Cuadro ampolloso distal de inicio brusco y hemorragias en astilla / Sudden onset of distal bullae and splinter hemorraghes

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Evaluation of a new LightCycler reverse transcription-polymerase chain reaction infectivity assay for detection of human parvovirus B19 in dry-heat inactivation studies.

BACKGROUND: Human parvovirus B19 (B19) is a widely distributed infectious agent, which causes a variety of illnesses including erythema infectiosum (fifth disease) especially in children, arthritis, aplastic crisis, and hydrops fetalis. B19 can be transmitted from asymptomatic blood donors to recipients of their blood components. Fifth disease has been reported in patients receiving red blood cells, platelets, solvent/detergent-treated plasma, and clotting factor concentrates. STUDY DESIGN AND METHODS: A new B19-specific Light Cycler (LC) reverse transcription-polymerase chain reaction (RT-PCR) infectivity assay was developed for quantitative analysis of the infectivity of B19 in virus validation studies. The cycling conditions and the primers of the new assay were designed to amplify spliced RNA forms but not precursor RNA or B19 genome. One 50 percent infectious dose, determined on UT7/Epo-S1 cells of low passage, equaled 3.74+/-0.1 log international units of B19 DNA. RESULTS: The efficiency of the dry-heat process (100 degrees C) on inactivation of B19 spiked and lyophilized with fibrinogen, a major component of the clotting factor concentrate and hemostatic dressing products, was investigated by use of B19-specific LC RT-PCR infectivity assay. At 1.3 to 1.7 percent residual moisture of fibrinogen, the infectivity of B19 was reduced dramatically by 3.3 to 5.1 log for 1 and 2 hours of dry-heat treatment, respectively. B19 infectivity was reduced 1.5, 2.8, and 3.8 log for 1, 2, and 3 hours of dry-heat treatment, respectively, at 0.5 to 0.7 percent residual moisture level. CONCLUSION: These findings suggest that level of residual moisture of lyophilized fibrinogen with B19 spike correlated with a different resistance of B19 to dry-heat treatment, and that low moisture may stabilize virus against heat.

Case report: detection of parvovirus B19 in a skin biopsy of a patient with erythema infectiosum.

We report the findings on a skin biopsy taken from a child acutely infected with parvovirus B19 showing the typical exanthematous rash. By indirect immunofluorescence with a monoclonal antibody to B19, viral capsid proteins were detected in epidermal cells localized mainly in the stratum basale. Additionally, B19 DNA was detected in epidermal cells of the stratum basale by in situ hybridization using a Dig-labelled B19 DNA probe. The detection of viral capsid proteins and viral DNA suggests the presence of complete viral particles. It is therefore concluded that B19 plays a direct role in the formation of the exanthematous rash in erythema infection.

[Parvovirus B19 and pediatric pathology]. / Parvovirus B 19 et pathologie pédiatrique.

B 19 parvovirus is a widespread virus with primary infestation generally occurring in childhood through family and community outbreaks. Its most typical manifestation is transient erythroblastopenia with aplastic crisis, often profound, mostly affecting patients with chronic hemolytic anemia, and eventually patients with defective erythropoiesis (chronic hypoplastic anemia, iron deficiency anemia). In normal individuals the primary infestation is usually asymptomatic but may give transient hematological signs for few days: moderate reticulocytopenia, thrombopenia and neutropenia. Clinically two phases of the infection are described: 1.) a first phase of viremia of 2 to 3 days which may be accompanied by fever and myalgias; 2.) a second phase which may last for several weeks with dermatological signs, the most typical being erythema infectiosum, vasculitis, arthralgias or arthritis. In pregnant women, the primary infestation with B 19 parvovirus may lead to fetal anemia and hydrops fetalis with uneven outcomes: fetal death, chronic erythroblastopenia after birth, spontaneous resolution. Although the incidence of fetal infestation in non immunized pregnant women is still unknown, the question is raised of the recognition and protection of non immunized pregnant women at high risk of exposition to infested subjects. Long term persistence of the virus in the organism may be responsible for chronic manifestation, essentially but not exclusively in immunodeficient-patients: prolonged erythroblastopenia and chronic rheumatologic manifestations. It may be also responsible for cases of juvenile arthritis, thrombocytopenic purpura and chronic neutropenia of childhood. The diagnosis of the viral infestation is mainly based upon the detection of specific IgM, then IgG, antibodies by Elisa technique.

