Correlation between pretreatment levels of interferon response genes and clinical responses to an immune response modifier (Imiquimod) in genital warts

A novel oral TLR7 agonist orchestrates immune response and synergizes with PD-L1 blockade via type I IFN pathway in lung cancer

Despite the groundbreaking impact of immune checkpoint blockade (ICB), response rates in non-small cell lung cancer remain modest, particularly in immune-excluded or immune-desert microenvironments. Toll-like receptor 7 (TLR7) emerges as a latent target bridging innate and adaptive immunity, offering a promising avenue for combination therapies to augment ICB efficacy. Here, we explored the anti-tumor activity of the novel oral TLR7 agonist TQ-A3334 and its potential to enhance anti-programmed death ligand 1 (PD-L1) therapy through a combination strategy in a syngeneic murine lung cancer model. Oral administration of TQ-A3334 significantly alleviated tumor burden in C57BL/6J mice, modulated by type I interferon (IFN), and exhibited low toxicity. This therapy elicited activation of both innate and adaptive immune cells in tumor tissue, particularly increasing the abundance of CD8+ TILs through type I IFN pathway and subsequent CXCL10 expression. In vitro examinations validated that IFN-α-stimulated tumor cells exhibited increased secretion of CXCL10, conducive to the promoted trafficking of CD8+ T cells. Furthermore, combining TQ-A3334 with anti-PD-L1 treatment exceeded tumor control, with a further increase in CD8+ TIL frequency compared to monotherapy. These findings suggest that TQ-A3334 can mobilize innate immunity and promote T cell recruitment into the tumor microenvironment; a combination of TQ-A3334 and anti-PD-L1 antibodies can intensify the sensitivity of tumors to anti-PD-L1 therapy, which demonstrates significant potential for treating poorly immune-infiltrated lung cancer.

miR-196b-TLR7/8 Signaling Axis Regulates Innate Immune Signaling and Myeloid Maturation in DNMT3A-Mutant AML

PURPOSE

DNMT3A mutations confer a poor prognosis in acute myeloid leukemia (AML), but the molecular mechanisms downstream of DNMT3A mutations in disease pathogenesis are not completely understood, limiting targeted therapeutic options. The role of miRNA in DNMT3A-mutant AML pathogenesis is understudied.

EXPERIMENTAL DESIGN

DNA methylation and miRNA expression was evaluated in human AML patient samples and in Dnmt3a/Flt3-mutant AML mice. The treatment efficacy and molecular mechanisms of TLR7/8-directed therapies on DNMT3A-mutant AML were evaluated in vitro on human AML patient samples and in Dnmt3a/Flt3-mutant AML mice.

RESULTS

miR-196b is hypomethylated and overexpressed in DNMT3A-mutant AML and is associated with poor patient outcome. miR-196b overexpression in DNMT3A-mutant AML is important to maintain an immature state and leukemic cell survival through repression of TLR signaling. The TLR7/8 agonist resiquimod induces dendritic cell-like differentiation with costimulatory molecule expression in DNMT3A-mutant AML cells and provides a survival benefit to Dnmt3a/Flt3-mutant AML mice. The small molecule bryostatin-1 augments resiquimod-mediated AML growth inhibition and differentiation.

CONCLUSIONS

DNMT3A loss-of-function mutations cause miRNA locus-specific hypomethylation and overexpression important for mutant DNMT3A-mediated pathogenesis and clinical outcomes. Specifically, the overexpression of miR-196b in DNMT3A-mutant AML creates a novel therapeutic vulnerability by controlling sensitivity to TLR7/8-directed therapies.

Interferon and Toll-Like Receptor 7 Response in COVID-19: Implications of Topical Imiquimod for Prophylaxis and Treatment

BACKGROUND

The innate immune system is recognized as an essential aspect of COVID-19 pathogenesis. Toll-like receptors (TLRs) are important in inducing antiviral response, triggering downstream production of interferons (IFNs). Certain loss-of-function variants in TLR7 are associated with increased COVID-19 disease severity, and imiquimod (ImiQ) is known to have immunomodulating effects as an agonist of TLR7. Given that topical imiquimod (topImiQ) is indicated for various dermatologic conditions, it is necessary for dermatologists to understand the interplay between innate immunity mechanisms and the potential role of ImiQ in COVID-19, with a particular focus on TLR7.

