[Usefulness of urine and blood cultures for diagnosing cytomegalovirus infection in the kidney transplant recipient]

OBJECTIVE

To prospectively and comparatively study the usefulness of urine (viruria) and blood (antigenemia pp65 and culture) (viremia) for the diagnosis of cytomegalovirus (CMV) infection in renal transplant (RT) recipients.

MATERIAL AND METHODS

All RT recipients at our hospital were studied from January 1995 to December 1996. After decontamination, urine specimens were inoculated into two MRC-5 cell line vials. Polymorphonuclear cells were extracted from peripheral blood by sedimentation in saline dextran and were used for antigenemia pp65 test and for culture in shell-vial.

RESULTS

A total of 1,335 specimens from 43 patients were studied. CMV was recovered from 110 out of the 913 (12%) urine specimens and from 101 out of the 422 (23.9%) blood specimens (antigenemia and/or viremia). CMV detection was first obtained by a positive blood test in 23 patients (88.4%), whereas the urine specimen was the first positive test in only three (11.6%) patients (p = 0.0001). A positive result in blood preceded a positive result in urine by a mean of 10.3 days (range: 2-73 days). Antigenemia and viremia were simultaneously positive in 61.5% of patients. In three patients a positive antigenemia preceded viremia by 14 days. In seven patients (26.9%) only the shell-vial culture was positive. Culture preceded antigenemia by a mean of 7.6 days. In the 26 patients, the time elapsed until the first positive blood specimen for CMV was 37.3 days (range: 11-88 days).

CONCLUSION

According to the results obtained we believe that blood (antigenemia pp65 and/or viremia) should be considered as the only really useful specimen for the diagnosis of infection/disease caused by CMV in RT recipients. The urine specimen lacks a diagnostic and clinical usefulness and therefore should not be used in these patients.

Renal graft rejection or urinary tract infection? The value of myeloperoxidase, C-reactive protein, and alpha2-macroglobulin in the urine

Previous investigations have shown that the determination of two acute-phase proteins in the urine, C-reactive protein (CRPu) and alpha2-macroglobulin (alpha2-MGu), allows a noninvasive diagnosis of acute renal graft dysfunction. A reliable differentiation between rejection and urinary tract infection can be made only when considering the C-reactive protein in serum and urine at the same time (CRPs:CRPu ratio). Therefore, a diagnostic procedure independent of parameters other than urinary proteins is needed. As granulocytes play only a minor role in graft rejection but are a common feature in urinary tract infection, we determined a marker of granulocytes (myeloperoxidase) in urine (MPOu). Eighty-nine renal transplant recipients were included in the study. In normal courses, CRPu, alpha2-MGu, and MPOu were within the normal range. In 15 cases of acute interstitial rejection, an increased excretion of CRPu and alpha2-MGu could be confirmed, but MPOu could not be detected. On the occasion of acute vascular rejection (n=6), with the exception of one case, MPOu could not be observed. The pattern of the three urinary proteins differed in urinary tract infections (n=40): MPOu could be detected in all cases, CRPu in 50% of cases, and alpha2-MGu in 73% of cases. In patients with cytomegalovirus infection (n=7), no MPOu, CRPu, or alpha2-MGu was found. In conclusion, the simultaneous measurement of the three proteins allows a complete, noninvasive, differential diagnostic procedure of renal graft dysfunction.

Quantity of cytomegalovirus viruria is a major risk factor for cytomegalovirus disease after renal transplantation

Studies have shown that risk factors for human cytomegalovirus (HCMV) disease after renal transplant include primary infection (virus of donor origin infecting a non-immune individual), re-infection (virus of donor origin infecting a immune individual), and the detection of viraemia (as a marker of virus dissemination). We now report that viral load in the urine is also a significant factor in HCMV disease and is one of the main mechanisms underlying the risk associated with viraemia and donor serostatus. Longitudinal analysis of a group of 196 renal recipient identified 35 recipients who were PCR positive for HCMV in urine. Elevated viral loads were present in symptomatic patients, viraemic patients, and patients experiencing primary HCMV infection. Disease was associated with the peak quantity of virus present in the urine during the post-transplant period (P = 0.0001), with viraemia (P = 0.0003), and with transplantation of a seropositive donor (P = 0.03). Univariate logistic regression analysis showed that increases of 0.25 log10 in viral load were associated with a 179% increased risk of disease (odds ratio = 2.79; 95% C.I. 1.22-6.39; P = 0.02). This effect persisted in a multivariate logistic analysis when viraemia was incorporated (odds ratio = 2.77; 95% C.I. 1.07-7.18; P = 0.04). In contrast, the significant association between viraemia and disease observed in univariate analysis (odds ratio = 23.75; 95% C.I. 3.69-152.90; P = 0.0009) became marginally non-significant in multivariate analysis once viral load had been controlled for (odds ratio = 34.54; 95% C.I. 0.75-1599.00; P = 0.07). The computed probability of disease showed that a rapid transition occurred at viral loads between 10(5.7) and 10(6.5) genomes/ml urine in non-viraemic patients compared to viral loads between 10(5.0) and 10(5.7) genomes/ml urine in patients with concurrent viraemia. The implications of these findings for understanding HCMV pathogenesis, improving patient management, and optimising trials of antiviral treatment are discussed.

The laboratory diagnosis of cytomegalovirus infections

Rapid and accurate diagnosis of cytomegalovirus (CMV) infection is imperative with the advent of effective antiviral therapy (gangiclovir, foscarnet, CMV hyperimmune globin). Applications of conventional cell culture (CC), shell vial assay (SV), serological testing, antigenemia assay (AG) as well as molecular methods [polymerase chain reaction (PCR), branch DNA (b-DNA) and hybrid capture (HC)] to various patient populations and specimen types are discussed. A three year study of 670 specimens [354 urines, 205 peripheral blood leukocytes (PBLs), 56 upper respiratory and 55 tissues] compared CMV CC and SV isolation rates. Of the total, 124 (18.5%) were positive by either or both techniques. For each specimen type the number of positives detected by SV was greater than CC (urine 28 vs 15, PBLs, 12 vs 2). However, of 124 positives, 21 were solely CC positive. A comparison of SV to AG in 230 PBLs yielded a sensitivity of 100% and specificity of 68.3%. The low specificity when compared to SV may be due to the increased sensitivity of AG. Fifty-nine PBLs were examined for differing immunostaining techniques [immunoperoxidase (IP) vs Immunofluorescence (IF)]. IF stained PBLs showed an increased number of positive cells per preparation and greater stain intensity for ease of interpretation.

