Cell-mediated immunity of cytomegalovirus infection in normal subjects and cardiac transplant patients.

Two assays of cell-mediated immunity, lymphocyte transformation and interferon production, were adapted to test for specific immunity to cytomegalovirus (CMV). Normal individuals seropositive for CMV had a mean transformation index of 7.9 in response to antigen of the Davis strain of CMV, whereas all of 14 seronegative normal individuals had transformation indexes of less than or equal to 3.0. Interferon production in seropositive and seronegative individuals was not statistically different. One to two months after CMV mononucleosis (after the termination of viruria), normal individuals had increased transformation indexes. Recipients of cardiac transplants within six months after transplant had normal levels of antibody to CMV; lymphocyte transformation and interferon production in these subjects were markedly decreased and returned to normal by three years and between one and three years after transplant, respectively. A syndrome of unexplained fever, hepatitis, pneumonitis, leukopenia, and atypical lymphocytes was common in a group of recipients with primary CMV infection. Shedding of virus was frequent in these symptomatic patients and in patients with repeat infection during the first three years after transplant. These assays appear to identify periods of immune deficits correlating with increased incidence of infection with CMV.     

Group day care and cytomegaloviral infections of mothers and children

Cytomegalovirus (CMV), the leading cause of congenital viral infection, occurs commonly among children in group day care. Urinary or salivary excretion of CMV was found frequently among children in three centers serving mostly middle-income white families. Although there was center-to-center variation, CMV excretion was uncommon among infants under one year of age; peak rates of viral shedding, ranging from 44% to 100%, were noted for two-year-olds. A longitudinal study at a single center indicated that children usually acquired CMV during their second year of life and usually shed virus for two years or longer. The high prevalence of silent CMV infection among the children in day care argues against the exclusion of any child known to have CMV infection; such children have sometimes been excluded because of the potential risk of CMV transmission to pregnant workers.     

Complications of infections attributed to cytomegalovirus in a group of 52 kidney transplant patients

Cytomegalovirus (CMV) infection after renal transplantation was studied over a one year period in 52 patients receiving immunosuppressive drugs. During the infectious episodes, viral shedding was systematically detected in the blood and urines by culture on MRC5 cells and CMV antibodies were titrated in the serum by ELISA (IgG: M. A. Bioproducts, IgM: immunocapture Wellcome) and compared to the initial antibody titer determined the day of transplantation. Primary CMV infection was observed in 6 of 22 seronegative patients, attested by CMV shedding from urine and/or blood and by the emergence of CMV IgM antibodies. This primary infection was severe, including at least 4 of the following features: fever greater than 38 degrees C, neutropenia, thrombocytopenia, cytolytic hepatitis, pneumonia, impaired renal function, neurological syndrome, usually occurring about 6 weeks after transplantation. Reactivation was found in 12 of 30 seropositive patients, as shown by excretion of CMV in the urine and significant rise of specific antibodies. This reactivation occurring about 9 weeks after surgery was symptomatic in 5 patients with severe illness and associated with the presence of IgM antibodies in 2 cases. Rise of CMV antibodies was observed in 10 seropositive patients without excretion of virus. It coincided with symptomatic infection in only three patients who displayed severe symptoms, with presence of CMV IgM antibodies in one case. As previously reported, we confirm that CMV infection is a frequent complication of organ transplantation. It may be clinically silent in renal transplant patients or cause problems ranging from fever to pneumonia or retinitis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Productive infection with cytomegalovirus and herpes simplex virus in renal transplant recipients: role of source of kidney.

Forty patients were prospectively studied for infection with cytomegalovirus (CMV) and herpes simplex virus (HSV) after renal transplantation. Although 85% had antibody to CMV and 95% had antibody to HSV prior to transplantation, excretion of CMV was found in 92.5%, usually as viruria, and HSV was recovered from 70%, most often from the oropharynx. Shedding of HSV reached a peak within the first month after transplantation when immunosuppression was most intense and then rapidly declined. In contrast, excretion of CMV was found in a greater proportion of patients during each interval up to about six months after transplantation and subsequently persisted in the majority of patients. Both serologic responses and viral isolation rates indicated more rapid activation of CMV but not of HSV in recipients of kidneys from cadavers than in patients who received kidneys from living related donors. At 60 days after transplantation, 76% of the recipients of kidneys from cadavers and only 33% of the recipients of kidneys from living, related donors had shed CMV (P = 0.003). These differences could not be accounted for by immunosuppressive treatment. Excretion of HSV was clearly associated with the time of most intense immunosuppression, but the major factor in initiation and maintenance of productive infection with CMV appeared to be the host vs. graft reaction.     

