Parvovirus B19 infection induces apoptosis of erythroid cells in vitro and in vivo.

OBJECTIVE: intrauterine parvovirus B19 infection is related to non-immune hydrops fetalis, the pathogenesis of which is based on the strict tropism of B19 for erythroid precursor cells and the massive destruction of the infected erythroid cells, although the mechanism of beta19-induced cytotoxicity has not been studied in detail. The purpose of this study is to provide empirical evidence that beta19 induces apoptosis of erythroid cells both in vitro and ill vivo. METHODS: we analysed culture cells infected in vitro by B19 and tissues of nine cases of hydrops fetalis caused by B19 intrauterine infection by histological and biological methods. RESULTS: cells infected iil vitro by B19 showed nuclear changes characteristic of apoptosis by light microscopic examination and DNA extracted from the infected cells was fragmented. Electron microscopic examination showed the nuclei of infected cells contained crescent-shaped clumps of heterochromatin with increased density and double staining with anti-B1 9 antibody and terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate-digoxigenin nick-end labeling (TUNEL) confirmed apoptosis of individual cells. Tissues of cases of hydrops fetalis caused by B19 contained erythroid cells with nuclear inclusions and characteristic nuclear changes of apoptosis by light microscopy. The double-staining confirmed apoptosis of erythroid cells in the tissues. Immunohistochemical analysis with antibodies against cellular factors involved in apoptosis showed that caspase3, p53 and p21 were positive in infected cells.

Serologic study of human parvovirus B19 infection in pregnancy in Japan.

OBJECTIVES: To clarify the relationship between hydrops fetalis and parvovirus outbreaks in the community, seroprevalence of B19 antibody among women of childbearing age, and adverse effects of intrauterine B19 infection. METHODS: Sera were collected from 168 cases of hydrops fetalis which were diagnosed between 1987 and 1997 in Miyagi prefecture, Japan, from 232 healthy pregnant women in 1987 and 277 healthy pregnant women in 1997 in Miyagi, and from 48 women infected with B19 during pregnancy. The sera were examined for B19 IgG and IgM antibodies by enzyme-linked immunosorbent assay and for B19 DNA by polymerase chain reaction. The number of cases of erythema infectiosum in Miyagi had been monitored each month. RESULTS: Thirteen of the 168 cases of hydrops fetalis were found to be caused by intrauterine B19 infection and 12 of the 13 cases clustered in two periods of outbreaks of erythema infectiosum in the community. The positive rates of B19 IgG antibody between 1987 and 1997 were significantly different: 33% in 1987 and 46% in 1997. Nine of the 48 women infected during pregnancy showed adverse effects of the fetus: eight hydrops fetalis and one early abortion with positive B19 DNA. The fetal death rate (>12 weeks of gestation) among them was 15% (7/48), far higher than the calculated 1% among the general population. The nine mothers with adverse fetal outcomes had contact with the infectious source at the 16 weeks of gestation or earlier. CONCLUSIONS: These data clearly showed a relationship between hydrops fetalis and parvovirus outbreaks in the community, and it may be important to follow the seroprevalence for an extrapolated period time to predict occurrence of hydrops fetalis caused by B19. Also the data indicated that the gestational week infection occurred is the most important determinant of an adverse effect to the fetus as described previously.

The incidence of, and factors leading to, parvovirus B19-related hydrops fetalis following maternal infection; report of 10 cases and meta-analysis.

