Bitter Taste Receptor as a Therapeutic Target in Orthopaedic Disorders

Non-gustatory, extraoral bitter taste receptors (T2Rs) are G-protein coupled receptors that are expressed throughout the body and have various functional responses when stimulated by bitter agonists. Presently, T2Rs have been found to be expressed in osteoclasts and osteocytes where osteoclasts were capable of detecting bacterial quorum-sensing molecules through the T2R38 isoform. In the innate immune system, stimulating T2Rs induces anti-inflammatory and anti-pathogenic effects through the phospholipase C/inositol triphosphate pathway, which leads to intracellular calcium release from the endoplasmic reticulum. The immune cells with functional responses to T2R activation also play a role in bone inflammation and orthopaedic disorders. Furthermore, increasing intracellular calcium levels in bone cells through T2R activation can potentially influence bone formation and resorption. With recent studies finding T2R expression in bone cells, we examine the potential of targeting this receptor to treat bone inflammation and to promote bone anabolism.

CypD-mPTP axis regulates mitochondrial functions contributing to osteogenic dysfunction of MC3T3-E1 cells in inflammation

Bone is a dynamic organ, the bone-forming osteoblasts and bone-resorbing osteoclasts form the physiological basis of bone remodeling process. During pathological process of numerous inflammatory diseases, these two aspects are uncoupled and the balance is usually tipped in favor of bone destruction. Evidence suggests that the inflammatory destruction of bone is mainly attributed to oxidative stress and is closely related to mitochondrial dysfunction. The mechanisms underlying osteogenic dysfunction in inflammation still need further investigation. Reactive oxygen species (ROS) is associated with mitochondrial dysfunction and cellular damage. Here, we reported an unexplored role of cyclophilin D (CypD), the major modulator of mitochondrial permeability transition pore (mPTP), and the CypD-mPTP axis in inflammation-induced mitochondrial dysfunction and bone damage. And the protective effects of knocking down CypD by siRNA interference or the addition of cyclosporin A (CsA), an inhibitor of CypD, were evidenced by rescued mitochondrial function and osteogenic function of osteoblast under tumor necrosis factor-α (TNF-α) treatment. These findings provide new insights into the role of CypD-mPTP-dependent mitochondrial pathway in the inflammatory bone injury. The protective effect of CsA or other moleculars affecting the mPTP formation may hold promise as a potential novel therapeutic strategy for inflammation-induced bone damage via mitochondrial pathways.

Monitoring tissue inflammation and responses to drug treatments in early stages of mice bone fracture using 50 MHz ultrasound

Bone fracture induces moderate inflammatory responses that are regulated by cyclooxygenase-2 (COX-2) or 5-lipoxygenase (5-LO) for initiating tissue repair and bone formation. Only a handful of non-invasive techniques focus on monitoring acute inflammation of injured bone currently exists. In the current study, we monitored in vivo inflammation levels during the initial 2 weeks of the inflammatory stage after mouse bone fracture utilizing 50 MHz ultrasound. The acquired ultrasonic images were correlated well with histological examinations. After the bone fracture in the tibia, dynamic changes in the soft tissue at the medial-posterior compartment near the fracture site were monitored by ultrasound on the days of 0, 2, 4, 7, and 14. The corresponding echogenicity increased on the 2nd, 4th, and 7th day, and subsequently declined to basal levels after the 14th day. An increase of cell death was identified by the positive staining of deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) assay and was consistent with ultrasound measurements. The increases of both COX-2 and Leukotriene B4 receptor 1 (BLT1, 5-LO-relative receptor), which are regulators for tissue inflammation, in the immunohistochemistry staining revealed their involvement in bone fracture injury. Monitoring the inflammatory response to various non-steroidal anti-inflammatory drugs (NSAIDs) treatments was investigated by treating injured mice with a daily oral intake of aspirin (Asp), indomethacin (IND), and a selective COX-2 inhibitor (SC-236). The Asp treatment significantly reduced fracture-increased echogenicity (hyperechogenicity, p<0.05) in ultrasound images as well as inhibited cell death, and expression of COX-2 and BLT1. In contrast, treatment with IND or SC-236 did not reduce the hyperechogenicity, as confirmed by cell death (TUNEL) and expression levels of COX-2 or BLT1. Taken together, the current study reports the feasibility of a non-invasive ultrasound method capable of monitoring post-fracture tissue inflammation that positively correlates with histological findings. Results of this study also suggest that this approach may be further applied to elucidate the underlying mechanisms of inflammatory processes and to develop therapeutic strategies for facilitating fracture healing.