Resistance to parvovirus B19 infection due to lack of virus receptor (erythrocyte P antigen).

BACKGROUND: The presence of a specific cellular receptor is thought to be necessary for susceptibility to viral infection. The erythrocyte P antigen is the cellular receptor for parvovirus B19. We hypothesized that the rare persons with the p phenotype, whose erythrocytes do not have this receptor, would be naturally resistant to B19 infection, which causes erythema infectiosum. METHODS: Blood samples were collected from two populations in cross-sectional studies. We determined the P antigen phenotype of the red cells and tested plasma for anti-B19-specific antibodies. Bone marrow from donors of known P antigen phenotype was inoculated with parvovirus B19. Infectivity was measured by assays of erythroid progenitor cells, dot blot analysis, and in situ hybridization for B19 DNA, and an immunofluorescence assay for viral-capsid proteins. RESULTS: Of the 17 subjects with the p red-cell phenotype, who did not have P antigen on their erythrocytes, none (0 of 11 and 0 of 6) had serologic evidence of previous parvovirus B19 infection. In contrast, the seropositivity rates in the two control groups were 71 percent (53 of 75, P < 0.001) and 47 percent (32 of 68, P = 0.03). In vitro, bone marrow from donors with the p phenotype maintained normal erythropoiesis despite very high concentrations of virus, with no evidence of infection of erythroid progenitor cells by parvovirus B19. CONCLUSIONS: People who do not have P antigen, which is the cellular receptor for parvovirus B19, are naturally resistant to infection with this pathogen.

[Human parvovirus B19 (HPV-B19), a clinical overview with emphasis of rheumatologic manifestations]. / Humanes Parvovirus B19 (HPV-B19), eine klinische Ubersicht mit Betonung der rheumatologischen Manifestationen.

The human parvovirus B19 (HPV-B19) causes a spectrum of diseases: Erythema infectiosum (fifth disease), aplastic crises in patients with chronic hemolytic anemias, chronic bone marrow failure in patients with congenital or acquired immune deficiency, vascular purpura, hydrops fetalis, abortion, intrauterine fetal death and HPV-19-arthropathy. In this review we will discuss the clinical pattern, the diagnostic questions and therapeutic possibilities particularly relating to rheumatic manifestations.

An outbreak of parvovirus B19 infection; a study of clinical manifestations and the incidence of fetal loss.

Eighty-five cases of B19 infection were diagnosed in Northern Ireland from 1984 to 1989; 65 of these occurred during 1989, the outbreak year. Of the total 85 cases, 15 had a rash, 21 had arthralgia, 47 had a rash and arthralgia, and 2 had aplastic crisis. The age range was 4-63 years with a mean of 26.9 years. Thirty cases (35%) were referred to hospital; 25 of these had arthralgia and 2 had aplastic crisis. Two thousand four hundred pregnant women at 12 weeks gestation in 1989 were screened for anti-B19 IgM; 8 were positive. Of these 8 patients, 7 progressed to delivery of a normal fetus and one had an intra-uterine death at 26 weeks gestation; no congenital abnormalities were noted in any fetus. The incidence of fetal involvement in maternal B19 infection in this study was therefore 12.5%.

The frequency of human parvovirus B19 infection in nonimmune hydrops fetalis.