SUMMARY

Our objective was to survey recent peer-reviewed scientific literature in the PubMed database, examine relevant evidence, and elucidate the relationships between IFNs, TLR7, the innate immune system, and topImiQ in the context of COVID-19. Despite limited studies on this topic, current evidence supports the critical role of TLRs in mounting a strong immune response against COVID-19. Of particular interest to dermatologists, topImiQ can result in systemic upregulation of the immune system via activation of TLR7. Key Message: Given the role of TLR7 in the systemic activation of the immune system, ImiQ, as a ligand of the TLR7 receptor, may have potential therapeutic benefit as a topical immunomodulatory treatment for COVID-19.

Evolving role of immunotherapy in the treatment of refractory warts

Cutaneous and genital warts are common dermatological conditions caused by the human papilloma virus (HPV). Although it is a benign condition, it causes disfigurement, has a tendency to koebnerize, and can be transmitted to others. This makes adequate and timely treatment important. There are several conventional treatments available with variable response. Topical and systemic immunotherapy has now found a significant place in the treatment of warts because of its nondestructive action, ease of use, and promising results. Through this review, we would like to present a brief overview of the various immunotherapeutic agents used. These include more established agents such as imiquimod, Mycobacterium w vaccine, bacillus Calmette-Guérin vaccine, measles, mumps, and rubella vaccine, Candida antigen, trichophyton antigen, tuberculin, zinc, cimetidine, levamisole, HPV vaccine, and autoimplantation therapy. Other agents such as contact immunotherapy which is sparsely used now than before and newer agents such as Corynebacterium parvum, sinecatechins, echinacea, propolis, glycyrrizinic acid, and Vitamin D have also been discussed. The mechanism of action of these agents, along with their dosage, mode of administration, duration of use, expected outcomes and comparative efficacy, evidence for their use, and expected side effects, if any, are reviewed.

Efficacy of imiquimod 5% cream for persistent human papillomavirus in genital intraepithelial neoplasm

OBJECTIVE

To assess the clinical response to imiquimod 5% cream in patients with persistent human papillomavirus (HPV) infection after treatment of genital intraepithelial neoplasia.

MATERIALS AND METHODS

Imiquimod 5% cream was applied to treat 76 women with persistent HPV after surgical therapy for cervical or vaginal intraepithelial neoplasia (CIN or VAIN). One sachet of cream was placed in the cervical os and vagina with an applicator twice weekly for 8 weeks. Repeated HPV evaluation and Papanicolaou (Pap) smear and/or biopsy were performed 3 months following treatment completion.

RESULTS

In total, 58 of the 76 patients (76.3%) were clear of HPV infection and had normal Pap smears after administration of imiquimod cream. Although atypia or mild dysplasia was noted in 15 of the 18 patients (83.3%) with persistent HPV infection after imiquimod cream treatment, the degree of severity was noticeably less than the initial diagnosis in most of these patients. Persistent HPV positivity was observed in 12 of the 64 patients (18.8%) with CIN and 6 of the 12 patients (50.0%) with VAIN.

CONCLUSION

Topical imiquimod 5% cream may be beneficial in most cases of genital intraepithelial neoplasia, especially CIN, with persistent HPV following surgical treatment.

Adjuvants and delivery systems in veterinary vaccinology: current state and future developments

Modern adjuvants should induce strong and balanced immune responses, and it is often desirable to induce specific types of immunity. As an example, efficient Th1-immunity-inducing adjuvants are highly in demand. Such adjuvants promote good cell-mediated immunity against subunit vaccines that have low immunogenicity themselves. The development of such adjuvants may take advantage of the increased knowledge of the molecular mechanisms and factors controlling these responses. However, knowledge of such molecular details of immune mechanisms is relatively scarce for species other than humans and laboratory rodents, and in addition, there are special considerations pertaining to the use of adjuvants in veterinary animals, such as production and companion animals. With a focus on veterinary animals, this review highlights a number of approaches being pursued, including cytokines, CpG oligonucleotides, microparticles and liposomes.

