Soluble triggering receptor expressed on myeloid cells-1 is a biomarker of anti-CCP-positive, early rheumatoid arthritis

OBJECTIVES

To assess serum soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) levels in disease-modifying antirheumatic drug (DMARD)-naïve early rheumatoid arthritis (ERA), to investigate the association of sTREM-1 levels with Disease Activity Score in 28 joints (DAS28) and seropositivity for anti-cyclic citrullinated peptide (CCP) antibody and to determine the predictive value of sTREM-1 with respect to clinical response to DMARD therapy.

METHODS

Twenty-two consecutive patients with DMARD-naïve ERA were prospectively evaluated for serum sTREM-1 by means of ELISA at diagnosis and at the following clinic visit after prednisone and/or DMARD has been administered, and related to DAS28 and serum level of anti-CCP antibody. We compared the sTREM-1 level to that of 31 patients with established RA as well as to 24 controls.

RESULTS

Serum sTREM-1 level was significantly higher in the DMARD-naïve ERA group (212.9 ± 388.9 ρg/mL) compared to established RA group (1478.0 ± 280.0 ρg/mL, P = 0.001) and normal control (34.4 ± 7.4 ρg/mL, P < 0.001). In the ERA group, elevated basal sTREM-1 level correlated with higher DAS28-CRP score (P = 0.001, HR 3.23, 95% CI 1.4-8.12), DAS28-ESR (P = 0.04, HR 2.34 95% CI 0.1-8.12), as well as predicted higher DAS28 score at the following encounter after DMARD treatment was administered (P = 0.001, HR 3.2 95% CI 1.1-7.2). Higher serum level of sTREM-1 correlated with higher titres of anti-CCP antibody (P < 0.001).

CONCLUSIONS

Our results suggest that serum sTREM-1 may provide a novel biomarker for DMARD-naïve ERA as well as for seropositivity for anti-CCP antibody and RA activity.

The accuracy of C-reactive protein, procalcitonin, and s-TREM-1 in the prediction of serious bacterial infection in neonates

In this prospective study, we examined the usefulness of C-reactive protein (CRP), soluble triggering receptor expressed on myeloid cells (s-TREM-1), and procalcitonin (PCT), in identifying serious bacterial infection (SBI) among neonates. Infants younger than 3 months with suspected SBI were included and serum concentrations of CRP, PCT, and s-TREM-1 were determined.

RESULTS

A total of 112 patients (19 with SBI and 93 with negative cultures) were evaluated. There were no statistical differences between the 2 groups regarding age, presence of fever, and serum concentrations of the different biomarkers. Performance of the different biomarkers were as follows: The sensitivities were 45%, 55%, and 82% for CRP, PCT, and s-TREM-1, respectively, whereas the specificities we 82%, 75%, and 48% for CRP, PCT, and s-TREM-1, respectively. The areas under the receiver operating characteristic curve were 0.6, 0.63, and 0.61, for CRP, PCT, and s-TREM-1, respectively.

CONCLUSIONS

In real-life pediatric practice, none of the tested biomarkers was sufficiently accurate to serve as a reliable indicator for the identification of SBI in neonates.

Evaluation of a possible inflammatory response after appendectomy for non-perforated appendicitis in children

BACKGROUND

The inflammatory process in the post-appendectomy period is not well characterized. In a pilot study, we prospectively followed the kinetics of different inflammatory mediators before and after appendectomy in children, and compared the results of the groups open appendectomy (OA) and laparoscopic appendectomy (LA).

MATERIAL AND METHODS

Levels of sP-selectin, tPA, MCP-1, IL-6, IL-8, sVCAM-1, and sCD40L were measured before appendectomy and on the next three consecutive days in the serum of 25 children (16 males and 9 females) aged 7 - 16 years (mean 12.6+/-2.47 years) with non-perforated acute appendicitis.

RESULTS

LA and OA were performed in 16 and 9 patients respectively. None of the markers of inflammation differed significantly by surgical approach at any point of observation. However, sP-selectin, MCP-1 and sVCAM-1 levels were found to have significantly different postoperative kinetics with a trend towards higher values in the laparoscopic group compared to the open appendectomy group (p=0.034, p=0.016 and p=0.025, respectively).

CONCLUSIONS

The cytokines sP-selectin, MCP-1 and sVCAM-1 may play a role in the possible post-appendectomy cytokine activation after non-perforated appendicitis. Since this phenomenon is more evident after LA than after OA, the contribution of the different LA procedures has to be further investigated.

