Controlled trial of acyclovir for chickenpox evaluating time of initiation and duration of therapy and viral resistance.

BACKGROUND: Chickenpox is prevalent in the US despite the availability of an effective vaccine. Acyclovir treatment is limited by concerns about efficacy if given after the first day of rash and by concerns about induction of viral resistance. OBJECTIVE: Evaluate initiation and duration of acyclovir treatment of chickenpox and its effect on viral resistance. STUDY DESIGN: Randomized, placebo-controlled, double blind trial in immunocompetent patients who were stratified by age at enrollment (children, 2 to 11 years; adolescents, > or = 12 to 18 years; adults, > or = 19 years) and duration of rash (< or = 24 h vs. >24 to 48 h). Lesions were staged, counted and cultured; temperatures and symptoms were recorded daily. INTERVENTION: Subjects presenting within 24 h of rash onset (Group A) were randomly assigned to 5 or 7 days of oral acyclovir treatment, 80 mg/kg/day up to a maximum of 3,200 mg/day in four divided doses. Subjects whose rash was >24 to 48 h old were randomized to receive 5 days of acyclovir treatment beginning on the first (Group B1) or second study day (Group B2). Matching placebos were used to ensure that subjects uniformly received 28 doses of study compound. RESULTS: Of the 177 subjects recruited Group A patients who were treated on the first day of rash had the greatest number of significantly shortened event times with 5 days of therapy being equivalent to 7 days. There also were some shorter times to events for Group B1 patients who began therapy on the second day of rash vs. Group B2 patients who started acyclovir on the third. These included: time to maximum lesion formation (adolescents, P = 0.007; children, P = 0.03); 50% healing in adolescents (P = 0.005); and residual facial lesions in adults (P = 0.047). The probability of viral shedding was significantly reduced for Group A subjects vs. Group B1 subjects (P = 0.006). Viruses shed during therapy remained susceptible to acyclovir and retained normal thymidine kinase function. CONCLUSIONS: Immunocompetent children, adolescents and adults with chickenpox displayed a gradation in their clinical responses to acyclovir that correlated with the time from onset of rash to initiation of therapy. Five days of therapy is sufficient because a 7-day course provided no additional benefit. The susceptibility to acyclovir of viruses shed during treatment did not change; however, the effect of therapy on resistance of latent virus was not assessed.

Phenotypic and genotypic characterization of acyclovir-resistant varicella-zoster viruses isolated from persons with AIDS.

Phenotypic and genotypic analyses were done on 17 varicella-zoster virus (VZV) isolates recovered from 10 persons with AIDS (mean CD4 cell count, 16.4/mm3) who had chronic VZV lesions. Eleven acyclovir-resistant isolates were recovered from 10 patients after a mean of 20.1 weeks of therapy. Six susceptible isolates were recovered before acyclovir treatment (n = 1), early during therapy (n = 4; mean time, 4.2 weeks), or after discontinuation of acyclovir (n = 1). Acyclovir-resistant VZV isolates were deficient in thymidine kinase (TK) or induced a TK with altered substrate specificity; all isolates were susceptible to foscarnet. Ten of 11 acyclovir-resistant mutants contained tk gene mutations, including single nucleotide substitutions in highly conserved binding sites (n = 2) as well as nucleotide deletions (n = 4) and insertions (n = 4). These findings suggest that multiple, nonuniform mutations within the tk gene are associated with acyclovir-resistant VZV phenotypes.

Cocaine amplifies HIV-1 replication in cytomegalovirus-stimulated peripheral blood mononuclear cell cocultures.

Cocaine and CMV each have been suggested to promote the progression of HIV-1 infection. In the present study, the interaction of cocaine and CMV was investigated in a PBMC coculture assay in which release of HIV-1 p24 Ag into coculture supernatants was used as an index of HIV-1 replication. CMV was an effective activation signal for HIV-1 replication when PBMC from CMV-seropositive donors were used in the coculture assay, and cocaine markedly increased replication of HIV-1 in these cocultures. The synergistic activity of cocaine was reduced by neutralizing antibodies to TNF-alpha and by pentoxifylline, an inhibitor of TNF-alpha mRNA production. Also, antibodies to transforming growth factor-beta (TGF-beta) eliminated the amplifying effect of cocaine on HIV-1 replication, whereas antibodies to IL-6 were inactive. The potentiating effect of cocaine could be reproduced by addition of rTNF-alpha or rTGF-beta to the cocultures of CMV-activated PBMC, although TGF-beta was substantially more potent than TNF-alpha. The possibility that TNF-alpha may act indirectly through stimulation of TGF-beta was suggested by the finding of reduced TGF-beta levels in culture supernatants of PBMC that were treated with CMV and cocaine in the presence of antibodies to TNF-alpha. Thus, cocaine amplifies HIV-1 replication in cocultures containing CMV-activated PBMC via a mechanism that appears to involve both TNF-alpha and TGF-beta. The results of this study support the possibility that cocaine and CMV could enhance HIV-1 replication and, thus, aggravate HIV-1-related disease.

