patients with long-lasting type 1 diabetes were examined for CVD at study start (1993; baseline), and followed through the Danish National Register for a median of 10.1 years (range 0.2 - 10.4 years). Plasma was collected in 1993 and stored at -80 degrees C till analysis of plasma alpha-defensin using an in-house radioimmunoassay. RESULTS: At baseline, plasma alpha-defensin was significantly higher in patients with than without nephropathy (median and interquartile ranges: 305 (205-321) vs. 223 (182-263) microg/L; P < 0.0001). During follow-up, 98 patients reached the primary end-point (fatal and non-fatal events of CVD). Prospectively, a baseline alpha-defensin within the upper versus the lower tertile significantly increased the co-variate adjusted risk for CVD-related morbidity and mortality to a hazard ratio of 2.8 (1.3-5.9) [median and 95% confidence intervals], P = 0.006. CONCLUSION: This study suggests that plasma alpha-defensin may serve as a clinical risk marker for CVD-related morbidity and mortality in type 1 diabetes. However, future studies are needed to clarify whether plasma alpha-defensin is causally linked to the development of CVD or an innocent bystander.

Psoriasis is associated with increased beta-defensin genomic copy number
Nat Genet. 2008 Jan;40(1):23-5
Psoriasis is a common inflammatory skin disease with a strong genetic component. We analyzed the genomic copy number polymorphism of the beta-defensin region on human chromosome 8 in 179 Dutch individuals with psoriasis and 272 controls and in 319 German individuals with psoriasis and 305 controls. Comparisons in both cohorts showed a significant association between higher genomic copy number for beta-defensin genes and risk of psoriasis.

Increased levels of alpha-defensin (-1, -2 and -3) in type 1 diabetic patients with nephropathy.
Nephrol Dial Transplant. 2008 Mar;23(3):914-8
OBJECTIVE: Diabetic nephropathy is associated with low-grade inflammation and activation of the complement system. Defensins, as part of the innate immune system, may play a regulatory role in the complement cascade and may also augment the production of proinflammatory cytokines. The aim of this study was therefore to elucidate whether alpha-defensin is associated with diabetic nephropathy, low-grade inflammation and lipid profiles. RESEARCH DESIGN AND METHODS: Data were obtained from 189 patients with type 1 diabetes selected from the FinnDiane Study. Patients were divided into three groups according to their albumin excretion rate (AER) in three consecutive overnight or 24-h urine collections: normoalbuminuria (AER <20 microg/min or <30 mg/24 h), microalbuminuria (20 200 microg/min or >300 mg/24 h). Alpha-defensin was determined by a novel, solid-phase radioimmunoassay (RIA) based on a monoclonal antibody, which recognizes alpha-defensin isoforms 1-3. RESULTS: Total serum alpha-defensin (-1, -2 and -3) concentrations were higher (P < 0.001) in patients with macroalbuminuria compared to micro- and normoalbuminuria, but no difference was observed between normoalbuminuria and microalbuminuria. In multiple linear regression analysis alpha-defensin was associated with systolic blood pressure (P = 0.032), HDL-cholesterol (P = 0.013), total cholesterol (P = 0.008), age (P = 0.001) and estimated glomerular filtration rate (P = 0.001), but not with low-grade inflammatory markers. CONCLUSIONS; Serum alpha-defensin (-1, -2 and -3) concentrations are increased in type 1 diabetic patients with diabetic nephropathy.

Association of beta-defensin-1 gene polymorphisms with Pseudomonas aeruginosa airway colonization in cystic fibrosis
Genes Immun. 2008 Jan;9(1):57-60
Lung disease and Pseudomonas aeruginosa (P. aeruginosa) airway colonization represent a major cause of morbidity and mortality in cystic fibrosis (CF). Human beta-defensin (hBD)-1 is believed to play an important role in mucosal innate immunity in the lung. This study aimed to investigate whether three single-nucleotide polymorphisms (SNPs) in the 5'-untranslated region of DEFB1, G-52A, C-44G and G-20A were associated with P. aeruginosa airway colonization in CF. A total of 224 CF patients and 196 control subjects were studied. DEFB1 SNPs were characterized by restriction fragment length polymorphisms. Patients' sputum samples were collected and analyzed by standard methods. Single SNP analysis suggested that CF patients carrying the -52AA and the -20GG genotypes had a higher rate of P. aeruginosa airway colonization than patients homozygous and heterozygous for the -52G and -20A alleles (P=0.01 and P=0.007, respectively). A significant association between the ACG haplotype and chronic P. aeruginosa infection was also identified (odds ratio (95% confidence interval): 3.00 (1.42-6.36), P=0.004). These results indicate that variant alleles in DEFB1 might contribute to the colonization of P. aeruginosa in CF.

