Molecular and serological assessment of parvovirus B-19 infection in Egyptian children with sickle cell disease.

BACKGROUND/PURPOSE: Human parvovirus B-19 (PB-19) is a cause of hemolysis, red blood cell aplasia, and severe conditions in patients with sickle cell anemia, but the molecular mechanisms of the infection are still insufficiently understood. This study aimed to detect PB-19 DNA together with its antibodies in the sera of Egyptian children with sickle cell disease and to assess the contribution of this infection, which causes transient cessation of erythropoiesis, in precipitating severe anemia in some cases. METHODS: One hundred children with sickle cell disease seeking medical advice in the pediatric-hematology clinic were recruited. Sera of the patients were compared with those of 60 healthy children regarding the presence of PB-19 immunoglobulin (Ig)G and IgM as well as detection of its DNA by nested-polymerase chain reaction technique. RESULTS: There were statistically significant differences in the prevalence of PB-19 IgM, IgG, and DNA among patients when compared with controls (p < 0.001, p = 0.001, and p < 0.001 respectively). Acute PB-19 infection detected by positive IgM and DNA was found in 30% of the patients, while chronic PB-19 infection detected by positive IgG and DNA was detected in 24% of the patients. Anemia was worse in children with acute PB-19 infection than in those with chronic infection, while anemia was mild in children with old infection. CONCLUSION: PB-19 infection is detected at high rates among Egyptian children with sickle cell disease and it may result in severe anemia. So, PB-19 must be suspected and screened for in such group of patients.

Molecular and serological assessment of parvovirus B19 infections among sickle cell anemia patients.

INTRODUCTION: Parvovirus B19 is a cause of hemolysis and red blood cell aplasia in patients with sickle cell anemia. The present study aimed to assess parvovirus B19 infection among sickle cell anemia patients. METHODOLOGY: All patients (n = 138) included in the study were sickle cell anemia patients. Blood donors were used as a control group. Assessment of parvovirus B19 antibodies and viral DNA was performed using established methods of detection and B19 recomBlot assay. RESULTS: Detectable levels of parvovirus B19 IgG were found in 52 samples (37.6%) whereas anti-parvovirus B19 IgM antibodies were detected in four (2.89 %) patients of the sickle-cell anemia group. Anti-B19 IgM-positive samples contained B19-viral DNA.  These four patients presented with fever, malaise, pallor and no cutaneous rash. Anti-parvovirus B19 antibodies were detected in 22 (39.3%) of the control blood donors group. Anti-parvovirus B19 IgM antibodies were not detected in the control group. Using the recomBlot assay, 58 test samples (42%) were found to contain detectable levels of Parvovirus B19 antibodies. All the samples that were positive for parvovirus B19 IgG by the ELISA were also positive by the recomBlot assay. Six samples were only positive by the recomBlot assay and not by the ELISA. Two of these six samples were positive for B19 viral DNA. CONCLUSIONS: Establishing the extent of parvovirus B19 infection in sickle cell anemia patients will help in proper management of aplastic crisis in such patients. The B19 recomBlot assay may be suitable as a confirmatory assay.

Cardiovascular magnetic resonance assessment of human myocarditis: a comparison to histology and molecular pathology.

BACKGROUND: Myocarditis can occasionally lead to sudden death and may progress to dilated cardiomyopathy in up to 10% of patients. Because the initial onset is difficult to recognize clinically and the diagnostic tools available are unsatisfactory, new strategies to diagnose myocarditis are needed. METHODS AND RESULTS: Cardiovascular MR imaging (CMR) was performed in 32 patients who were diagnosed with myocarditis by clinical criteria. To determine whether CMR visualizes areas of active myocarditis, endomyocardial biopsy was taken from the region of contrast enhancement and submitted to histopathologic analysis. Follow-up was performed 3 month later. Contrast enhancement was present in 28 patients (88%) and was usually seen with one or several foci in the myocardium. Foci were most frequently located in the lateral free wall. In the 21 patients in whom biopsy was obtained from the region of contrast enhancement, histopathologic analysis revealed active myocarditis in 19 patients (parvovirus B19, n=12; human herpes virus type 6 [HHV 6], n=5). Conversely, in the remaining 11 patients, in whom biopsy could not be taken from the region of contrast enhancement, active myocarditis was found in one case only (HHV6). At follow-up, the area of contrast enhancement decreased from 9+/-11% to 3+/-4% of left ventricular mass as the left ventricular ejection fraction improved from 47+/-19% to 60+/-10%. CONCLUSIONS: Contrast enhancement is a frequent finding in the clinical setting of suspected myocarditis and is associated with active inflammation defined by histopathology. Myocarditis occurs predominantly in the lateral free wall. Contrast CMR is a valuable tool for the evaluation and monitoring of inflammatory heart disease.

Yield and future issues of nucleic acid testing.

Despite the much lower actual yield than that estimated for hepatitis C virus (HCV) and human immunodeficiency virus (HIV) nucleic acid testing (NAT)-only positives in the USA and Germany, look-back procedures have revealed that no HCV transmission has occurred in Germany since the introduction of NAT. This indicates sufficient sensitivity of the pool-PCR approach. The slow ramp-up of hepatitis B virus (HBV) however, may require a different approach. It has been shown in Germany that the pooling of samples followed by virus enrichment results in a significant yield. Single donation testing for HBV would not increase the yield, because virus enrichment from mini-pool results in a similar sensitivity to that of single donation testing. Both strategies may be useful for extending future NAT to HBV screening. New candidate viruses for NAT are Parvo B19 and hepatitis A virus (HAV) because of their extreme resistance to inactivation procedures. Their low pathogenicity and epidemiologic characteristics, however, make them candidate viruses only for pooled source plasma. The main future issues of NAT will be related to the automation of pooling, extraction and amplification as a single homogeneous process. Depending on the throughput, automated single donation NAT as demonstrated by the 'Tigris' system may be an option, as far as all transfusion-relevant viruses will be included. In the near future high throughput systems will rely on pooled donor samples, most probably in conjunction with efficient enrichment procedures. For these systems, automation of the extraction and amplification process will be one of the first steps. These procedures will also limitthe costs of NAT and keep it available for use with future candidate viruses.