Rheumatoid arthritis and ankylosing spondylitis - pathology of acute inflammation

Histomorphological analysis of inflammatory lesions in rheumatoid arthritis (RA) and ankylosing spondylitis (AS) display similarities but also major differences. Ankylosing spondylitis is characterised by two key pathological findings: sacroiliac joint and spinal inflammation and new bone formation with the possible consequence of bone fusion, usually in the axial skeleton. In AS the primary site of inflammation is located at the enthesis or subchondral bone marrow with bone marrow oedema, lymphocytic infiltrates, increased osteoclast density and increased microvessel density are typical findings in acute inflammation. In RA joint inflammation has its origin in the synovial membrane of peripheral joints. Osteitis in the subchondral bone marrow reveals similar findings compared to AS and it is suggested to occur secondary to inflammation in the synovial membrane. Structural damage defines the outcome in both diseases. However, in AS it is defined by new bone formation and in RA by the destruction of cortical bone.

Inflammation and repair mechanisms

Although both rheumatoid arthritis (RA) and ankyosing spondylitis (AS) belong to the group of chronic inflammatory rheumatic diseases, they are quite different regarding mechanisms of inflammation and repair. While RA is an erosive destructive disease with the synovium as the primary site of inflammation, the immune response in AS takes place primarily at the cartilage/bone interface, and the pathological but also the clinical picture is determined by an until not yet well defined interaction between inflammation and new bone formation. Most recently, first insights into the molecular mechanisms between inflammation and bone destruction or new bone formation could be obtained. Key molecules involved in bone homeostasis seem to differ between RA and AS patients. While the molecules sclerostin and dickkopf 1, both inhibitors of osteoblasts, are elevated in RA they are found to be rather low in AS. It can be expected that the rapidly expanding new field of osteoimmunology will help to clarify the pathogenesis of the these two diseases with possible implications for new treatment targets.

Synovitis-acne-pustulosis-hyperostosis-osteitis syndrome and psoriatic arthritis exhibit a different immunogenetic profile

BACKGROUND AND OBJECTIVES

Patients with psoriatic arthritis (PsA) as well as those with synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome share some common features, and in fact, for many authors the SAPHO concept fits well into the broader concept of PsA. However, some clinical features are unique to the SAPHO syndrome, and in the other hand, these patients do not show the known association between the HLA-B27 antigen and the spondyloarthropathies. To date, there are no studies comparing the immunogenetic profile of these two conditions, so the main objective of the present report was to analyse whether or not both entities may share the same genetic basis.

PATIENTS AND METHODS

All patients with SAPHO syndrome (n=25) seen in a single university hospital from 1985 to 2005 were recruited and followed up in standardised manner in order to study their main characteristics and HLA profile. The HLA-Cw6, DR and B27 antigen distribution of these cases was compared to that of 50 patients with psoriasis vulgaris, 120 with PsA, and 170 healthy blood donors. PsA patients were classified in accordance with their predominant pattern observed in the last 5 years of disease evolution. Odds ratios (OR) values were calculated to measure the strength of the association between HLA antigens and disease, while the statistical significance of the association was assessed with a two-tailed Fisher's exact test. P<0.05 values were considered significant.

RESULTS

No association was found between HLA-Cw6, B27, or DR antigens, and SAPHO syndrome. HLA-Cw6 was strongly associated with psoriasis, OR 12 (95% CI: 5.6-26, p<0.0001) and PsA, OR 10 (95% CI: 5.4-19.5, p<0.0001), however this antigen was equally distributed among the three articular categories of PsA. HLA-DR4 was found under-represented in PsA patients compared to controls, OR 0.4 (95% CI: 0.2-0.7, p=0.002). HLA-DR7 correlated well with psoriatic oligoarthritis, OR 9.6 (95% CI: 2.9-28, p<0.0001), HLA-DR8 was found associated with polyarthritis, OR 6.7 (95% CI: 2-25, p=0.002), while HLA-B27 was over-represented in psoriatic spondylitis, OR 10 (95% CI: 3.3-25, p<0.0001).

CONCLUSIONS

Psoriasis/PsA and SAP-HO syndrome show a different immunogenetic background, however the genetic basis of SAPHO syndrome remains unknown.

[Implant-associated post-traumatic osteomyelitis. Bacterial biofilms and the immune defence as protagonists of the local inflammatory process]

BACKGROUND

Formation of bacterial biofilms on implants is a severe complication following orthopaedic surgery. In the present study we addressed the role of the immune response, particularly with regard to the pathogenesis of the disease.

METHODS

In a prospective study comprising 74 patients with implant-associated post-traumatic osteomyelitis, peripheral blood cells as well as cells recovered from the infected site during surgery were characterised phenotypically and functionally.

RESULTS

We found massive infiltration of polymorphonuclear neutrophils (PMN), which were highly activated, particularly regarding their bactericidal potential, such as increased production of superoxides and upregulation of activation-associated surface receptors.

CONCLUSION

PMN are activated in response to the implant-associated osteomyelitis; they also infiltrate the infected tissue, but cannot control the infection. By release of their cytotoxic entities they could contribute to tissue destruction and eventually to osteolysis.

