A therapeutic human IgG4 monoclonal antibody that depletes target cells in humans

It is traditionally held that human IgG4 MoAbs should not deplete target cells in vivo, as this isotype is inactive in a number of in vitro assays that measure effector function. We have previously challenged this dogma, and the current study was designed to investigate the in vivo biological effects in humans of a MoAb of human IgG4 isotype. Nine patients with refractory rheumatoid arthritis (RA) fulfilling ARA criteria, and one with ankylosing spondylitis (AS) received a human IgG4 Campath-1 MoAb (with specificity against the pan-lymphocyte antigen CD52) as part of a two-stage therapeutic protocol. In stage 1, patients received a single dose of this MoAb. Stage 2, starting 48 h later, comprised a 5-day course of a human IgG1 Campath-1 MoAb with identical V-region (CAMPATH-1H), as previously used in the management of RA patients. The intervening 48 h provided a window of opportunity to monitor the biological effects of the IgG4 MoAb for comparison with the IgG1. The two MoAbs were also compared for in vitro biological activity. IgG4 depleted peripheral blood lymphocytes (PBL), albeit less efficiently than IgG1. It produced a first-dose reaction of similar intensity, although associated circulating tumour necrosis factor-alpha (TNF-alpha) levels were lower. TNF-alpha release from whole blood in vitro was also greater with the IgG1 MoAb. The study design did not permit conclusions to be drawn regarding therapeutic efficacy of the IgG4 MoAb. In summary, a human IgG4 Campath-1 MoAb depletes target cells in vivo. Importantly, this study demonstrates for the first time in humans that in vitro assays may not predict the in vivo effector function of therapeutic MoAbs.

Tenascin-C and human tendon degeneration

We investigated the distribution of tenascin in supraspinatus tendons to determine whether an alteration in tenascin expression was associated with human tendon degeneration. Tenascin was present in all of the tendons studied, although with two distinct patterns of expression. First, tenascin was associated with organized, fibrous regions of the tendon matrix that were typical of the normal tendon structure. This distribution is consistent with a role for tenascin in collagen fibril organization, perhaps maintaining the interface between fibrils and adjacent structures. Second, although tenascin was generally absent from poorly organized matrix in degenerate tendons, it was strongly associated with some rounded cells in disorganized fibrocartilaginous regions that were more abundant in pathological specimens. Tenascin was also found around infiltrating blood vessels, with more intense staining associated with a mononuclear cell infiltrate. Western blotting of tendon extracts showed differences in tenascin isoform expression, with only the small (200-kd) tenascin isoform found in normal tendons. Degenerate tendons also expressed the 300-kd isoform, consistent with a role for the larger tenascin isoform in tendon disease, potentially stimulating tenocyte proliferation, cell rounding, and fibrocartilaginous change. Proteolytic fragments of tenascin were detected but only in ruptured tendons, an indication of matrix remodeling in degenerate tendons, with fragment sizes consistent with the activity of matrix metalloproteinase enzymes.

Monoclonal antibody therapy of diffuse cutaneous scleroderma with CAMPATH-1H

A worker in a polyvinyl chloride factory with rapidly progressive diffuse cutaneous scleroderma was treated with the humanized monoclonal antibody (Mab) CAMPATH-1H. Treatment was followed by rapid and substantial improvement in skin score, which was maintained during followup without additional therapy. The mode of action of CAMPATH-1H and its relationship to clinical improvement are discussed.

Survival after aortic dissection in giant cell arteritis

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CAMPATH-1H in rheumatoid arthritis--an intravenous dose-ranging study