Pharmacologic basis for high-dose oral acyclovir prophylaxis of cytomegalovirus disease in renal allograft recipients.

The incidence of cytomegalovirus disease, the most important infectious complication of renal transplantation, was reduced in renal allograft recipients by a regimen of prophylactic high-dose oral acyclovir. To analyze the pharmacologic aspects of our prophylactic approach, we evaluated safety, pharmacodynamics, and in vitro susceptibility data. One hundred four recipients of cadaveric renal allografts received either oral acyclovir (n = 53) in doses of up to 3,200 mg/day or a placebo (n = 51) for 12 weeks posttransplant. Leukocyte count and serum creatinine were selected as markers of laboratory safety and were evaluated pretransplant, at study midpoint (creatinine only), and at study completion. Concentrations of acyclovir in plasma were determined to verify the ability of the dosing strategy to achieve predicted values. Viral resistance was assessed by calculation of in vitro 50% inhibitory concentrations (IC50s) of acyclovir for the cytomegalovirus strains collected from the subjects. Our results showed no difference in leukocyte count or serum creatinine between the acyclovir and placebo recipients. Plasma acyclovir concentrations were maintained within the expected limits and did not differ between patients who developed cytomegalovirus disease and those who did not. The mean acyclovir IC50s for cytomegalovirus isolates were 42.6 mumol/liter in the acyclovir recipients and 48 mumol/liter in the placebo recipients. We conclude that the clinical benefit of high-dose oral acyclovir therapy occurred despite plasma drug concentrations below the mean IC50 for the patient viral isolates. Furthermore, the use of the regimen did not produce leukopenia, adversely affect renal function, or alter the susceptibility of cytomegalovirus strains to acyclovir. This approach and dose adjustment scheme may be appropriate for other immunocompromised patients at risk for cytomegalovirus infection and disease.

Evaluation of centrifugation cultures of bronchoalveolar lavage fluid for the diagnosis of cytomegalovirus pneumonitis.

Cytomegalovirus (CMV) pneumonitis is one of the most severe manifestations of CMV disease among immunocompromised patients. The diagnosis of CMV pneumonitis traditionally has required the use of invasive procedures such as lung biopsy. In this retrospective study, we evaluated a centrifugation culture method in samples of bronchoalveolar fluid for the noninvasive diagnosis of CMV pneumonitis. During a 9-mo period, 75 bronchoalveolar lavage samples were collected from 58 patients with pneumonitis. We analyzed the data from 21 patients in whom lung tissue samples were obtained within 14 days of the bronchoalveolar lavage. Centrifugation cultures of bronchoalveolar fluid were positive for CMV in 12 cases. CMV pneumonitis was confirmed in samples of lung tissue from five (42%) of the 12 patients, whereas no evidence of CMV pneumonitis was found in the remaining seven (58%) cases. Of nine patients with negative centrifugation cultures, CMV pneumonitis was confirmed in two (22%). When compared with conventional cultures, we found bronchoalveolar lavage fluid centrifugation cultures to be highly sensitive (100%) and specific (92%) for the detection of CMV infection. However, detection of CMV by centrifugation culture proved to be only moderately sensitive (71%) and nonspecific (50%) for the diagnosis of CMV pneumonitis.

Laboratory studies of acute varicella and varicella immune status.

We evaluated varicella-zoster virus (VZV) culture and serum antibody methods utilizing specimens from 620 children enrolled in protocols for prevention or treatment of varicella and samples routinely submitted to the Clinical Virology Laboratory. In a foreskin fibroblast tube culture system, we initially isolated VZV from only 29 (51%) of 57 children cultured on the first day of varicella. After modifying the method, the proportion of culture-positive children increased significantly to 36 (80%) of 45 (p less than 0.005 by corrected X2), and the median days-to-positivity were significantly shortened from 5.6 to 3.8 days (p less than 0.001, Wilcoxon rank-sum test). The Viran fluorescent antibody to membrane antigen (FAMA) assay was difficult to read and not reproducible. The standard FAMA was more sensitive than the Merck ELISA antibody test for detecting vaccine-induced antibody. The Whittaker ELISA did not detect vaccine-induced antibody but was comparable to FAMA for immune status testing (sensitivity, 95%; specificity, 92%) and for diagnosis of acute varicella.