A double-blind, placebo-controlled, randomized trial of montelukast for acute bronchiolitis

BACKGROUND

Cysteinyl leukotrienes are implicated in the inflammation of bronchiolitis. Recently, a specific cysteinyl leukotriene receptor antagonist, montelukast (Singulair [MSD, Haarlem, Netherlands]), has been approved for infants in granule sachets.

OBJECTIVE

Our goal was to evaluate the effect of montelukast on clinical progress and on cytokines in acute bronchiolitis.

METHODS

This was a randomized, placebo-controlled, double-blind, parallel-group study in 2 medical centers. Fifty-three infants (mean age: 3.8+/-3.5 months) with a first episode of acute bronchiolitis were randomly assigned to receive either 4-mg montelukast sachets or placebo, every day, from hospital admission until discharge. The primary outcome was length of stay, and secondary outcomes included clinical severity score (maximum of 12) and changes in type 1 and 2 cytokine levels (including interleukin4/IFN-gamma ratio as a surrogate for the T-helper 2/T-helper 1 ratio) in nasal lavage.

RESULTS

Both groups were comparable at baseline, and cytokine levels correlated positively with disease severity. There were neither differences in length of stay (4.63+/-1.88 [placebo group] vs 4.65+/-1.97 days [montelukast group]) nor in clinical severity score and cytokine levels between the 2 groups. No differences in interleukin 4/IFN-gamma ratio between the 2 groups were seen. There was a slight tendency for infants in the montelukast group to recover more slowly than those in the placebo group (clinical severity score at discharge: 6.1+/-2.4 vs 4.8+/-2.2, respectively).

CONCLUSIONS

Montelukast did not improve the clinical course in acute bronchiolitis. No significant effect of montelukast on the T-helper 2/T-helper 1 cytokine ratio when given in the early acute phase could be demonstrated.

House dust mites on skin, clothes, and bedding of atopic dermatitis patients

BACKGROUND

Atopic dermatitis is a common allergic condition in children, often associated with a positive skin reaction to house dust mite allergens.

AIM

To determine the presence of house dust mites on the skin, clothes, and bedding of patients with atopic dermatitis.

METHODS

Nineteen patients with atopic dermatitis were examined during a 2-year period. Samples from affected and healthy skin surfaces were obtained with adhesive tape, and dust samples from bedding and clothes were collected with a vacuum cleaner at the start of the study and 3-6 weeks later, and examined for the presence of house dust mites. The findings were compared with those of 21 healthy controls.

RESULTS

The most common mite species on skin were Dermatophagoides pteronyssinus and Dermatophagoides farinae, which were found in nine patients and three controls. The patient group showed a significantly larger percentage of samples with mites than did the control group (34.9% and 7.9%, respectively) (P < 0.001), and a significantly larger percentage of individuals with at least one positive sample (84.2% and 14.2%, respectively) (P < 0.0001). No correlation was found between the number of mites on the skin and clothes/bedding of patients, or between patients and controls with regard to the number of mites on the clothes and bedding.

CONCLUSIONS

Patients with atopic dermatitis showed a higher prevalence of mites on their skin than did healthy individuals, which could be involved in allergic sensitization and disease exacerbation.

Determination of immunity to vaccinia virus by using diluted inactivated vaccinia vaccine solution for skin testing

AIMS

We evaluated the usefulness of skin test prepared by inactivation of vaccinia vaccine in predicting immunity to vaccinia. Skin test was injected to 77 healthy adults. Twenty had a recent smallpox vaccination (group 1). Thirty-seven were long term vacinees (group 2), while 20 subjects had never been vaccinated for smallpox (group 3).

RESULTS

Mean size of induration was 7.9, 5.3 and 0.4 mm for subjects from groups 1, 2 and 3, respectively (P<0.03 for difference between groups). Induration >or=5 mm correlated with neutralizing antibody titer >1:32 (r=0.73, P<0.0001).

CONCLUSIONS

The skin test is a potentially useful tool for the assessment of immunity to vaccinia.

Immunogenicity and safety of a novel IL-2-supplemented liposomal influenza vaccine (INFLUSOME-VAC) in nursing-home residents

