role of interleukin 16 in the immunopathogenesis of rheumatoid arthritis

Rheumatoid Arthritis [RA] is a chronic inflammatory disease characterized by hyperplasia of the synovium and excessive cellular infiltration, which leads to progressive joint destruction. We analyzed, interleukin 16 [IL16], in relation to disease activity to characterize its biologic function in RA. Secreted IL-16 was measured by enzyme immunoassay in sera from 30 RA patients and 30 healthy controls [HC], and also in synovial fluid [SF] from 16 RA patients and 15 patients with non-RA synovitis as controls. IL-16 expression in peripheral blood mononuclear cells [PBMC] was characterized by flow cytometric analysis after intracellular cytokine staining for IL-16. In synovial tissue specimens, both were done: Immunohistochemistry for localization of IL-16, and histopathology, in which the tissue scored semiquantitatively for synovial hyperplasia and cellular infiltration. IL-16 was detected at significantly higher levels in sera and SF of RA patients in comparison to HC and non-RA synovitis [p<0.001 and p<0.0001 respectively]. Also, IL-16 was detected significantly higher in SF in comparison to sera in RA patients [p<0.001]. Flow cytometry of PBMC showed that a great proportion of both CD4+ and CD8+ cells expressed IL-16 protein. Also, immunohistochemistry revealed more CD4+ and less frequency of CD8+ cells in synovial infiltration. A significant correlation between IL-16 expression and local inflammatory activity could not be established [p>0.21] by microscopic analysis of the synovial cells infiltrate. In addition, no significant association was observed between serum, SF, and synovial tissue expression of IL-16 and clinical disease activity in RA [p>0.61, p>0.5 and p>0.42 respectively]. This indicated that, IL-16 played a regulatory rather than a proin-flammatory role in the immunopathogenesis of RA

Multi-drug resistant pseudomonas aeruginosa as a cause of chronicity in ear infections

Pseudomonas aeruginosa is the most commonly recovered organism from chronic suppurative otitis media [CSOM]. P. aeruginosa has high intrinsic resistance to many antibiotics, and this situation is worsened in infections caused by strains acquiring additional multi-resistance. The aim of this work was to assess the role of P. aeruginosa in the chronicity of ear infection. Routine basic and enriched media [nutrient agar and blood agar] were used as well as P. aeruginosa selective agar [PASA] for isolation. Two pigment enhancer media were used for differentiation: Kings A agar and Kings B agar. The anti-microbial resistance patterns of isolated P. aeruginosa were studied with specific regards to new beta-lactamases, including extended spectrum beta-lactamase [ESBL] and metallo-beta-lactamase [MBL]. Seventy six samples were collected from chronic discharging ear, 61 P. aeruginosa isolates were recovered [80.26%] on all media used. Gram positive bacteria were 100% inhibited on PASA, Kings A and Kings B, while Gram negative isolates were 100% inhibited on PASA only and not on other used media. The demarcation of P. aeruginosa colonies was detected in 100% on PASA, 19.67% on Kings A, 36.07% on Kings B, while nutrient and blood agar media could not demarcate colonies at all. ESBL was positive in 54.1%, negative in 24.59%, and indeterminate in 21.31% of pseudomonas isolates. The results of MBL test were 9.84% positive, 65.57% negative, 24.59% indeterminate. This reflects the serious problem of impending resistance of P. aeruginosa to all known sensitive drugs which increases the risk of chronicity of infections caused by these aggressive strains. Careful and experienced interpretation of the routinely done susceptibility testing of P. aeruginosa should be performed so as to predict the production of the new beta lactamases and to correctly formulate the susceptibility results in order not to mislead the clinicians. Special tests for confirmation of such resistance mechanisms are sometimes needed