Prenatal diagnosis of fetal cytomegalovirus infection in seropositive pregnant women

Thirty two pregnant women, immune to human cytomegalovirus (HCMV) before conception, were examined with a combination of amniocentesis, and blood sampling for fetal HCMV infection. The pregnant women had no history of recurrent infection and they all had normal ultrasonographic findings. Maternal sera and amniotic fluids were examined for anti-HCMV antibodies and viral DNA by enzyme immunoassay and polymerase chain reaction (PCR). All maternal sera were negative for viral DNA and IgM anti-HCMV antibodies. However, HCMV DNA was detected in the amniotic fluid of four pregnant women. These four cases were considered as fetal HCMV infections. Three of them were followed up after birth. The three neonates appeared clinically normal at birth, but HCMV DNA was detected in their urine specimens and in two of them in the cord blood sera. Although the neonates were asymptomatic at birth, the possibility of developing sequelae later on, cannot be excluded. The results show that HCMV recurrent maternal infection is silent and difficult to be suspected and diagnosed. They also show that fetal HCMV infection is not rare among pre-immune pregnant women.

Monitoring of cytomegalovirus infection and disease in bone marrow recipients by reverse transcription-PCR and comparison with PCR and blood and urine cultures

Preemptive therapy is a promising strategy for the prevention of serious cytomegalovirus (CMV) disease after bone marrow (BM) transplantation but requires relevant diagnostic tests. We compared the clinical value of a reverse transcription (RT)-PCR method, which detected a late viral mRNA in peripheral blood leukocytes (PBL), with a PCR method that detected the viral DNA in PBL and with viral culture from leukocytes and urine for the diagnosis of symptomatic CMV infection after BM transplantation. Forty-five consecutive BM recipients were prospectively tested at weekly intervals by the four methods. CMV infection, demonstrated either by the culture of CMV or by repeated detection of viral DNA, was observed in 28 patients, but only 14 developed CMV-related clinical symptoms. The clinical sensitivity and specificity of each technique for detection of symptomatic infection were, respectively, 36 and 74% for urine culture, 43 and 84% for leukocyte culture, 100 and 65% for PCR, and 71 and 94% for RT-PCR. Although PCR detection of DNA in PBL was the earliest and most sensitive technique for the diagnosis of CMV infection, RT-PCR was more predictive of the onset of CMV-related clinical symptoms. These data suggest that both molecular methods should be used for identifying BM recipients at highest risk of CMV disease.

Cytomegalovirus infections in Toronto child-care centers: a prospective study of viral excretion in children and seroconversion among day-care providers

OBJECTIVES

To prospectively determine the rate of cytomegalovirus shedding in children and the rate of seroconversion to cytomegalovirus in providers at 38 infant-toddler day care centers in Toronto, Canada.

METHODS

Urine was collected for shell vial assay in 471 children between the ages of 3 and 42 months. Providers (n = 206) were tested for the presence of cytomegalovirus antibody by latex agglutination. Of the 68 providers who were seronegative, 56 were retested approximately 1 year later.

RESULTS

Viruria was documented in 79 (17%) children and antibody in 67% of providers. Seropositivity was significantly related to country of birth outside Canada, presence of children at home < 5 years of age and increased household size. Seroconversion was documented in 12.5% (n = 7). Of these providers 71% worked at centers where workers never wore gloves for diaper changing vs. 33% of those who did not seroconvert (P = 0.06), and all were younger than 30 years vs. 59% of those who did not seroconvert (P = 0.04). In centers with viruria the association of seroconversion with lack of glove use was enhanced (P = 0.04). Seroconversion was marginally more likely in providers working with infants only than with infants and toddlers or with toddlers alone. Logistic regression confirmed that seroprevalence was more likely in providers who were born outside Canada, had children younger than age 5 years in the household and with an increased number of people in the household. Seroconversion was more likely if the provider worked at centers not using gloves for diaper changes, worked with infants only rather than with toddlers and infants and was < 30 years old, with each factor contributing independently to the model.

CONCLUSIONS

Cytomegalovirus infection is common in children and providers in Toronto day-care centers.

Time to detection of cytomegalovirus (CMV) DNA in blood leukocytes is a predictor for the development of CMV disease in CMV-seronegative recipients of allografts from CMV-seropositive donors following liver transplantation

In 35 cytomegalovirus (CMV)-seronegative recipients of livers from CMV-seropositive donors, 32 (91%) developed CMV infection and 24 of them (75%) experienced disease. Polymerase chain reaction for CMV DNA in leukocytes had the best positive and negative predictive values for the development of disease within 2 months from transplantation, and shell-vial or tube culture viremia was the best predictor thereafter. In patients who developed CMV disease, CMV DNA was first detected at 46 days (median; range, 13-128) after transplantation, significantly earlier than the 77 days (range, 46-174) for those who did not develop CMV disease (P = .02). By a semiquantitative method, the CMV DNA level in the first positive sample did not predict disease development. However, the maximum CMV DNA level during infection was significantly higher in patients who developed CMV disease. In CMV-seronegative recipients of livers from CMV-seropositive donors, the time to DNA positivity following transplantation may predict disease progression and be useful as a guide for the initiation of preemptive therapy.

Cytomegalovirus infection in human immunodeficiency virus type 1-infected children

BACKGROUND

Cytomegalovirus (CMV) is a frequent opportunistic infection in human immunodeficiency virus type 1 (HIV-1)-infected children. The interactions of CMV and HIV-1 in coinfected children are not well-characterized.

OBJECTIVE

To evaluate the prevalence of asymptomatic CMV infection and symptomatic CMV disease and to assess the influence of CMV on clinical and laboratory markers of HIV disease progression in CMV-coinfected children.

METHODS

Serial urine CMV cultures were performed on 500 children (131 HIV-1-infected (HIV+), 129 seroreverters born to HIV-infected mothers, and 240 HIV-uninfected (HIV-)). The clinical, immunologic and virologic data of 131 HIV+ children were analyzed.