Rubella viraemia and antibody responses after rubella vaccination and reimmunization.

Eleven 4-13 year old schoolgirls, who were seronegative by haemagglutination inhibition (HI) and radioimmunoassay (RIA) tests despite having been given HPV77-DE5 vaccine 3-9 years previously, were revaccinated with RA27/3. They showed evidence of residual immunity since they had accelerated immune responses, little or no rubella-specific IgM, no viraemia, and no vaccine-induced reactions. In contrast, all but one of the five adult women who were primary vaccinees showed a more delayed immune response. Three of four women tested had viraemia and two had vaccine-induced reactions. Enhanced HI and enhanced RIA showed that many of the schoolgirls had antibody before challenge, as did a fifth adult, who also showed an accelerated immune response, yet became viraemic.

RA27/3 rubella vaccine. A four-year follow-up.

RA27/3 rubella vaccine was given to 418 subjects aged 1 to 17 years in 1974, 201 of whom participated in a four-year follow-up study. Two vaccine-associated complications were reported. A 5-year-old boy had transient arthritis of the hip, and a 1-year-old boy had a pigmented macule at the inoculation site. Rubella reinfection was uncommon, occurring at most in three of our subjects. All of the 186 susceptible children seroconverted, and 182 had hemagglutination-inhibiting (HI) titers of 8 or greater at four-year follow-up (geometric mean titer, 30.3). In the four children whose HI titers declined to undetectable levels, both HI and neutralizing (Nt) antibodies had developed immediately postimmunization, and two had Nt titers at follow-up despite loss of HI antibodies. RA27/3 vaccine boosted HI titers in 15 seropositive subjects, but titers returned to preimmunization levels four years later. We concluded that RA27/3 vaccine produced durable immunity with very low rates of rubella reinfection and secondary vaccine failure during the four years since immunization.

Primary virus isolation by a satellite laboratory.

A hospital-based satellite laboratory designed to isolate viral pathogens frequently found in renal transplant and hematology-oncology patients was compared with a system based on isolation by a state-wide reference laboratory. The hospital-based laboratory identified 12 viral isolates from the total 97 clinical specimens submitted. The hospital-based laboratory identified seven viral isolates from the first 50 clinical specimens, whereas the statewide reference laboratory identified six isolates from identical paired specimens. The average time from specimen collection to reporting results for the 97 specimens was 9.2 days for the hospital laboratory, as compared with 11.2 days for the first 50 duplicate specimens sent to the state laboratory. The cost per clinical specimen was $18.10, which compares favorably with costs for routine aerobic bacteriology. The use of a satellite laboratory system for primary viral isolation appears to provide rapid, accurate, and accessible viral diagnosis at an affordable cost.

The microbiology of serous and mucoid otitis media.

One hundred forty-four serous and mucoid effusions were cultured for aerobic bacteria, Mycoplasma pneumoniae, and virus. Thirty percent of all effusions yielded an unequivocally positive culture for aerobic bacteria. Although serous effusions were culture positive as often as mucoid effusions, Haemophilus influenzae was isolated predominantly from serous effusions and Staphylococcus epidermidis predominantly from mucoid samples. Only one of 73 effusions yielded a viral isolate (Herpesvirus hominis). None of 33 effusions yielded M pneumoniae, and only one of 17 effusions yielded an anaerobe (Propionibacterium). These findings suggest that aerobic bacteria may play a role in the pathogensis of serous and mucoid otitis media.

Evaluation of Wistar RA27/3 rubella virus vaccine in children.

Because the Wistar RA27/3 strain rubella virus vaccine has potentially important advantages over rubella vaccines currently licensed in the United States, a field trial was conducted in Minnesota and Wisconsin in 1974 to evaluate RA27/3 in this country. Two hundred eighty-five (99.7%) of 286 susceptible children given RA27/3 subcutaneously seroconverted, with a geometric mean hemagglutination inhibition (HI) titer of 81.2. Twenty-eight (23%) of 122 children with rubella antibodies before immunization had fourfold or greater rises in rubella HI titers. The highest percentage of booster responses occurred in children with low preimmunization titers. Side effects were reported in 34% of subjects, but only one reaction associated with RA27/3 was serious: in a 5-year-old boy, arthritis of the left hip developed 31 days after immunization. This study indicates that RA27/3 vaccine produced a very high rate of seroconversion with high postimmunization HI titers. The ability to elicit significant booster responses in children with low levels of HI antibodies suggests that RA27/3 could be used to boost immunity in women of childbearing age whose rubella titers have declined to undetectable levels.

California arbovirus (La Crosse) infections. III. Epidemiology of California encephalitis in Minnesota.

