Uncoupling of bone metabolism in rheumatoid arthritis patients with or without joint destruction: assessment with serum type I collagen breakdown products.

In this study we investigate bone metabolism in patients with rheumatoid arthritis (RA), with or without joint destruction, using serum biochemical markers of bone turnover. Three hundred eighteen patients (disease duration >2 years; mean 9 years) were divided into those with joint destruction, that is, with Larsen wrist X-ray index > or =2 (n = 173) and those without joint destruction, that is, with Larsen wrist X-ray index <2 (n = 145). Bone formation was assessed by serum osteocalcin levels and bone resorption by a new assay for serum type I collagen C-telopeptide breakdown products (serum CTX). Osteocalcin levels were significantly lower in both destructive (-17%) and nondestructive (-22%) groups compared with 319 healthy gender- and age-matched control subjects (p < 0.001 for both groups), but were similar in the two arthritis groups. CTX levels were increased in patients with destructive arthritis compared with controls (+35%, p < 0.001), but were not different between those with nondestructive arthritis and controls. In patients with joint destruction, decreased bone formation rate was amplified in those on steroids (n = 72) compared with nonusers (n = 101) as demonstrated by lower osteocalcin levels (p = 0.02). CTX levels, but not osteocalcin levels, were positively correlated with indices of disease activity and, moreover, of joint destruction (p < 0.002-0.0001). These results indicate that bone metabolism is uncoupled in patients with RA. Bone formation appears to be reduced both in patients with and without joint destruction, whereas resorption is increased only in patients with joint destruction in relation to disease activity.

Possible genetic association between interleukin-1alpha gene polymorphism and the severity of chronic polyarthritis.

Interleukin-1 (IL-1) has been implicated in the pathogenesis of rheumatoid arthritis (RA). IL-1alpha gene polymorphism was analysed for the exon V and promoter region in 51 patients with destructive and 47 with non-destructive RA, as well as in 94 controls. The two biallelic polymorphisms in the promoter region and the exon V were 100% linked. The rare IL-1A2 allele carriage rate was 45% in the control population. It was increased in destructive (54.4%) and decreased in non-destructive RA (26.8%, destructive versus non-destructive, p < 0.007). All indices of disease activity and joint destruction were significantly lower in the patients positive for IL-1A1, and higher in those positive for IL-1A2. The present findings suggest that this IL-1alpha gene polymorphism may contribute to the pathogenesis of chronic polyarthritis. The presence of the IL-1A2 allele could constitute a risk factor for the development of destructive arthritis and could be used early in the course of the disease as a prognostic marker.

Elevated levels of soluble interleukin-1 receptor type II and interleukin-1 receptor antagonist in patients with chronic arthritis: correlations with markers of inflammation and joint destruction.

OBJECTIVE: To compare plasma levels of interleukin-1 receptor antagonist (IL-1Ra), soluble IL-1 receptor type I (sIL-1RI), and soluble IL-1 receptor type II (sIL-1RII) in patients with chronic polyarthritis, and to establish correlations between levels of these naturally occurring IL-1 inhibitors and indices of disease activity and joint destruction. METHODS: Levels of IL-1Ra, sIL-1RI, and sIL-1RII were measured in plasma samples from patients with chronic polyarthritis, using specific radioimmunoassays. Levels were correlated with indices of disease activity and joint destruction. RESULTS: Plasma levels of IL-1Ra, sIL-1RI, and sIL-1RII were significantly higher in polyarthritis patients than in controls. IL-1Ra levels correlated positively with all indices of disease activity and joint destruction (P < 0.0001). In contrast, sIL-1RII levels correlated negatively with indices of joint destruction, such as the Larsen score in the wrist (P < 0.04). Interestingly, sIL-1RII levels were higher in patients with nondestructive arthritis (Larsen score < or =1) than in patients with destructive arthritis. Levels of sIL-1RI did not correlate with indices of disease activity or joint destruction. CONCLUSION: The present findings indicate that increased levels of IL-1Ra, a natural antiinflammatory acute-phase protein, may reflect increased production and activity of IL-1. In contrast, endogenous sIL-1RII, unlike sIL-1RI, may constitute a natural antiinflammatory factor in chronic polyarthritis. These differences should be taken into account when these antiinflammatory molecules are considered as prognostic markers or for therapeutic use.

