Broad proteomic screen reveals shared serum proteomic signature in patients with psoriatic arthritis and psoriasis without arthritis.

OBJECTIVE: To identify novel serum proteins involved in the pathogenesis of PsA as compared with healthy controls, psoriasis (Pso) and AS, and to explore which proteins best correlated to major clinical features of the disease. METHODS: A high-throughput serum biomarker platform (Olink) was used to assess the level of 951 unique proteins in serum of patients with PsA (n = 20), Pso (n = 18) and AS (n = 19), as well as healthy controls (HC, n = 20). Pso and PsA were matched for Psoriasis Area and Severity Index (PASI) and other clinical parameters. RESULTS: We found 68 differentially expressed proteins (DEPs) in PsA as compared with HC. Of those DEPs, 48 proteins (71%) were also dysregulated in Pso and/or AS. Strikingly, there were no DEPs when comparing PsA with Pso directly. On the contrary, hierarchical cluster analysis and multidimensional scaling revealed that HC clustered distinctly from all patients, and that PsA and Pso grouped together. The number of swollen joints had the strongest positive correlation to ICAM-1 (r = 0.81, P < 0.001) and CCL18 (0.76, P < 0.001). PASI score was best correlated to PI3 (r = 0.54, P < 0.001) and IL-17 receptor A (r = -0.51, P < 0.01). There were more proteins correlated to PASI score when analysing Pso and PsA patients separately, as compared with analysing Pso and PsA patients pooled together. CONCLUSION: PsA and Pso patients share a serum proteomic signature, which supports the concept of a single psoriatic spectrum of disease. Future studies should target skin and synovial tissues to uncover differences in local factors driving arthritis development in Pso.

Effectiveness of Remission Induction Strategies for Early Rheumatoid Arthritis: a Systematic Literature Review.

PURPOSE OF REVIEW: To review the effectiveness of remission induction strategies compared to single csDMARD-initiating strategies according to current guidelines in early RA. RECENT FINDINGS: Twenty-nine studies, heterogeneous on, e.g., specific treatment strategy and remission outcome used, were identified. Using DAS28-remission over 12 months, 13 (76%) of 17 remission induction strategies showed significantly more patients achieving remission. Pooled relative "risk" was 1.73 [95%CI 1.59-1.88] for bDMARD-based remission induction strategies and 1.20 [95%CI 1.03-1.40] for combination csDMARD-based remission induction strategies compared to single csDMARD-initiating strategies. When additional glucocorticoid "bridging therapy" was used in single csDMARD-initiating strategies, the higher proportion patients achieving remission in remission induction strategies was no longer statistically significant (pooled RR 1.06 [95%CI 0.83-1.35]). For other remission outcomes, results were in line with above. Remission induction strategies are more effective in achieving remission compared to single csDMARD-initiating strategies, possibly more so in bDMARD-based induction strategies. However, compared to single csDMARD-initiating strategies with glucocorticoids, induction strategies may not be more effective.

Suppression of bone turnover by B-cell depletion in patients with rheumatoid arthritis.

UNLABELLED: The role of B cells in inflammatory bone formation and resorption is controversial. We investigated this in patients with rheumatoid arthritis (RA) treated with rituximab, a B-cell depleting antibody. We found a significant suppression in bone turnover, possibly a direct effect or as a consequence of a reduction in inflammation and disease activity. INTRODUCTION: RA is the most prevalent inflammatory joint disease, in which B cells play an important role. However, the role of B cells in bone turnover is controversial and RA subjects treated with rituximab, a B-cell depleting monoclonal antibody, provide an ideal model for determining the role of B cells in inflammatory bone resorption. METHODS: Serum from 46 RA patients, collected pre- and post-rituximab therapy, was analysed for biomarkers of bone turnover (procollagen type I amino-terminal propeptide [P1NP], osteocalcin, ß-isomerised carboxy-terminal telopeptide of type 1 collagen [ßCTX] and osteoprotegerin [OPG]). RESULTS: A significant decrease in bone resorption was observed 6 months after rituximab (median change ßCTX -50 ng/L, 95%CI -136, -8 p < 0.001, this equates to -37%; 95%CI -6, -49), mirrored by a reduction in disease activity. Similarly, there was a significant increase in P1NP, a marker of bone formation (median change P1NP 5.0 µg/L, 95%CI -1.0, 11.2, p = 0.02; 13%; 95%CI -3, 39), but no significant change in osteocalcin or OPG levels. The percentage change from baseline of ßCTX in a subgroup of patients (not on prednisolone or bisphosphonate) was significantly correlated with the percentage reduction in DAS28 score (r (s) = 0.570, p = 0.014). CONCLUSIONS: In conclusion, we have found that B-cell depletion increases bone formation and decreases bone resorption in RA patients; this may be a direct effect on osteoblasts and osteoclasts, respectively, and be at least partially explained by the decreased inflammation and disease activity.