RESULTS

CMV was recovered in 40 of 131 HIV+ (31%), 22 of 129 seroreverters (17%) and 30 of 240 HIV- (13%) children. Of the 40 HIV+ children with CMV coinfection, 7 developed symptomatic CMV disease (17.5%) including chorioretinitis (3), colitis (2) and pneumonitis (2). The HIV+ children with symptomatic CMV disease had significantly lower mean CD4+ T lymphocyte proportions (17% vs. 26%; age-adjusted P = 0.013) and greater HIV p24 antigen concentrations (329 pg/ml vs. 57 pg/ml; age-adjusted P = 0.13) than HIV+ children with asymptomatic CMV infection. In a subset of children coinfected with CMV before 6 months of age (n = 11), 5 (45%) developed symptomatic CMV disease, and 4 of these 5 children died within 10 months of diagnosis of CMV disease. At the time of the first positive CMV culture in these children, mean CD4+ T lymphocyte proportions did not differ according to the presence or absence of CMV-related symptoms (symptomatic CMV+, 21% vs. asymptomatic CMV = 38%; P = 0.14). In HIV+ children with symptomatic CMV disease, p24 antigen concentrations were greater than in those with asymptomatic CMV infection (461 vs. 190 pg/ml, P = 0.06).

CONCLUSIONS

Symptomatic CMV disease occurred in young CMV-coinfected children with low CD4+ lymphocytes and elevated HIV p24 antigen concentrations. Whether progressive immunodeficiency allows the emergence of CMV disease or CMV infection causes more rapidly progressive HIV-1 disease or whether there is a more complex relationship remains to be determined.

[Incidence of congenital cytomegalovirus infection in newborn infants of different socioeconomic strata]

Cytomegalovirus is the main agent of congenital viral infections. The aim of this study was to compare the incidence of congenital cytomegalovirus infections of two groups of newborns of differing socioeconomic status. Cytomegalovirus was isolated from urine or oropharingeal secretions in 218 children born in a private clinic and 471 born in a public hospital. Positive viral isolates were confirmed with indirect immunofluorescence using monoclonal antibodies. Infection was detected in 12 children (1.82%), four coming from the private clinic (1.86%) and 8 coming from the public hospital (1.81%). Ninety two percent of infected children were asymptomatic. Urine and oropharingeal secretion samples had the same yield for viral isolation. It is concluded that the incidence of congenital cytomegalovirus infection is similar to that described in developed countries.

Measurement of human cytomegalovirus-associated DNA polymerase activity in patient urine as a potential diagnostic tool

Virus-associated DNA polymerase activity has recently been proposed for the detection of human cytomegalovirus (HCMV) in urine, a method that should allow rapid and quantitative determination of the viral load. In this report, the virus-associated DNA polymerase activity recovered from the urine of a group of patients shedding HCMV was measured using a poly(dA) oligo(dT) 12-18 synthetic template after polyethylene glycol precipitation of the virions. Detection of virus-associated DNA polymerase activity was compared to the classical methods most widely used to diagnose HCMV shedding in urines such as virus culture followed by indirect immunofluorescence and pp65 gene-specific polymerase chain reaction. Although less sensitive than the polymerase chain reaction and cross-reactive with other herpesvirus DNA polymerases, the activity measured in the urine samples was correlated with the number of positive nuclei found in shell vials (r = 0.89). The diagnostic threshold of the assay could be placed between 50 and 100 fluorescent nuclei per shell with a diagnostic sensitivity of 56%. Being simple and quantitative, the measurement of virus-associated DNA polymerase activity could be of value in some clinical conditions where it is necessary to assess viral load in urine. This method is proposed as an alternative to more laborious quantitative assays and to support qualitative polymerase chain reaction.

Molecular epidemiology of cytomegalovirus infection in kindergarten children

This study was conducted to determine the source of cytomegalovirus (CMV) excretion in children who had persistent viruria. A total of 287 children, ages 3-5 years, enrolled in two kindergartens were followed for 9 months, and 28.8% of 139 CMV-infected children were found to have shed virus persistently in urine for > or = 3 months. A polymerase chain reaction (PCR)-based method provided direct evidence to demonstrate differences in CMV strains shed by 32 persistent shedders selected at random. The glycoprotein B (gB) nucleotide regions of CMV were amplified and analyzed by restriction enzyme digestion. The CMV strains shed by most of these children showed different restriction profiles compared with strains from their playmates. It is considered that persistent reactivation of endogenous CMV is the most plausible explanation.

Prolonged infection of mouse brain neurons with murine cytomegalovirus after pre- and perinatal infection

The susceptibility of mice at different developmental stages to a relatively low titer of cell culture-passaged murine cytomegalovirus (MCMV) infection was compared in terms of the urinary excretion of MCMV examined by plaque assay and in terms of the distribution of viral infection, determined by immunohistochemistry, using antibodies specific to the early nuclear antigen of MCMV. Viral infection on day 8.5 of gestation (E8.5) into the conceptus and intraperitoneal infection on day 15.5 of gestation (E15.5), postnatal day 2 (P2), postnatal day 11 (P11), and 30 days after birth (P30), respectively, were performed. Embryonal and perinatal mice were more susceptible to MCMV in terms of urinary excretion of the virus and the presence of viral antigen-positive cells in the brain, lungs, and kidneys. In the embryonal and perinatal infection, the viral antigen-positive cells in the neurons of the cerebral cortex and hippocampus were retained late after birth, even though the positive cells in the lungs and kidneys had disappeared. In the mice infected on E8.5, small clusters of viral antigen-positive cells were detected only in the cortex and hippocampus late after birth, without the urinary excretion of virus. These results suggest that when mice are infected with MCMV at the embryonal and perinatal stages, elimination of the infected neurons is delayed compared with that of the other cells in the lungs and kidneys. These findings provide a model for the analysis of pathogenesis of the subclinical congenital CMV infection that manifested clinically late after birth in humans as brain disorders.

Evaluation of antigen and antibody detection in urine specimens from children with congenital human cytomegalovirus infection

Fetal infection with human cytomegalovirus (HCMV) is the leading viral cause of brain damage among newborns at birth or later in life. Efforts to screen newborns routinely for shedding of the virus by immunoassay have been hampered by inhibitors in urine, reportedly the host protein beta2-microglobulin (beta 2m). An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of HCMV antigen in which the reactivity was not affected by the presence of beta 2m, but nevertheless inhibition was observed when urine samples with high levels of virus were tested. The presence of antibodies to HCMV was demonstrated in these urine samples by antibody ELISA and immunoblot using the major antigenic protein of HCMV (pp150) expressed in Escherichia coli; this offers an alternative explanation for the inhibition in ELISA. The presence of HCMV antibodies correlated significantly with congenital HCMV infection (as detected by tissue culture isolation of virus from urine samples of newborns), especially with asymptomatic cases (sensitivity 70%; specificity 94%). The data indicate a local (renal) immune response to HCMV in congenitally infected children, which may have future diagnostic applications.

