Uptake of extracellular Ca2+ is a requirement for production of interferon-gamma by cord blood mononuclear cells

We studied the response of adult peripheral and cord blood mononuclear cells (MNCs) to graded concentrations of phytohemagglutinin (PHA) to characterize the requirements for proliferation and interferon-gamma (IFN-gamma) production. As the concentration of PHA was decreased, the proliferative response of both adult and cord blood MNCs decreased in parallel. At high concentrations of PHA (a: 120) cord blood MNCs display normal high proliferation but IFN-gamma production was greatly diminished compared with adult MNCs. Addition of the calcium ionophore, A23187, to PHA-stimulated adult MNCs had no effect on proliferation or IFN-gamma production at any of the concentrations of PHA tested. Furthermore, A23187 alone had no effect on proliferation or IFN-gamma secretion. Similarly, the addition of A23187 to PHA-stimulated cord-blood MNCs had no effect on proliferation. However, when A23187 was added to high dose (1:120) PHA-stimulated cord blood MNCs IFN-gamma production increased to levels comparable with adult PHA-stimulated MNCs. A similar pattern of response was seen when exogenous calcium chloride was added in place of A23187.

Induction of interferon-gamma by cord blood mononuclear cells is calcium dependent

Human cord blood mononuclear cells (MNCs) are deficient in their ability to produce interferon-gamma (IFN-gamma). Previous studies have shown that phytohemagglutinin (PHA)-stimulated neonatal MNCs produced significantly less IFN-gamma than adult PHA-stimulated MNCs. The deficient IFN-gamma production is partly due to the absence of a macrophage-derived soluble mediator. Supernatants from PHA-stimulated adult macrophages and phorbol myristate acetate (PMA)-stimulated U937 cells (which were dialyzed prior to culture to remove PMA) increased IFN-gamma production in neonatal PHA-stimulated MNC (14 to 217 units/ml and 14 to 293 units/ml, respectively). The requirement for a soluble macrophage mediator was replaced by the addition of exogenous calcium chloride (CaCl2) to PHA-stimulated cord blood MNCs. The increase in IFN-gamma production by exogenous CaCl2 was blocked by the addition of the calcium channel blocker, manganese chloride (MnCl2). Furthermore, the increased IFN-gamma production by PHA-stimulated cord blood MNC in the presence of PHA-stimulated adult macrophage supernatant or PMA-stimulated U937 supernatant was abrogated by the addition of MnCl2, chlorpromazine, and verapamil. These data suggested that the soluble factor produced by PHA-stimulated adult macrophage supernatant and PHA-stimulated U937 supernatant induced IFN-gamma production in PHA-stimulated cord blood MNC by inducing calcium-dependent signals at more than one site.

Pharmacokinetics of acyclovir in the term human pregnancy and neonate

Concern about neonatal herpes often leads to cesarean delivery of infants in women with a history of genital herpes. The antiviral drug acyclovir has been used effectively to suppress genital herpes simplex virus recurrences in nonpregnant adults. Its administration to pregnant women with recurrent genital herpes may reduce herpes simplex virus recurrences and thus may decrease the cesarean section rate among this population. To study the pharmacokinetics, safety, and patient tolerance of suppressive oral acyclovir, either 200 mg (n = 7) or 400 mg (n = 8) was administered orally every 8 hours to pregnant women with a history of recurrent herpes simplex virus, from 38 weeks' gestation until delivery. The mean +/- SD plasma levels for the 200 and 400 mg groups, respectively, were: first dose peak, 1.7 +/- 0.6 and 2.3 +/- 1.0 mumol/L; steady-state trough, 0.7 +/- 0.3 and 0.8 +/- 0.6 mumol/L; steady-state peak, 1.9 +/- 1.0 and 3.3 +/- 1.0 mumol/L. In late gestation maternal acyclovir pharmacokinetics were similar to those of nonpregnant adults from other studies. Acyclovir was concentrated in the amniotic fluid; however, there was no accumulation in the fetus (mean maternal/infant plasma ratio at delivery was 1.3). Acyclovir was well tolerated, and no toxicity was seen in the mothers or infants. The administration of acyclovir, 400 mg every 8 hours, appears appropriate for use in an efficacy and safety study regarding suppression of herpes simplex virus recurrences during the last weeks of pregnancy.