Decrease in immunoglobulin free light chains in patients with rheumatoid arthritis upon rituximab (anti-CD20) treatment correlates with decrease in disease activity.

OBJECTIVES: Immunoglobulin (Ig) free light chains (FLCs) are short-lived B cell products that contribute to inflammation in several experimental disease models. In this study, FLC concentrations in inflamed joints of patients with rheumatoid arthritis (RA) as compared to patients with osteoarthritis were investigated. In addition, the relationship of FLCs and disease activity upon B cell depletion (rituximab) in patients with RA was studied. METHODS: Synovial fluid (SF) and tissue from patients with RA were analysed for local presence of FLCs using ELISA and immunohistochemistry. In addition, FLC concentrations were measured (at baseline, 3 and 6 months after treatment) in 50 patients with RA with active disease who were treated with rituximab. Changes in FLCs were correlated to changes in disease activity and compared to alterations in IgM, IgG, IgA, IgM-rheumatoid factor (RF) and IgG-anti-citrullinated protein antibody (ACPA) concentrations. RESULTS: FLCs were detected in synovial tissue from patients with RA, and high FLC concentrations were found in SF from inflamed joints, which positively correlate with serum FLC concentrations. Serum FLC concentrations significantly correlated with disease activity score using 28 joint counts, erythrocyte sedimentation rate (ESR) and C reactive protein, and changes in FLC correlated with clinical improvement after rituximab treatment. Moreover, effect of treatment on FLC concentrations discriminated clinical responders from non-responders, whereas IgM-RF and IgG-ACPA significantly decreased in both patient groups. CONCLUSIONS: FLCs are abundantly present in inflamed joints and FLC levels correlate with disease activity. The correlation of FLC concentrations and disease activity indicates that FLCs may be relevant biomarkers for treatment response to rituximab in patients with RA and suggests that targeting FLC may be of importance in the therapy of RA.

The multi-biomarker disease activity test for assessing response to treatment strategies using methotrexate with or without prednisone in the CAMERA-II trial.

OBJECTIVES: The CAMERA-II trial compared two tight-control, treat-to-target strategies, initiating methotrexate with prednisone (MTX+pred) or MTX with placebo (MTX+plac), in early RA-patients. The multi-biomarker disease activity (MBDA) blood test objectively measures RA disease activity with a score of 1-100. In CAMERA-II, response profiles of the MBDA score, its individual biomarkers, and DAS28 were assessed. METHODS: We evaluated 92 patients from CAMERA-II of whom clinical data and serum for MBDA testing at baseline and ≥ 1 time-point from months 1, 2, 3, 4, 5, 6, 9, or 12 were available. Changes (∆) from baseline for DAS28 and MBDA score and comparisons of ∆DAS28 and ∆MBDA score over time within the MTX+pred versus the MTX+plac strategy were tested for significance with t tests. Changes in biomarker concentration from baseline to months 1-5 were tested with Wilcoxon signed rank test and tested for difference between treatment arms by Mann-Whitney U test. RESULTS: MBDA and DAS28 showed similar response profiles, with gradual improvement over the first 6 months in the MTX+plac group, and in the MTX+pred group faster improvement during month 1, followed by gradual improvement. The 12 MBDA biomarkers could be grouped into 4 categories of response profiles, with significant responses for 4 biomarkers during the MTX+plac strategy and 9 biomarkers during the MTX+pred strategy. CONCLUSIONS: MBDA tracked treatment response in CAMERA-II similarly to DAS28. More individual MBDA biomarkers tracked treatment response to MTX+pred than to MTX+plac. Four response profiles could be observed. TRIAL REGISTRATION: CAMERA-II International Standard Randomised Controlled Trial Number: ISRCTN 70365169 . Registered on 29 March 2006, retrospectively registered.

