A conservative method of testing whether combination analgesics produce additive or synergistic effects using evidence from acute pain and migraine.

Fixed-dose combination analgesics are used widely, and available both on prescription and over-the-counter. Combination drugs should provide more analgesia than with any single drug in the combination, but there is no evidence in humans about whether oral combinations have just additive effects, or are synergistic or even subadditive. We suggest that the measured result for the combination would be the summation of the absolute benefit increase (effect of active drug minus effect of placebo) of each component of a combination if effects were (merely) additive, and greater than the sum of the absolute benefits if they were synergistic. We tested measured effects of combination analgesics against the sum of the absolute benefits in acute pain and migraine using meta-analysis where individual components and combinations were tested against placebo in the same trials, and verified the result with meta-analyses where individual components and combinations were tested against placebo in different trials. Results showed that expected numbers needed to treat (NNT) for additive effects were generally within the 95% confidence interval of measured NNTs. This was true for combinations of paracetamol plus ibuprofen and paracetamol plus opioids in acute pain, and naproxen plus sumatriptan in migraine, but not where efficacy was very low or very high, nor combinations of paracetamol plus dextropropoxyphene. There was no evidence of synergy, defined as supra-additive effects.

Systematic review of systematic reviews of acupuncture published 1996-2005.

Systematic reviews of acupuncture have tended to support its use, but few applied rigorous inclusion criteria. We tested the credibility of conclusions of systematic reviews of acupuncture published since 1996 by applying rigorous inclusion criteria. Reinterpretation used randomised and double blind trials with valid outcomes or design, and with information available from at least four trials or from 200 patients. Qualified support for acupuncture was originally reported in 12 out of 35 systematic reviews, and strong support was found in another six. Applying stricter inclusion criteria, however, showed that none of the 35 reviews supported acupuncture, predominantly because there were too few patients in the randomised, double blind studies. Six reviews with more than 200 patients in randomised, double blind studies had good evidence of no benefit. Systematic reviews of acupuncture have overstated effectiveness by including studies likely to be biased. They provide no robust evidence that acupuncture works for any indication.

Importance of dose of type II collagen in suppression of collagen-induced arthritis by nasal tolerance.

OBJECTIVE: To determine the influence of the dose of collagen given nasally on the induction of specific mucosal tolerance in collagen-induced arthritis. METHODS: The severity of clinical arthritis induced in DBA/1 mice was studied after the nasal administration (before disease induction) of 1 of 4 doses (across a 2-log range) of bovine type II collagen (CII). Parameters of immunity included lymphocyte proliferation and cytokine production in vitro in response to antigen stimulation, and the production of anticollagen IgG antibody subclasses. RESULTS: The 3 highest doses (20, 80, and 320 microg) ameliorated disease severity, whereas the lowest dose (5 microg) aggravated disease. These findings correlated well with antigen-specific T cell proliferation and cytokine and antibody production. T cell proliferation was suppressed by the higher doses of CII, whereas the low dose enhanced T cell proliferation, indicating it primed the T cells. Suppression of T cell proliferation could be overcome by the addition of exogenous interleukin-2 (IL-2) to these cultures. Decreased T cell proliferation was associated with suppression of both Th1 (interferon-gamma [IFNgamma]) and Th2 (IL-4) cytokines and all the subclasses of anticollagen IgG in mice receiving 20, 80, or 320 microg of collagen. Overall, the highest dose of collagen (320 microg) was less effective at suppressing the immune response and disease than the 20-microg or 80-microg doses. There was an increased production of antibodies of all IgG isotypes, and of the Th1-associated cytokines IFNgamma and IL-2, in animals that had received the lowest dose of 5 microg collagen nasally. CONCLUSION: Nasal administration of antigens is effective in inducing tolerance and reducing disease severity, but the effects are dose dependent. Low doses can prime the immune system and aggravate disease; high doses may not suppress disease. Suppression of the immune response, which correlates with suppression of disease, is not obviously associated with a type I to type II T cell switch, but rather with an overall suppression of both forms of T cell response, with a potential role for anergy of T cells in this process.