Detection of cytomegalovirus using 'boosted' nested PCR

As a part of a study of an outbreak of CMV infections in a neonatal care intensive care unit, a modified nested PCR was developed for detection of CMV DNA in clinical specimens. Standard nested PCR involves a critical step; passage of PCR products from the first reaction round to the second round. We have adapted a 'boosted' nested PCR which implies amplification in one single step, thus reducing the contamination problems. Nasopharyngeal aspirates and urine samples from patients with perinatal CMV infections, breast milk from some of their mothers, amniotic fluids, urine samples and lymphocytes from seropositive healthy adults were examined by PCR and culture. In the total of 614 of clinical specimens, the PCR test yielded positive results in 51 samples from 14 patients, whereas CMV was isolated in 25 samples from 11 cases only. All samples from healthy individuals were negative. CMV DNA was detected in all culture-positive samples, but all samples from healthy adults were negative. 29/68 culture negative specimens were positive by PCR. No cross-reactivity to other herpes viruses or to human DNA was observed. Our findings show a high sensitivity and a high specificity of the 'boosted' nested PCR. We conclude that the described PCR method can be used for the rapid detection of CMV in clinical specimens with a greatly reduced risk of contamination, and it has proved to be a very useful tool in diagnostic work.

Multiplex polymerase chain reaction for human herpesvirus-6, human cytomegalovirus, and human beta-globin DNA

Human cytomegalovirus and human herpesvirus-6 are closely related viruses which cause similar diseases, have similar cellular repositories of latent infection, and may be detected largely in the same types of clinical specimens. DNA amplification appears likely to play an increasing role in the diagnosis of recent and remote infection with these agents. A sensitive multiplex polymerase chain reaction was therefore developed for the two viruses and for human beta-globin DNA. Optimization of parameters such as the primers, primer concentrations, magnesium concentration, and buffer constituents was crucial in achieving a sensitive assay. Preliminary results indicated that the assay could simultaneously monitor DNA extraction from clinical specimens and allow detection of HCMV or HHV-6 in patients with diseases possibly caused by either pathogen.

Optimization of PCR-based diagnostics for human cytomegalovirus

Various techniques of DNA template preparation for the PCR-based analysis of human CMV in biological fluids have been compared. Structural polymorphism of a CMV DNA segment (part of the major immediate early gene) in clinical isolates is described; the molecular markers (nucleotide substitutions, deletions, insertions) localized in the analyzed amplicon appear to be suitable for molecular-epidemiological studies. A scheme of spreading of the molecular markers in the population is suggested.

HIV-1 DNA in fibroblast cultures infected with urine from HIV-seropositive cytomegalovirus (CMV) excretors

Interactions between HIV-1 and CMV may be important in the pathogenesis of AIDS. We have studied whether active CMV infection alters the cell tropism of HIV-1 in dually-infected individuals. Urines from HIV-seropositive individuals excreting CMV were compared to urines from CMV non-excretors. Sixty-six urines from HIV-seropositive individuals were tested. Infectious HIV-1 was not detected in any of the concentrated urines tested. The urines were filtered, concentrated, DNase-treated and cultured on HIV-1 non-permissive human forestin fibroblasts. HIV-1 DNA was detected by PCR with pol gene primers in 5 of 39 MRHF cell cultures inoculated with CMV culture positive urine (p = 0.037). HIV-1 DNA was not detected by PCR in uninfected fibroblasts, in fibroblasts inoculated with CMV uninfected urine from 27 HIV-seropositive patients or in fibroblasts cultured with 9 CMV culture positive urines from 16 HIV-seronegative renal transplant recipients. Supernatant fluid from an HIV-1 PCR-positive culture was passaged onto another fibroblast monolayer, and these cells were negative for HIV-1 DNA. Direct inoculation of fibroblasts with HIV-1 did not yield evidence of infection by PCR. CMV infection may facilitate HIV-1 DNA entry into ordinarily non-permissive cells.

Failure of high-dose oral acyclovir to suppress CMV viruria or induce ganciclovir-resistant CMV in HIV antibody positive patients

Ninety-three symptomatic HIV antibody positive patients were randomized to receive zidovudine (ZDV) 600 mg/day and acyclovir (ACV) 4,800 mg orally per day versus ZDV 600 mg/day plus placebo. Urine was obtained at 3-month intervals and cultured for cytomegalovirus (CMV) in diploid fibroblast cells. The percent of urine specimens positive for CMV was 7.1% in the ZDV group and 5.8% in the ZDV plus ACV group (p = 0.55); 27% of patients had at least one urine culture positive for CMV while taking ZDV, versus 20% of patients taking the combination of ZDV plus ACV (p = 0.52). We conclude that ACV at a dosage of 4,800 mg/day does not suppress CMV excretion in urine of symptomatic HIV antibody positive patients taking concurrent ZDV. Use of ACV did not appear to induce resistance of CMV to ganciclovir since the ID50 of isolates from the two treatment groups did not differ.

Longitudinal analysis of cytomegalovirus load in renal transplant recipients using a quantitative polymerase chain reaction: correlation with disease

Serial surveillance samples of urine collected from 103 renal transplant recipients were analysed by polymerase chain reaction (PCR) for the presence of human cytomegalovirus (HCMV) DNA. The PCR results were consistently negative in 70 patients, none of whom developed HCMV disease, and PCR positive in 33 patients of whom 10 developed HCMV disease (P < 0.001). In 12 patients, PCR results were positive in three or more consecutive samples indicating extensive HCMV replication. HCMV load in 104 samples from these patients was analysed using a quantitative co-amplification PCR system. The maximal viral burden in the symptomatic patients ranged from 10(5.9) to 10(7.12) genomes/ml urine (median 10(6.5)) and in the asymptomatic patients from 10(4) to 10(5.7) genomes/ml urine (median 10(5.2)). The 10(1.3) difference between these median values was significant (P < 0.01). Individual kinetic profiles of viral burden showed that high levels of HCMV correlated with clinically apparent disease. In the majority of the asymptomatic individuals HCMV load remained between 10(4) and 10(5.1) genomes/ml urine; however, in two patients fluctuations in viral load were observed involving higher viral levels (up to 10(5.7) genomes/ml urine) suggesting that immune responses able to modulate viral replication could be studied in individual patients. Analysis of the temporal appearance and quantity of HCMV in the urine with alterations in white cell numbers showed that leukopenia occurred following the appearance of HCMV in the urine of symptomatic patients but preceded HCMV in the urine of asymptomatic patients (P = 0.01). Overall, these results show that longitudinal analysis using fully quantitative PCR methods for HCMV can provide insight into the natural history of HCMV disease in renal transplant recipients.