Influenza and its complications account for substantial morbidity and mortality, especially among the elderly. In young adults, immunization provides 70-90% protection, while among the elderly the vaccine may be only </=50% effective; hence, the need for new, more immunogenic vaccines. We compared the safety and immunogenicity of a novel, interleukin-2 (IL-2) -supplemented trivalent liposomal influenza vaccine (designated INFLUSOME-VAC) with that of a commercial trivalent split virion vaccine in community-residing elderly volunteers (mean age 81 years) in winter of 2000/2001. Eighty-one individuals were randomly assigned to be vaccinated intramuscularly, either with the standard vaccine (n=33) or with INFLUSOME-VAC (n=48) prepared from the former. The two vaccines contained equal amounts of hemagglutinin (HA) ( approximately 15 microgram of each viral strain); INFLUSOME-VAC consisted of liposomal antigens admixed with liposomal human IL-2 (Lip IL-2) (33 microgram = 6x10(5) IU/dose). At 1 month post-vaccination, seroconversion rates (tested by hemagglutination inhibition) for the A/New Caledonia (H1N1) and A/Moscow (H3N2) strains were significantly higher (P=0.04) in the INFLUSOME-VAC group (65 versus 45%, 44 versus 24%, respectively). Moreover, INFLUSOME-VAC induced a greater anti-neuraminidase (NA-N2) response (P<0.05). Anti-IL-2 antibodies were undetected, and no increase in anti-phospholipid IgG antibodies was found in the INFLUSOME-VAC group. Adverse reactions were similar in both groups. Thus, INFLUSOME-VAC appears to be both safe and more immunogenic than the currently used vaccine in the elderly.

Immunogenicity and safety of a novel liposomal influenza subunit vaccine (INFLUSOME-VAC) in young adults

Influenza and its complications account for substantial morbidity and mortality among young adults and especially among the elderly. In young adults, immunization provides 70-90% protection, while among the elderly the vaccine may be only 30-40% effective; hence the need for new, more immunogenic vaccines. We compared the safety and immunogenicity of a novel IL-2-supplemented liposomal influenza vaccine (designated INFLUSOME-VAC) with that of a commercial subunit vaccine and a commercial split virion vaccine in young adults (mean age 28 years) in the winter of 1999-2000. Seventy-three healthy young adults were randomly assigned to be vaccinated intramuscularly with the following: a commercial subunit vaccine (n = 17, group A), INFLUSOME-VAC (n = 36, group B), and a commercial split virion vaccine (n = 20, group C). The three vaccines contained equal amounts of hemagglutinin (approximately 15 microg each) from the strains A/Sydney (H3N2), A/Beijing (H1N1), and B/Yamanashi. INFLUSOME-VAC induced higher geometric mean HI titers and higher-fold increases in HI titers against all three strains, compared with the two commercial vaccines. In addition, seroconversion rates for the A/Sydney and B/Yamanashi strains were significantly higher (P < 0.05) compared with the split virion vaccine, and significantly higher for the three strains compared with the subunit vaccine (69-97% vs 35-65%, P < or = 0.02). Moreover, the anti-neuraminidase response was significantly greater (P = 0.05) in group B vs group A. INFLUSOME-VAC caused mild local pain at the injection site in a significantly higher proportion of the vaccinees (83%). Thus, INFLUSOME-VAC is an immunogenic and safe vaccine in young adults.

A novel liposomal influenza vaccine (INFLUSOME-VAC) containing hemagglutinin-neuraminidase and IL-2 or GM-CSF induces protective anti-neuraminidase antibodies cross-reacting with a wide spectrum of influenza A viral strains

A liposomal influenza vaccine (INFLUSOME-VAC) was developed with the objective of overcoming the major drawbacks of the currently used influenza vaccines: their relatively low efficacy in certain high-risk groups (the elderly, infants, the immunosuppressed) and the need for annual immunization. INFLUSOME-VAC consists of liposomes containing the viral surface proteins hemagglutinin (HA) and neuraminidase (NA) derived from various influenza strains and IL-2 or GM-CSF, as an adjuvant. Vaccination of mice showed that, whereas conventional vaccines induced a low- and short-term response against HA and very low or no anti-NA response, INFLUSOME-VAC produced high titers of both anti-HA and anti-NA antibodies (Abs) in young and old mice that persisted for at least 6 months. Moreover, the anti-NA Abs efficiently cross-reacted with several N2 viral subtypes spanning 20 years, and such vaccines afforded partial protection against heterosubtypic viral infection.

Immunoadjuvant activity of interferon-gamma-liposomes co-administered with influenza vaccines