Early treatment with acyclovir for varicella pneumonia in otherwise healthy adults: retrospective controlled study and review

The effect of early acyclovir therapy on the course of varicella pneumonia in previously healthy adults was assessed. Medical records from five university-affiliated medical centers were retrospectively reviewed; included were all immunocompetent adults with a clinical diagnosis of primary varicella, a chest radiograph consistent with varicella pneumonia, and an arterial blood gas measurement indicating significant hypoxia. Of the 38 patients who met the study criteria, 11 had had a course of intravenous acyclovir initiated within the first 36 hours of hospitalization; the mean time from admission to initiation of therapy in this early-treatment group was 9.6 hours. The group that received early acyclovir treatment had a lower mean temperature beginning on the fifth day of hospitalization (37.0 degrees C vs. 37.7 degrees C; P = .011) and a lower mean respiratory rate beginning on the sixth day of hospitalization (21 vs. 28 respirations per minute; P = .004). Early acyclovir therapy also resulted in a significant improvement in oxygenation beginning on the sixth day of hospitalization in patients with follow-up arterial blood gas measurements (P = .035). Thus, early institution of acyclovir therapy is associated with reduction in fever and tachypnea and improvement in oxygenation in otherwise healthy adults with varicella pneumonia.

Antibody response to herpes simplex virus glycoproteins gB and gD

The antibody response to herpes simplex virus (HSV) glycoproteins B and D was evaluated using these cloned glycoproteins in an ELISA assay and compared to a standard Western blotting procedure. The ELISA assay appeared to be more sensitive for detecting gB and gD antibodies. Antibodies to gB but not gD were detected in the acute sera of patients presenting with their first episode of true primary genital herpes. The geometric mean HSV gB titer (log 2) was also significantly higher than the geometric mean gD titer in the convalescent sera of these patients (7.9 +/- 0.7 vs. 5.5 +/- 0.9, P less than .003). A cross-reaction between HSV gB and varicella zoster virus (VZV) gp II was demonstrated. Thus, it is possible that a previous VZV infection could prime the immune system to respond rapidly and more vigorously to HSV gB. Indeed, in this report we demonstrated a significant correlation between the VZV ELISA absorbance and the titer to HSV gB and also detected a higher VZV ELISA absorbance and HSV gB titer in the acute sera of patients with a true primary HSV infection compared to other HSV seronegative VZV seropositive patients. Use of this quantitative assay should allow further investigation into the relationship of the immune response to these important targets and the clinical course of HSV disease.

Comparison of intramuscular recombinant alpha interferon (rIFN-2A) with topical acyclovir for the treatment of first-episode herpes genitalis and prevention of recurrences

Intramuscular recombinant alpha interferon (rIFN-2A; 9 million IU given for 5 days during a 9-day treatment period) was compared with topical acyclovir in a double-blind, placebo-controlled trial for the treatment of first-episode genital herpes simplex virus (HSV) infection and for subsequent alteration of the frequency of recurrences. rIFN-2A (within 96 h of onset of the first episode) was not superior to topical acyclovir in a well-matched group of 105 patients. The early use of rIFN-2A also did not alter the frequency or severity of genital HSV recurrences within either the first or second 6 months following therapy. Separate analyses by HSV type and by type of infection (primary versus nonprimary) did not change this conclusion. Furthermore, there was significant toxicity associated with rIFN-2A therapy. rIFN-2A is not indicated for the treatment of genital HSV infections.

Intravenous acyclovir therapy of first episodes of genital herpes: a multicenter double-blind, placebo-controlled trial

PURPOSE

A collaborative multicenter double-blind, placebo-controlled trial of intravenous acyclovir treatment of first-episode genital herpes was performed in order to substantiate previous findings on the efficacy and safety of this drug, to evaluate the influence of parenteral therapy on recurrence frequency, and to obtain further data on the natural history of genital herpes.

PATIENTS AND METHODS

Eighty-two patients with first episodes of genital herpes simplex virus (HSV) infection were randomly assigned in a double-blind fashion to treatment with intravenous acyclovir (5 mg/kg every eight hours) or placebo for five days. Before therapy, all lesions in the genital/perineal area and in extragenital sites were cultured. New lesions appearing in both areas after the onset of therapy were cultured separately. Lesions in all groups were cultured until completely healed. Sera were collected from all patients on entry to the study and on Day 21 to determine presence or absence of antibodies to HSV-1 and HSV-2. Time to healing, time to crusting, time to cessation of viral shedding, and appearance of new lesions during therapy were compared for each treatment group.