Humoral immune responses and cytomegalovirus excretion in children with asymptomatic infection

Forty-two seropositive children aged 3 to 5 years attending a kindergarten were followed up for 1 year in order to examine the relationship between humoral immunity and cytomegalovirus (CMV) excretion status. Anti-CMV antibodies were measured at the beginning and end of the study by enzyme-linked immunosorbent assay, neutralizing antibody test, and immunoblot techniques. Among these children, 32 persistently shed virus in urine, 2 intermittently shed CMV, and 4 experienced reactivation during the study. Virus was never isolated from 4 seropositive children. The level of anti-CMV IgG antibody in seropositive children who remained nonshedders was significantly higher than in children who shed virus during follow-up. On immunoblots, all seropositive nonshedders reacted to a CMV-specific 65 kD antigen, whereas most shedders (80%) did not. These findings suggest that humoral immunity plays a role in controlling persistent CMV infection in children with asymptomatic infection. However, the humoral immunity measured by the neutralizing test and the presence of antibodies against CMV-specific envelope antigens (116 kD/55 kD) apparently play a limited role in modifying persistent excretion and regulating reactivation of latent CMV. Immune evasion by CMV to block these antigens may explain these results.

Effects of enhancing agents on detection of cytomegalovirus in clinical specimens

Dimethyl sulfoxide, dexamethasone, and calcium were tested in combination for their enhancing effects on cytomegalovirus detection in shell vial cultures on 1,579 clinical specimens obtained primarily from adult solid-organ transplant recipients. Fluorescent-focus counts were elevated for the cytomegalovirus-positive urine specimens (P < 0.01) and throat washings (P < 0.05) but not for the tissue biopsy or blood samples. Epidermal growth factor also increased focus counts but provided no additional benefit when used in combination with the other agents. The triple-combination treatment did not increase the number of positive specimens identified.

Detection of human cytomegalovirus in urine of infants by polymerase chain reaction

Polymerase chain reaction (PCR), viral isolation and serological methods were used to diagnose HCMV infection in infants. Specimens of urine and clotted blood were collected from suspected cases of congenital or HCMV infection who attended the Pediatric Clinic, Siriraj Hospital. Prevalence of HCMV infection was found in 3 per cent of infants aged under 14 days and increased to 48 per cent in infants aged over 14 days. PCR was the most sensitive technique, it could detect HCMV infection in 29 per cent of the study infants, whereas, detection rate by isolation was 17 per cent and by specific IgM ELISA was 15 per cent. Sensitivity and specificity of PCR compared with isolation and/or serology were 93 per cent and 96 per cent, respectively. Detection of HCMV in urine by PCR can be used as a sensitive and rapid test for diagnosis of HCMV infection in infants.

[The optimization of the PCR for detecting cytomegalovirus in the urine of newborn infants]

A quantitative comparison of 4-primer PCR-diagnosticum potentials for detection of cytomegalovirus DNA in urine specimens in different methods for DNA isolation was carried out. Comparatively simple DNA isolation procedures were considered for express diagnosis in clinical conditions. A scheme of successive use of diagnostic preparations was proposed.

Impaired cell-mediated immunity to cytomegalovirus (CMV) in leukemic children with prolonged CMV viruria

To determine the role of cell-mediated immunity (CMI) to cytomegalovirus (CMV) in leukemic children after CMV infection, CMI to CMV antigen was studied using CMV-specific lymphocyte blastogenic responses (LBR) and interferon (IFN) production. Four children, who continuously secreted CMV in urine more than 2 years after symptomatic CMV infection (CMV disease) (group 1), showed impaired LBR to CMV antigen, though they had normal LBR to phytohemagglutinin (PHA) and concanavalin A (Con A). Impairment of LBR either to AD-169 strains or autologous and heterologous wild strains was observed. IFN production was not detected in three of four children. Six leukemic children, who had no viruria after cessation of CMV disease (group 2), showed good responses to CMV antigens. IFN was detected in all six children in group 2. Eight leukemic children, who were seropositive to CMV at the onset of leukemia (group 3), showed good responses to CMV antigens and IFN production. These results suggest that impaired cell-mediated immunity to CMV antigen might contribute to prolonged excretion of CMV in urine in leukemic children.

Low correlation of human cytomegalovirus DNA amplification by polymerase chain reaction with cytomegalovirus disease in organ transplant recipients

Seventy-five organ transplant recipients underwent prolonged virological and serological follow-up for early detection of human cytomegalovirus (HCMV) infection after transplantation. HCMV DNA detection by nested polymerase chain reaction (PCR) and HCMV early structural antigen (pp65) detection were carried out in 576 peripheral blood leucocyte (PBL) samples. Furthermore, 563 blood specimens were investigated by a commercially available enzyme-linked immunosorbent assay (ELISA) for the detection of specific immunoglobulins G, M, and A against HCMV structural antigens. In eight of nine symptomatic organ transplant recipients, HCMV DNA was detected in one or more consecutive blood samples. HCMV DNA PCR was also positive in one or more samples from eight patients who never developed HCMV-related symptoms. HCMV pp65 antigen was detected almost exclusively in PBL samples from organ transplant recipients suffering from HCMV disease. However, antigenaemia was not detected in four PCR positive patients presenting clinical signs attributable to HCMV infection. Two of the initially HCMV DNA positive samples were not confirmed by retesting and hybridisation. The results of the present study demonstrate that despite the high specificity of nested PCR, HCMV DNA may be detected in the absence of clinical symptoms attributable to HCMV infection. In asymptomatic reactivation, limited replication of viral DNA may be responsible for positive results of PCR without any clinical relevance. In this context, pp65-antigen detection from PBL seems to have a better prognostic value, but is not always detected when clinical symptoms are present.