Comparative serial virologic and serologic studies of symptomatic and subclinical congenitally and natally acquired cytomegalovirus infections.

Infants with congenitally (38) and natally (17) acquired cytomegalovirus infection were prospectively studied by means of virologic and multiple serologic assays. These infections were characterized by chronic viral excretion (measured in years). The quantity of virus excreted in the urine during early infancy was significantly greater in infants who acquired infection in utero, particularly amon those born with overt disease; thereafter, all three groups (congenital symptomatic, congenital asymptomatic, and natal) excreted similar amounts of virus. The patterns of antibody responses, particularly the fluorescent antibody response to the early antigen and the complement-fixing antibody response, further indicated that congenitally infected infants (especially symptomatic ones) bear a greater antigenic burden than do natally infected infants. From a diagnostic standpoint, the test for fluorescent antibody to the late antigen was the most sensitive assay, whereas the test for complement-fixing antibody proved to be the least useful, The indirect hemagglutination assay, although performed only in infants with natal infection, was only slightly less sensitive than the fluorescent antibody procedure; by the former technique, diagnostic rises were detected in all but one infant after the onset of viruria.     

Specific cell-mediated immunity in children with congenital and neonatal cytomegalovirus infection and their mothers.

Cell-mediated immunity (CMI) to cytomegalovirus (CMV) and herpes simplex virus type 1 (HSV-1) was examined in 35 mothers and 30 of their offspring with congenital or neonatal CMV infection by means of the lymphocyte transformation assay. Eleven offspring did not respond to CMV antigen, and 15 of the 19 positive children displayed lower responses than those of normal immune adults. Productive infection in the younger children at the time of assay and the presence of disease correlated strongly with the absence of responses. The mothers as a group also demonstrated impaired CMI to CMV while reacting normally to HSV-1 antigen. Neither time after transmission of infection nor viral excretion was significantly associated with impaired CMI, although a trend toward diminished responses was evident among women who were shedding virus. Mitogen stimulation was normal in all test subjects. These findings imply that deficient specific CMI may play a role in the genesis of persistent CMV infection and fetal pathology.     

Comparison of culture and serology for the diagnosis of cytomegalovirus infection in kidney and liver transplant recipients

This study compared culture, including the shell vial procedure, with serology, including IgM cytomegalovirus (CMV) antibody testing, for the diagnosis of CMV infection in 42 subjects undergoing cadaveric renal or liver transplantation. Of 35 subjects who developed active CMV infection, 31 had positive cultures, while IgM CMV antibodies were detected in 29. Subjects with symptomatic CMV infection were more likely than asymptomatic subjects to have positive cultures of leukocytes (17/18 vs. 9/17, P = .01). In contrast, symptomatic and asymptomatic subjects did not differ in their IgG or IgM CMV antibody test responses. In subjects with symptomatic infection, viral shedding typically began early in the course of infection, often preceding symptoms, while the serologic response usually followed the appearance of symptoms. With the use of the shell vial procedure to facilitate detection of positive cultures, symptomatic CMV infections following kidney or liver transplantation can be recognized earlier and more reliably using viral culture than by serologic testing.     

Specific cell-mediated immunity and infections with herpes viruses in cardiac transplant recipients

Immune responses and infections with herpes viruses were studied prospectively in 36 cardiac transplant reclpients. Specific lymphocyte transformation and interferon production in response to viral antigens, viral culture results, antibody levels, responses to phytohemagglutinin, and T-cell numbers were determined. Responses to phytohemagglutinin and T-cell numbers were depressed for six to 12 weeks. Cytomegalovirus infection occurred in 100 percent of seropositive patients and in 62 percent of seronegative patients. Primary infection was more frequently symptomatic. Heart implantation from a seropositive patient was significantly correlated with subsequent infection in seronegative patients. Depression of transformation in response to cytomegalovirus correlated with prolonged shedding. Herpes simplex infection occurred in 95 percent of seropositive patients but decreased after 12 weeks. Asymptomatic shedding was rare, and primary infection did not occur. Return of transformation in response to herpes simplex was associated with decreased Infection. Herpes zoster occurred in 22 percent during the first year, and transformation responses to varicella-zoster returned thereafter. Depression of interferon production in response to viruses did not correlate with infection as well as did lymphocyte transformation.     