An essential role for IL-17 in preventing pathogen-initiated bone destruction: recruitment of neutrophils to inflamed bone requires IL-17 receptor-dependent signals

IL-17 and its receptor are founding members of a novel family of inflammatory cytokines. IL-17 plays a pathogenic role in rheumatoid arthritis (RA)-associated bone destruction. However, IL-17 is also an important regulator of host defense through granulopoiesis and neutrophil trafficking. Therefore, the role of IL-17 in pathogen-initiated bone loss was not obvious. The most common form of infection-induced bone destruction occurs in periodontal disease (PD). In addition to causing significant morbidity, PD is a risk factor for atherosclerotic heart disease and chronic obstructive pulmonary disease (COPD). Similar to RA, bone destruction in PD is caused by the immune response. However, neutrophils provide critical antimicrobial defense against periodontal organisms. Since IL-17 is bone destructive in RA but a key regulator of neutrophils, we examined its role in inflammatory bone loss induced by the oral pathogen Porphyromonas gingivalis in IL-17RA-deficient mice. These mice showed enhanced periodontal bone destruction, suggesting a bone-protective role for IL-17, reminiscent of a neutrophil deficiency. Although IL-17RA-deficient neutrophils functioned normally ex vivo, IL-17RA knock-out (IL-17RA(KO)) mice exhibited reduced serum chemokine levels and concomitantly reduced neutrophil migration to bone. Consistently, CXCR2(KO) mice were highly susceptible to alveolar bone loss; interestingly, these mice also suggested a role for chemokines in maintaining normal bone homeostasis. These results indicate a nonredundant role for IL-17 in mediating host defense via neutrophil mobilization.

Classification of Non-Bacterial Osteitis: Retrospective study of clinical, immunological and genetic aspects in 89 patients

OBJECTIVE

To define non-bacterial osteitis (NBO) as a clinical entity possibly associated with autoimmune manifestations. Patients with sterile osteitis were analysed to develop diagnostic criteria.

METHODS

A total of 89 patients with non-bacterial inflammatory bone lesions were observed for a median of 49 months. History, diagnostic imaging, laboratory and histological data were obtained. Mutation analysis in the genes PSTPIP1 and PSTPIP2 was performed.

RESULTS

Patients had an onset of disease at a median age of 10 yrs [interquartile range (IQR) 7.5-12] and suffered a median period of 21 (IQR 9-52) months with a median of three foci per patient. Twenty percent of all the patients demonstrated associated autoimmune disorders, particularly of the skin and bowel. The majority of bone lesions were located in the vertebrae and metaphyses. Slight-to-moderate elevation of inflammation values were found in all the patients and antinuclear antibodies were elevated in 30%. Non-steroidal anti-inflammatory drugs (NSAIDs) were effective in 85% of the patients. HLA-B27 and Human Leukocyte Antigen-DR (HLA-DR)-classification did not differ from the general population. Autoimmune diseases in 40% of all the families, multiply affected family members, linkage to 18q21 and mouse models strongly indicate a genetic basis for NBO. We observed three different courses of disease regarding the duration of complaints, rate of complications and associated autoimmune manifestations leading to a new classification of NBO.

CONCLUSIONS

Clinical analysis of our cohort leads us to define NBO as a distinct disease entity with three clinical presentations: acute NBO, chronic recurrent multifocal osteomyelitis or persistent chronic NBO. Diagnostic criteria were proposed to differentiate NBO from diseases with similar clinical presentation.

Maldaptation of the link between inflammation and bone turnover may be a key determinant of osteoporosis

Currently the etiology of osteoporosis is attributed to various endocrine, metabolic, and mechanical factors. We hypothesize that many cases of osteoporosis are also partially attributable to a maladaptation of the link between inflammation and bone turnover. We explore the spatial and temporal link between inflammation and osteoporosis in conditions such as aging, menopause, reflex sympathetic dystrophy, HIV, pregnancy, transplantation, and steroid administration. While nutritional and mechanical factors clearly play a role in many of these situations, the spatial and temporal concordance of osteoporosis and inflammation is buttressed by emerging molecular evidence. Modern bone biology of humans may reflect dual functional legacies of mineral storage and structural support. Osteoporosis may result from disequilibrium between structural demand for key minerals and their biologic demand during maladaptive states of inflammation.

[Bacterial osteitis. Special considerations in immunocompromised patients]

With increasing life expectancy and better medical competence, the number of older patients with multimorbidity is growing. Patients with a deficient immune system need more attention during diagnosis and treatment of osteomyelitis.