Novel chondroitin sulfate-modified ligands for L-selectin on lymph node high endothelial venules.

The migration of lymphocytes into lymph nodes via high endothelial venules (HEV) is dependent on the expression of L-selectin on the lymphocyte cell surface. HEV express several L-selectin ligands including CD34, GlyCAM-1, MAdCAM-1 and two sulfated glycoproteins (Sgp) of 200 kDa and 170 kDa which remain to be identified. In this investigation, labeling with sodium [35S]sulfate, which is incorporated into and forms part of the functional carbohydrate ligand, has been used to isolate and characterize macromolecular L-selectin ligands. High endothelial cells (HEC) cultured from rat lymph node HEV were shown to express ligands for L-selectin. HEC synthesized two groups of sulfated glycoproteins of 150 kDa and > 200 kDa, which were present in conditioned medium. These coeluted on anion exchange chromatography at 1.0-1.2 M NaCl and supported calcium-dependent L-selectin-mediated cell adhesion. In common with known L-selectin ligands, Sgp 150/> 200 were shown to be O-sialoglycoproteins; however, in contrast to other ligands, Sgp 150/> 200 contained chondroitin sulfate glycosaminoglycan modifications which were required for L-selectin recognition. Chondroitin sulfate-modified ligands for L-selectin were expressed at the HEC surface and by HEV in lymph nodes, suggesting that they may participate in lymphocyte interactions with HEV in vivo.

Analysis of T cell responses to the autoantigen in Goodpasture's disease.

Goodpasture's disease is a rare form of glomerulonephritis characterized by the production of autoantibodies to the glomerular basement membrane (GBM). In order to understand the development of autoimmunity to the GBM, it is important to examine mechanisms underlying T cell responses to the autoantigen. A MoAb P1, with the same specificity as patients' autoantibodies, was used to affinity-purify the antigen from collagenase-digested human GBM. This material was enriched in the NC1 domain of the alpha 3 chain of type IV collagen (alpha 3(IV)NC1), known to be the principal target of anti-GBM antibodies, but also contained lower quantities of alpha 4(IV)NC1. In proliferation assays, T cells from 11/14 patients with Goodpasture's disease showed significant responses (SI > or = 2.0) to affinity-purified human GBM. Peak responses were demonstrated at 7 or 10 days at antigen concentrations of 10-30 micrograms/ml. As in other autoimmune disorders, the presence of autoantigen-reactive T cells was also demonstrated in 5/10 healthy volunteers. Tissue typing revealed that all patients possessed HLA-DR2 and/or -DR4 alleles, while normal individuals whose T cells responded possessed DR2 and/or DR7 alleles. The specificity of the T cell response in Goodpasture's disease was further investigated using monomeric components of human GBM purified by gel filtration and reverse phase high performance liquid chromatography (HPLC). Two antigenic monomer pools were obtained, which were shown by amino-terminal sequence analysis to contain alpha 3(IV)NC1 and alpha 4(IV)NC1, respectively. In all patients tested, significant T cell proliferation was observed in response to one or both of these alpha (IV)NC1 domains. These results demonstrate that patients with Goodpasture's disease possess T cells reactive with autoantigens known to be recognized by anti-GBM antibodies.

Identification of the Goodpasture antigen, alpha 3(IV) NC1, and four other NC1 domains of type IV collagen, by amino-terminal sequence analysis of human glomerular basement membrane separated by two-dimensional electrophoresis.