Mosquitoes (eggs, larvae, and adults), small woodland animals, and residents of an area where California encephalitis is endemic were studied to elucidate the host-vector cycle of La Crosse virus. Elementary schoolchildren from surrounding communities and gray squirrels from another area were tested to compare the prevelence of serum antibodies to La Crosse virus in areas where the disease is endemic with the prevalence of these antibodies in areas where the disease is not endemic. From 1971 to 1974, eight isolations of La Crosse virus were made. Three of the isolates were from adult mosquitoes, one from Aedes triseriatus eggs, and four from A. triseriatus larvae. The isolation of virus from field-collected eggs and larvae confirms previous studies from Wisconsin that suggest that La Crosse virus overwinters in eggs of the mosquite A. triseriatus. In an area where California encephalitis is endemic, 10 of 19 small woodland animals (53%), which are the natural hosts of A. triseriatus, had hemagglutination-inhibiting and neutralizing antibodies to La Crosse virus. In contrast, none of 10 squirrels from an area where the disease is not endemic had such antibodies. Fourteen of 79 residents of this area (17.7%) had both types of antibody. Eleven of the 14 seropositive residents lived in one small sector of the community studied, an indication that foci of La Crosse virus activity may be very localized. Elementary schoolchildren from surrounding communitites had a significantly lower prevalence of hemagglutination-inhibiting antibody to La Crosse virus than did the residents of the area where California encephalitis was endemic.

Isolates of California encephalitis (La Crosse) virus from field-collected eggs and larvae of Aedes triseriatus: identification of the overwintering site of California encephalitis.

California encephalitis is caused primarily by La Crosse virus, a mosquito-borne agent of which the vector is the mosquito Aedes triseriatus. Once La Crosse virus has been detected in a given geographical area, observations in the same area during subsequent seasons usually have revealed continuing presence of the virus. Field studies were conducted around the homes of children who had had California encephalitis in an effort to define the mechanism by which the virus survived the winter. Eggs and larvae of A. triseriatus collected from natural breeding sites during the springs and summers of 1972-1974 were processed for viral isolation. Collections made during 1972 and 1973 yielded no virus. Eggs, obtained on April 29, 1974 from a basal tree hole of an American elm located approximately 150 feet from the homes of two children who had had California encephalitis in 1970, contained virus, as did larvae aspirated on May 16, 1974, from the same tree hole. This study in Minnesota confirms previous data from Wisconsin and suggests that La Crosse virus may be passed transovarially in A. triseriatus and may overwinter in the diapause stage of eggs.

Diagnosis of California (La Crosse) encephalitis by precipitin techniques: a prospective study.

Counterelectrophoresis (CEP) and immunodiffusion (ID) were evaluated prospectively as methods for the early and rapid laboratory diagnosis of California encephalitis (CE). CEP and ID studies were done on paired sera from 127 patients with acute central nervous system infections. After the precipitin tests were completed, conventional hemagglutination-inhibition, neutralizing, and complement fixing antibody titers were measured. The CEP system detected antibodies in 7 (41%) of 17 CE patients during their acute illness and in all 17 patients during convalescence. The ID method was less sensitive; 3 of 17 acute sera and 16 of 17 convalescent sera were ID positive. Comparative precipitin studies indicated that La Crosse virus was the infecting California group subtype in all 17 CE patients. Because CEP can be performed in 1.5 h, is at least as sensitive as hemagglutination-inhibition, neutralizing, and complement fixing tests, and can detect prospectively 41% of CE patients during their acute illness, it is recommended as a rapid diagnostic test for CE.

California arbovirus (La Crosse) infections. II. Precipitin antibody tests for the diagnosis of California encephalitis.

Precipitin antibodies to California group arboviruses were studied by double agar gel immunodiffusion (ID) and counterimmunoelectrophoresis (CEP). Forty children with California encephalitis (CE), 12 patients with other forms of meningoencephalitis, and 120 residents of endemic CE areas were tested. Precipitin antibodies were detected only in the 40 patients with CE, whereas hemagglutination-inhibiting, neutralizing, and complement-fixing antibodies were also found in persons without a history of CE. Precipitin antibodies did not persist for more than a year, in contrast to the other three antibodies which may be detected for 2 or more years. Of the children with CE, 36% had precipitin antibodies in their acute sera by CEP and 44% by ID. Precipitin responses were subtype-specific, and the patients reacted most strongly with La Crosse virus. The results indicated that precipitin techniques would be useful for the early detection of CE in some patients and that the presence of precipitin antibodies in a patient with acute central nervous system infection is strongly suggestive of CE. In addition, precipitin tests can be used to distinguish the California subtype responsible for CE in a given area.