Pål Johansen

Intralymphatic allergen administration renders specific immunotherapy faster and safer: A randomized controlled trial

The only causative treatment for IgE-mediated allergies is allergen-specific immunotherapy. However, fewer than 5% of allergy patients receive immunotherapy because of its long duration and risk of allergic side effects. We aimed at enhancing s.c. immunotherapy by direct administration of allergen into s.c. lymph nodes. The objective was to evaluate safety and efficacy compared with conventional s.c. immunotherapy. In a monocentric open-label trial, 165 patients with grass pollen-induced rhinoconjunctivitis were randomized to receive either 54 s.c. injections with pollen extract over 3 years [cumulative allergen dose 4,031,540 standardized quality units (SQ-U)] or 3 intralymphatic injections over 2 months (cumulative allergen dose 3,000 SQ-U). Patients were evaluated after 4 months, 1 year, and 3 years by nasal provocation, skin prick testing, IgE measurements, and symptom scores. Three low-dose intralymphatic allergen administrations increased tolerance to nasal provocation with pollen already within 4 months (P < 0.001). Tolerance was long lasting and equivalent to that achievable after standard s.c. immunotherapy (P = 0.291 after 3 years). Intralymphatic immunotherapy ameliorated hay fever symptoms (P < 0.001), reduced skin prick test reactivity (P < 0.001), decreased specific serum IgE (P < 0.001), caused fewer adverse events than s.c. immunotherapy (P = 0.001), enhanced compliance (P < 0.001), and was less painful than venous puncture (P = 0.018). In conclusion, intralymphatic allergen administration enhanced safety and efficacy of immunotherapy and reduced treatment time from 3 years to 8 weeks.

Revisiting PLA/PLGA microspheres: an analysis of their potential in parenteral vaccination.

Poly(lactide) and poly(lactide-co-glycolide) microspheres have been studied for controlled antigen delivery and immune response enhancement for more than a decade. Early developments of such vaccines were basically technology-driven, stemming from the well-established biocompatibility of these polymers in concert with their innate properties to tailor rates of bioerosion and release. More recently, other features have become equally or even more appealing, such as the adjuvancy of such microspheres and their ability to elicit cellular effector responses, so-called cytotoxic T-cell responses, in addition to antibody responses observed already in the very early studies. In this review, we intended to revisit microsphere-based vaccines designed for the parenteral route and attempted to outline major developmental issues, as well as to analyze immunological fundamentals and data associated with antigen delivery by microspheres.

Epicutaneous allergen administration as a novel method of allergen-specific immunotherapy

BACKGROUND Subcutaneous allergen-specific immunotherapy is an effective treatment of IgE-mediated allergies, but it requires repeated allergen injections with a risk of systemic allergic reactions. Transcutaneous immunotherapy may improve patient compliance and safety. OBJECTIVE To assess the safety and efficacy of epicutaneous allergen immunotherapy. METHODS This monocentric, placebo-controlled, double-blind trial was conducted from March 2006 to December 2007 at the University Hospital Zurich. Thirty-seven adult patients with positive skin prick and nasal provocation tests to grass pollen were randomized to receive patches containing either allergen (n = 21) or placebo (n = 16). Treatment took place before and during the pollen season 2006, and follow-up visits took place before (n = 26) and after the pollen season 2007 (n = 30). The primary outcome measures were nasal provocation tests. RESULTS Allergen-treated patients showed significantly decreased scores in nasal provocation tests in the first (P < .001) and second year (P = .003) after treatment. In contrast, placebo-treated patients had decreased scores in the first treatment year, 2006 (P = .03), but the effect diminished in the second year (P = .53). Although improvement of nasal provocation test scores was not significantly better in the verum versus placebo group, the overall treatment success was rated significantly higher by the allergen-treated group than by the placebo group (2006, P = .02; 2007, P = .005). No severe adverse events were observed. Occurrence of eczema after allergen patch applications proved stimulation of specific T-cell responses, but was noted as an adverse effect of the treatment. CONCLUSION Epicutaneous allergen immunotherapy is a promising strategy to treat allergies and merits further investigation.