Forty-one patients with active and refractory rheumatoid arthritis(RA) received a total of 100, 250 or 400 mg of CAMPATH-1H (CAMPATH is a trademark of Glaxo-Wellcome group companies, registered in the US Patent and Trademark Office) over 5 or 10 days in an open, uncontrolled study. Following therapy, patients were monitored for adverse effects and disease activity for 6 months. Therapy was associated with prolonged peripheral blood lymphopenia in all dosing cohorts. During the month immediately following therapy, lymphopenia was most profound in the 400 mg cohorts. The first dose of monoclonal antibody (Mab) was associated with a 'flu'-like syndrome, more pronounced at higher initial doses. One patient developed haemolytic-uraemic syndrome. There were a number of dose-related infections during the early post-treatment period and one fatal opportunistic infection which followed additional immunosuppressive therapy. Antiglobulin responses developed in 9 of 31 patients tested. The majority of patients showed symptomatic improvement following therapy and 20% of patients maintained a 50% Paulus response at 6 months, all of whom were in the 250 or 400 mg cohorts. CAMPATH-1H appears to be an effective treatment for RA. Allowing for the small number of patients treated, infections were more common with higher doses, although this was not true for adverse events overall, and therapeutic responses were more sustained at higher dosing levels. The broad specificity of CAMPATH-1H may be appropriate for the immunotherapy of RA and future studies should aim to define a dose with an optimal therapeutic ratio.

Prevalence and possible pathological significance of calcium phosphate salt accumulation in tendon matrix degeneration

OBJECTIVES

To investigate the prevalence of calcium phosphate mineral salt accumulation in degenerative supraspinatus 'tendinitis' compared with a normal sample of human tendons, and to determine whether there is an association of calcium salt deposition with pathological changes in the tendon extracellular matrix.

METHODS

Cadaver tendons (supraspinatus and common biceps tendons, n = 96) and fragments of supraspinatus tendons obtained during shoulder surgery (n = 31) were analysed for calcium content by atomic absorption spectroscopy, phosphorous content using a spectrophotometric assay, and matrix composition (collagen, glycosaminoglycans and DNA) using standard biochemical techniques.

RESULTS

We established baseline values of calcium concentration in macroscopically normal cadaver tendons (mean 1.1 (SD 0.35) micrograms/mg dry wt, n = 60) and found that 33% (nine of 27) of ruptured tendons from patients with 'degenerative tendinitis' contained an excess of calcium (more than 2SD greater than the normal sample mean). Five of these specimens had increased concentrations of phosphorous and calcium:phosphorous (molar) ratios consistent with a variety of possible calcium crystals, including calcium pyrophosphate, hydroxyapatite, and tricalcium phosphate, in addition to mixed or amorphous calcium phosphate deposits. Four of these specimens contained normal concentrations of phosphorous, consistent with deposits of calcium oxalate or calcium carbonate, although this was not confirmed biochemically. In contrast, surgical specimens (n = 4) from patients with 'calcifying tendinitis' (radiographically detected calcium deposits) all contained salts with a mineral composition consistent with hydroxyapatite. The presence and identity of crystal deposits was subsequently confirmed in five specimens by radiographic microanalysis. Analysis of the tendon matrix demonstrated a number of significant differences between normal and degenerate (ruptured) tendons, including a reduction in collagen content, an increase in sulphated glycosaminoglycans (predominantly dermatan sulphate) and an increase in DNA (cellular) content. However, there were no significant differences between degenerate tendons that were 'calcified' and those degenerate specimens that contained normal concentrations of calcium.

CONCLUSIONS

Although there was a relatively high prevalence of calcium salts in degenerate tendons, which might contribute to the pathological process (such as increased matrix collagen degradation), these data are consistent with the hypothesis that 'dystrophic calcification' of degenerate tendon matrix is a pathological entity distinct from cell mediated 'calcifying tendinitis'. Calcification is probably one possible outcome (or end point) of chronic tendon injury, although the possibility exists that in many cases, the presence of calcium salts may contribute to the tendon matrix degeneration.

CAMPATH-1H, a humanized monoclonal antibody, in refractory rheumatoid arthritis. An intravenous dose-escalation study

OBJECTIVE

To evaluate the biologic response, tolerability, and potential clinical effect of a humanized antilymphocyte monoclonal antibody, CAMPATH-1H, in patients with rheumatoid arthritis (RA).

METHODS

Forty adult patients with active, refractory RA were treated with CAMPATH-1H, given intravenously, in a multicenter, open, single-dose-escalation study. Patients were assigned to dose groups of 1, 3, 10, 30, 60, and 100 mg CAMPATH-1H.