A Dutch consensus statement on the diagnosis and treatment of ANCA-associated vasculitis.

INTRODUCTION: Despite the availability of several guidelines on the diagnosis and treatment of antineutrophil cytoplasmic antibody-associated vasculitis (AAV), clinical routine practice will only improve when an implementation strategy is in place to support clinical decision making and adequate implementation of guidelines. We describe here an initiative to establish national and multidisciplinary consensus on broad aspects of the diagnosis and treatment of AAV relevant to daily clinical practice in the Netherlands. METHODS: A multidisciplinary working group of physicians in the Netherlands with expertise on AAV addressed the broad spectrum of diagnosis, terminology, and immunosuppressive and non-immunosuppressive treatment, including an algorithm for AAV patients. Based on recommendations from (inter)national guidelines, national consensus was established using a Delphi-based method during a conference in conjunction with a nationally distributed online consensus survey. Cut-off for consensus was 70% (dis)agreement. RESULTS: Ninety-eight professionals were involved in the Delphi procedure to assess consensus on 50 statements regarding diagnosis, treatment, and organisation of care for AAV patients. Consensus was achieved for 37/50 statements (74%) in different domains of diagnosis and treatment of AAV including consensus on the treatment algorithm for AAV. CONCLUSION: We present a national, multidisciplinary consensus on a diagnostic strategy and treatment algorithm for AAV patients as part of the implementation of (inter)national guideline-derived recommendations in the Netherlands. Future studies will focus on evaluating local implementation of treatment protocols for AAV, and assessments of current and future clinical practice variation in the care for AAV patients in the Netherlands.

Novel optical spectral transmission (OST)-guided versus conventionally disease activity-guided treatment: study protocol of a randomized clinical trial on guidance of a treat-to-target strategy for early rheumatoid arthritis.

BACKGROUND: Assessment of disease activity is a critical component of tight-control, treat-to-target treatment strategies of rheumatoid arthritis (RA). Recently, the HandScan has been validated as a novel method for objectively assessing RA disease activity in only 1.5 min, using optical spectral transmission (OST) in hands and wrists. We describe the protocol of a randomized controlled clinical trial (RCT) to investigate whether HandScan-guided treatment aimed at 'HandScan remission' (HandScan arm) is at least as effective as and more cost-effective than clinically guided treatment aimed at ACR/EULAR 2011 Boolean remission (DAS arm). METHODS/DESIGN: The study is a multi-center, double-blind, non-inferiority RCT of 18 months duration. Patients ≥ 18 years with newly diagnosed, disease-modifying antirheumatic drug (DMARD)-naïve RA according to the ACR 2010 classification criteria, will be randomized to the DAS arm or the HandScan arm. The efficacy of the arms will be compared by evaluating Health Assessment Questionnaire (HAQ) scores (primary outcome) after 18 months of DMARD therapy, aimed at remission. The equivalence margin in HAQ scores between study arms is 0.2. Secondary outcomes are differences in cost-effectiveness and radiographic joint damage between treatment arms. The non-inferiority sample size calculation to obtain a power of 80% at a one-sided p value of 0.05, with 10% dropouts, resulted in 61 patients per arm. In both arms, DMARD strategy will be intensified monthly according to predefined steps until remission is achieved; in both arms DMARDs and treatment steps are identical. If sustained remission, defined as remission that persists consistently over three consecutive months, is achieved, DMARD therapy will be tapered. DISCUSSION: The study protocol and the specifically designed decision-making software application allow for implementation of this RCT. To test a novel method of assessing disease activity and comparing (cost-)effectiveness with the contemporary method in treat-to-target DMARD strategies in early RA patients. TRIAL REGISTRATION: Dutch Trial Register, NTR6388. Registered on 6 April 2017 ( NL50026.041.14 ). Protocol version 3.0, 19-01-2017.

A functional study on the migration of human monocytes to human leukemic cell lines and the role of monocyte chemoattractant protein-1.