Herpes simplex virus and human papillomavirus genital infections: new and investigational therapeutic options

Human papillomavirus and Herpes simplex virus are the most common genital viral infections encountered in clinical practice worldwide. We reviewed the literature focusing on new and experimental treatment modalities for both conditions, based on to the evidence-based data available. The modalities evaluated include topical agents such as immune response modifiers (imiquimod, resiquimod, and interferon), antivirals (penciclovir, cidofovir, and foscarnet), sinecatechins, microbiocidals (SPL7013 gel, and PRO 2000 gel), along with experimental (oligodeoxynucleotides), immunoprophylactic, and immunotherapeutic vaccines.

Molecular signatures induced by interleukin-2 on peripheral blood mononuclear cells and T cell subsets

Experimentally, interleukin-2 (IL-2) exerts complex immunological functions promoting the proliferation, survival and activation of T cells on one hand and inducing immune regulatory mechanisms on the other. This complexity results from a cross talk among immune cells which sways the effects of IL-2 according to the experimental or clinical condition tested. Recombinant IL-2 (rIL-2) stimulation of peripheral blood mononuclear cells (PBMC) from 47 donors of different genetic background induced generalized T cell activation and anti-apoptotic effects. Most effects were dependent upon interactions among immune cells. Specialized functions of CD4 and CD8 T cells were less dependent upon and often dampened by the presence of other PBMC populations. In particular, cytotoxic T cell effector function was variably affected with a component strictly dependent upon the direct stimulation of CD8 T cells in the absence of other PBMC. This observation may provide a roadmap for the interpretation of the discrepant biological activities of rIL-2 observed in distinct pathological conditions or treatment modalities.

The Toll-like receptor 7 (TLR7) agonist, imiquimod, and the TLR9 agonist, CpG ODN, induce antiviral cytokines and chemokines but do not prevent vaginal transmission of simian immunodeficiency virus when applied intravaginally to rhesus macaques

The initial host response to viral infection occurs after Toll-like receptors (TLRs) on dendritic cells (DC) are stimulated by viral nucleic acids (double-stranded RNA, single-stranded RNA) and alpha interferon (IFN-alpha) and IFN-beta are produced. We hypothesized that pharmacologic induction of innate antiviral responses in the cervicovaginal mucosa by topical application of TLR agonists prior to viral exposure could prevent or blunt vaginal transmission of simian immunodeficiency virus (SIV). To test this hypothesis, we treated rhesus monkeys intravaginally with either the TLR9 agonist, CpG oligodeoxynucleotides (ODN), or the TLR7 agonist, imiquimod. Both immune modifiers rapidly induced IFN-alpha and other antiviral effector molecules in the cervicovaginal mucosa of treated animals. However, both CpG ODN and imiquimod also induced proinflammatory cytokine expression in the cervicovaginal mucosa. In the vaginal mucosa of imiquimod-treated monkeys, we documented a massive mononuclear cell infiltrate consisting of activated CD4(+) T cells, DC, and beta-chemokine-secreting cells. After vaginal SIV inoculation, all TLR agonist-treated animals became infected and had plasma vRNA levels that were higher than those of control monkeys. We conclude that induction of mucosal innate immunity including an IFN-alpha response is not sufficient to prevent sexual transmission of human immunodeficiency virus.

Disease-Independent Skin Recruitment and Activation of Plasmacytoid Predendritic Cells Following Imiquimod Treatment

BACKGROUND

Imiquimod, an immune response modifier that is used topically to treat different types of skin cancer, induces the production of proinflammatory cytokines that stimulate an antitumor immune response. We assessed characteristics of the imiquimod-induced immune activation in epithelial and lymphoproliferative neoplasias of human skin. We focused on plasmacytoid predendritic cells (PDCs), the primary producer of interferon alpha (IFN-alpha) after imiquimod activation in vitro.

METHODS

We used Affymetrix oligonucleotide arrays to compare gene expression profiles from tumors from 16 patients, 10 with superficial basal cell carcinomas (sBCCs), five with cutaneous T-cell lymphomas (CTCLs), and one with Bowen's disease, before and after topical imiquimod treatment. We used quantitative immunohistochemistry with PDC-specific antibodies against BDCA-2 and CD123 to characterize the PDC population before and after imiquimod treatment in these specimens. Activation status of PDCs from four sBCC patients was assessed by intracellular IFN-alpha staining and flow cytometry.

