Traditional and new approaches in detection of invasive aspergillosis

The increasing incidence of invasive aspergillosis, this life thereatening infection in immunocompromised patients emphasizes the need to improve the current limited diagnostic tools. Invasive techniques are harmful in these cases so we tried in the present study to establish non invasive diagnostic methods to assist clinicians with the diagnosis of invasive Aspergillosis. We used the two new techniques, the nested PCR technique for detection of Aspergillus DNA in blood and the immunoenzymatic assay [ELISA] for detection of galactomonnan antigen in serum using platelia Aspergillus antigen kit. We evaluated their sensitivity and specificity in relation to culture technique of sputum samples for isolation of Aspergillus. Forty patients with underlying different hematological malignancy and forty control subjects were included in our study. Thirteen cases [32.5] were direct examination positive; four of them [10%] were culture positive while the entire control subjects were negative for both. We found that 13 [32.5] of the patient group were PCR positive and 28 [70%] were ELISA positive while in control group 4 [10%] were PCR positive and 2 [5%] were ELISA positive. The diagnostic performance of Aspergillus galactomannan detection and PCR for Aspergillus in comparison to Aspergillus culture showed high sensitivity of both techniques [100%] while their specificity were [89.3%] and [88.2%] respectively. Although the high sensitivity of both new techniques, the use and interpretation of them are yet of some limited value in the diagnosis of invasive aspergillosis in high risk group because of the high positive results. For a better evaluation of both new techniques in the diagnosis of pulmonary aspergillosis, a long-term study with a larger population sample is necessary with involvement of quantitative PCR assay that may give more knowledge about a particular PCR cut-off values and perhaps permitting better distinction between contamination, colonization and infection

influence of platelets collagen receptor expression and platelets glycoprotein Ia allele polymorphisms in acute coronary disease

Platelets play an important part in arterial thrombosis therefore it is important to consider the role of adhesion molecules of the platelet surface that play a role in increasing arterial risk. Glycoprofein Ia/IIa is the major platelet collagen receptor and is responsible for platelet adherence to exposed vascular subendothelium. A four fold variation of the platelets receptor density of the collagen receptor glycoprotein Ia/IIa correlating with platelet function to adhere to collagen type I and type III. GPIa/IIa surface expression is influenced by two linked single nucleotide polymorphism [807CT, 873GA] in glycoprotein Ia gene. Individuals with low receptor,densities are homozygos for the 807C/873G allele [CC] genotype whereas individuals homozygos for the 807T/873A allele [TT] genotype have high receptor densities with increased risk of thrombosis. The aim of this study was to evaluate the prevalence of platelet glycoprotein Ia allele polymorphism and platelet collagen receptor [CD49/CD29] density in patients with acute coronary syndrome and control subjects to clarify their possible involvement of their genotype and density as risk factors of the disease, and also to study the association between these findings and the other risk factor for myocardial infarction. The study including 41 patients with a mean age 55.23 years [ +/- 10.98] with a male to female ratio of 33:8. They were compared to 22 controls with a mean age of 49.74 years [ +/- 12.05] and a male to female ratio of 11:11.Glycoprotein Ia gene polymorphism analysis was done by PCR technique for patients and control group together with flowcytometric study of platelet collagen receptor [CD49/CD29] density. Plateletes glycoprotein Ia/IIa receptor% among cases showed a mean of 79.22% [ +/- 12.95] in comparison to 70.9% [ +/- 13.68] among controls. The difference was statistically significant. As regards gene rearrangements, the frequencies of homozygotes T807 allele [TT genotype] were significantly higher in patients with ACS than in controls [24.39% vs 13.63% p<0.05]. The prevalence of [CC] genotypes was also higher in control than in patients [31.8% vs 17%, p<0.05]. Platelets glycoprotein receptor Ia/IIa% [R%] among these groups showed a significant difference between TT cases [mean of 90.5% +/- 3.5], CC cases [mean of 66.5% +/- 5.75] and CT cases [mean of 79.8% +/- 4.82]. Studying other risk factors [obesity, hypertension [HTN], diabetes mellitus [DM] and lipid profile including total cholesterol, low density lipoprotein [LDL] and high density lipoprotein [HDL]] among our group of patients comparing to control subjects, showed no marked significant difference but not for triglycerides [TG] where was significantly higher in our patients compared to control. It was concluded that TT genotype was over presented among patients with acute coronary syndrome compared to healthy controls, whether this genotype is associated with more severe type of coronary heart disease or not this deserve larger scale study