In the present study the migration of human monocytes towards the supernatants of five different human myeloid leukemic cell lines, four different human lymphatic leukemic cell lines and blasts derived from three different patients with acute myeloid leukemia (AML) was studied and the role of monocyte chemoattractant protein (MCP)-1 was established with an ELISA assay. Large differences in migration of monocytes towards the leukemic cell supernatants were shown (variation of approximately 10 to 150% compared to positive control), but high amounts of monocyte migration was always restricted to myeloid leukemic cells (cell lines or patient blasts). MCP-1 turned out to play a major role in the migration, firstly since there was a direct correlation between the amount of migration and the concentration of MCP-1 in the supernatants, and secondly since the addition of anti-hMCP-1 was able to inhibit migration to background level in all cases. Cytotoxicity experiments with a MTT test using MCP-1-stimulated monocytes against two human myeloid leukemic cell lines showed no increase in cell death compared to unstimulated monocytes. It is concluded that monocyte migration towards leukemic cells is restricted to the myeloid lineage and is regulated by MCP-1, which is produced in different amounts by the leukemic cells. Besides, MCP-1 does not increase the direct toxic effects of monocytes on leukemic cells.

Quantification of natural antibody producing B cells in rats by an improved ELISPOT technique using the polyvinylidene difluoride membrane as the solid support.

We describe here a new type of solid support for the ELISPOT assay, the PVDF membrane. In parallel tests, spot yields on this membrane were superior to those obtained with the frequently used nitrocellulose (NC) membrane, coated with the same rat anti-IgM and anti-IgG antibodies, incubated with the same rat spleen cell suspensions, and developed with the same combination of AP-labeled conjugates and substrate. We therefore used the PVDF membrane, coated with anti-rat IgM and IgG antibodies, ssDNA or bromelain-treated mouse erythrocytes (BrMRBC) (exposing phosphatidylcholine (PC) as major autoantigen) to develop ELISPOT assays for the quantification of isotype-specific natural antibody secreting cells (ASC) in rats. We confirmed the isotype specificity of the binding of the anti-rat IgM and anti-rat IgG coating antibodies and conjugates with the secreted rat antibodies in this assay, and, by inhibition of spot formation with soluble antigen, their specificity for ssDNA and BrMRBC. An in-house 18-well culture device for the easy manufacture of PVDF-lined culture wells greatly facilitated coating, blocking, and washing procedures, as compared to the original method in 24 well culture plates. This simple, fast, specific and sensitive ELISPOT assay was used to make an inventory of the numbers of natural splenic ASC in Wistar and Fischer rats.

Detection of CD 14 on migrated monocytes by specific antibody: a possible quantification for blood monocyte chemotaxis.

In the present study we investigated the possibility to use antigen-antibody recognition for detection of monocyte chemotaxis in the 48-well microchamber assay. The described method is based on recognition of cell-specific antigenic determinants present on the migrated monocytes. After conventional 48-well chemotaxis, the migrated cells were incubated with an antibody against the monocyte surface marker CD14 (3C10 hybridoma). Subsequent incubation with enzyme-coupled antibodies and their substrate allowed the antigen and hence the migrated cells carrying this antigen, to be detected and measured in a microplate reader. Our results show that chemotaxis of normal blood monocytes towards the monocyte chemoattractants FMLP and MCP-1 could be detected with the anti-CD14 antibody 3C10 in combination with a horse-radish peroxidase coupled antibody, and that the optical density is a measure for cell number per well (positive correlation, r = 0.95). Incubation of monocytes with the applied chemoattractants FMLP and MCP-1 did not change the CD14 expression as was determined by FACScan analysis. Therefore we conclude that it is possible to use antibodies directed against antigenic determinants like CD14 to detect blood monocyte migration in a more objective way compared to subjective counting of cells on a filter. Eventually, this method can be valuable, especially for chemokine research since chemokines exert their effects on specific target cell populations. By varying the detection antibody, other cell populations besides monocytes may be quantified.

The Systemic Lupus Erythematosus Responder Index (SRI); a new SLE disease activity assessment.

Systemic Lupus Erythematosus (SLE), because of its complex and multisystemic presentation, lacks a reliable and sensitive gold standard for measuring disease activity. In addition, there is no standardized method for defining response to therapy. Several disease activity indices have been developed over the years, each with their own positive and negative aspects. Growing insight in the pathogenesis of inflammatory diseases like SLE leads to the introduction of specific targeted biologic therapies. To investigate the efficacy of these new biologic agents, disease activity must be monitored regularly by a reliable and validated instrument. Recent studies on new biologics for treatment of SLE use a new composite measurement for disease activity and response in SLE. This new disease activity assessment, called SLE Responder Index (SRI), comprises criteria from three different internationally validated indices, SELENA-SLE Disease Activity Index (SELENA-SLEDAI), Physician Global Assessment (PGA) and the British Isles Lupus Assessment Group (BILAG) 2004. This review gives an overview of current available disease activity indices in relation to the newly developed composite SRI.

