The use of acyclovir in children

Acyclovir represents a significant advance in the treatment of herpes simplex and varicella zoster virus infections and appears to be safe and well-tolerated. Physicians now have several drugs to choose from in the treatment of these infections. Hopefully there will be other antiviral chemotherapeutic agents that will be effective for therapy of cytomegalovirus and Epstein-Barr virus infections. Coincident with the development of antivirals, continued progress in the area of rapid viral diagnosis is critical for early institution of therapy. Direct diagnosis of HSV or VZV from clinical specimens or lesions using monoclonal antibodies, enzyme-linked immunoassays or DNA probes are promising techniques for the future. Investigation into improved rapid diagnosis for neonatal and maternal HSV infections and HSV encephalitis should further improve outcome with antiviral therapy.

Comparison of monoclonal and polyclonal antibody for confirmation of cytomegalovirus isolates by fluorescent staining

A fluorescein isothiocyanate-labeled monoclonal cytomegalovirus antibody reagent incorporating Evans blue (Syva/Genetic Systems, Palo Alto, Calif.) was compared to a fluorescein isothiocyanate-labeled polyclonal antibody (Dynatech Diagnostics, Inc., South Windham, Maine) for identification of cytomegalovirus in tissue culture. A total of 191 cultures, 86 positive and 105 negative for cytomegalovirus by cytopathic effect in WI38 cells, were stained in parallel and examined by fluorescent microscopy. No false-negative results were noted with either reagent; however, the polyclonal antibody-stained slides required the use of a separate counterstain to decrease nonspecific fluorescence. The polyclonal reagent gave a false-positive reaction with one varicella-zoster virus isolate and four simian cytomegalovirus isolates. No false-positive results were noted with the monoclonal reagent.

Current status and prospects for oral acyclovir treatment of first episode and recurrent genital herpes simplex virus

Herpes simplex genitalis is an increasingly common primary or recurrent HSV infection. Acyclovir (ACV) has been found to diminish virus shedding and clinical symptoms in patients with first episode genital HSV when given topically or intravenously. As most patients with first episode disease do not require hospitalization and recurrent disease is usually less severe than the primary infection, out-patient treatment forms the basis of practical management. Acyclovir is absorbed orally with plasma concentrations which exceed in vitro inhibitory concentrations for HSV1 and HSV2. In double blind studies in over 100 recipients with first episode HSV, oral ACV treatment (200 mg, 5 times daily) significantly reduced virus shedding, new lesion formation, duration of genital lesions and clinical symptoms in both men and women when compared with placebo recipients. No toxicity was observed. Recurrence rates following the first episode were similar in placebo and ACV groups. A multi-centre double blind trial of oral ACV treatment of recurrent HSV infection in 250 patients showed that the duration of virus shedding and lesions was significantly shorter in ACV versus placebo recipients. These effects were more pronounced when therapy was self-initiated by patients early on during a recurrence or during the prodromal period. Oral acyclovir has significant clinical and virological effects in both primary and recurrent genital HSV infections.

Deficient lymphokine production of newborn lymphocytes

Lymphokine production by newborn lymphocytes was assessed by measuring migration inhibition factor (MIF) and leukocyte inhibition factor (LIF) of isolated mononuclear cells from cord blood, 1-7-days-old newborns, and adult controls. Ficoll-Hypaque separated mononuclear cells were stimulated with phytohemagglutinin (PHA) or allogeneic lymphocytes in a mixed leukocyte culture (MLC), and the supernatants were harvested at optimal times for lymphokine assays. Thymidine incorporation into DNA was also assayed to calculate a proliferative index. MIF was assessed by the inhibition of adult mononuclear phagocyte cell migration under agarose; LIF was assessed by polymorphonuclear cell migration under agarose. Although the proliferative responses of cord and newborn cells are equivalent or greater than those of adult controls, the PHA-induced MIF production in cord blood and newborn lymphocytes was only 46% and 12.5% respectively of mean adult levels; MLC-induced MIF production was 44% and 7%, respectively of mean adult levels. PHA-induced LIF production in cord blood was 27% of adult levels. These differences are only appreciated if dilutions of the supernatants are assayed. Simultaneous assay of MIF and LIF production in dilution of supernatants from adult lymphocytes showed higher LIF activity, whereas in cord lymphocytes MIF activity was greater than LIF activity. This further emphasizes the non-identity of MIF and LIF. These results indicate another abnormality of T cellular immunity in newborns not detected by T-cell enumeration or proliferative responses and parallels other defects in specialized T cell function such as cytotoxicity and immune interferon production.

