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.

Assessment of the specificity of a commercial human parvovirus B19 IgM assay.

BACKGROUND: It is important to investigate a possible cross-reaction of anti-rubella IgM in the IDEIA Parvovirus B19 IgM test because many B19 infections are either asymptomatic or have clinical symptoms similar to those of rubella virus infections. Epstein-Barr virus (EBV) IgM, cytomegalovirus (CMV) IgM, measles IgM and rheumatoid factor (RF) IgM cross-reactions were also studied. OBJECTIVES: In the period from February to September 1994 (including a parvovirus B19 epidemic) more than 10,000 serum samples were examined for parvovirus B19 IgM in Denmark. This gave an opportunity to evaluate the commercial IDEIA Parvovirus B19 ELISA kit (DAKO A/S, Glostrup, Denmark), which was used routinely at Statens Serum Institut from the beginning of 1994 and onwards. STUDY DESIGN: A total of 123 parvovirus B19 IgM positive sera were tested for reactivity in rubella IgM EIA. A total of 78 rubella IgM positive sera, 60 EBV VCA-IgM positive sera, 30 CMV IgM positive sera and 24 measles virus IgM positive sera were tested for reaction in IDEIA Parvovirus B19 IgM test. Finally, 25 parvovirus IgM positive sera were tested for specific IgM against measles virus, EBV (VCA), CMV and for RF. RESULTS: One anti-B19 IgM positive serum sample reacted positively in the rubella IgM test. Of rubella IgM positive serum samples 4% cross-reacted in IDEIA Parvovirus B19 IgM test, as did 17 and 20% of EBV VCA-IgM and CMV IgM positive serum samples respectively. None of measles virus IgM positive serum samples cross-reacted in the IDEIA Parvovirus B19 IgM test. Of 25 initially parvovirus B19 IgM positive sera 20% cross-reacted in EBV VCA IgM test and 8% in the CMV IgM test. None reacted positively in measles virus IgM test; 28% showed weak reactivity in RF IgM test. CONCLUSIONS: Precautions must be taken when results of IgM assays are interpreted. Epidemiological and clinical observations must be considered.