In an attempt to potentiate the relatively low immunogenicity of the currently used influenza vaccines, especially in high-risk groups, monovalent and divalent subunit vaccine preparations were co-administered with free or liposome-associated murine interferon gamma (mIFNgamma) as an adjuvant. Recombinant murine IFNgamma was entrapped (50-70% efficiency) in two types of large multilamellar vesicles: mIFNgamma-LIP A-'conventional' liposomes, and mIFNgamma-LIP B- 'surface-depleted' liposomes, in which 60 and 8% of the associated cytokine was located at the external liposome membrane, respectively. Subunit preparations containing the viral surface proteins hemagglutinin and neuraminidase (HN) were injected once, i.p. (0.5 microg each), into BALB/c mice, alone and combined with free or liposomal mIFNgamma (mIFNgamma-LIP, 0.5 or 3.0 microg). Sera were tested 3-16 weeks post-vaccination by hemagglutination inhibition (HI), and by ELISA for IgG1 and IgG2a antibodies (Abs). In addition, protective immunity against intranasal viral infection was assayed at 11 and 17 weeks post-vaccination. The results showed that: (a) Vaccination with HN alone produces very low HI and IgG titers and does not afford any protection. (b) Although co-administration with free mIFNgamma (particularly using 3.0 microg) markedly enhances HI titer as well as the IgG1 and IgG2a levels, protection is negligible (0-33%). (c) In most cases, mIFNgamma-LIP is significantly more potent than free mIFNgamma (2-40-fold increase in Ab titer), and the low dose (0.5 microg) is generally more efficient than the high dose. Up to 83% of the mice co-vaccinated with mIFNgamma-LIP were protected against viral challenge. (d) Both the IgG2a level and the HI titer appear to be crucial for protection. (e) Although the two liposomal preparations differ in their cytokine release profile in vivo and in their bioactivity in vitro, their adjuvant activity is comparable.

Delivery of cytokines by liposomes: hematopoietic and immunomodulatory activity of interleukin-2 encapsulated in conventional liposomes and in long-circulating liposomes

Although liposomal delivery of interleukin-2 (IL-2) and other cytokines improves their pharmacokinetics and biologic activity in vivo, there are no comparative functional studies of various liposomal formulations as cytokine carriers. In the present investigation, recombinant human IL-2 was encapsulated in two formulations of large (mean diameter 0.75-1.5 microns) multilamellar vesicles (MLV, referred to as conventional liposomes) or in small (mean diameter, 60 nm), unilamellar, long-circulating liposomes (referred to as sterically stabilized liposomes, SSL). The biologic activity of the liposomal formulations and of free IL-2 was tested in parallel in vitro and in mice. The main observations were as follows: (a) All the liposomal IL-2 (Lip-IL-2) formulations were more efficient than soluble IL-2 in stimulating spleen cell proliferation and lymphokine-activated killer (LAK) cell activation in vitro, particularly at low cytokine doses (1-100 CU/mL). (b) After i.v. injection, the circulation time of MLV-IL-2 and SSL-IL-2 was 7 and 17 times greater, respectively, than that of soluble IL-2. (c) In comparison with IL-2, all Lip-IL-2 formulations caused a marked increase in the leukocyte levels in blood, spleen, and peritoneal exudate, especially in those of myeloid origin (neutrophils, eosinophils, immature granulocytes, and macrophages). (d) Although SSL-IL-2 exhibited the longest circulation time, MLV-IL-2 was more potent in elevating leukocyte levels and in triggering LAK cell activity in vivo. (e) The route of Lip-IL-2 administration greatly affected the immunomodulatory activity in the various compartments. (f) MLV-IL-2 proved to be a much more efficient immunoadjuvant than free IL-2 for influenza subunit vaccines as well as for tumor cell vaccines. These findings lend support to our previous studies in which we demonstrated the superior immunomodulatory activity of liposomal IL-2, and suggest that cytokine pharmacokinetics, biodistribution, and pharmacodynamics are markedly influence both by liposomal formulation and route of administration.

A novel influenza subunit vaccine composed of liposome-encapsulated haemagglutinin/neuraminidase and IL-2 or GM-CSF. I. Vaccine characterization and efficacy studies in mice

The aim of this study was to improve the potency of the currently used influenza subunit vaccines, which are of relatively low efficiency in high-risk groups. Influenza A virus (Shangdong/9/93) haemagglutinin/neuraminidase (H3N2), granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2) were encapsulated, each separately or combined, in multilamellar vesicles composed of dimyristoyl phosphatidylcholine. BALB/c mice were immunized once, i.p. or s.c., with 0.05-2.0 microg HN administered either as free antigen (F-HN), adsorbed to aluminum hydroxide (Al-HN), or encapsulated in liposomes (Lip-HN), separately or together with 1 x 10(2)-4.5 x 10(4) units of free or encapsulated cytokines. Serum antibodies were assayed on days 11-360 by the haemagglutination-inhibition (HI) test and ELISA. Protective immunity against intranasal virus challenge was determined at 9-14 months post-vaccination. The following results were obtained: (1) The efficiency of encapsulation in liposomes was 95, 90 and 38% for HN, IL-2 and GM-CSF, respectively, and the liposomal preparations were highly stable as an aqueous dispersion for > 2 months at 4 degrees C. (2) Following immunization with 0.5 microg Lip-HN, there was an earlier, up to 50-fold stronger, and 3-5 times longer response than that obtained with nonliposomal HN. (3) Coimmunization with free cytokines further increased the response 2-20 times and the two cytokines had an additive effect. (4) Liposomal cytokines were 2-20 times more effective than the free cytokines and their stimulatory effect was more durable. (5) A 100% seroconversion (HI titer > or = 40) was achieved with only 10-25% of the routinely used antigen dose, by encapsulating either antigen or cytokine. (6) The level of protection following vaccination with the combined liposomal vaccines was 70-100% versus 0-25% in mice immunized with Al-HN alone, and no toxicity was observed. In conclusion, our animal experiments show that the liposomal vaccines are superior to the currently used influenza vaccines, increasing the response by 2-3 orders of magnitude in mice. This approach may also prove valuable for subunit vaccines against other microorganisms.