RESULTS

Expression of various IFN-alpha-inducible genes (e.g., CIG5, G1P2, OASL, IFIT1, STAT1, IFI35, OAS1, ISG20, MxA, and IRF7), the so-called IFN-alpha signature, was increased similarly in both sBCC and CTCL lesions after imiquimod treatment. PDCs were recruited and activated in both lesion types, and they produced IFN-alpha after imiquimod treatment in vivo (mean percentage of PDCs producing IFN-alpha = 14.5%, 95% confidence interval [CI] = 4.9% to 24%; range = 3.3%-27%, n = 4 lesions). Imiquimod induced similar immune activation patterns in all three diseases, and these patterns were associated with the number of PDCs recruited to the treatment site. Two imiquimod-treated sBCC patients who did not mount an inflammatory response to imiquimod and whose lesions lacked the IFN-alpha signature after treatment had fewer PDCs in treated lesions compared with other treated patients with such a response.

CONCLUSIONS

Imiquimod induces immune activation patterns that relate to the number of the PDCs recruited to the treatment site, thus supporting the role of PDC in responsiveness to imiquimod in humans.

Imiquimod treatment induces expression of opioid growth factor receptor: a novel tumor antigen induced by interferon-alpha?

PURPOSE

Imiquimod represents a synthetic local immune response modifier that has demonstrated efficacy in clearing basal cell carcinoma. Via interaction with Toll-like receptor 7 on immune cells, imiquimod induces local production of cytokines, such as interferon (IFN)-alpha.

EXPERIMENTAL DESIGN

To more closely define and elucidate mechanisms leading to basal cell carcinoma clearance in vivo, we examined gene expression profiles of skin basal cell carcinoma before and after treatment with 5% imiquimod cream (Aldara) by using high-density oligonucleotide arrays.

RESULTS

We show that imiquimod predominantly induces genes involved in different aspects of immune response. In addition to effects on immunity, imiquimod treatment modulates the expression of genes involved in the control of apoptosis and oncogenesis. Array data indicated that imiquimod treatment induces expression of opioid growth factor receptor, a molecule recently reported to be a target for antitumor antibody responses. Immunohistochemistry revealed in vivo up-regulation of opioid growth factor receptor protein on tumor and on infiltrating cells after treatment. By using basal cell carcinoma cell lines treated with IFN-alpha or imiquimod, we show that opioid growth factor receptor up-regulation is IFN-alpha-mediated, rather then directly imiquimod-mediated. By using tissue microarray containing 52 basal cell carcinomas, we demonstrate opioid growth factor receptor expression in almost half of the cases. Expression of opioid growth factor receptor correlated with a longer recurrence-free period in basal cell carcinoma that recurred after radiotherapy (Kaplan-Meier analysis, P = 0.041).

CONCLUSIONS

In addition to its immunomodulatory and antiproliferative activity, opioid growth factor receptor seems to have a prognostic significance in basal cell carcinoma patients. Our data add to the growing list of basal cell carcinoma-associated tumor antigens.

Molecular Analysis of the Effect of Topical Imiquimod Treatment of HPV 2/27/57-Induced Common Warts

Imiquimod is effective in the treatment of genital warts and clinical studies suggest activity against common warts as well. We have analyzed the effect of topical imiquimod on gene expression and virus load in human papilloma virus (HPV) 2/27/57-induced common warts. mRNA was extracted from keratinocyte culture, from normal skin, from three untreated common warts and from three common warts treated topically with 5% imiquimod cream twice daily. Differential gene expression was demonstrated by RT-PCR and by cDNA microarray hybridization. We further analyzed viral DNA content in scales from three superficially pared imiquimod-treated warts by real-time PCR. Comparison of normal skin with wart tissue revealed that HPV 2/27/57 infection led to an induction of IL-6, IL-10 and interferon-gamma inducible protein (IP10) and to an up-regulation of TGF-beta. We could further detect expression of PCTAIRE-3, WNT2B, frizzled-3, notch-2, notch-4 and BRCA2 in normal skin and common warts. Analysis of imiquimod-treated warts demonstrated that imiquimod enhanced IL-6 expression and induced IL-8, GM-CSF, MRP-8 and MRP-14. It could also be shown that imiquimod led to an infiltration of wart tissue with macrophages and to a strong decrease of viral copy number in warts within 3 months of treatment. Our data thus provide molecular proof of principle for imiquimod treatment of cutaneous common warts.