The expression of innate immunity genes in Italian Crohn disease patients.
Eur J Histochem. 2007 Jul-Sep;51(3):199-202.
Crohn's disease (CD) is a chronic idiopathic inflammatory bowel disease characterized by the interaction of both hereditary and environmental factors. Intestinal flora and pathogens such as bacteria, viruses and fungi, are thought to be the first step leading to an inflammatory status, which is subsequently amplified in genetically susceptible patients thus triggering the disease. Since the innate immune system is believed to be very important in regulating the flora of the gastrointestinal tract, we decided to study the influence of two important molecules of the innate immune system in CD. Frozen intestinal biopsies from 49 Crohn patients and 10 healthy individuals were collected at the gastroenterology unit of Children's Hospital Burlo Garofolo in Trieste and innate immunity gene expression was evaluated by using both in situ RT-PCR and quantitative PCR. We have analyzed the expression and localization of both MBL2 and DEFB1 genes in intestinal biopsies of Italian Crohn patients by in situ RT-PCR and quantitative PCR. DEFB1 is expressed equally in all subjects. Importantly, MBL2 transcripts were upregulated in CD patients compared to healthy controls. MBL2 expression in controls is normally extremely low, detectable only by quantitative PCR with a Taqman probe. We demonstrated the MBL2 and DEFB1 expression in intestinal biopsies of patients suffering from CD. Our results showed that the MBL2 gene is expressed by cells in the basal lamina, whilst DEFB1 is expressed by epithelial cells.

Human beta defensin-1 and -2 expression in the gingiva of patients with specific periodontal diseases
J Periodontal Res. 2007 Oct;42(5):429-37
BACKGROUND AND OBJECTIVE: beta defensin antimicrobial peptides are important in epithelial innate immunity, and their differential expression is associated with periodontal diseases. The aims of this study were to determine the mRNA expression of human beta defensin-1 and -2 in the gingival tissue of patients with gingivitis, aggressive periodontitis and chronic periodontitis, and to evaluate the relationship between defensin expression and type and/or severity of periodontal destruction. MATERIAL AND METHODS: Fifteen patients in each group with gingivitis, aggressive periodontitis and chronic periodontitis, and 10 healthy subjects, were included in the study (n=55). The periodontal status of the subjects was determined by periodontal clinical measurements and radiographical evaluations. Transcriptional levels of human beta defensin-1 and -2 genes in gingival samples were assessed by using the quantitative real-time polymerase chain reaction technique, and the data were evaluated statistically by the relative expression Software Tool 2 for groupwise comparisons. RESULTS: Expression of the human beta defensin-1 gene was lower in gingivitis and aggressive periodontitis groups, and significantly higher in the chronic periodontitis group, than in the control group (p<0.001). Human beta defensin-2 mRNA expression in the gingivitis group was lower than in the control group; however, the difference was statistically significant only in half of the gingivitis patients (p<0.001). Human beta defensin-2 mRNA levels were higher in some chronic periodontitis patients, but lower in the others when compared with the control group (p<0.001). Expression of the human beta defensin-2 gene increased in the aggressive periodontitis group relative to the control group. CONCLUSION: This study suggests that human beta defensin-1 and -2 genes in the gingival epithelium show differential expression in patients with specific periodontal diseases, and aggressive and chronic periodontitis types demonstrate different gingival beta defensin-1 and -2 expression patterns.

