Parvovirus B19 infection in pediatric oncology patients: diagnostic value of clinical and serologic parameters compared with nested PCR.

BACKGROUND: Oncology patients are at particular risk for parvovirus B19 infection, which may cause severe, persistent, usually nonspecific illness in this group. AIM: This study was designed to assess the prevalence and impact of parvovirus B19 in pediatric oncology patients receiving chemotherapy, and to define the optimal diagnostic tests in such patients. SUBJECTS AND METHODS: Fifty-nine children under chemotherapy (39 with acute lymphocytic leukemia and 20 with solid tumors) with mean age of 4.96+/-1.94 years, in addition to 30 healthy children of matched age and sex, were enrolled in this study. Clinical and laboratory data were collected by examination and from patients' records. Specific parvovirus B19 immunoglobulin (Ig) M and IgG antibodies were assessed by enzyme-linked immunosorbent assay, and parvovirus DNA was detected by nested polymerase chain reaction (PCR) for all patients and controls. RESULTS: Parvovirus DNA was detected in 16 (27.1%), IgM in 3 (5.1%), and IgG in 36 (61%) patients. IgM had sensitivity, specificity, and accuracy of 18.75%, 100%, and 77.9%, respectively, whereas those of IgG were 81.25%, 53.4%, and 61%, respectively. PCR-positive patients had significantly higher frequency of unexplained anemia, red blood cell transfusions, and longer hospital stay than PCR-negative patients (P<0.001). Multiple linear regression analysis showed that unexplained anemia and multiple red blood cell transfusions were the most important variables that can predict PCR positivity. CONCLUSIONS: Parvovirus B19 is not an uncommon problem in pediatric oncology patients who exhibited weak antibody response and nonspecific clinical features. Screening of these patients with PCR rather than serology is recommended when infection is suspected.

Glucosidase acid beta gene mutations in Egyptian children with Gaucher disease and relation to disease phenotypes.

INTRODUCTION: More than 200 mutations have been found in patients with Gaucher disease (GD) and some mutations usually have a high frequency in certain populations. Genotype/phenotype correlation in patients with GD has not been established. This study was designed to determine underlying mutations in Egyptian children with GD and to assess their relation to disease phenotypes. METHODS: This study comprised 17 patients with GD and 10 healthy controls. Thirteen patients were type 1 GD, 2 type 2, and 2 type 3. DNA was extracted from peripheral blood leukocytes. Exons 9 and 10 were amplified by polymerase chain reaction, and deoxyribonucleic acid sequencing was done with an ABI 310 genetic analyzer. RESULTS: Wild type allele was detected in 95% (19/20) and a normal variant in 5% (1/20) of controls. L444P allele was encountered in 50% (13/26) of the alleles in type 1 patients, H451P in 7.7% (2/26) and recombinant alleles (RecNcil, RecNcil + M450L, RecFs, RecFs + M450L) in 34.6% (9/26). L444P and Rec alleles each occurred in 50% (2/4) of type 2 and 3 patients. A new mutation was seen in this study {g.7336A>C, (M450L)} and 2 mutant alleles were not determined. Type 1 GD patients had L444P/L444P genotype (23.1%) and Rec alleles/L444P (53.8%), while type 2 and 3 GD patients had Rec alleles/L444P genotypes (100%) with a poor phenotype/genotype correlation. CONCLUSIONS: L444P and Rec alleles are common in the studied patients. Novel mutations are continuously detected, adding to the expanding panel of GD mutations. No significant genotype-phenotype association was observed.