Topical treatment strategies for non-melanoma skin cancer and precursor lesions

The ability to manage non-melanoma skin cancers and pre-malignant lesions with topical pharmacologic agents is highly compelling. This article examines currently available products and discusses their emerging roles and limitations. These include fluorouracil, diclofenac sodium, imiquimod, and photodynamic therapy.

Topical imidazoquinoline therapy of cutaneous squamous cell carcinoma polarizes lymphoid and monocyte/macrophage populations to a Th1 and M1 cytokine pattern

Imidazoquinolines are topical immune response modifiers. Imiquimod (IMI), the first imidazoquinoline, is approved for the treatment of genital human papillomavirus disease and has shown success as a therapeutic agent for cutaneous premalignant and malignant tumours. To define the pattern of polarization of the local immune response to invasive cutaneous squamous cell carcinoma (SCC) we pretreated 10 SCCs that were > 3 cm in diameter for 2 weeks with IMI. The tumours were treated on Monday, Wednesday and Friday and excised the next Monday. A battery of immunohistochemical markers was used to define the mononuclear cell populations in the diagnostic, and the excisional biopsy specimens. The total inflammatory infiltrate was increased after IMI therapy: the greatest increase was in the CD8 T cells with a marked relative decrease in the CD68 monocytic/macrophages; the majority of the CD8 T cells showed expression of cytotoxic granules, T cell-restricted intracellular antigen (TIA) and granzyme B. The relative numbers of monocytes/macrophages were decreased after therapy with IMI with a decrease in CD68+, CD23+, and CD14+ cells and an increase in MAC-397+, and factor XIIIa+ cells. The epidermal dendritic cells showed a > 75% decrease in CD1a+ cells. The immunohistochemical marker profile after IMI therapy is consistent with that induced by a Th1 and M1 cytokine polarization pattern. This cytokine pattern is known to be more effective in defence against tumours as well as viral infections.

Treatment of verrucous carcinoma with imiquimod and CO2 laser ablation

An 82-year-old female patient presented with a large perianal hyperkeratotic tumor extending into the anal canal. Staging did not reveal any metastatic spread. Diagnosis of verrucous carcinoma or Buschke-Löwenstein tumor, respectively, was based on typical clinical and histologic features. Moreover, human papillomavirus 6b DNA sequences could be detected by PCR. Surgical excision could not be performed due to the general health status of the patient; thus, alternative therapy methods were necessary. Treatment with imiquimod cream 5% (Aldara), a topical immune response modifier applied once a day and left for 12 h, led to significant partial tumor regression and clear demarcation of the tumor. The remaining tumor, now feasible for treatment with CO2 laser, was removed in two sessions in local anesthesia. In a third session, tumor parts in the anal canal were vaporized. This case demonstrates that the combination of imiquimod and CO2 laser ablation is an effective treatment option for verrucous carcinoma.

Prolonged imiquimod treatment and graft-versus-host reaction: histological mimicry in the skin infiltration pattern of the monocyte-macrophage-dendrocyte lineage

Factor-XIIIa-positive dendrocytes belong to the monocyte-macrophage-dendrocyte (MMD) lineage which is considered to play a pivotal role in the skin response to the immune response modifier imiquimod. The same cells are also boosted in low-grade graft-versus-host reaction (GVHR) with skin manifestations. Both conditions are characterized by specific epidermal damage. The aim of the present study was to compare them using immunohistochemistry to identify MMD subsets and other inflammatory cells in the dermis. We compared 3 cases of long-term (4, 9 and 11 months) imiquimod topical applications on normal skin, 25 low-grade GVHR controlled by immunosuppressive therapy and 25 control cases with normal skin. Compared to the normal dermis, cells of the MMD lineage were considerably boosted in the dermis of GVHR and at the imiquimod-treated sites. By contrast, only minimal accumulations of lymphocytes and Langerhans cells were disclosed in the dermis. The pattern of dermal infiltration by MMD cells was similar in GVHR and after imiquimod treatment. However, intraindividual differences in densities were obvious irrespective of the skin condition. In conclusion, there is great mimicry in the MMD involvement in the dermis during low-grade GVHR and after chronic applications of imiquimod.

