The aim of our study was to assess the cytokine profile of sickle cell disease (SCD) patients in steady state and in vaso-occlusive crisis (VOC). VOC has a complex nature, involving interactions between sickle red blood cells (RBC), the endothelium, and leucocytes. Endothelial damage due to recurrent adhesion of sickle RBCs may disrupt endothelial function, leading to altered cytokine release. It is therefore pertinent to study the cytokine profile of SCD patients in steady state and in crisis prior to exploring its contribution to vasoocclusive manifestations, since it is believed that an altered balance of proinflammatory and anti-inflammatory cytokines plays an important role in painful crisis. Cytokines including IL1b, IL-2, IL-4, IL-6, IL-8, TNF-a, and IFN-g were measured by commercially available ELISA kits in SCD patients (n = 60); in steady state (n = 26) and in painful crisis (n = 34) and compared with nonanemic age-and sex-matched normal Omani controls (n = 20). SCD patients in crisis showed elevated levels of TNF-a (P < 0.092) and IL-6 (P < 0.024) when compared with steady state. It was also observed that SCD patients in steady state showed a significant elevation in IL-1b (P < 0.04), IL-6 (P < 0.0001), and IFN-g (P < 0.02) as compared to normal subjects. It is thus evident that both type I and type II cytokines are significantly altered in SCD patients. In steady state, type II proinflammatory cytokines are elevated, whereas in crisis, an additional augmentation of type I cytokines occurs, with persistent elevation of type II cytokines, emphasizing the role of perturbed endothelium and activated monocytes in the pathophysiology of vaso-occlusion in sickle cell crisis. Am.

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Objectives: The aim of this study was to determine the prevalence of hepatitis B surface antigen (HBsAg), hepatitis B core antibodies (anti-HBc) and hepatitis B virus (HBV) DNA among a selected group of Omani blood donors. Materials and Methods: Two hundred HBsAg-negative donors were screened for anti-HBc. Those found to be positive were investigated for HBV DNA by polymerase chain reaction. HBsAg was retested on these sera following an immune complex dissociation technique. Results: HBsAg was present in 2.8% of the donors. Forty-one out of 200 (20.5%) HBsAg-negative donors were positive for anti-HBc. Eleven were positive for HBsAg after dissociation, whereas 8 gave readings just over the cutoff. HBV DNA was not detected in this group. Conclusion: Findings indicate that testing donors for HBsAg alone is not sufficient to eliminate HBV from the blood supply in Oman.

ObjectiveTo investigate the diagnostic utility of interferon-gamma (IFN-γ) and adenosine deaminase (ADA) in tuberculous pleural effusions by determining the best cutoff levels of these two markers for pleural tuberculosis, in the context of the local epidemiological settings in Qatar.MethodsWe prospectively studied IFN-γ and ADA levels in the pleural fluid of patients presenting to Hamad General Hospital between June 1, 2009 and May 31, 2010.ResultsWe studied 103 patients with pleural effusions, 72 (69.9%) with pleural tuberculosis, and 31 (30.1%) with nontuberculous etiologies. The mean IFN-γ concentration for the group with tuberculous effusions was significantly higher than that in the group with nontuberculous effusions (1.98 ± 81 vs 0.26 ± 10 pg/mL [P < 0.0001]). The mean ADA activity for the tuberculous effusions group was significantly higher than that in group with nontuberculous effusions (41.30 ± 20.09 vs 14.93 ± 14.87 U/L [P < 0.0001]). By analysis of receiver operating characteristic (ROC) curves, the best cutoff values for IFN-γ and ADA were 0.5 pg/mL and 16.65 U/L, respectively. The results for IFN-γ vs ADA were: for sensitivity, 100% vs 86%, respectively; for specificity, 100% vs 74%, respectively; for positive predictive value, 100% vs 88.5%, respectively; and for negative predictive value, 100% vs 69.7%, respectively.ConclusionIFN-γ and ADA could be used as valuable parameters for the differentiation of tuberculous from nontuberculous effusion, and IFN-γ was more sensitive and specific for tuberculous effusion than ADA.

Aim: Determine reference ranges of lymphocyte subsets in healthy Qatari adults. Patients & Methods: Blood samples (n = 150) were investigated using four colors flow cytometery. Results: The mean percentage and absolute values of the lymphocyte subsets were: CD3: 73.6 ± 6.1%; 2,072 ± 644 cells/μl; CD4: 41.1 ± 7.9%; 1,167 ± 396 cells/ μl; CD8: 33.8 ± 7.1%; 967 ± 364 cells/μl; B cells (CD19+): 11.3 ± 3.9%; 318 ± 144 cells/μl and natural killer (NK) cells (CD16/56+): 16.5 ± 6.3%, 440 ± 401 cells/μl, respectively. The CD4/CD8 ratio was 1.3 ± 0.5. The ratio, CD3+ and CD4+ percentage and CD4+ cell counts were significantly higher in females; CD8+ and NK cell count and CD8+ percentage were significantly higher in males. The impact of age was less certain. Conclusion:The reference values of lymphocyte subsets appear to be specific to this population, demonstrating the importance of establishing local reference ranges. Keywords: B cells • CD3 • CD4 • CD8 • flow cytometry • lymphocyte subsets • natural killer cells • reference ranges, IntroductionLymphocyte immunophenotyping by flow cytometry is an important tool in differential diagnosis of congenital and acquired immune deficiencies, lymphoproliferative disorders and acute leukemias [1]. In addition, it is used for monitoring treatment response and disease progression with anti-retroviral and immunosuppressive therapy. Various studies suggest that lymphocyte subsets reference ranges are influenced by age, sex, ethnicity, and environment [2][3][4][5]. The variations in the values of the lymphocyte subsets emphasize the importance of establishing local reference ranges to allow for meaningful comparisons and accurate interpretation of immunophenotyping data across different cultures and ethnic groups. Lifestyle factors, e.g. smoking, have also been shown to influence lymphocyte subset values [6,7].Indeed, reference range for peripheral blood lymphocyte subsets have been established in many studies across different countries, revealing variations in the normal range for lymphocyte subsets according to age, sex, race, and environmental factors [3,4,[8][9][10][11][12][13][14][15][16]. Establishment of an internal normal range of lymphocyte subsets is a important for each population considering the effect of environmental factors, age, ethnical diversity on the immune system. Hence, this study aims to determine the laboratory reference ranges for lymphocyte subsets in healthy Qatari adults using flow cytometry.This article reports the local reference range for peripheral blood lymphocyte subsets, both percentages and absolute counts, in a representative sample of 150 healthy adult Qatari population.The results have been stratified by age, sex, and smoking status. The population selected is largely homogenous (100% Qatari Arabs) so effect of race was not investigated. The results are briefly compared with other population data from published studies. Materials & methods SubjectsA total of 150 healthy Qatari volunteers (18-55 yr old; all Qatari Arabs) were recruited for the stud...