High levels of neutralizing autoantibodies against IL-1 alpha are associated with a better prognosis in chronic polyarthritis: a follow-up study.

Neutralizing autoantibodies to interleukin (IL)-1 alpha were detected in a subset of chronic polyarthritis patients characterized by an increased proportion of patients with primary Sjögren's syndrome or self-limiting inflammatory arthritis, diseases with a much better prognosis than rheumatoid arthritis (RA). The evolution of anti-IL-1 alpha antibody levels was followed over 3 years. Incidence and levels were higher in patients with a benign form of polyarthritis. In these patients levels remained stable or increased over the follow-up period. In contrast, incidence and levels were lower and some RA patients became negative. Negative correlations were observed between the levels of anti-IL-1 alpha antibodies and the clinical and biological indices of disease activity. The relative risk factor of developing RA was 12 in the absence of high anti-IL-1 alpha antibody levels and 18.2 when associated with the presence of HLA-DR4. In conclusion, the presence of anti-IL-1 alpha autoantibodies appears to be protective and their detection could represent a marker of good prognosis for destruction.

Increased incidence of neutralizing autoantibodies against interleukin-1 alpha (IL-1 alpha) in nondestructive chronic polyarthritis.

Cytokines such as IL-1 and tumor necrosis factor alpha (TNF alpha) play a critical role in chronic joint inflammation and destruction. To study their regulation, we looked for circulating antiproinflammatory cytokine autoantibodies in 318 patients with chronic arthritis by immunoprecipitation with protein G. Anti-IL-1 alpha but not anti-IL-1 beta or anti-TNF alpha IgG antibodies were detected in 9% of blood donors and 18.9% of chronic arthritis patients. These antibodies were found more commonly and at a higher level in patients with nondestructive arthritis. Negative correlations were observed between the antibody levels and indices of disease activity and joint destruction. There was a negative association between the presence of anti-IL-1 alpha antibodies and that of HLA-DR4. These circulating anti-IL-1 alpha antibodies were not complexed with IL-1 alpha and could block specifically the biological activity of IL-1 alpha and its binding to membrane IL-1 receptors. These results indicate that these antibodies are beneficial, suggesting their contribution in the clinical presentation.

Identification of human IgG autoantibodies specific for IL-10.

Since autoantibodies to IL-1alpha, interferon-alpha (IFN-alpha) and IL-6 have been described, this study concentrated on the search for autoantibodies to hIL-10 using an assay based on the precipitation of 125I-hIL-10 autoantibody complexes using Protein G-Sepharose. Among 1860 tested sera, only seven were found to specifically precipitate IL-10, thus indicating the rare occurrence of such autoantibodies. Four of those seven anti-IL-10 autoantibody sera were specific for hIL-10, two recognized both human and viral IL-10, while the last one recognized human, viral and murine IL-10, thus suggesting the existence of at least three different epitopic specificities. The purification of anti-IL-10 autoantibody from one serum demonstrated the existence of a single (IgG1, lambda) autoantibody that neutralized IL-10 biological activity. Thus, autoantibodies to IL-10 may represent natural antagonists to IL-10.

Sequence analysis of human coronavirus 229E mRNAs 4 and 5: evidence for polymorphism and homology with myelin basic protein.

Human coronaviruses (HCV) are important pathogens responsible for respiratory, gastrointestinal and possibly neurological disorders. To better understand the molecular biology of the prototype HCV-229E strain, the nucleotide sequence of the 5'-unique regions of mRNAs 4 and 5 were determined from cloned cDNAs. Sequence analysis of the cDNAs synthesized from mRNA 4 revealed a major difference with previously published results. However, polymerase chain reaction amplification of this region showed that the sequenced cDNAs were produced from minor RNA species, an indication of possible genetic polymorphism in this region of the viral genome. The mutated messenger RNA 4 contains two ORFs: (1) ORF4a consisting of 132 nucleotides which potentially encodes a 44-amino acid polypeptide of 4653 Da; this coding sequence is preceded by a consensus transcriptional initiation sequence, CUAAACU, similar to the ones found upstream of the N and M genes; (2) ORF4b of 249 nucleotides potentially encoding an 83-amino acid basic and leucine-rich polypeptide of 9550 Da. On the other hand, mRNA 5 contains one single ORF of 231 nucleotides which could encode a 77-amino acid basic and leucine-rich polypeptide of 9046 Da. This putative protein presents a significant degree of amino acid homology (33%) with its counterpart found in transmissible gastroenteritis coronavirus (TGEV). The proteins in the two different viruses exhibit similar molecular weights and are extremely hydrophobic. Interestingly, a sequence homology of five amino acids was found between the protein encoded by ORF4b of HCV-229E and an immunologically important region of human myelin basic protein.