RESULTS

Patients receiving acyclovir experienced a significant reduction in the median duration of pain (4.3 versus 4.8 days, p = 0.019), viral shedding (1.9 versus 8.4 days, p less than 0.001), and time to healing (8.4 versus 11.5 days, p = 0.02) compared with placebo recipients. These differences were largely attributable to the effect of therapy in the subset of patients with primary disease in whom acyclovir reduced the median duration of pain from 10.6 days to 4.2 days, the median duration of viral shedding from 17.1 days to 1.9 days, and the median time to healing from 14.2 days to 8.3 days. The rate of subsequent recurrence of genital herpes was not altered by acyclovir treatment: 24 of 32 acyclovir recipients (75 percent) experienced one or more recurrences during a mean follow-up of 14 months compared with 19 of 27 placebo recipients (70 percent). Among patients experiencing recurrences, the mean number of recurrences per month among acyclovir recipients was 0.25 compared with 0.19 for patients given placebo.

CONCLUSION

This multicenter trial confirms the efficacy of intravenous acyclovir in the management of first-episode genital herpes, especially in patients with primary infection. However, therapy did not alter the frequency of recurrences.

Therapy of herpes zoster with oral acyclovir

Oral acyclovir therapy for herpes zoster has been studied in double-blind, placebo-controlled trials of two dosages, 400 mg and 800 mg five times per day for 10 days. Compared with placebo recipients, recipients of the high-dosage acyclovir experienced a significantly shortened period of viral shedding, significantly accelerated time to 50 percent scabbing, significantly accelerated time to 50 percent healing, and after two days of therapy, significantly less frequent formation of new lesions. The duration and severity of acute pain were less in acyclovir recipients, with differences in pain severity achieving statistical significance (p = 0.03) between Days 3 and 10 and correlating with the treatment differences in new lesion formation. In studies of the 400 mg five times per day dose schedule, differences between acyclovir and placebo recipients were not significant. In a six-month follow-up of recipients in the higher dosage study, the acyclovir recipients experienced less post-zoster pain than placebo recipients; differences in the prevalence of pain were most significant for the presence of a persistent pain in the first three months of follow-up. Oral acyclovir at these dosages appears to be free of adverse reactions. In summary, oral acyclovir at a dosage of 800 mg five times per day for 10 days for treatment of acute herpes zoster is superior to 400 mg five times per day and favorably alters the course of the disease.

Promising new antiviral drugs

We now have a basis for a more rational approach to rapid evaluation and development of antiviral drugs by screening for activity in vitro, testing for toxicity and efficacy in animals, and clinical testing in humans. Acyclovir is a prototype of this improved process. Interferon has a beneficial effect against CMV infection in renal transplant patients and has promising results in the treatment of papillomas and rhinovirus infections. It does not seem to be as effective against genital herpes or varicella zoster as acyclovir. Ribavirin is effective against respiratory syncytial virus infections and Lassa fever. Varicella-zoster virus is highly sensitive to bromovinyl deoxyuridine in vitro. Phosphonoformate is effective in herpes simplex in animals but of little clinical benefit topically in human recurrent A2 herpes. Zidovudine may decrease mortality rates and infectious complications in patients with acquired immunodeficiency syndrome. DHPG (9-(1,3-dihydroxy-2-propoxymethyl]guanine is useful in treatment of cytomegalovirus and infection in immunocompromised patients. The prodrug of acyclovir results in high blood levels of acyclovir and shows promise in the treatment of varicella-zoster infections. Many halogenated pyrimidine nucleoside analogs are being developed. Buciclovir is another acyclic guanosine analog effective against herpes simplex virus in vitro. 2'-nor-cyclic guanosine monophosphate has a broad antiviral spectrum of action. Interleukin-2 is being investigated. Combined therapies of two or more antiviral drugs or antiviral drugs and other treatments are being studied.

Treatment of cytomegalovirus retinopathy with ganciclovir

Ganciclovir is an experimental antiviral drug with activity against human cytomegalovirus (CMV). Forty patients with acquired immune deficiency syndrome (AIDS) and CMV retinopathy were treated with ganciclovir on a compassionate protocol basis. Initial treatment doses ranged from 5.0 to 14.0 mg/kg/day for 9 to 26 days. Signs of drug response were a halt to enlargement of lesions, decreased opacification of retinal tissue, and resolution of hemorrhage and vasculitis. Complete response was seen in 88% of patients and incomplete response was seen in 9%. Vision improved or remained stable in 88% of patients. Initial treatment did not eradicate live virus from the eye. To prevent reactivation of disease, 26 patients received low-dose maintenance therapy ranging from 1.5 to 7.5 mg/kg/day, once or twice daily, 3 to 7 days per week. Reactivation of disease developed for unknown reasons in 50% of patients on continuous, uninterrupted maintenance therapy for longer than 3 weeks. Reversible neutropenia, requiring cessation of treatment, developed in 30% of patients on initial treatment and in 38% of patients on maintenance therapy. Rhegmatogenous retinal detachment was a late complication in seven patients. By reducing or delaying visual loss, ganciclovir appears to be useful in the management of CMV retinopathy in patients with AIDS.