Immune activation and enhanced urinary zinc concentrations in allograft recipients

OBJECTIVES

Zinc metabolism is frequently abnormal in renal allograft recipients. These abnormalities may be immune mediated because zinc metabolism is affected by inflammation.

METHODS

We determined urinary zinc and neopterin concentrations in 24 allograft recipients (18 kidney, 3 combined kidney-pancreas and 3 liver allografts) daily for 1-41 days. In addition, serum zinc concentrations were measured in 11 patients.

RESULTS

Serum zinc was decreased and urinary zinc concentrations were increased in kidney as well as liver transplant recipients when compared with healthy controls. Urinary zinc concentrations were only slightly elevated in patients with uncomplicated post-transplant course, but the increase was more pronounced in renal allograft recipients with acute tubular necrosis. Urinary zinc concentrations were drastically increased during rejection of various organs. In addition, significant associations between urinary zinc and neopterin concentrations were observed.

CONCLUSION

Our results suggest that enhanced urinary zinc excretion in allograft recipients is due to immune activation. The data indicate that cytokines play a role in zinc metabolism.

[Asymptomatic bacteriuria and pyuria during pregnancy]

BACKGROUND

The presence of pyuria and the role of mixed culture in the diagnosis of asymptomatic bacteriuria in pregnant women have been evaluated

METHODS

One hundred and sixty four pregnant women without any symptomatology have been studied using two cultures of mid-stream urine samples and pyuria quantification. In addition culture of bladder urine has been carried out in 17 of these patients (12 with pure cultures and 5 with mixed cultures).

RESULTS

110 samples were culture negative without pyuria; 7 were pure cultures with pyuria; 19 pure culture without pyuria and the remaining 28 patients yielded mixed culture with or without pyuria in the first culture. Twenty of these 28 mixed cultures were negative in the second culture. A estimated frequency of asymptomatic bacteriuria in pregnancy was 16% and pyuria was only found in 27% of pregnant women with asymptomatic bacteriuria.

CONCLUSION

The pyuria is not a useful marker for the diagnosis of asymptomatic bacteriuria in pregnancy.

Cytomegalovirus DNA polymerase activity and an 80 kDa-associated polypeptide: a potential diagnostic tool for CMV disease

CMV has been reported to be associated with a DNA polymerase activity (DPA). In this communication its purification, characterization and potential diagnostic value were examined. CMV DNA polymerase was prepared from cell free supernatants of CMV (AD 169) infected cultures. Separation and purification of the enzyme was accomplished by column chromatography of the purified, lysed virus. CMV DPA was measured on an oligo (dT)-poly (dA) template primer. SDS-PAGE and western blot analysis under reducing conditions using an anti-CMV early antibody showed an 80 kDa protein band that was associated with the peak of polymerase activity. However, CMV isolates and CMV from urines from CMV retinitis patients immunoblotted by the same Ab revealed 140 kDa and 80 kDa bands under non-reducing and reducing conditions respectively, the latter was also associated with a 58 kDa band. The diagnostic value of the CMV associated DAP was tested using CMV positive urines. The latter demonstrated high PAA-sensitive DPA activity, compared to normal, HSV positive urines and urines from HBSAg positive patients. Taken collectively, these findings indicate the potential usefulness of CMV-associated DNA polymerase activity in the diagnosis and follow-up of patients with CMV-related illnesses.

The prevalence of type 1 diabetes mellitus at follow-up of Swedish infants congenitally infected with cytomegalovirus

In a Swedish prospective study of congenital cytomegalovirus (CMV) infection, 76 infants were shown to be infected among 16,474 newborns screened by virus isolation in urine. Seventy-three of the excreters were followed up and one developed Type 1 diabetes, as compared to 38 of the 19,483 children born during the same period (p = 0.14, Fisher's one-tailed test). Thus we found no evidence that the combined finding of congenital CMV infection and Type 1 diabetes mellitus was related.

Interleukin-6 and neopterin in renal transplant recipients: a longitudinal study

Serum and urine interleukin-6 (IL-6) levels and serum neopterin/creatinine ratios were longitudinally studied in 86 renal transplant recipients until 4 months after transplantation. During acute rejection and acute tubular necrosis (ATN), serum and urine IL-6 levels were elevated compared to during stable transplant function (P < 0.001). During acute rejection, serum IL-6 levels increased at least 2 days before plasma creatinine started to rise (P < 0.05), indicating its early involvement in the rejection process. During cytomegalovirus (CMV) disease, serum, but not urine, IL-6 levels were higher (P < 0.01), and serum neopterin/creatinine values were higher than during stable transplant function, ATN, or acute rejection (P < 0.01). No significant differences with stable transplant function occurred during cyclosporin A toxicity. Measurement of serum IL-6 provided a sensitivity of 84% and a specificity of 85% for the diagnosis of acute rejection episodes not coinciding with ATN. All cases of CMV disease could be diagnosed by measurement of serum neopterin/creatinine, which provided a specificity of 73%.

Cytomegalovirus transmission in special-care centers for mentally retarded children

This study aimed to determine whether special-care centers for mentally retarded children are high-risk settings for cytomegalovirus (CMV) transmission. Serum and urine specimens obtained from 311 mentally retarded children aged 3 to 12 in three centers were compared for CMV seropositivity and CMV viruria with specimens from 360 normal children of the same ages. A seropositivity rate of 73.5% and a viruria rate of 8.7% were found among the children attending special-care centers. These rates were significantly higher than the 59.2% seropositivity and 1.7% viruria found among normal children. By logistic regression analysis, it was shown that the prevalence of CMV viruria in the class/center was one of the most important determinants for acquiring CMV infection. The data suggest that acquisition of CMV from playmates or classmates occurs frequently in special-care centers and that horizontal transmission of virus is the most plausible explanation for the higher prevalence of CMV infection among mentally retarded children.

Influence of human cytomegalovirus on immune reconstitution after bone marrow transplantation

HCMV infection diagnosed by the highly sensitive polymerase chain reaction (PCR) technology in blood, urine and skin biopsies of patients after bone marrow transplantation (BMT) correlated with the reconstitution of peripheral blood lymphocytes and dermal immunohistological alterations to evaluate the interaction of viral infection with the recovery of the immune system, as well as with the induction or aggravation of graft-versus-host disease (GVHD). In a prospective study 73% of 63 patients showed viremia at a median time of 25 days after BMT. Only 44% of these cases that also presented with a higher frequency of acute GVHD symptoms developed HCMB disease later on. In the skin, similar immunohistological alternations, as well as frequent primary local HCMV infection before the development of cutaneous signs of GVHD, was found, suggesting the direct involvement of anti-HCMV immune responses in the induction of GVHD-associated organ lesions.