Longitudinal study of influenza B symptomatology and interferon production in children and college students

A longitudinal study of symptomatology and interferon production in 35 patients (13 children, 20 college students and 2 medical staff members) with influenza B viral infections is presented. The mean duration of illness was 11.3 days. Cough persisted for 9.8 days and nasal symptoms continued for 8.5 days. The mean duration of fever was 4.7 days. Diarrhea occurred in 8 patients; it had its onset on about the fourth day and persisted for 4 days. Interferon levels correlated directly with fever and generally with systemic symptoms but not with other aspects of disease severity, duration or serum hemagglutination-inhibiting antibody responses.

Treatment of first episodes of genital herpes simplex virus infection with oral acyclovir. A randomized double-blind controlled trial in normal subjects

We performed a double-blind placebo-controlled trial of oral acyclovir in the treatment of first episodes of genital herpes simplex virus infections in 48 young adults (31 women and 17 men). Subjects were randomized to receive either placebo or acyclovir (200 mg per dose) five times daily for 10 days; they were examined on at least eight visits until healed and at monthly visits thereafter. Acyclovir treatment, as compared with placebo, significantly reduced virus shedding, new lesion formation after 48 hours, and the duration of genital lesions in both men and women. The total duration and severity of clinical symptoms (such as pain, adenopathy, dysuria, and malaise) were significantly reduced by acyclovir in both men and women by the third and fourth day, respectively (P less than or equal to 0.025), as compared with placebo. No toxicity was observed. Recurrence rates have so far been similar in placebo and acyclovir recipients. Oral acyclovir treatment of first-episode genital herpes simplex virus infections is clinically effective, but it does not seem to prevent virus latency or associated recurrent disease.

Treatment of cytomegalovirus pneumonia after marrow transplant with combined vidarabine and human leukocyte interferon

Seven marrow transplant recipients were treated with human leukocyte interferon and vidarabine for cytomegalovirus pneumonia. Although the mean virus titer in biopsy and autopsy lung specimens from five patients decreased from 5 x 10(4) to 1 x 10(2) 50% tissue culture infective doses, there was little clinical evidence of efficacy and only one patient survived. Treatment was stopped in four patients because of declining neutrophil counts, and two of these four patients also showed severe neurotoxicity. The combination of these agents was neither safe nor effective for the treatment of cytomegalovirus pneumonia after marrow transplantation.

Necrotizing vasculitis in a case of disseminated neonatal herpes simplex infection

A term newborn suffered disseminated herpes simplex virus (HSV) type II infection five days after cesarean section delivery for fetal distress. The mother had no history or evidence of herpetic lesions; the father had a history of genital herpetic lesions. The infant's terminal course was dominated by disseminated intravascular coagulation (DIC) with hepatic and renal failure. Microscopic examination revealed a necrotizing vasculitis of small and medium-sized lung and peripancreatic arteries. Nuclear inclusions characteristic of HSV were found in these arteries, as well as in the adrenal parenchyma, spleen, and lymph node; electron microscopy confirmed replication of virus within the arterial endothelial cells. The mechanism of arterial damage in severe herpetic infection contrasts with the immune-complex mechanism postulated for other viral vasculitides. Direct, virally induced arterial damage resulting in exposure of collagen may set the stage of DiC, a commonly fatal complication of this disease.

Double-blind controlled study of central nervous system side effects of amantadine, rimantadine, and chlorpheniramine

A total of 52 healthy, adult volunteers were randomly assigned to five treatment groups to be treated twice daily for 4 days with 100 mg of amantadine, 100 mg of rimantadine, 4 mg of chlorpheniramine or placebo alone, or 100 mg of amantadine in combination with chlorpheniramine. The results of tests measuring performance on tasks of attention, reasoning, and memory were unaffected by treatment. Subjective side effects in recipients of amantadine, rimantadine, and chlorpheniramine were comparable and minimal. Side effects appeared to be enhanced in subjects receiving both amantadine and chlorpheniramine.

Virus inhibition assay for measurement of acyclovir levels in human plasma and urine

A simple microplate virus inhibition assay which measures the levels of acyclovir in plasma and urine samples from patients was developed. The assay is based upon the inhibition of the cytopathic effect of herpes simplex virus type 1 on human fibroblast cells. The extent of inhibition of virus cytopathic effect, caused by dilutions of samples from patients, allowed determination of acyclovir concentrations to be made. The assay, which measured biological activity, could detect acyclovir levels of greater than or equal to 1.0 microM. Peak and valley levels measured in plasma samples from two patients were comparable to values obtained by radioimmunoassay. The assay is simple, rapid, and quantitative, and it can be adapted to routine use for a large number of specimens.