OBJECTIVES: to clarify the approximation of the frequency of B19-related nonimmune hydrops fetalis (NIHF), and to know the critical period during which maternal infection led to NIHF. METHODS: we investigated the characteristics of 10 cases of antenatal B19 infection diagnosed over the past 10 years in Miyagi prefecture, Japan, and performed a meta-analysis of these cases and those previously reported in the literature. RESULTS: NIHF caused by intrauterine B19 infection was diagnosed between 11 and 23 weeks of gestation in 10 women over the past 10 years in Miyagi prefecture, Japan. The source of infection was the mother's older child in six out of 10 cases, and children at a kindergarten where the mothers worked in two cases. The interval between the onset of infection and the diagnosis of NIHF ranged from 2 to 6 weeks. B19 infection was responsible for 10 (15.2%) in 66 cases of aetiology unknown NIHF in this study, and for 57 (19.1%) of 299 cases of non-malformed or aetiology-unknown NIHF by meta-analysis of the literature. Meta-analysis of the 165 reported cases of antenatal B19 infection, including the 10 cases described above, showed that there was a 10.2% excess risk of fetal death in women infected with B19 during pregnancy and a 12.40% excess risk in women infected during the first 20 weeks of pregnancy. Transplacental transmission was confirmed in 69 (24.1%) of 286 cases. The mean gestational age at diagnosis of NIHF was 22.8 +/- 5.1 weeks. The mean interval between the onset of maternal infection and diagnosis of NIHF was 6.2 +/- 3.7 weeks. CONCLUSIONS: these approximations will be useful for counselling and management for pregnant women. The critical period during which maternal infection led to NIHF correlated with the hepatic period of hematopoietic activity. These findings suggest that parvovirus B19 may have an affinity for erythroid lineage cells at the hepatic stage of hematopoiesis, which may strongly influence the clinical features of feto-maternal B19 infection.

A Turner syndrome woman with a ring X chromosome [45,X/46,X,r(X)(p22.3q27)] whose child also had a ring X chromosome.

OBJECTIVE: To describe a woman with Turner syndrome with ring X chromosome mosaicism who had a child who possessed the same ring X chromosome. DESIGN: Polymorphisms of genes located on the X chromosome from genomic DNA of the mother, father, and the child were evaluated. PATIENT(S): The mother's karyotype was 45,X [48]/46,X,r(X)(p22.3q27) [2], and the child's karyotype was 45,X[33]/46,X,r(X)(p22.3q27) [17]. INTERVENTION(S): Polymerase chain reaction was used to amplify short tandem repeats from the loci of the hypoxanthine phosphoribosyltransferase gene and the androgen receptor gene. RESULT(S): Alleles for both genes in the child originated from both parents in a heterozygous fashion. The alleles originating from the mother originated from the ring X chromosome. However, the amount of amplified DNA was less than that of a normal X chromosome. CONCLUSION(S): The ring X chromosome of the mother was most likely transmitted to the newborn. Thus, an ovum with the ring X chromosome can be fertile and can produce a viable zygote.

Scanning electron microscopy of fragmentary marker chromosomes observed by light microscopy.

To study the fine structure of fragmentary marker chromosomes, we performed scanning electron microscopy (SEM) on samples isolated from two carriers (Case 1: 46, XY/47, XY, +mar/48, XY, +mar, +mar; Case 2: 47, XY, +mar). In both cases, light microscopic observation revealed that marker chromosomes lacked a centromere and were fragmented in appearance. However, SEM observation of the metaphasic cells in both cases showed three variations. One variation was a structure that seemed to be metacentric, another was a structure that seemed to be submetacentric, and the remaining one was essentially fragmentary. However, neither the usual chromatid nor centromere formations were observed in the metacentric-like and submetacentric-like structures, even when both cases were observed by SEM. Moreover, the marker chromosomes of the boy of Case I, who suffered from various clinical troubles, included a greater population of metacentric-like or submetacentric-like structures than of essentially fragmentary structures. The marker chromosomes of the fetus of Case 2, who suffered from no clinical problems, included a much greater population of essentially fragmentary structures than metacentric-like or submetacentric like structures. Therefore, SEM observation of fragmentary marker chromosomes that are visible on light microscopy might be used to define specific structures. Moreover, SEM observation might provide clinical criteria relating to the pathogenesis of fragmentary marker chromosomes found on light microscopy.