Acute respiratory syncytial virus bronchiolitis potential effect on development of childhood atopic diseases

This study aimed to evaluate the potential effect of Respiratory Syncytial Virus [RSV]-associated respiratory tract infection on the development of childhood atopic diseases. The study comprised 90 children [59 males and 31 females; with mean age of 21 +/- 6.9] hospitalized with acute upper respiratory tract infection [URI] with or without acute bronchiolitis [AB] in Children Hospital, and Al Amin Hospitals, Al Taief, KSA over a period of 6 months. Symptoms included, cough sneezing coryza, running nose and eyes, fever, difficulty in breathing, headache and malaise. Symptoms severity was assessed as absent [0], mild [1], moderate [2], or severe [3]. Patients' atopic status was assessed by skin prick testing. Nasopharyngeal lavage [NPL] was performed and the obtained NPL fluid was used for determination of RSV-specific IgA antibody activity. Blood samples were obtained for ELISA estimation of serum levels of interferon-gamma [INF- gamma], interleukins [IL] 4, 10 and 12. Clinical evaluation defined 28 infants [31.1%] with acute bronchiolitis [AB group] and 62 infants [68.9%] with URI. Patients developed AB were significantly [p<0.05] younger than those with URI but with no gender predilection Skin prick testing detected 17 atopic infants [18.9%]; 10 infants in AB group [35.7%] and 7 in URI group [11.3%] with a significant difference in favor of AB group, [x[2]=7.353, P<0.01]. The mean total symptom score was 11.7 +/- 4.2 and patients developed BA had a significantly [p<0.05] higher symptom score than those with URI. NPL proved a reliable and reproducible means of collecting nasal secretions during an acute URI with no significant associated complications. The NPL fluid of all patients with AB was positive for RSV antibodies, while detected in 43 specimens obtained from infants with URI; 5 atopic [71.4%] and 38 non-atopic [69.1%] with a total detection rate of RSV antibodies of 71 of 90 specimens [71.9%]. Serum levels of IL-4 and IL-10 showed a significant [p<0.05] increase and levels of INF- gamma and IL-12 were significantly decreased in AB group compared to URI group with a significant [p<0.05] decrease of serum INF- gamma in atopic compared to non-atopic patients in AB group only. The IL-4/IFN- gamma and IL-10/IL-12 ratios in AB group were significantly higher as a total and in both atopic and non-atopic patients compared to its counterpart in patients with URI with a positive significant correlation between IL-4/IFN- gamma [r=0.437, p=0.02] and IL-10/IL-12 [r=0.440, p=0.019] ratios in patients with AB and their severity symptoms. Using receiver operating characteristic [ROC] curve defined IL-4/IFN- gamma as a specific and IL-10/IL-12 as a sensitive predictors of severity of AB with AUC=0.827 and 0.442, respectively and serum IFN- gamma level as the most sensitive predictor and IL-4/IFN- gamma ratio as the most specific predictor of the development of atopy secondary to URI irrespective of the development of AB or not with AUO=0.267 and 0.725, respectively. It could be concluded that RSV-induced acute bronchiolitis is associated with local respiratory immune imbalance towards T2/T1, a picture suggestive of liability to develop allergic respiratory diseases later on and the ratio between serum levels of IL-4 and INF- gamma could be used as a specific predictor of the probability of future development of allergic respiratory diseases

Mycoplasma pneumonia and acute chest syndrome in sickle cell disease

Acute chest syndrome [ACS] is the leading cause of hospitalization, morbidity, and mortality in patients with sickle cell disease. Radiographic and clinical findings in ACS resemble pneumonia, however etiologies other than infectious pathogens have been implicated, including pulmonary fat embolism [PFE] and infarction of segments of the pulmonary vasculatures. Data were analyzed from the prospective study of 70 patients with ACS with sickle cell disease, ACS was defined as a new pulmonary infiltrate involving at least complete segment of the lung, excluding atelectasis. In addition, the patients had to have chest pain, fever >38.5C, tachypnea, wheezing or cough. Samples of blood and deep sputum were analyzed for evidence of bacteria. Mycoplasma pneumonia infection was determined by analysis of paired serologies. Detailed information on patient characteristics, presenting signs and symptoms, treatment and clinical outcome were collected. 12.5% of 70 patients with ACS had serological and PCR evidence of mycoplasma pneumonia, infection was higher in patients ages 5 to 9.9 years reaching 50%, all infection occurred in hemoglobin type SS. M. pneumonia is commonly associated with sickle cell disease and occurs in very young children. Aggressive treatment with broad spectrum antibiotics, including Ig from the macrolide class, is recommended for all patients as well as bronchodilator therapy, early transfusion, and respiratory support when clinically indicated