A novel influenza subunit vaccine composed of liposome-encapsulated haemagglutinin/neuraminidase and IL-2 or GM-CSF. II. Induction of TH1 and TH2 responses in mice

This study was aimed at analyzing, in parallel, the humoral and cellular immune responses elicited in mice immunized with liposomal influenza A (Shangdong/9/93) subunit vaccines composed of haemagglutinin/neuraminidase (H3N2) and IL-2 or GM-CSF. Recently, we reported that such vaccines evoke a more rapid, stronger and longer-lasting (over 1 year) humoral response, as well as protective immunity against viral infection, following a single administration, as compared with the response induced by the free antigen given alone or together with soluble cytokines. In the present study, BALB/C mice were immunized once, i.p., s.c., i.m. or i.n., with nonliposomal or liposomal vaccines and the humoral (antibody titer and isotypes) and cellular (DTH, cytotoxicity, cytokine production) responses were assessed at various times (2-56 weeks). The main findings were: (a) the combined liposomal vaccines consisting of encapsulated antigen and encapsulated cytokine, but not the free antigen, elicited a high titer of serum IgG1, IgG2a, IgG3 and IgM antibodies; (b) the combined liposomal vaccines were efficient following administration by the various routes, and induced a local (in lung) IgA response in i.n. vaccinated mice; (c) the liposomal vaccines triggered DTH and cytotoxic responses, as well as cytokine (mainly IL-4) production. Together, these and other findings indicate that our cytokine-supported liposomal influenza vaccines efficiently stimulate both Th1 and Th2 responses and that such vaccines may be more potent in high-risk groups than the currently used subunit vaccines.

Delivery of cytokines by liposomes. III. Liposome-encapsulated GM-CSF and TNF-alpha show improved pharmacokinetics and biological activity and reduced toxicity in mice

In an attempt to potentiate the therapeutic index of cytokines, recombinant mouse granulocyte/macrophage colony-stimulating factor (GM-CSF) and recombinant human tumor necrosis factor alpha (TNF-alpha) were encapsulated in large (0.3-2.2 microns) multilamellar vesicles composed of various lipids, using several encapsulation methods. Liposomal cytokine activity was tested in vitro and in vivo and was compared with that of the soluble cytokines. The main observations were as follows: (a) The mean encapsulation efficiency, as determined by bioassays, was 49-79%, depending on the formulation, for GM-CSF, and 48% for TNF-alpha; (b) some of the entrapped cytokine preparations displayed high stability at 4 degrees C, with < 30% loss of biologic activity during a 4-month period; (c) release of TNF-alpha, but not of GM-CSF, from the liposomes was required for their biological activity in vitro; (d) plasma half-lives (t1/2 alpha, t1/2 beta) and the area under the curve (AUC) of the entrapped cytokines were 10-20 times greater than those of the soluble cytokines; (e) the toxicity of liposomal TNF-alpha was one-third and one-seventh that of soluble TNF-alpha in normal and tumor-bearing mice, respectively; (f) administration of liposomal GM-CSF (5 x 10(4)-2 x 10(5) U, one to five times) to normal and 5-fluorouracil-treated mice led to a two- to fourfold increase in the absolute number of peritoneal and spleen leukocytes and of GM colony-forming cells in the spleen, as compared with the levels obtained using soluble GM-CSF; and (g) under the experimental conditions used, neither free nor liposomal GM-CSF significantly increased the absolute number of blood leukocytes, although liposomal GM-CSF markedly (threefold) enhanced the level of blood granulocytes. Collectively, these findings suggest that liposome-entrapped GM-CSF and TNF-alpha may be more efficacious immunomodulators than the soluble cytokines.