Background: Acute myeloid leukemia (AML) escape from immunosurveillance by immunosuppression. CD200 and CD56 expression represented an independent prognostic factor in many hematological malignancies but its importance in AML patients remains to be identified. Methods: CD200 and CD56 expression were assessed in the bone marrow blasts for Fifty-two (52) newly diagnosed AML by flowcytometry before start of therapy. Results: CD200 + expression was reported in 28.8% of patients while 17.3% of patients showed CD56 + expression. M4 FAB revealed high frequency of both CD200 + and CD56 + expression. The overall survival of CD200 + patients was 19.2% compared to 35.3% in CD200-(P= 0.049). On the other hand, CD56 + patients had the lowest complete remission rate (22.2% vs. 53.4%). In addition, CD56 + population had significant bad influence on overall survival than those of CD56population (11.1 % vs. 35.5 %, P= 0.047). Conclusions: CD200 and CD56 positive expression by myeloblasts at diagnosis denote poor prognostic indicator and correlated with poor cytogenetic findings. CD200 could be used as therapeutic target in AML.

Objectives: this study was carried out to evaluate the prevalence of sensory-neural hearing loss (SNHL) among telephone operators and its risk factors specially the effect of headset noise on the hearing ability of the telephone operators. Methods: a cross-sectional study was carried out on 58 telephone operators and 30 administration staff workers at Mansoura Telecommunications Company in Egypt. All participants were interviewed using a structured questionnaire including personal, medical and occupational history; and underwent an audiometric examination. Audiometric evaluation was done to evaluate hearing threshold levels (HTLs) for air and bone conduction for both right and left ears of all participants. Background noise was measured both at telephone operator and administration departments. Results: telephone operators had significantly higher prevalence of acoustic shock symptoms and decreased hearing sensitivity (46.6% and 37.9 %, respectively) compared to the controls (3.3% and 13.3%, respectively). Telephone operator had significantly higher HTLs compared to the controls, for air and bone conduction for both ears at lower and higher frequencies without the characteristic notch of noise induced hearing loss (NIHL). Among telephone operators, headset users had higher HTLs compared to headset non users, for air and bone conduction at the higher frequencies for both ears but more obviously in the left ear. There were 26 (44.8%) cases of SNHL among the telephone operators versus no cases among the controls; all of them were bilateral in distribution. Among other studied factors, only headset use (OR= 5.2, 95%CI = 1.7-16.1) and age (OR= 1.1, 95%CI = 1.0-1.2) were significant risk factors for developing SNHL among telephone operators. Conclusion: telephone operators are exposed to sudden repeated unexpected loud sounds due to headset use which could affect their hearing ability.