Virus-specific IgG and IgM antibodies in normal and immunocompromised subjects infected with cytomegalovirus

Levels of IgG and IgM antibodies t human cytomegalovirus (CMV) were measured using a solid-phase radioimmunoassay. Individuals positive by complement-fixation test consistently had detectable IgG titers by radioimmunoassay, but no quantitative relationship was apparent. An elevated IgM titer was considered specific for CMV infection because sera from individuals with other herpesvirus infections did not cross-react. In patients with mononucleosis, elevated titers of IgM antibody to CMV correlated (P less than 0.001) with active infection and were highest during viremia. Titers of IgG antibody to CMV during and after symptomatic infection were similar to those of asymptomatic positive individuals. Increases in CMV-specific IGM were observed in both primary and reactivated infections in cardiac transplant recipients. In a small group of cardiac transplant recipients with recurrent symptomatic disease, IgM titers were low at the time of viruria and did not increase with CMV tissue involvement, a result which suggests that quantitative deficiencies in IgM may be related to the severity of CMV infections.     

Cytomegalovirus in the lungs of patients with AIDS. Respiratory pathogen or passenger?

A total of 166 consecutive clinical episodes of pneumonitis in patients with acquired immune deficiency syndrome (AIDS) or antibody positive for human immune deficiency virus (HIV) were investigated for evidence of cytomegalovirus (CMV) infection in their lungs and at peripheral sites to determine the pathogenicity of this virus in the lung and its relationship to peripheral CMV shedding. Evidence of CMV infection was sought in bronchoalveolar lavage (BAL) fluid, blood, saliva, and urine using a specific monoclonal antibody to antigens produced by CMV-infected cells within 24 h. Although CMV was detected in 31 (19%) of BAL fluid specimens, in only six episodes was this the sole pathologic finding. In the remaining episodes either another infectious agent, Kaposi's sarcoma, or lymphoid interstitial pneumonitis was found or no pathogen was detected. None of the patients were given specific anti-CMV treatment, and all but two recovered, including those patients in whom CMV was the sole finding at BAL. The presence of peripheral shedding of CMV did not have any significance in mortality or morbidity. Our findings are in direct contrast to those in recipients of allogeneic bone marrow transplants, in whom CMV pneumonitis is associated with a high mortality. We postulate that this difference is because AIDS patients cannot mount the destructive immune response to CMV in the lung, which we believe to be the basis of the pathology seen in the former group. We conclude that CMV is not a pathogen in the lungs of patients with HIV infection, and we suggest that its presence at this site does not warrant specific therapy in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cytomegalovirus infection and specific cell-mediated immunity after marrow transplant

Patients were studied prospectively after marrow transplant to correlate cytomegalovirus (CMV) infection with the in vitro lymphocyte transformation response to CMV antigen. Ninety-two (58%) of 158 patients developed CMV infection. The lymphocyte response to CMV antigen of patients who were seropositive before transplant was significantly suppressed immediately after transplant. Isolation of CMV was associated with further suppression of responses; seroconversion to CMV was associated with a significant increase. The lymphocyte response of 73 long-term survivors was similar to that of normal persons. The presence of antibody to CMV in the donor before transplant had little effect on the lymphocyte response of patients after transplant even though the patients' lymphocyte s were of donor origin. As in previously reported studies of immunity to other herpesviruses after marrow transplant, it was concluded that recovery of the response to CMV antigen is related primarily to active virus infection and not to patient or donor pretransplant immunity.     