Improving Stability and Release Kinetics of Microencapsulated Tetanus Toxoid by Co-Encapsulation of Additives

AbstractPurpose. Tetanus toxoid (Ttxd) encapsulated in polyester microspheres (MS) for single injection immunization have so far given pulsatile in vitro release and strong immune response in animals, but no boosting effect. This has been ascribed to insufficient toxoid stability within the MS exposed to in vivo conditions over a prolonged time period. This study examined the effect of co-encapsulated putative stabilizing additives. Methods. Two different Ttxd were encapsulated in poly(D,L-lactic-co-glycolic acid) (PLGA 50:50) and poly(D,L-lactic acid) (PLA) MS by spray-drying. The influence of co-encapsulated additives on toxoid stability, loading in and release from the MS, was studied by fluorimetry and ELISA. Results. Co-encapsulated albumin, trehalose and γ-hydroxypropyl cyclodextrin all improved the toxoid encapsulation efficiency in PLGA 50:50 MS. Albumin increased the encapsulation efficiency of antigenic Ttxd by one to two orders of magnitude. Further, with albumin or a mixture of albumin and trehalose ELISA responsive Ttxd was released over 1−2 months following a pulsatile pattern. Conclusions. Optimized Ttxd containing MS may be valuable for a single-dose vaccine delivery system.

Administration routes affect the quality of immune responses: A cross-sectional evaluation of particulate antigen-delivery systems

Particulate delivery systems such as liposomes and polymeric nano- and microparticles are attracting great interest for developing new vaccines. Materials and formulation properties essential for this purpose have been extensively studied, but relatively little is known about the influence of the administration route of such delivery systems on the type and strength of immune response elicited. Thus, the present study aimed at elucidating the influence on the immune response when of immunising mice by different routes, such as the subcutaneous, intradermal, intramuscular, and intralymphatic routes with ovalbumin-loaded liposomes, N-trimethyl chitosan (TMC) nanoparticles, and poly(lactide-co-glycolide) (PLGA) microparticles, all with and without specifically selected immune-response modifiers. The results showed that the route of administration caused only minor differences in inducing an antibody response of the IgG1 subclass, and any such differences were abolished upon booster immunisation with the various adjuvanted and non-adjuvanted delivery systems. In contrast, the administration route strongly affected both the kinetics and magnitude of the IgG2a response. A single intralymphatic administration of all evaluated delivery systems induced a robust IgG2a response, whereas subcutaneous administration failed to elicit a substantial IgG2a response even after boosting, except with the adjuvanted nanoparticles. The intradermal and intramuscular routes generated intermediate IgG2a titers. The benefit of the intralymphatic administration route for eliciting a Th1-type response was confirmed in terms of IFN-gamma production of isolated and re-stimulated splenocytes from animals previously immunised with adjuvanted and non-adjuvanted liposomes as well as with adjuvanted microparticles. Altogether the results show that the IgG2a associated with Th1-type immune responses are sensitive to the route of administration, whereas IgG1 response associated with Th2-type immune responses were relatively insensitive to the administration route of the particulate delivery systems. The route of administration should therefore be considered when planning and interpreting pre-clinical research or development on vaccine delivery systems.

Use of A-type CpG oligodeoxynucleotides as an adjuvant in allergen-specific immunotherapy in humans: a phase I/IIa clinical trial

Background B‐type CpG oligodeoxynucleotides (ODN) is currently used in clinical trials because of its prolonged half–life, which is due to its phosphorothioate backbone. A‐type CpG ODN is a stronger inducer of IFN but has an unstable phosphodiester backbone that has so far prohibited its clinical use. However, upon association with virus‐like particles (VLP) consisting of the bacteriophage Qβ coat protein, A‐type CpG ODN can be stabilized and can become an efficient adjuvant in mice. Therefore, the phase I/IIa study presented represents the first test of A‐type CpGs in humans.

Triggering TLR7 in mice induces immune activation and lymphoid system disruption, resembling HIV-mediated pathology

Chronic immune activation is a major cause for progressive immunodeficiency in human immunodeficiency virus type-1 (HIV) infection. The underlying trigger, however, remains largely unknown. HIV single-stranded RNA is a potent immune activator by triggering Toll-like receptor (TLR) 7/8. Thus, we hypothesized that sustained TLR7 triggering induces chronic immune activation and thereby contributes to progressive immunodeficiency. We used the synthetic compound R848 or a mixture of uridine-rich HIV single-stranded (ss) RNA oligonucleotides--both are potent TLR7/8 agonists--to explore the effects of sustained TLR7 triggering on the murine lymphoid system. Sustained TLR7 triggering induced an immunopathology reminiscent of progressive lymphoid destruction in HIV disease; we observed lymphopenia, elevated proinflammatory cytokines, splenomegaly, contracted lymphoid subsets, and lymphoid microarchitecture alteration with reduced marginal zone B-lymphocytes. Upon exposure to inactivated vesiculo-stomatitis virus, antibody production was abolished, although splenic lymphocytes were activated and total IgG was elevated. Our data imply that HIV itself may directly contribute to immune activation and dysfunction by stimulating TLR7. Thus, manipulation of TLR7 signaling may be a potential strategy to reduce chronic hyper-immune activation and, thereby, disease progression in HIV infection.