Grassheads in the tracheobronchial tree: two different outcomes

Many vegetable foreign bodies can produce serious pulmonary complications because of chemical irritation to the airway. Barley grass, a type of grasshead, does not induce such a reaction because of its resistance to organic decay. Complications which may occur are illustrated by the clinical course of two patients with aspiration of this foreign body. In the first patient the grasshead entered the trachea with the flowering unit first and the stem following. In the second patient the stem entered the trachea first. Recurrent pneumonias were noted in the first patient. Despite its presence in the right stem bronchus for three years, no further episodes of pneumonia followed its removal. In the second patient the grassheads could not be removed endoscopically. They migrated into the right lower lobe producing pneumonia and ultimately resulting in a brain abscess. The difference of entry of the same foreign body into the trachea, stem first versus flowering unit first, is an essential factor in altering the clinical outcome.

Lymphokine production by human milk lymphocytes

To assess the functional capability of human milk lymphocytes, we studied phytohemagglutinin-induced lymphokine production by breast milk and, for comparison, peripheral blood lymphocyte cultures. Two lymphokines, lymphocyte-derived chemotactic factor (LDCF) and immune interferon, were assayed in supernatants of milk and blood lymphocyte cultures obtained from women 2 to 6 days postpartum. Eleven parallel milk and blood samples were studied for LDCF production. In nine experiments, both milk and blood lymphocytes produced LDCF. In the two other experiments, milk cells did not produce LDCF. In 10 milk cultures studied, all produced interferon activity. Acid and heat lability characteristics were typical of immune interferon. These results further characterize milk lymphocytes as immunologically competent and possibly important effector cells in neonatal immunity.

A prospective double-blind study of side effects associated with the administration of amantadine for influenza A virus prophylaxis

During a study of efficacy of amantadine prophylaxis of influenza A virus infection in young adults, gross and subtle side effects were monitored. Eighty-eight students were randomly selected to receive either amantadine or placebo for four weeks or both in a sequential crossover design of two weeks each. Side effects (i.e., dizziness, nervousness, and insomnia) occurred in 33% of those receiving amantadine and in 10% of those receiving placebo (P less than 0.005). Although side effects were well tolerated by most subjects, six volunteers discontinued amantadine because of marked complaints. Cessation of side effects occurred in more than half of those continuing amantadine. Sixteen students receiving amantadine had decreased performance on sustained attention tasks as compared with ones receiving placebo (P less than 0.05). Gross and subtle side effects of amantadine observed in this study on currently recommended dosage are higher than previously reported, which may be an important factor in consideration of mass prophylaxis.

Cellular (T cell) immunity in the human newborn

The cellular immune system of the human newborn, like the rest of the immunologic apparatus, is anatomically intact, antigenically inexperienced, and functionally deficient. The latter is suggested by the newborns' enhanced susceptibility to infection, diminished delayed cutaneous hypersensitivity reactions, and selective abnormalities (when compared to adults) of measures of cellular immunity in vitro. These include impaired proliferative response to ubiquitous antigens, depressed lymphotoxin, migration inhibition factor, and immune interferon production, and diminished cytotoxic reactions including cell-mediated lympholysis. By contrast, other aspects of neonatal T cell function, such as to mitogens or allogeneic lymphocytes, natural interferon and leukocyte inhibition factor production, and number and percentage of E-rosette-forming cell are generally normal. These decreased functional properties may provide an explanation for the newborns' susceptibility to infection and for the occasional occurrence of engraftment of foreign cells from either the mother or from prenatal or neonatal blood transfusion.

Epidemic measles in young adults. Clinical, epidemiologic, and serologic studies

An outbreak of measles at the University of California at Los Angeles provided the opportunity to study clinical, epidemiologic, and serologic characteristics of the disease in young adults in the present vaccine era. Of the 34 cases studied, 18 occurred in persons who thought they were immune. Fifteen of 19 seronegative students vaccinated during the epidemic responded with a secondary (IgG) antibody response. Antibody prevalence studies indicated that 91% of the student population had measles antibody at the onset of the outbreak, and history relating to measles correlated poorly with antibody prevalence. Of 212 adults vaccinated, 58% complained of one or more symptoms. Seventeen percent were confined to bed, and in three women vaccine-associated illness was notably severe. That measles will continue to be a problem in adults with our present national approach to immunization is predicted.

Simple sensitive microbioassay for adenine arabinoside and hypoxanthine arabinoside in human plasma

Previous methods using low- or high-pressure liquid chromatography and UV absorbance for quantitation of arabinosides in plasma can practically detect only >/=200 ng of adenine arabinoside and >/=100 ng of hypoxanthine arabinoside per ml, and they require expensive equipment and expert technical assistance. We describe in this report a simple quantitative microbioassay for arabinosides in human plasma based on their ability to inhibit the cytopathic effect of vaccinia virus in an adenosine deaminase-free cell culture system. Using prior separation of nucleosides in plasma by thin-layer chromatography, followed by the microbioassay, we quantitated adenine arabinoside with a sensitivity of approximately 4 ng/ml and hypoxanthine arabinoside at approximately 625 ng/ml. This assay method is simple, sensitive, and reproducible, requires small plasma samples, measures biological activity, and is adaptable to routine use. It is an important tool for evaluating the pharmacology of adenine arabinoside and Ara-AMP in patients in current clinical trials.