Two-dimensional (2-D) electrophoresis of collagenase-digested human glomerular basement membrane (GBM), containing the Goodpasture antigen, revealed a range of monomeric (24-30 kD) and dimeric (43-56 kD) subunits present across a pI range of 3-10. Five distinct alpha(IV)-chains were identified by amino-terminal sequence analysis of 18 of these components transferred to polyvinylidene difluoride membrane. The positions of the well-characterised 26-kD alpha 1(IV)-chain and 24-kD alpha 2(IV)-chain were confirmed. A highly cationic 28-kD monomer was identified as the alpha 3(IV)-chain, while more neutral 28-kD monomers were found to contain the alpha 4(IV)-chain. Sequences from neutral 26-kD monomers corresponded to the known cDNA sequence of the alpha 5(IV)-chain. The presence of charge isoforms of the alpha 1(IV)- and alpha 4(IV)-chains was confirmed by identification of several monomers with different pI but the same sequence. Sequence analysis of dimeric components demonstrated homodimers of alpha 1(IV), alpha 2(IV) and alpha 4(IV), and suggested the presence of heterodimers of alpha 3/alpha 5 and alpha 1/alpha 5. 2-D Western blots of human GBM, with anti-GBM autoantibodies, a monoclonal antibody (P1) to the Goodpasture antigen and a monoclonal antibody to the alpha 3(IV)-chain, demonstrated that the major autoantigenic epitope was localised to the alpha 3(IV)-chain, but that there was also reactivity with the alpha 4(IV)-chain.

Tissue-specific distribution of the Goodpasture antigen demonstrated by 2-D electrophoresis and western blotting.

The target of autoantibodies in Goodpasture's disease, the Goodpasture antigen has recently been characterized as the NC1 domain of the alpha 3 chain of type IV collagen. In order to study the Goodpasture antigen in different organs, NC1 domains were isolated from basement membranes (BM) of human glomeruli (GBM), tubules (TBM), alveoli (ABM), placenta (PBM) and aorta (VBM). NC1 preparations were separated by 2-D electrophoresis, and silver stained or immunoblotted to determine the subunit structure and antigenicity of different basement membranes. All basement membranes contained monomeric components of MW 26 kDa and 24 kDa, and associated dimers, corresponding to the 2-D location of alpha 1(IV) and alpha 2(IV) chains respectively. However, GBM, ABM, and to a lesser extent TBM possessed an extra set of monomeric components of MW 28 kDa and associated dimers corresponding to the proposed location of alpha 3 (IV) and alpha 4 (IV) chains. 2-D-separated polypeptides were Western blotted with autoantibodies from patients with Goodpasture's disease, a monoclonal antibody to the Goodpasture antigen (P1) and a monoclonal antibody to the bovine alpha 3 (IV) chain. The predominant binding of all these reagents was to cationic 28 kDa monomers of GBM, ABM and TBM, corresponding to the alpha 3 (IV) chain, although autoantibodies and Pl also bound to neutral 28 kDa monomers, corresponding to the alpha 4 (IV) chain. Autoantibodies bound weakly to more neutral components of PBM and VBM, but neither monoclonal antibody bound to these basement membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Restricted specificity of the autoantibody response in Goodpasture's syndrome demonstrated by two-dimensional western blotting.

The autoantigen in Goodpasture's syndrome is known to be contained within the non-collagenous (NC1) domain of type IV collagen. We have examined the specificity of autoantibodies to glomerular basement membrane (GBM) using the technique of 2-D electrophoresis followed by Western blotting. Protein stains of 2-D gels of collagenase-digested human GBM revealed extensive charge and size heterogeneity. Major components were of mol. wt 24-30 kD and 43-56 kD, corresponding to monomeric and dimeric subunits of NCl. Western blotting of 2-D gels with IgG from patients with anti-GBM disease demonstrated that the most antigenic components migrated as cationic 28-kD monomers (pI 10) and similarly charged dimers, although other components were recognized less strongly. The mobility of the strongly antigenic polypeptides was different to that of the known alpha 1 and alpha 2 chains of type IV collagen. Autoantibodies from all 20 patients studied showed the same pattern of reactivity, regardless of their clinical features (in particular, the presence or absence of pulmonary haemorrhage) or HLA type. A monoclonal antibody (P1) to human GBM bound in a similar pattern, particularly recognizing the cationic components. 2-D gels of affinity-purified GBM from a P1 column showed enrichment of the 28-kD monomers, which were recognized by human autoantibodies on Western blotting. These results demonstrate that the autoimmune response in Goodpasture's syndrome is of restricted specificity, and support the suggestion that the major autoantigenic determinant is present on the novel alpha 3 chain of type IV collagen.