Respiratory pharmacology. Antiviral agents

In summary, there are numerous clinically useful antiviral agents currently available, with many more investigational drugs on the horizon. The future of antiviral chemotherapy looks bright, and the principles behind successful therapy will remain the same. It is hoped that with the advent of effective therapy, improved rapid viral diagnosis and early treatment of patients will be possible to maximize beneficial effects.

Suppression of recurrent genital herpes simplex virus infection with recombinant alpha 2 interferon

This double-blind, placebo-controlled study evaluated the efficacy and safety of sc administered recombinant alpha 2 interferon (IFN-alpha 2) in the suppression of frequently recurrent genital herpes simplex virus (HSV) infection. Seventy-six otherwise healthy subjects who had eight or more recurrences during the preceding year received 1 X 10(6) IU of IFN-alpha 2, 3 X 10(6) IU of IFN-alpha 2, or placebo three times per week for 12 weeks. Recipients of the higher dose of IFN-alpha 2, had fewer outbreaks during the study (2 vs. 3), a shorter period of viral shedding (2 vs. 4 days), less itching (1 vs. 3 days), and a faster healing time (6 vs. 8 days). The lower dose of IFN-alpha 2 was not effective. Significant side effects (fever, malaise, myalgia, fatigue, and arthralgia) occurred after the first injection of 3 X 10(6) IU of IFN-alpha 2 in 91% of the subjects, but subsequent injections produced only mild and intermittent side effects that were well tolerated. Mild leukopenia was noted in subjects treated with IFN-alpha 2. Treatment with IFN-alpha 2 resulted in moderate suppression and decreased duration of recurrent genital HSV infection in patients with frequent recurrences.

Antibody response to type-common and type-unique epitopes of herpes simplex virus polypeptides

Herpes simplex virus type 1 (HSV1) and type 2 (HSV2) polypeptides with type-common and type-unique epitopes were identified using cross-adsorbed hyperimmune rabbit sera and Western blotting techniques. Twelve HSV1 and fourteen HSV2 polypeptides with type-specific epitopes were identified. Cross-adsorbed human sera reacted to a subset of the type-specific epitopes defined by rabbit sera. Human sera with both HSV1- and HSV2-specific antibodies were identified by their reaction to HSV1-type-specific epitopes after adsorption with HSV2, and HSV2-type-specific epitopes after adsorption with HSV1. Mixing experiments demonstrated the sensitivity of this assay for detecting HSV2-type-specific antibody in the presence of HSV1 antibody. This technique has proven useful in the study of immune response to individual HSV polypeptides during human HSV infections, while the presence of these type-unique epitopes on HSV polypeptides allows for the detection of type-specific antibodies in human sera.

Impaired production of gamma-interferon by newborn cells in vitro is due to a functionally immature macrophage

The decreased production of gamma-(PHA-induced) interferon (IFN) by leukocytes of normal newborns could be due to functionally immature T cells, macrophages, or both. We studied gamma-IFN production by macrophages and T cells, alone and in combination, obtained from 50 cord blood samples and 14 adult blood samples in a series of experiments. Adherent macrophages were cultivated for 7 days before the addition of T cells. After 48 hr, PHA-stimulated macrophage-T cell supernatants were harvested and assayed for IFN by a microassay. Macrophage-T cell cultures of autologous and nonautologous cells in 14 adults showed enhanced IFN production (GMT 121 +/- 5 IU) as compared with Ficoll-Hypaque mononuclear cells (GMT 42 +/- 5 IU). No IFN was detected in supernatants from PHA-stimulated Ficoll-Hypaque cord cells alone or macrophage-T cord combined cultures. Combined cord macrophages and adult T cells produced minimal IFN (GMT 13 +/- 3 IU); however, cord T cells combined with adult macrophages showed enhanced IFN production (GMT 195 +/- 47 IU). This cord macrophage dysfunction was not due to an inhibitor and improved with the time of in vitro cultivation. These results indicate that the neonatal macrophage is primarily responsible for the impaired gamma-IFN response by the newborn cells.