IgM and IgG antibody responses after immunization of children with inactivated monovalent (A/New Jersey/76) and bivalent (A/New Jersey/76-A/Victoria/75) influenza virus vaccines

The character of the immune response to inactivated monovalent influenza A/New Jersey/76 and bivalent influenza A/New Jersey/76-A/Victoria/75 vaccines was studied in children six months to 18 years of age. Titers of hemagglutination-inhibiting antibody in sera taken after vaccination were measured before and after treatment with 2-mercaptoethanol. IgG antibody predominated in responses to the influenza A/Victoria/75 component of bivalent vaccines. In contrast, specific IgM antibody to influenza A/New Jersey/76 virus developed after administration of both monovalent and bivalent vaccines and appeared to characterize the immune response to this antigenic "shift" strain in children. Prevalences of IgM antibody against influenza A/New Jersey/76 virus did not differ significantly by age. This finding implies that type rather than extent of previous experience with influenza determines the IgM antibody response to an antigenic "shifts." Split-product vaccines produced significantly fewer IgM antibody responses to influenza A/New Jersey/76 virus than did whole-virus vaccines, a phenomenon that may correlate with their diminished reactogenicity and immunogenicity in children.

Clinical trials with inactivated monovalent (A/New Jersey/76) and bivalent (A/New Jersey/76-A/Victoria/75) influenza vaccines in Los Angeles children

Clinical and serologic responses to inactivated influenza virus vaccines were studied in 444 children in Los Angeles under doubld-blind, placebo-controlled protocols. One- and two-dose regimens employing monovalent (A/New Jersey/76) and bivalent (A/New Jersey/76-A/Victoria/75) vaccine were studied in separate trials. In a single dose, whole-virus vaccines were more potent than split-product vaccines as primary inducers of immunity against influenza A/New Jersey/76 virus. Split-product vaccines were better tolerated clinically and, after two-dose regiments, produced rates of seroconversion (greater than 90%) against A/New Jersey/76 virus comparable to those produced by two doses of whole-virus vaccines. Analysis of heterotypic antibody responses induced by monovalent A/New Jersey/76 vaccines revealed only slight increases in antibody against influenza A/Victoria/75 virus. After vaccination with bivalent vaccines, levels of antibody against influenza A/Victoria/75 virus were significantly higher in subjects who received high doses of split-product vaccines than in subjects who received whole-virus vaccines.

Combined antiviral effects of interferon, adenine, arabinoside, hypoxanthine arabinoside, and adenine arabinoside-5'-monophosphate in human fibroblast cultures

Adenine arabinoside and human interferon are currently being evaluated in clinical trials against herpes- and poxvirus infections. Interferon production is also a normal antiviral response. It is therefore important to examine the combined actions of interferon and antiviral arabinosides for possible synergy or antagonism. We have examined the antiviral activities of human fibroblast interferon, adenine arabinoside, hypoxanthine arabinoside, and adenine arabinoside 5'-monophosphate individually, using plaque inhibition of vaccinia and herpes simplex type 2 viruses in human skin fibroblast cultures. By combining doses of interferon and arabinosides that, acting alone, give intermediate degrees of plaque inhibition, we were able to compare the combined antiviral activity with that calculated from the activity of each inhibitor alone, assuming that the activities are statistically independent. Our results show that the plaque-inhibitory activities of interferon and the arabinosides tested are statistically independent. The results also show that the arabinosides do not destabilize the antiviral state previously induced by interferon, and that interferon pretreatment does not interfere with subsequent arabinoside action in infected cells. We have also found that arabinosides do not affect the induction of interferon synthesis by either Newcastle disease virus or double-stranded ribonucleic acid, and are not themselves interferon inducers.

In vitro susceptibility of varicella zoster virus to adenine arabinoside and hypoxanthine arabinoside

The in vitro susceptibility of varicella zoster (VZ) isolates to adenine arabinoside (ara-A) and hypoxanthine arabinoside (ara-Hx) was determined in human skin fibroblasts. Using a system in which deamination was inhibited, and using a modified plaque reduction method, the antiviral activities of ara-A and ara-Hx were separated. The plaque inhibitory concentration of ara-A for all VZ isolates tested was 1 to 2 mug/ml and 80 to 100 mug/ml for ara-Hx. A comparison of antiviral activity based upon total plaque suppression gave a rate of 40 to 50:1, in favor of ara-A.