Intrauterine infection of human parvovirus B19 has recently been identified as an etiology for nonimmune hydrops fetalis (NIHF) and fetal death. To examine the frequency of B19 infection in cases of NIHF, forty two cases of NIHF of unknown cause were tested for the presence of B19 antibodies by enzyme-linked immunosorbent assay (ELISA) and B19 DNA by polymerase chain reaction (PCR). Three maternal sera were positive for B19 IgM antibody and one fetal serum was positive for B19 DNA. Overall, four (10%) of the 42 cases were positive for B19 infection. All of the four cases positive for B19 infection were found during or just before an outbreak of erythema infectiosum and the incidence was calculated at 36% if only cases found during the outbreak were collected. In all four cases of B19 infection, NIHF was diagnosed at 20 to 23 weeks of gestation, which suggested that B19 infection might be a particular threat to the fetus during this stage of gestation. In conclusion, B19 infection may contribute to 10% of cause unknown NIHF and the incidence may be higher if cases during outbreaks are exclusively collected.

B19 parvovirus infection in children with malignant solid tumors receiving chemotherapy.

Two children with rhabdomyosarcoma developed severe anemia following chemotherapy; anemia was more severe compared to that observed following earlier chemotherapy cycles. While one patient had a brisk reticulocytosis, the other had no demonstrable reticulocytes. Both patients had evidence of acute B19 parovirus infection and subsequently developed appropriate antibody response. A diagnosis of B19 parvovirus infection should be considered in any patient who develops persistent or severe anemia while on chemotherapy.

Papular-purpuric 'gloves and socks' syndrome: not only parvovirus B19.

We previously described an acute dermatosis characterized by pruritic erythematous and slightly papular lesions on the hands and feet in a 'gloves and socks' distribution associated with oral aphthoid lesions and fever (papular-purpuric 'gloves and socks' syndrome = PPGSS). We strongly suspected a viral origin, but serologic tests for a large panel of viruses remained negative. Subsequently, 2 cases of PPGSS with serologic evidence of a parvovirus B19 infection have been reported in the literature. Since then we observed 5 additional patients with a PPGSS. Parvovirus B19 infection could be confirmed in only 2 cases. Our findings suggest that the PPGSS can be another, yet undescribed manifestation of parvovirus infection. However, this cannot be shown in all the cases. As the papular acrodermatitis of childhood, this syndrome may be caused by various viral agents.

Laboratory testing in patients with morbilliform viral eruptions.

The explosion of immunologic testing capabilities over the past 20 years has enabled clinicians to accurately diagnose many conditions that previously were very difficult to identify solely on a clinical basis. Among these disorders are the viral exanthems. Infections with some of these viruses are of relatively little import (erythema infectiosum), whereas others have more significant consequences (HIV, cytomegalovirus). Clinical suspicions may be pursued more fully now, sometimes even in an office setting.

[Erythema infectiosum in pregnancy. A follow-up of children after 2 years]. / Erythema infectiosum i svangerskapet. Oppfølging av barna etter to år.

During an epidemic of erythema infectiosum in Norway 1984-86, infection with human parvovirus B19 was diagnosed in 22 pregnant women by detection of specific IgM antibodies. Information about the outcome of pregnancy was obtained in 19 cases. 17 women delivered live babies. In two cases, spontaneous abortion occurred in week 16 of the pregnancy. In 11 cases, cord blood and serum samples were obtained from the children at an age of between six and 15 months. No specific IgM antibodies were found in cord blood. Clinical information on 16 children at two years of age revealed normal growth and development in 15 cases. One child was hyperactive and showed delayed language development. B19 IgG antibodies were detected in three children with normal growth and development. According to our findings, there was no association between infection with human parvovirus B19 in pregnancy and congenital abnormalities.

Skin tuberculosis as seen at Ga-Rankuwa Hospital.

The experience with cutaneous tuberculosis at Ga-Rankuwa Hospital is reviewed. A total of 92 cases of skin tuberculosis was seen over the past 12 years. All recognized forms of cutaneous tuberculosis were encountered, plus some forms which were difficult to classify. Lupus vulgaris was the most common true infection and papulonecrotic tuberculid the most common tuberculid. The classification and pathogenetic mechanisms are briefly discussed.