Detection of cytomegalovirus in urine samples by an enzyme-linked immunosorbent assay using a monoclonal antibody against the viral 150-kilodalton protein

McKeating et al. (J.A. McKeating, P.D. Griffiths, and J.E. Grundy, J. Gen. Virol. 68:785-792, 1987; J. A. McKeating, J. E. Grundy, Z. Varghese, and P. D. Griffiths, J. Med. Virol. 18:341-348, 1986; J. A. McKeating, S. Stagno, P. R. Stirk, and P. D. Griffiths, J. Med. Virol. 16:367-373, 1985) reported previously that beta 2 microglobulin inhibits the detection of human cytomegalovirus (CMV) in urine specimens by an enzyme-linked immunosorbent assay (ELISA) with a monoclonal antibody against the glycoprotein of CMV. They postulated that beta 2 microglobulin binds to the viral glycoproteins and masks the antigenic determinants. We developed here an ELISA method for the detection of CMV in urine by using a monoclonal antibody against the viral 150-kDa protein to capture the viral antigen. This assay detected CMV both in culture medium and in urine specifically at concentrations higher than 10(3) PFU/ml and quantitatively at concentrations higher than 10(4) PFU/ml. The sensitivity of the ELISA increased about 10-fold when peroxidase-labeled F(ab')2 from goat anti-human immunoglobulin G was used as a secondary detecting antibody in combination with concentration of the virus in urine samples by ultracentrifugation. The inhibition of ELISA by beta 2 microglobulin was not observed in this ELISA system. When 56 urine specimens from renal transplant recipients were examined for CMV antigens, the ELISA system had a sensitivity of 78% and a specificity of 97%. The positive and negative predictive values of the assay were 95 and 86%, respectively. Furthermore, CMV antigens in urine were quantitated by the assay during the course of typical CMV disease of renal transplant recipient. These results suggest strongly that the measurement of CMV antigens in urine by our rapid and quantitative ELISA system provides very useful data for the monitoring of CMV infections in renal transplant recipients and making decisions about therapy.

Detection of human cytomegalovirus in peripheral mononuclear cells and urine samples using PCR

Samples of peripheral blood lymphocytes from 105 different blood donors were investigated for the presence of human cytomegalovirus (HCMV) DNA using the polymerase chain reaction (PCR) with primers specific for the Pst I w fragment (IE region). Viral DNA sequences were detected in 53 samples, a fifth of which had been previously serotyped as HCMV negative. In the latter cases, Western blot analysis re-determined two out of three individuals that were resampled as seropositive. PCR could therefore be used to extend existing methods employed for the identification of HCMV infected blood samples prior to transfusion to individuals in high risk groups. In addition, the value of PCR as a diagnostic test was evaluated in a small pilot study by comparing the results obtained with urine samples from babies suffering congenital infection and from other high risk patients, with data obtained by isolation of infectious virus or through the detection of immediate early antigens in infected cultures. Data from this study indicated that PCR is at least as sensitive as the other methods used in HCMV diagnosis.

Detection of cytomegalovirus in urine of HIV-infected patients by DNA-DNA hybridization comparison with virus isolation, immunofluorescence and immunoperoxidase

Immunofluorescence and immunoperoxidase test directed against early viral antigens, and DNA-DNA hybridization were compared with viral isolation for their abilities to detect Cytomegalovirus (CMV) in the urine of 89 HIV infected patients. From the 100 urine samples collected, 70 were found positive by at least one method. Considering viral isolation as the "gold standard" technique, immunofluorescence and immunoperoxidase had a sensitivity of 92.3% and 88% respectively, with a specificity in both cases of 95%. DNA-DNA hybridization showed a sensitivity of 90% but with lower (60%) specificity. All of the three assays were effective in detecting CMV from urine and the technical advantage of each is discussed.

Improved amplification of cytomegalovirus DNA from urine after purification of DNA with glass beads

Cytomegalovirus can be detected in a variety of specimens including leukocytes, urine, saliva, feces, and various tissues by polymerase chain reaction (PCR) amplification of viral DNA. Although methods for amplification are fairly standard, sample preparation is not well characterized, especially for tissue. Typically, preparation of samples for PCR amplification ranges from simple boiling to phenol/chloroform extraction and quantification before testing. Several reports have described inhibition of the PCR in some samples types. Here we show that reliable detection of cytomegalovirus DNA in urine is obtained only after some degree of DNA purification, presumably because of PCR inhibition by a yet unidentified component present in a few of the urine samples tested. Glass, in the form of fine beads, was used to adsorb DNA such that protein and other substances could be selectively eluted before the recovery of DNA for PCR amplification. Urine samples prepared by this method did not show inhibition, and results correlated well with those by tissue culture for detection of cytomegalovirus.

[Detection of cytomegalovirus in urine by the shell-vial technique: usefulness of diluting the sample]

To assess the toxicity of urine samples on human fibroblast cell monolayer using Shell-vial technique for cytomegalovirus antigen detection. A total of 227 urine samples were processed, inoculated on Shell-vial simultaneously, being either diluted (1:1) and non diluted in transport media. After 24-48 hours incubation, the fibroblast cells monolayer was stained using fluorescein-marked monoclonal anti-cytomegalovirus antibodies. Cytomegalovirus was detected in 9.6% of samples inoculated with diluted urine, and in 5.2% of samples inoculated with non-diluted urine. Destruction of monolayer cells was seen in 13.2 and 22.4, respectively. With Shell-vial technique for detecting cytomegalovirus in urine samples, a high number of positive results was obtained using diluted urine. Also a significant minor destruction of cells monolayer was observed with the same inoculum.

Antigenemia in the diagnosis and monitoring of active cytomegalovirus infection after liver transplantation

In 45 liver transplant recipients, the value of weekly monitoring of cytomegalovirus (CMV) antigenemia for early diagnosis of active CMV infection was compared with serology and rapid viral isolation. Active CMV infection occurred in 23 patients. The sensitivities of the antigenemia assay and serology (of blood) and rapid viral isolation (from blood or urine) were 96%, 96%, 57%, and 70%, respectively. First diagnostic results of these methods were obtained a median of 25, 36, 31, and 49 days, respectively, after transplant. CMV infection was symptomatic in 20 patients; antigenemia was present at the onset of disease in 13 of these. Maximum CMV antigenemia levels were higher in patients with severe disease than in those with mild or asymptomatic infection. CMV antigenemia is a sensitive, early, quantitative marker of active CMV infection after liver transplantation.