Antimicrobial peptides in chronic anal fistula epithelium
Scand J Gastroenterol. 2007 Sep;42(9):1063-9
OBJECTIVE: Anal fistulas are the result of chronic infection of an intersphincteric gland. Despite the passage through mesenchymal tissue, fistulas seldom lead to systemic infection. Antimicrobial peptides are secreted by a variety of epithelia, belonging to the innate immune system and are potential factors contributing to infection control. The aim of this study was to investigate whether epithelium is present in the fistulas and what the origin might be. MATERIAL AND METHODS: Forty-seven chronic anal fistulas from patients, excluding Crohn's disease, were compared with healthy rectal and perianal control tissue. Expression of antimicrobial peptide mRNA was analysed by real-time polymerase chain reaction (RT-PCR) and immunohistochemistry. Tissue was further studied by cytokine and cytokeratin staining. RESULTS: Chronic anal fistulas express high levels of hBD-2 and hBD-3 and the newly identified antimicrobial peptides RNase7 and psoriasin compared to rectal mucosa from control patients. Perianal skin has almost identical levels of RNase7 and psoriasin expression to those in fistulas. IL-1b and IL-8 were the only cytokines detectable in fistulas. Fistulas are lined with squamous epithelium that expresses identical cytokeratines as skin. CONCLUSIONS: Epithelialization and local production of antimicrobial peptides in anal fistulas serve as defence mechanisms to prevent local and systemic infection by microbes from faeces passing through the fistula tract.

Elevated alpha-defensin levels in plasma of patients with pulmonary sarcoidosis.
Respirology. 2007 May;12(3):339-45.
BACKGROUND AND OBJECTIVES: Pathogens such as mycobacteria and proprionibacterium have been implicated in the pathogenesis of sarcoidosis. alpha-Defensins (DF) are naturally occurring antimicrobial peptides. The aim of the present study was to assess whether DF are increased in the airway and/or systemic circulation in patients with pulmonary sarcoidosis and whether DF levels are related to sarcoidosis disease activity. METHODS: DF levels in plasma and BAL fluid (BALF) were measured in 30 patients with pulmonary sarcoidosis and in 10 controls. Plasma and BALF DF levels were compared according to disease activity. Molecular forms were analysed using reverse-phase (RP) HPLC to confirm plasma and BALF DF kinetics in pulmonary sarcoidosis. RESULTS: DF concentrations in plasma and BALF were higher in patients with pulmonary sarcoidosis than in the controls. Plasma DF levels correlated with lysozyme but not with angiotensin-converting enzyme. These levels were high in patients in whom more organs were involved, whereas BALF DF levels were higher in patients at stage II or III than with those at sarcoidosis I. RP-HPLC showed high plasma levels of pro-defensins, DF precursors from the bone marrow, in sarcoidosis, although DF in peripheral neutrophils and BALF were the mature type. CONCLUSIONS: High plasma DF concentrations resulted from bone marrow stimulation and seemed to be associated with disease activity, whereas BALF DF were released from accumulated neutrophils in the lungs and may contribute to parenchymal involvement in sarcoidosis.

Genomic variations within DEFB1 are associated with the susceptibility to and the fatal outcome of severe sepsis in Chinese Han population.
Genes Immun. 2007 Jul;8(5):439-43.
Sepsis is a systemic inflammatory response syndrome to infection. Human beta-defensin 1 (DEFB1) is a multifunctional mediator in infection and inflammation, which has been largely explored in ex vivo studies. The present case-control study was designed to investigate whether DEFB1 genomic variations are associated with the susceptibility to and the outcome of severe sepsis in 211 patients with severe sepsis and 157 ethnic-matched healthy controls. After correcting for multiple testing, the -44G/C was the only polymorphism found to show significant associations with both the susceptibility to and the fatal outcome of severe sepsis (P=0.0049, odd ratio (OR) 1.971 and P=0.002, OR 2.406, respectively). Haplotype -20A/-44C/-52G showed a protective role against severe sepsis (P=0.0066, OR 0.6751), whereas haplotype -20G/-44G/-52G served as a risk factor for the fatal outcome of severe sepsis (P=0.0052, OR 2.427). These findings provide further evidence that beta-defensin 1 may play a role in the pathogenesis of severe sepsis.