Antibody response to cytomegalovirus after renal transplantation: comparison of patients with primary and recurrent infections

The specific antibody response of 22 renal transplant patients with primary cytomegalo-virus (CMV) infection was compared to that of 21 patients with recurrent infection using seven different techniques to measure antibody. With primary infection seroconversion occurred between two and 12 weeks postoperatively, and geometric mean titers increased rapidly during this interval with each test except virus neutralization. In the group with recurrent CMV infection, geometric mean titers declined slightly initially and then increased rapidly to reach peak levels by 10 weeks. In both primary and recurrent infections, IgM antibody was detectable by radioimmunoassay and indirect immunofluorescence; the former procedure was clearly the more sensitive. After absorption to remove rheumatoid factor, 20 of the 22 patients with primary infection and eight of the 21 with recurrent infection had IgM antibody to CMV by radioimmunoassay which often persisted for over six months. The former group had significantly more viremia and symptomatic infections than the latter. Two critically ill patients failed to develop IgM or neutralizing antibody.     

Asymptomatic primary cytomegalovirus infection: virologic and immunologic features.

We followed 45 seronegative adolescents for acquisition of cytomegalovirus (CMV); 6 (5 female, 1 male) seroconverted after a median of 7.5 months. All were free of signs and symptoms. CMV was isolated from 32 (59.2%) of 54 urines, 2-80 weeks after infection; viruria was less frequent after 6 months. CMV was isolated from saliva of 3 subjects, vaginal swabs of 2 of 5, and 1 white blood cell (WBC) sample. CMV DNA was detected by polymerase chain reaction in WBCs and plasma from all subjects tested. The proportion of WBC samples with CMV DNAemia was 75%-80% within 16 weeks of infection, declining to 0%-25% after 48 weeks. The rate of plasma DNAemia was 25%-40% at 8-16 weeks, declining with time. IgG antibody to CMV, glycoprotein B (gB), and neutralizing antibody were present after 6-8 weeks. Lymphocyte proliferative responses to CMV and to gB were low, compared with those of controls. CMV shedding was of shorter duration than expected. Although antibody response was prompt and vigorous, CMV DNA could be detected in blood for months.     

Virological and immunological correlates of mother-to-child transmission of cytomegalovirus in The Gambia

BACKGROUND: Cytomegalovirus (CMV) is the most common congenital infection and can follow primary and recurrent maternal infection. We studied correlates of vertical transmission of CMV in The Gambia, where most children acquire CMV during the first year of life. METHODS: A cohort of 281 mothers and infants was recruited at birth. Infants were prospectively followed up for CMV infection during the first year of life. Excretion of CMV and antiviral immune response were studied at birth in mothers of children infected in utero, early during infancy, or late during infancy or not infected at 1 year of age. RESULTS: Congenital infection was diagnosed in 3.9% of newborns, and 85% of children were infected by 1 year. Excretion of CMV in colostrum or in the genital tract was more common in mothers of congenitally (100%) or early infected children (48%) than in mothers of late-infected (20%) or uninfected children (27%). Higher rates of viral excretion were associated with significantly higher levels of serum anti-CMV immunoglobulin G and higher frequencies of CMV-specific CD4+ T cells. CONCLUSION: In the context of recurrent maternal infection, transmission of CMV in utero and during early postnatal life is associated with excretion of the virus in colostrum and the genital tract.     

A Fully Protective Congenital CMV Vaccine Requires Neutralizing Antibodies to Viral Pentamer and gB Glycoprotein Complexes but a pp65 T-Cell Response Is Not Necessary

A vaccine against congenital cytomegalovirus infection is a high priority. Guinea pig cytomegalovirus (GPCMV) is the only congenital CMV small animal model. GPCMV encodes essential glycoprotein complexes for virus entry (gB, gH/gL/gO, gM/gN) including a pentamer complex (gH/gL/GP129/GP131/GP133 or PC) for endocytic cell entry. The cohorts for protection against congenital CMV are poorly defined. Neutralizing antibodies to the viral glycoprotein complexes are potentially more important than an immunodominant T-cell response to the pp65 protein. In GPCMV, GP83 (pp65 homolog) is an evasion factor, and the GP83 mutant GPCMV has increased sensitivity to type I interferon. Although GP83 induces a cell-mediated response, a GP83-only-based vaccine strategy has limited efficacy. GPCMV attenuation via GP83 null deletion mutant in glycoprotein PC positive or negative virus was evaluated as live-attenuated vaccine strains (GP83dPC+/PC-). Vaccinated animals induced antibodies to viral glycoprotein complexes, and PC+ vaccinated animals had sterilizing immunity against wtGPCMV challenge. In a pre-conception vaccine (GP83dPC+) study, dams challenged mid-2nd trimester with wtGPCMV had complete protection against congenital CMV infection without detectable virus in pups. An unvaccinated control group had 80% pup transmission rate. Overall, gB and PC antibodies are key for protection against congenital CMV infection, but a response to pp65 is not strictly necessary.     