Autoimmune effects of hexachlorobenzene in the rat.

We investigated whether autoimmune disregulation underlies the formerly reported induction of IgM hypergammaglobulinemia and lymphoid organ enlargement by hexachlorobenzene (HCB) in rats. To this end blood, liver, and lymphoid organs were collected from male Wistar rats after feeding a semisynthetic diet containing 0, 500, or 1000 mg HCB/kg for 3 weeks. Sera prepared from the blood were analyzed for total and (auto)antigen-specific antibody levels by ELISA, organs were weighed, and spleens were further investigated morphologically using immunohistochemically stained cryosections. Present experiments confirmed the ability of HCB to increase total IgM, but not IgG, levels and to increase relative spleen, lymph node, and liver weights. HCB treatment elevated IgM, but not IgG, levels against single-stranded DNA, native DNA, rat IgG (representing rheumatoid factor), and bromelain-treated mouse erythrocytes that expose phosphatidylcholine as a major autoantigen. Antibody levels against the foreign antigens sheep erythrocytes, tetanus toxoid, and bovine serum albumin remained unaffected. The IgM autoantibodies proved to be polyreactive. Morphometric analysis of spleen sections showed that HCB caused a proportionally equal expansion of all splenic compartments, but when individual spleen weights were taken into account a significantly larger expansion of the predominantly B cell-containing marginal zones could be noted. The latter compartment also contained an increased number of macrophages that can be recognized by the monoclonal antibody ED3. The ability of HCB to elevate serum antibody levels against autoantigens, but not foreign antigens, indicates that HCB probably does not act by polyclonal B cell activation. The IgM isotype, the repertoire, and the polyreactivity of the serum autoantibodies suggest that HCB activates a recently described B cell subset shown to be committed to the production of these autoantibodies and associated with various systemic autoimmune diseases. Since the marginal zone is considered to be the splenic lodging site of this B cell subset and since increases of ED3+ macrophages have been associated with autoimmune diseases in the rat, the observed changes of the marginal zones in HCB-treated rats is in line with this notion.

Analysis of monocyte chemotactic protein-1 production in different major histocompatability complex-restricted antigen presentation systems.

In the present study the production of the CC chemokine monocyte chemotactic protein-1 (MCP-1) in several MHC II-restricted antigen presentation systems was investigated in vitro. To assess which type of antigen-presenting cell (APC) influences MCP-1 production during antigen presentation, cultures enriched for different APC populations were prepared and MCP-1 production was determined. Our results showed that APCs that effectively induce a T cell response also produce elevated amounts of MCP-1. The MCP-1 production is highest in the memory-driven secondary response against a single antigen. Despite a massive T cell proliferation, low MCP-1 concentrations are found in Con A-induced cultures. These results suggest that T cell proliferation alone is not sufficient for MCP-1 production and that stimulation of the APC during the process of antigen presentation results in MCP-1 production. Based on our results and the literature, we propose a model for MCP-1 as an enhancer of the adaptive immune response.

Identification of the major chemokines that regulate cell influxes in peritoneal dialysis patients.