Epicutaneous allergen-specific immunotherapy ameliorates grass pollen–induced rhinoconjunctivitis: A double-blind, placebo-controlled dose escalation study

BACKGROUND Epicutaneous allergen administration using a patch may be an alternative to subcutaneous or sublingual immunotherapy. OBJECTIVE To optimize treatment dose and to demonstrate the efficacy and safety of epicutaneous immunotherapy. METHODS This monocentric, placebo-controlled, double-blind trial included 132 patients with grass pollen-induced rhinoconjunctivitis. In February 2008, patients were randomly allocated to receive placebo or 3 different doses of allergen. Before and during the pollen season 2008, patients received 6 weekly patches. Efficacy was assessed 4 to 5 months later (n = 110) and during the pollen season of the treatment-free follow-up year in 2009 (n = 93). The primary outcome was patient-reported changes in hay fever symptoms assessed by a visual analog scale. Secondary outcome measures were weekly visual analog scale symptom scores during pollen season, use of rescue medication, changes in conjunctival and skin reactivity, as well as safety. RESULTS Hay fever symptoms during the pollen season were reduced by more than 30% in 2008 and by 24% in 2009 in the high-dose group as compared with that in the placebo group, and the alleviation of symptoms in the follow-up year was dependent on the treatment dose. Higher allergen doses were associated with drug-related adverse events (AEs), predominantly manifested by pruritus, erythema, wheal, or eczema. Eleven systemic AEs of grades 1 to 2 required treatment and led to study exclusion. The dropout rate due to AEs was 8.3%. No drug-related serious AE was recorded. CONCLUSION Epicutaneous immunotherapy is safe and efficacious in a dose-dependent manner after 6 patches only.

Inflammasome activation and IL-1β target IL-1α for secretion as opposed to surface expression

Interleukin-1α (IL-1α) and -β both bind to the same IL-1 receptor (IL-1R) and are potent proinflammatory cytokines. Production of proinflammatory (pro)–IL-1α and pro–IL-1β is induced by Toll-like receptor (TLR)-mediated NF-κB activation. Additional stimulus involving activation of the inflammasome and caspase-1 is required for proteolytic cleavage and secretion of mature IL-1β. The regulation of IL-1α maturation and secretion, however, remains elusive. IL-1α exists as a cell surface-associated form and as a mature secreted form. Here we show that both forms of IL-1α, the surface and secreted form, are differentially regulated. Surface IL-1α requires NF-κB activation only, whereas secretion of mature IL-1α requires additional activation of the inflammasome and caspase-1. Surprisingly, secretion of IL-1α also required the presence of IL-1β, as demonstrated in IL-1β–deficient mice. We further demonstrate that IL-1β directly binds IL-1α, thus identifying IL-1β as a shuttle for another proinflammatory cytokine. These results have direct impact on selective treatment modalities of inflammatory diseases.

A Virus-Like Particle-Based Vaccine Selectively Targeting Soluble TNF-α Protects from Arthritis without Inducing Reactivation of Latent Tuberculosis

Neutralization of the proinflammatory cytokine TNF-α by mAbs or soluble receptors represents an effective treatment for chronic inflammatory disorders such as rheumatoid arthritis, psoriasis, or Crohn’s disease. In this study, we describe a novel active immunization approach against TNF-α, which results in the induction of high titers of therapeutically active autoantibodies. Immunization of mice with virus-like particles of the bacteriophage Qβ covalently linked to either the entire soluble TNF-α protein (Qβ-C-TNF1–156) or a 20-aa peptide derived from its N terminus (Qβ-C-TNF4–23) yielded specific Abs, which protected from clinical signs of inflammation in a murine model of rheumatoid arthritis. Whereas mice immunized with Qβ-C-TNF1–156 showed increased susceptibility to Listeria monocytogenes infection and enhanced reactivation of latent Mycobacterium tuberculosis, mice immunized with Qβ-C-TNF4–23 were not immunocompromised with respect to infection with these pathogens. This difference was attributed to recognition of both transmembrane and soluble TNF-α by Abs elicited by Qβ-C-TNF1–156, and a selective recognition of only soluble TNF-α by Abs raised by Qβ-C-TNF4–23. Thus, by specifically targeting soluble TNF-α, Qβ-C-TNF4–23 immunization has the potential to become an effective and safe therapy against inflammatory disorders, which might overcome the risk of opportunistic infections associated with the currently available TNF-α antagonists.