RESULTS

There was a profound, immediate, and sustained reduction of the peripheral lymphocyte count; the most susceptible were the levels of CD4+ and CD8+ cells, which remained depressed during the study period. Sixty-three percent of patients developed antibodies to CAMPATH-1H. Side effects occurred frequently throughout the first 24 hours following infusion, and included fever, headache, nausea, vomiting, and hypotension. All of the immediate drug toxicities resolved within the initial 24-hour postdosing period. One patient developed a reactivation of Mycobacterium xenopi infection 10 weeks following infusion. Sixty-five percent of patients developed a clinical response; the mean duration of response was 2 weeks.

CONCLUSION

CAMPATH-1H is a lymphocyte-depleting antibody that is biologically potent even after single-dose therapy. There was no correlation between biologic effect and clinical response. Sustained lymphocyte suppression was observed. Acute infusion toxicities were observed in most patients. The role of depleting monoclonal antibodies in the treatment of RA should be reevaluated.

Collagenase (MMP-1) and TIMP-1 in destructive corneal disease associated with rheumatoid arthritis

The aim of the study was to immunolocalise interstitial collagenase (MMP-1) and the tissue inhibitor of metalloproteinases (TIMP-1) in ulcerating corneas from patients with rheumatoid arthritis, to determine whether changes in expression are associated with destructive corneal disease. Collagenase was expressed by stromal cells in 8 of 8 ulcerating corneas but was not seen in normal tissue (n = 3). TIMP-1 was abundant throughout the normal stroma, but was much reduced or absent from diseased corneas. Collagenase staining was frequently more intense near the epithelial surface and associated with a cellular infiltrate consisting of activated antigen-presenting cells (HLA-DR+), many of which were macrophages (CD68+) and derived from the epithelium or limbus (S100+). Interstitial collagenase produced by infiltrating macrophages and/or stimulated corneal fibrocytes is probably a major mediator of collagen degradation in rheumatoid corneal ulceration. In addition, reduced levels of TIMP-1 expression are consistent with collagenase activity and tissue destruction. Epithelial-stromal cell interactions and the production of local inflammatory mediators are of major importance in the pathogenesis of corneal destruction, although the precise nature of the antigenic stimulation and/or cellular interactions remains to be elucidated.

Magnetic resonance imaging protocol optimization for evaluation of hyaline cartilage in the distal interphalangeal joint of fingers

RATIONALE AND OBJECTIVES

To identify a single magnetic resonance imaging (MRI) protocol that will provide optimal signal-to-noise ratio, resolution, and image contrast with minimal susceptibility artifacts and that will allow clear delineation and visualization of cartilage, fluid, bone, tendons, and ligaments within the distal interphalangeal (DIP) joint of the human hand.

METHODS

A highly optimized 2.4 T MRI system was constructed from a 31-cm horizontal bore magnet, using a solenoid radiofrequency coil. This was used to study the DIP joints of 16 healthy, asymptomatic volunteers.

RESULTS

A range of image contrast protocols were explored, including spin-echo T1 and T2, field echo, chemical shift suppression to give water only images, and magnetization transfer. Susceptibility variations were explored by changing the field strength from 0.6 to 2.4 T. A spin-echo protocol with TR = 1500 msec and TE = 30 msec can routinely produce images with resolution 0.075 x 0.150 for a slice thickness of 1 mm in 13 minutes. That protocol can visualize simultaneously compact and trabecular bone, two layers of cartilage, synovial fluid, and synovium within the joint, tendons and ligaments, and the volar plate.

CONCLUSIONS

Although the contrast is not fully optimized for any one tissue, the spin echo protocol (TR = 1500, TE = 30) provides sagittal MR images, which clearly delineate the major structures of interest within the DIP joint, and which will be used in future studies to compare changes in the DIP joint because of aging or osteoarthritis. Experience gained by applying the above methods to a total of 16 healthy, asymptomatic volunteers has enabled a single sequence to be identified, which although not optimized for any one tissue, nevertheless visualized simultaneously and clearly delineated compact and trabecular bone, two layers of cartilage, synovial fluid, and synovium within the joint.