To investigate which members of the recently discovered family of chemotactic cytokines (chemokines) are important in leukocyte recruitment to a bacterial inflammation site, four different chemokines in the effluent of peritoneal dialysis patients suffering from acute bacterial peritonitis were measured. The presence of two neutrophil-attracting chemokines, interleukin-8 and human melanoma growth-stimulating activity (huGRO alpha), and two monocyte-attracting members of the chemokine superfamily, monocyte chemotactic protein-1 (MCP-1) and regulated on activation normal T cell expressed and secreted (RANTES), was investigated in patient effluents just before, during, and after a peritonitis episode. This was studied in seven peritonitis effluents of five patients by using chemokine-specific enzyme-linked immunosorbent assays. Cell populations in the dialysates were differentiated on cytocentrifuge preparations. The contribution of the detected chemokines to neutrophilic and monocytic cell influxes in the inflamed peritoneal cavity was analyzed by correlating concentrations of chemokines to the relevant cell numbers present in the dialysates of these patients. The detection of the neutrophil-attracting chemokine interleukin-8 during peritonitis was in accordance with other studies. Moreover, a second neutrophil chemoattractant, huGRO alpha, was identified in vivo. Both were elevated during inflammation (P < 0.02) and contributed significantly to the neutrophilic cell influx (P < 0.05). One of the monocyte-attracting chemokines, RANTES, could not be detected in any of the effluents, whereas the other, MCP-1, was significantly elevated during peritonitis (P < 0.02). In contrast to the other chemokines measured, MCP-1 concentration was relatively high in steady-state peritoneal dialysates. An absolute correlation between dialysate MCP-1 concentration and the number of macrophages in these effluents was absent. However, in a 48-well chemotaxis assay, monocyte migration toward peritonitis, as well as steady-state patient dialysates, could be blocked with antibodies to MCP-1. It was concluded, therefore, that MCP-1 is the most important monocyte chemoattractant in peritoneal dialysis steady-state and peritonitis patients; whereas, besides interleukin-8, huGRO alpha was identified as a major neutrophil-attracting chemokine in the peritonitis situation.

Expression of MCP-1 by reactive astrocytes in demyelinating multiple sclerosis lesions.

The pathology of multiple sclerosis (MS) is characterized by breakdown of the blood-brain barrier (BBB), accompanied by infiltration of macrophages and T lymphocytes into the central nervous system (CNS). The migration of these cells into the CNS parenchyma may be partly regulated by chemokines. The aim of this study was therefore to investigate the cellular localization of the potent monocyte- and T-cell-attracting chemokine monocyte chemoattractant protein (MCP)-1 by immunohistochemistry on postmortem brain tissue from MS and normal control cases. Brain tissue samples of six MS patients and four patients without a history of brain disease were neuropathologically classified according to characteristic (immuno)histochemical staining patterns. Frozen tissue sections of active demyelinating MS lesions, chronic active demyelinating MS lesions, and normal control brain were immunohistochemically stained with a monoclonal antibody directed against MCP-1. In active demyelinating MS lesions as well as in chronic active MS lesions, reactive hypertrophic astrocytes were strongly immunoreactive for MCP-1, whereas perivascular and parenchymal foamy macrophages did not express MCP-1 protein. These results suggest a significant role for the beta-chemokine MCP-1, synthesized in vivo by reactive hypertrophic astrocytes, in the recruitment and activation of myelin-degrading macrophages and thereby contributing to the evolution of MS lesions.

Infection of human endothelial cells with Staphylococcus aureus induces the production of monocyte chemotactic protein-1 (MCP-1) and monocyte chemotaxis.

Bacterial infection coincides with migration of leucocytes from the circulation into the bacterium-infected tissue. Recently, we have shown that endothelial cells, upon binding and ingestion of Staphylococcus aureus, exhibit proinflammatory properties including procoagulant activity and increased intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression on the cell surface, resulting in hyperadhesiveness, mainly for monocytes. The enhanced extravasation of monocytes to bacterium-infected sites is facilitated by the local production of chemotactic factors. From another study we concluded that the locally produced chemokine MCP-1 is important in the recruitment of monocytes to the peritoneal cavity in a model of bacterial peritonitis. In the present study we investigated whether cultured human endothelial cells after infection with bacteria produce and release MCP-1, which in turn stimulates monocyte chemotaxis. We observed that endothelial cells released significant amounts of MCP-1 within 48 h after ingestion of S. aureus. This was dependent on the number and the virulence of the bacteria used to infect the endothelial cells. The kinetics as well as the amount of MCP-1 released by S. aureus-infected endothelial cells differed markedly from that released by endothelial cells upon stimulation with IL-1beta. Supernatant from S. aureus-infected or IL-1beta-stimulated cells promoted monocyte chemotaxis which was almost entirely abrogated in the presence of neutralizing anti-MCP-1 antibody, indicating that most of the chemotactic activity was due to the release of MCP-1 into the supernatant. Our findings support the notion that endothelial cells can actively initiate and sustain an inflammatory response after an encounter with pathogenic microorganisms, without the intervention of macrophage-derived proinflammatory cytokines.