Cytomegalovirus viruria and DNAemia in healthy seropositive women

Viruria and DNAemia patterns were investigated in 205 seroimmune women enrolled in a prospective cytomegalovirus (CMV) reinfection study. CMV DNA was detected at least once in urine and blood specimens from 83% and 52% of patients, respectively. At baseline, 39% of patients had viruria, and 24% had DNAemia. Intermittent viruria and viremia was observed throughout the study. There were no differences in baseline CMV positivity by polymerase chain reaction or in longitudinal DNAemia and viruria between the women with and without serological evidence of reinfection. In young seropositive women, CMV DNAemia and viruria are common, which suggests that naturally acquired immunity to CMV does not alter shedding patterns.     

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.     

Specific impairment of cell-mediated immunity in mothers of infants with congenital infection due to cytomegalovirus.

Specific lymphocyte-mediated cytotoxicity to cytomegalovirus (CMV) in eight infants (six to 27 months old) with congenital CMV infection and in the mothers of six of these infants was evaluated with use of a 51chromium (51Cr)-release microassay. The control population consisted of 25 normal newborns, children, and adults. The titers of indirect hemagglutinating (IHA) antibody to CMV in the infected infants ranged from 1:16 to 1:1,024. All of these infants had detectable specific immune release of 51Cr that ranged from 3.3% to 48.9% (mean +/-SE, 21.0%+/-5.6%). The mothers of these infants demonstrated significantly elevated titers of IHA antibody to CMV (geometric mean titer, 1:410) as compared with a mean titer of 1:22 in controls (t = 5.71; P less than 0.001) but showed significantly depressed specific immune release (9.2% +/- 3.2%) compared with that of normal seropositive controls (24.8% +/- 2.8%; t = 3.31; P less than 0.001). In addition, two adult nulliparous women with persistent CMV viruria were also found to have depressed specific immune release to CMV (10.8% and 16.2%). These data suggest that a specific impairment in cell-mediated immunity to CMV occurs in mothers of infants with congenital CMV infection and in some persons who persistently excrete CMV.     

Late onset of fatal cytomegalovirus infection after renal transplantation. Primary or reactivation infection?

Cytomegaloviurs (CMV) infections are a recognized problem in the first six months after renal transplantation. Studies have suggested that primary infections produce symptomatic disease, whereas reactivation infections are usually asymptomatic. Two patients are described who developed fatal CMV infections in the second year after transplantation. Both patients had typical CMV disease with fever, pneumonitis, and hepatitis. Results of serologic studies in one patient were characteristic of primary infection, with seroconversion at the time of disease and appearance of specific IgM antibodies. The other patient had a similar antibody response at the time of his illness, but serial antibody tests showed that he had had a transient seroconversion earlier, in the second month after transplanation, that was not associated with clinical symptoms. These patients indicate that CMV infection must be considered in the differential diagnosis of serious febrile illnesses even in the late posttransplantation period and may occur either as the result of primary or reactivation infection. Serologic studies at the time of illness may not allow distinction between the types of infection.     

Immunoglobulins A, G, and M to cytomegalovirus during recurrent infection in recipients of allogeneic bone marrow transplantation.

Occurrence and significance of specific IgA and IgM to cytomegalovirus (CMV) in recurrent CMV infection was evaluated in 21 allogeneic T lymphocyte-depleted bone marrow transplantation (BMT) recipients who had been previously CMV seropositive. Of 17 patients with CMV infection, viruria was detected in 94%, CMV-specific IgA in 88% and IgM in 76%, and a fourfold rise in IgG in 65%. The median time between BMT and detection of viruria was 69 days, of IgA 70, of IgM 62, and of IgG 88 days. The IgM and IgA responses lasted for 14 and 30 days (median time), whereas high IgG titers persisted. Twelve patients developed CMV disease; in these the appearance of viruria, IgA, and IgM preceded the rise of IgG (P less than .02). CMV-specific IgA and IgM are valuable diagnostic tools in BMT recipients with recurrent CMV infection.