The levels of collagenase, tissue inhibitor of metalloproteinases-1 (TIMP-1), collagenase approximately TIMP-1 complexes and glycosaminoglycan (GAG) in sequential samples of synovial fluid aspirated from patients with osteoarthritis

OBJECTIVE

Collagen turnover in connective tissues is thought to be controlled by the balance between the levels of interstitial collagenase and tissue inhibitor of metalloproteinases (TIMP-1). The aim of this study was to measure the level of total collagenase (MMP-1), TIMP-1, collagenase approximately TIMP-1 complex and glycosaminoglycan (GAG) in sequential samples of osteoarthritic knee synovial fluid from well documented patients to determine if these parameters changed with time and correlated with clinical indices.

METHODS

Twenty-one patients were recruited and randomly allocated to receive tiaprofenic acid, indomethacin or naproxen. Total collagenase, TIMP-1, collagenase approximately TIMP-1 complex and GAG were measured in 80 osteoarthritic synovial fluids taken over a period of six months.

RESULTS

The majority of fluids contained a molar excess of TIMP-1 over collagenase, although in seven fluids collagenase was present in excess; six of these samples were from a single patient. GAG levels were relatively unchanged over the six months studied.

CONCLUSION

The levels of collagenase and TIMP-1 varied between patients and over time in individual patients. No collagenase approximately TIMP-1 complex was found in any fluid. There was no significant difference in the median levels of collagenase, TIMP-1 or GAG in the different treatment groups. High levels of collagenase were found in one patient with a crystal related disease. These immunoassays give valuable information on the levels of collagenase and TIMP-1 in individual patients with time and may help to determine the mechanisms controlling the turnover of cartilage collagen in different arthritides.

Human shoulder tendon biopsy samples in organ culture produce procollagenase and tissue inhibitor of metalloproteinases

OBJECTIVE

To investigate the production of the matrix metalloproteinase (MMP), collagenase (MMP-1), and its natural inhibitor, the tissue inhibitor of metalloproteinases (TIMP) by diseased human tendon samples in organ culture.

METHODS

Portions of tendons were excised from the shoulders of patients undergoing shoulder surgery, classified as either proximal to the lesion (abnormal) or distal to the lesion (normal) according to their macroscopic appearance at surgery, and placed in organ culture for periods of up to 28 days. The release of collagenase and TIMP activity in the conditioned culture medium was measured.

RESULTS

Procollagenase and TIMP were both produced by all the tendon samples for an extended period of time. The levels of enzyme and inhibitor varied between patients, but in most of them TIMP levels were greater than collagenase levels. In one sample of calcified tendon, procollagenase levels were greater than those of TIMP. The mean level of collagenase produced by tendon proximal to the lesion and tendon distal to the lesion were not significantly different (95.2 (SD 106.8) U/g and 34.0 (45.3) U/g, respectively), while the corresponding figures for TIMP were 109.7 (62.3) U/g and 53.0 (27.9) U/g (p = < 0.05), although there was considerable variation in some samples. Western blotting and collagen fragment analysis confirmed that the collagenolytic activity detected was attributable to the metalloproteinase fibroblast collagenase (MMP-1).

CONCLUSIONS

Tendon tissue can actively secrete procollagenase, an enzyme that, once activated, is capable of remodelling collagen, the major connective tissue component of tendon. Collagenase is produced even in unstimulated cultures, although the concentrations of TIMP are usually greater than that of collagenase in most samples. Some activation of collagenase appeared to have occurred. These results indicate that tendon tissue cells are capable of producing a remodelling response, even in end stage tendon disease.

Structure of full-length porcine synovial collagenase reveals a C-terminal domain containing a calcium-linked, four-bladed beta-propeller

BACKGROUND

The collagenases are members of the family of zinc-dependent enzymes known as the matrix metalloproteinases (MMPs). They are the only proteinases that specifically cleave the collagen triple helix, and are important in a large number of physiological and pathological processes. Structures are known for the N-terminal catalytic' domain of collagenases MMP-1 and MMP-8 and of stromelysin (MMP-3). This catalytic domain alone, which comprises about 150 amino acids, has no activity against collagen. A second domain, of 200 amino acids, is homologous to haemopexin, a haem-binding glycoprotein.