[Infection by cytomegalovirus in patients with acquired immunodeficiency syndrome (AIDS): clinical, virological, and histopathological correlations]

Between April 1986 and June 1987, 50 patients meeting the CDC criteria for AIDS were studied for serological and virological evidence of CMV infection. Attempts for virus isolation from peripheral blood, urine and saliva were performed in cell culture lines of human foreskin fibroblasts and CMV specific IgG and IgM were assayed by IFI and IgG by ELISA. A total of 121 blood, 119 urine and 96 saliva samples were collected. During the study period viremia was noted at least once in 12.5%, viruria in 23.2%, and excretion in saliva in 21.9%. When admitted in the study, 20% (10/50) of the patients had anti-CMV IgM antibodies and 100% (50/50) of them had IgG anti-CMV antibodies (IFI). Five of the 40 patients IgM negative at admission presented anti-CMV IgM antibodies during the study, suggesting CMV reactivation or reinfection. Active CMV infection based on virus isolation and/or IgM positivity was demonstrated in 60% of the patients. Histopathological studies were performed in 24 patients. CMV was found in 50% of the autopsies, mainly in the digestive system, lungs and adrenals. There was no correlation between clinical, virological (serology and isolation) and histopathological diagnosis.

[Beta 2-microglobulinuria in cytomegalovirus infections following kidney transplantation]

In a prospective study the occurrence of cytomegalovirus (CMV) infection was diagnosed by demonstrating CMV-immediate early antigen (IEA) in the blood in 13 out of 68 (19%) patients who had undergone renal transplantation (27 women, 41 men, mean age 46.3 [21-64] years). Twenty-four hour urine samples were collected at the same time for quantitative determination of selected marker proteins by immunoluminometric assays (IgG and transferrin as glomerular markers, alpha 1-microglobulin and beta 2-microglobulin as tubular markers). In all 13 confirmed cases of CMV infection there was an isolated rise in urinary beta 2-microglobulin excretion amounting to more than three times the normal. In 11 of the 13 cases the beta 2-microglobulinuria was noted before the CMV-IEA test became positive. This suggests that quantitative assay of beta 2-microglobulin in the urine may be of value in the early diagnosis of CMV infection--a matter of some prognostic importance--and may hence offer additional support for therapeutic decisions.

[Detection of cytomegalovirus by the immunoperoxidase technique and viral isolation]

An Immunoperoxidase assay was applied to detect early antigens of cytomegalovirus (CMV) in 150 urine samples from immunocompromised patients, using the commercial available monoclonal antibody against CMV E13. The detection of early antigen by IP (IPCMV) is compared to the conventional cell culture isolation regarding specificity and sensitivity in order to evaluate is usefulness in the diagnostic of CMV infections. The IPCMV showed a sensitivity of 89.8% and a specificity of 91.3% when compared to the isolation method. The great advantage of the IPCMV is based on the shorter time results are achieved, since 48-72 Hs can be enough to provide evidence of CMV infection, while in the isolation technique cytopathogenic effect was present around 14 days after sample inoculation.

Inhibitory effects of urine on the polymerase chain reaction for cytomegalovirus DNA

The inhibitory effects of urine samples taken from neonates and older children, some of which were known to be infected with cytomegalovirus, on the polymerase chain reaction (PCR) were investigated. Urea was the major inhibitory component of urine and inhibited the PCR at a concentration of more than 50 mM. Urine samples from older children were more inhibitory than those from neonates. This correlated with the higher concentration of urea generally found in urine samples from older children compared with neonatal urines. Two of 13 neonatal urine samples, however, were inhibitory despite low urea concentrations--presumably due to metabolites derived from parenteral nutrition. The inhibitory effects of urine were effectively removed by simple dialysis or ultrafiltration. The sensitivity and specificity of PCR for detecting cytomegalovirus DNA in urine were further improved by using "nested" primers and a modified PCR protocol entailing the use of reduced reactants in the first 20 cycles of a two-stage 50 cycle PCR.

Detection of cytomegalovirus by the polymerase chain reaction. A simple, rapid and sensitive non-radioactive method

Cytomegalovirus (CMV) is an important pathogen in persons who are immunocompromised or who have received organ transplants. The rate of symptomatic CMV infection is relatively higher after liver transplantation, and CMV hepatitis may be difficult to differentiate from rejection or cholangitis without recourse to liver biopsy and tissue culture. In this study we have used the polymerase chain reaction (PCR) to amplify and detect CMV-DNA sequences directly from the saliva and urine of liver transplant recipients. The procedure is simple, rapid and specific, and was found to be as sensitive as tissue culture for the diagnosis of CMV.

Optimizing recovery of cytomegalovirus in the shell vial culture procedure

We have investigated three factors that may be related to the recovery of cytomegalovirus (CMV) using the shell vial culture procedure. First, we compared fluorescent-antibody staining of shell vial cultures using a monoclonal antibody to a CMV immediate early antigen at 16 vs 40 hr after inoculation. Of 332 routinely submitted specimens cultured in duplicate and stained at the different times, 25 (7.5%) were positive at 16 hr and 32 (9.6%) were positive at 40 hr. The increased yield was 28%. Second, we analyzed the effect of using duplicate shell vials (both stained at 40 hr) for all routinely submitted CMV cultures. During a 6-month period, 272 (12.5%) of the 2157 cultures processed with duplicate shell vials were positive, including 222 positive in both vials and 50 positive in only one. Assuming that a single-vial setup would have detected 50% of those positive in only one of the two vials, the increased yield attributable to the duplicate vial was estimated at 10% (25/(222 + 25)). Third, we investigated the effects of seeding density and culture age on the shell vial assay. Cell age of greater than 1 day was associated with a decrease in sensitivity both in cultures that were confluent and in those that were subconfluent at the time of inoculation. Incorporating these findings in the routine shell vial culture procedure used in our Clinical Virology Laboratory has resulted in a greater overall detection of CMV in shell vial cultures than in conventional 6-week tube cultures.