Comparison of Western Blot Analysis to microneutralization for the detection of type-specific herpes simplex virus antibodies

A newly developed system (as described in the previous paper) employing separated herpes simplex virus (HSV) polypeptides electrophoretically transferred to nitrocellulose paper, Western Blot Analysis (WBA), was compared to microneutralization (MN) for the detection of type-specific antibody to HSV types 1 and 2 in 98 human sera. Sera containing HSV1-specific antibodies reacted at least twofold more densely (as quantitated by densitometric scanning) to HSV1 than HSV2 polypeptides, while sera with HSV2-specific antibodies reacted twofold more densely to HSV2 polypeptides. The reliability of this system was determined (1) by analysis of sera from patients with true primary herpes simplex infections, (2) by adsorption studies that removed cross-reacting antibodies, and (3) by comparison with neutralization. Of 36 sera found to have HSV1-type-specific antibody by WBA, 83% had MN ratios of less than 85 (indicating HSV1 antibody), while of 28 sera found to have HSV2-type-specific antibody by WBA, 89% had MN ratios of greater than 85 (indicating HSV2 antibodies). The MN ratio obtained on sera felt to have both HSV1-type-specific and HSV2-type-specific antibody by WBA ranged from 67 to 160. WBA agreed more closely with clinical isolates and adsorption studies than MN. This system not only accurately determines the HSV-type-specific antibody status of patients but provides important information on the specific immunogenic proteins.

Impaired production of gamma-interferon by newborn cells in vitro is due to a functionally immature macrophage

The decreased production of gamma-(PHA-induced) interferon (IFN) by leukocytes of normal newborns could be due to functionally immature T cells, macrophages, or both. We studied gamma-IFN production by macrophages and T cells, alone and in combination, obtained from 50 cord blood samples and 14 adult blood samples in a series of experiments. Adherent macrophages were cultivated for 7 days before the addition of T cells. After 48 hr, PHA-stimulated macrophage-T cell supernatants were harvested and assayed for IFN by a microassay. Macrophage-T cell cultures of autologous and nonautologous cells in 14 adults showed enhanced IFN production (GMT 121 +/- 5 IU) as compared with Ficoll-Hypaque mononuclear cells (GMT 42 +/- 5 IU). No IFN was detected in supernatants from PHA-stimulated Ficoll-Hypaque cord cells alone or macrophage-T cord combined cultures. Combined cord macrophages and adult T cells produced minimal IFN (GMT 13 +/- 3 IU); however, cord T cells combined with adult macrophages showed enhanced IFN production (GMT 195 +/- 47 IU). This cord macrophage dysfunction was not due to an inhibitor and improved with the time of in vitro cultivation. These results indicate that the neonatal macrophage is primarily responsible for the impaired gamma-IFN response by the newborn cells.

Serologic analysis of first-episode nonprimary genital herpes simplex virus infection. Presence of type 2 antibody in acute serum samples

Acute serum samples from patients with nonprimary first-episode genital herpes were evaluated for the presence of type-specific antibody to herpes simplex virus type 1 and type 2. A standard microneutralization assay and western blot analysis, which identified the response to individual polypeptides of type 1 and type 2 herpes, were performed in both unadsorbed serum samples and serum samples adsorbed with either type 1 or type 2 antigens to remove cross-reacting antibodies. Of 24 serum samples examined, seven were found to contain only type 1 antibodies, 11 had type 2 antibodies alone, and six serum samples had both type 1 and type 2 antibodies. It is believed that a majority of the 17 patients whose acute serum samples already contained type 2 antibody were experiencing their first clinically apparent recurrence of a previous asymptomatic type 2 infection. Physicians should, therefore, acknowledge that patients with first-episode nonprimary herpes 2 infection may not have had a recent sexual contact with a herpes simplex virus-infected partner.

The effects of acyclovir on antibody response to herpes simplex virus in primary genital herpetic infections

The humoral response to herpes simplex virus (HSV) was examined in 21 patients with primary HSV infection who were participating in a placebo-controlled trial of oral acyclovir as therapy for first-episode genital herpes. A standard microneutralization assay and a western blot analysis, which detects the antibody response to individual polypeptides of HSV types 1 and 2, were used. Placebo-treated, HSV type-2-infected patients typically responded to HSV type-2 polypeptides that had molecular masses of 125, 84, 68, 59, 46, and 40 kilodaltons. Treatment with acyclovir diminished the humoral response both to HSV, as measured by the type-specific neutralizing-antibody titer, and to specific polypeptides, especially those with molecular masses of 50-100 kilodaltons, a range that includes polypeptides with molecular masses corresponding to those of glycoproteins D and E of HSV.