RESULTS

The crystal structure of full-length MMP-1 at 2.5 A resolution gives an R-factor of 21.7%. Two domains are connected by an exposed proline-rich linker of 17 amino acids, which is probably flexible and has no secondary structure. The catalytic domain resembles those previously observed, and contains three calcium-binding sites. The haemopexin-like domain contains four units of four-stranded antiparallel beta sheet stabilized on its fourfold axis by a cation, which is probably calcium. The domain constitutes a four-bladed beta-propeller structure in which the blades are scarcely twisted.

CONCLUSIONS

The exposed linker accounts for the difficulty in purifying full-length collagenase. The C-terminal domain provides a structural model for haemopexin and its homologues. It controls the specificity of MMPs, affecting both substrate and inhibitor binding, although its role remains obscure. These structural results should aid the design of site-specific mutants which will reveal further details of the specificity mechanism.

Shoulder pain in a community-based rheumatology clinic

The objective of this study was to assess the prevalence of different shoulder disorders likely to be experienced by a rheumatologist in a community-based rheumatology clinic. We assessed patients with shoulder pain presenting to a large general practice at a community-based rheumatology clinic. It was found that the more common conditions seen were rotator cuff lesions (65%), pericapsular soft tissue pain (11%), acromioclavicular joint pain (10%) and referred pain from cervical spine (5%). In conclusion this study has established the spectrum of shoulder disorders referred from general practice to a highly accessible community-based rheumatology clinic. The diagnostic processes to distinguish the different conditions rely chiefly on an accurate history and directed examination.

Antibodies to the 65 kDa mycobacterial stress protein in west Africans with rheumatoid arthritis, tuberculosis and malaria

We have studied IgG antibodies to recombinant mycobacterial 65 kDa heat-shock protein in West African rheumatoid arthritis (RA) patients and local control groups, including those with tuberculosis or malaria. Mean levels were higher among the patients with RA than among healthy controls, but did not achieve statistical significance. Our findings may relate to the level of mycobacterial exposure in West Africa.

The effects of elemental diet and subsequent food reintroduction on rheumatoid arthritis

The role of diet in rheumatoid arthritis (RA) remains controversial and there have been no controlled studies on the use of elemental diet in the treatment of RA. Elemental diet is an hypoallergenic protein-free artificial diet consisting of essential amino acids, glucose, trace elements and vitamins. This study was carried out to assess the role of elemental diet and subsequent food reintroduction in RA. Elemental diet (E028) (and a small number of foods) was given to 24 patients with definite RA in order to induce a remission and then foods were gradually introduced. Where a food was suspected of causing symptoms it was removed from the diet. Twenty-three control patients supplemented their usual diet with E028. After the elemental diet there was a statistically significant improvement in the diet group in grip strength (P = 0.008) and Ritchie score (P = 0.006) but not in ESR, CRP, thermographic joint score or functional score. The diet group lost more weight than the control group and this correlated with the improvement in grip strength. This improvement was not present following food reintroduction. As the improvements took place in more subjective disease parameters and because of the difficulties in adequately blinding studies of diet in arthritis, a placebo effect must be considered. There was a high default rate, only 38% of those patients originally enrolled completed the study. In conclusion, this study shows that elemental diet can cause an improvement in a number of disease parameters in RA but this is not sustained by an individualized diet. It also illustrates some of the difficulties involved in the study of diet in arthritis.

Community survey of shoulder disorders in the elderly to assess the natural history and effects of treatment

OBJECTIVE

To assess the natural history and response to treatment of shoulder disorders in a community elderly population.

METHOD

This community study of shoulder pain in the elderly reviewed patients three years after an earlier prevalence study.

RESULTS

One hundred and eight of the original 136 patients with an identifiable shoulder disorder were available for reexamination. Eighty (74%) had persisting signs on examination, with persistent symptoms leading to impairment of personal care (21%) and household tasks (27%), and pain on movement (34%). There was no difference between treated and non-treated groups in terms of outcome.

CONCLUSIONS

The results of this study serve to confirm and highlight the chronicity of shoulder lesions in this age group and the consequent personal suffering and implications for health care.