The imidazoquinolines and their place in the therapy of cutaneous disease

The imidazoquinolines arose from efforts to develop a nucleoside analogue. Although molecularly similar to nucleosides, the imidazoquinolines did not have nucleoside-like activity. However, the imidazoquinolines induced immune modulatory cytokines, in part, because of their ability to activate toll receptors (TLR)s. Imiquimod, the first FDA-approved imidazoquinoline, has been marketed as a 5% cream, which is approved for the therapy of genital warts. The advantage of imiquimod therapy over other therapies for genital warts is the decrease in recurrence rate with the establishment of an adaptive immunological response or immunological memory/surveillance response. As tumours and viral infections are handled similarly by the immune system, there has been great interest in the use of topical imiquimod for the treatment of cutaneous neoplasms, particularly non-melanoma skin cancers. Future efforts in imidazoquinoline research is focused around the development of analogues with modifications in the immunological profiles, potency and penetration parameters that better focus these new analogues for the therapy of specific intracellular infections and neoplasms, as well as the development of imidazoquinolines for conditions related either directly or indirectly to patterns of immune dysregulation.

Molluscum contagiosum: recent advances in pathogenic mechanisms, and new therapies

Two poxviruses, Molluscum contagiosum virus (MCV) and Variola virus are specific to humans. MCV is present worldwide and is directly passed by direct skin to skin contact to produce cutaneous and, rarely, mucosal lesions. It occurs predominantly in preadolescent children, sexually active adults, participants in sports with skin to skin contact, and in individuals with impaired cellular immunity. MCV characteristically proliferates within the follicular epithelium, and with routine fixation produces an area of retraction artifact separating layers 1 to 3 of CD34+ stromal cells that immediately surround the follicle from the surrounding dermis. This feature may be obscured when the lesions are inflamed, usually after rupture into the surrounding dermis. MCV is a cytoplasmically replicating virus. MCV-infected cells grow in size, while internal organelles are dislocated and eventually obliterated by a large intracytoplasmic inclusion. Rupture and discharge of the virus-packed cells occurs in a process similar to membrane debris and MCV accumulate in the crater-like ostium; MCV infection is spread by contact with infectious debris. In HIV-1-positive patients the histologic features, as well as the clinical features, may be atypical in patients with MCV infections. Not only are the lesions often large, but they may be verrucous and markedly hyperkeratotic. Recent sequencing of the MCV genome has increased our understanding and investigations into its mechanisms for avoiding host defense mechanisms. These include regions which encode for homologues of cellular chemokines and chemokine-binding proteins, a homolog of MHC1 and a viral FLICE-like inhibitory protein. Treatment, until recently, has depended upon tissue destruction including curettage, cryotherapy, CO(2) laser, electrodesiccation, trichloracetic acid and cantharadin. Recently, topical immune modulators have been used with some success. Understanding of the MCV genome is providing the basis for the development of drugs for therapy and prevention of MCV infections.

Prospective molecular profiling of melanoma metastases suggests classifiers of immune responsiveness

We amplified RNAs from 63 fine needle aspiration (FNA) samples from 37 s.c. melanoma metastases from 25 patients undergoing immunotherapy for hybridization to a 6108-gene human cDNA chip. By prospectively following the history of the lesions, we could correlate transcript patterns with clinical outcome. Cluster analysis revealed a tight relationship among autologous synchronously sampled tumors compared with unrelated lesions (average Pearson's r = 0.83 and 0.7, respectively, P < 0.0003). As reported previously, two subgroups of metastatic melanoma lesions were identified that, however, had no predictive correlation with clinical outcome. Ranking of gene expression data from pretreatment samples identified approximately 30 genes predictive of clinical response (P < 0.001). Analysis of their annotations denoted that approximately half of them were related to T-cell regulation, suggesting that immune responsiveness might be predetermined by a tumor microenvironment conducive to immune recognition.