Sequence analysis of the membrane protein gene of human coronavirus 229E.

Human coronaviruses (HCV) are ubiquitous pathogens which cause respiratory, gastrointestinal, and possibly neurological disorders. To better understand the molecular biology of the prototype HCV-229E strain, the complete nucleotide sequence of the membrane protein (M) gene was determined from cloned cDNA. The open reading frame is preceded by a consensus transcriptional initiation sequence UCUAAACU, identical to the one found upstream of the N gene. The M gene encodes a 225-amino acid polypeptide with a molecular weight (MW) of 25,822, slightly higher than the apparent MW of 19,000-22,000 observed for the unprocessed M protein obtained after in vitro translation and immunoprecipitation. The M amino acid sequence presents a significant degree of homology (38%) with its counterpart of transmissible gastroenteritis coronavirus (TGEV). The M protein of HCV-229E is highly hydrophobic and its hydropathicity profile shows a transmembranous region composed of three major hydrophobic domains characteristic of a typical coronavirus M protein. About 10% (20 amino acids) of the HCV-229E M protein constitutes a hydrophilic and probably external portion. One N-glycosylation and three potential O-glycosylation sites are found in this exposed domain.

Cloning, physical mapping and cross-hybridization of the canine adenovirus types 1 and 2 genomes.

Cloned HindIII fragments of the type 1 and type 2 canine adenovirus (canAd) genomes were mapped with respect to the BamHI, EcoRI, HincII, PaeR7 and PstI restriction endonuclease cleavage sites. Considering the large differences found between the canAd-1 and canAd-2 DNA molecules, in terms of number and location of restriction sites, cross-hybridization experiments were performed. Homologous DNA sequences were located on the canAd-1 and canAd-2 physical maps. Both viruses are genetically related to the extent of 57%. Our results confirm the existence of two distinct Ad species in the dog.

Genotypic characterization of type-2 variants of canine adenovirus.

Two canine adenovirus (CAV) isolates, apparently distinct from type-1 (Utrecht) and type-2 (Toronto A26/61) reference strains in their biochemical and/or immunologic properties, were submitted to DNA-restriction endonuclease analysis. Both isolates, designated IAF-81-2116 and IAF-75-95, appeared as genotypic variants of CAV-2. Isolate IAF-81-2116 was recovered from the intestine of a young pup with diarrheal disease. Seemingly, relatively small changes in the original CAV-2 DNA sequence allowed the virus to replicate at an unusual site in the dog.

Comparative analysis of the canAV-1 and canAV-2 genomes.

The molecular weights of canine adenovirus type 1 (canAV-1, strain Utrecht) and type 2 (canAV-2, strain Toronto A26/61) DNAs were determined by contour length measurements and restriction endonuclease analysis. In each case, an average molecular weight value of 20 (+/- 0.5) X 10(6) daltons was obtained with both methods. Similar in size, the canAV-1 and canAV-2 DNA molecules were, however, cleaved at very distinct positions by a variety of restriction endonucleases. The observed lack of DNA sequence homology confirms the existence of at least two different canine adenovirus species [Intervirology 23: 23-28 (1985)].

[Intracellular changes induced by the canine infectious laryngotracheitis virus (CAV-2)]. / Modifications intracellulaires induites par le virus de la laryngotrachéite infectieuse canine (CAV-2).

Canine infectious laryngotracheitis virus, an adenovirus designated CAV-2, induces numerous changes in the nucleus and cytoplasm of canine kidney cells (MDCK). The following features could be observed on ultrathin sections examined in the electron microscope: a shift of the nucleolus towards the nuclear membrane and a compression of the latter by the virus particles; the release of virions into the cytoplasm following the tearing or evagination of the nuclear membrane; the attachment of virus particles onto the numerous microtubules of the infected cell. Microfilaments appear to be involved into the vectorial movement of virus particles towards the cytoplasmic membrane in the final phase of infection.