The effects of 5% imiquimod cream on high-grade vulval intraepithelial neoplasia

OBJECTIVES

The aim of this study was to investigate the effects of topical 5% Imiquimod (3M Pharmaceuticals, St. Paul, Minnessota) on high-grade vulval intraepithelial neoplasia (VIN).

METHODS

A prospective uncontrolled observational study was performed. Fifteen patients with histologically confirmed VIN 3 were asked to self-administer 5% Imiquimod cream to their vulval lesions up to three times weekly for 16 weeks. Review was conducted at 1, 2, 3, 4, 6, and 9 months postrecruitment. Lesions were photodocumented and at 4 months any areas demonstrating a clinical response were biopsied.

RESULTS

Of 15 patients recruited, 4 demonstrated a clinical improvement in their disease, 3 of whom had negative biopsies posttreatment. Local side effects limited the frequency of application such that 7 patients applied the cream once weekly, 6 twice weekly, and 2 three times weekly.

CONCLUSIONS

5% Imiquimod cream appears to have an effect when used on high-grade VIN. The frequency of application was limited by local side effects which may have reduced the clinical responses seen. Measures to alleviate local side effects may allow more aggressive use of Imiquimod and lead to improved responses.

Production of interferons and change of the lymphocyte subpopulation phenotype in peripheral blood at cervical papillomavirus infection

IFN-gamma and IFN-alpha production in vitro by peripheral blood cells activated by phytohemagglutinin or the Newcastle disease virus was impaired in patients with a benign process, cervical intraepithelial neoplasm and cancer in situ associated with human papillomavirus infection. In case of IFN-gamma and IFN-alpha production impairment following cervical papillomavirus infection, the increased severity of disease was accompanied by remarkable IFN system suppression. The lower synthesis of both IFN correlated with changes of some lymphocyte-subpopulation phenotype in peripheral blood. Lower CD4+ and CD3+ DR+ T cell concentrations were observed in papillomavirus-infected patients with impaired IFN production; impaired IFN-gamma production was accompanied by lower CD4/CD8 index.

Clearance of infection with Mycobacterium bovis BCG in mice is enhanced by treatment with S28463 (R-848), and its efficiency depends on expression of wild-type Nramp1 (resistance allele)

The mouse bcg host resistance gene is known to control the activation of host macrophages for killing of intracellular parasites like Leishmania donovani as well as intracellular bacteria, including Mycobacterium bovis BCG and Salmonella enterica serovar Typhimurium. The Nramp1 gene has been mapped to this locus and affects the efficiency of macrophage activation. It has been shown that imidazoquinoline compounds, including S28463, are able to improve the clearance of a number of intracellular pathogens such as herpes simplex virus 2, human papillomavirus, and Leishmania. The goal of this study was to determine whether S28463 is efficient against infection with another intracellular pathogen, M. bovis BCG, and to determine the molecular basis underlying this effect. To achieve this, B10A.Nramp1(r) and B10A.Nramp1(-/-) mice were infected with M. bovis BCG and treated with S28463. The bacterial content in the spleen from these mice was assayed by a colony-forming assay. In addition, in vitro experiments were performed using bone marrow-derived macrophage cell lines from these mice. These cells were treated with S28463 and/or gamma interferon (IFN-gamma), and nitric oxide (NO) production was measured. Our study was able to show that S28463 acts in synergy with IFN-gamma to increase the production of NO in vitro. We were also able to demonstrate that mice that carried the resistant allele of the Nramp1 gene and were infected with M. bovis BCG responded to treatment with S28463, resulting in a decreased bacterial load after 2 weeks of treatment. Mice that do not express the Nramp1 gene responded only to a very large dose of S28463, and the response was not as efficient as that observed in mice carrying a wild-type Nramp1 allele. Our data provide evidence for the potential of S28463 as an immunomodulator that may be helpful in designing efficient strategies to improve host defense against mycobacterial infection.