A genetic approach to inactivating chemokine receptors using a modified viral protein

We have developed a genetic system, called degrakine, that specifically and stably inactivates chemokine receptors (CKR) by redirecting the ability of the HIV-1 protein, Vpu, to degrade CD4 in the endoplasmic reticulum (ER) via the host proteasome machinery. To harness Vpu's proteolytic targeting capability to degrade new receptors, we fused a chemokine with the C terminal region of Vpu. The fusion protein, or degrakine, accumulates in the ER, trapping and functionally inactivating its target CKR. We have demonstrated that degrakines based on SDF-1 (CXCL12), MDC (CCL22) and RANTES (CCL5) specifically inactivate their respective receptor functions. Using a retroviral vector expressing the SDF-1 degrakine, we have established that CXCR4 is required for the homing of hematopoietic stem/progenitor cells (HSPC) to the bone marrow immediately after transplantation. Thus the degrakine provides an effective genetic tool to dissect receptor functions in a number of biological systems in vitro and in vivo.

Targeting cytokines to inflammation sites

To increase the half-life of a cytokine and target its activation specifically to disease sites, we have engineered a latent cytokine using the latency-associated protein (LAP) of transforming growth factor-beta 1 (TGF-beta 1) fused via a matrix metalloproteinase (MMP) cleavage site to interferon (IFN)-beta at either its N or C terminus. The configuration LAP-MMP-IFN-beta resembles native TGF-beta and lacks biological activity until cleaved by MMPs, whereas the configuration IFN-beta-MMP-LAP is active. LAP provides for a disulfide-linked shell hindering interaction of the cytokine with its cellular receptors, conferring a very long half-life of 55 h in vivo. Mutations of the disulfide bonds in LAP abolish this latency. Samples of cerebrospinal fluid (CSF) or synovial fluid from patients with inflammatory diseases specifically activate the latent cytokine, whereas serum samples do not. Intramuscular injection in arthritic mice of plasmid DNA encoding these constructs demonstrated a greater therapeutic effect of the latent as compared to the active forms.

Acetabular osteitis in ankylosing spondylitis: does fibrillin figure in its pathogenesis?

In the hip and sacroiliac joints, ankylosing spondylitis attacks the acetabulum over the femoral head and the ilium in preference to the sacrum. Both sites involve inflammation in bone subjacent to fibrocartilage with relative sparing of opposing, hyaline cartilage-surfaced mates. This disease appears to target connective tissues rich in fibrillin-1. A cell-mediated autoimmune response may be involved.

Tissue reactions to particles of bone-substitute materials in intraosseous and heterotopic sites in rats: discrimination of osteoinduction, osteocompatibility, and inflammation

Two rat models were used to characterize tissue-specific reactions to particles of bone-substitute materials: one for osteocompatibility in a healing tibial wound and the other in a heterotopic, subcutaneous site. Small, unicortical tibial wounds in rats healed spontaneously, beginning with the rapid proliferation of intramedullary woven bone. That temporary bone was resorbed by osteoclasts and finally, the cortical wound was healed with lamellar bone and the medullary space was repopulated with marrow. When various particulate materials were implanted into fresh wounds, three types of reactions were observed. (1) Demineralized bone powder (DBP) and non-resorbable calcium phosphate (nrCP) were incorporated into the reactive medullary and cortical bone. (2) Polymethylmetlhacrylate (PMMA) particles were surrounded with a fibrous layer, but did not impair bone healing. (3) Polyethylene (PE) shards and resorbable calcium phosphates (rCPs) were inflammatory and inhibited osseous repair. Subcutaneous sites showed osteoinductive, fibrotic, or inflammatory responses to these materials. Only DBP induced endochondral osteogenesis subcutaneously. The nrCP evoked a fibrous reaction. In contrast, rCPs, PMMA, and PE shards generated inflammatory reactions with each particle being surrounded by fibrous tissue and large multinucleated giant cells. In conclusion, only DBP showed osteoinductive as well as osteocompatible properties. The nrCP was osteocompatible. The rCPs stimulated various degrees of inflammatory responses. PMMA was osteocompatible and did not interfere with the bone healing process. PE was not osteocompatible and generated foreign body reactions in both sites. Use of the two sites distinguishes osteoinductive, osteocompatible, and inflammatory properties of particles of bone-substitute materials.

Antibody responses in patients with staphylococcal septicemia against two Staphylococcus aureus fibrinogen binding proteins: clumping factor and an extracellular fibrinogen binding protein

We analyzed the serum antibody responses against two Staphylococcus aureus fibrinogen binding proteins, the cell-bound clumping factor (Clf) and an extracellular fibrinogen binding protein (Efb). The material consisted of 105 consecutive serum samples from 41 patients suffering from S. aureus septicemia and 72 serum samples from healthy individuals. An enzyme-linked immunosorbent assay (ELISA) was developed. Healthy individuals showed variable levels of antibodies against the studied antigens, and cutoff levels (upper 95th percentile) against these antigens were determined. No correlation was seen between serum antibody levels against Clf and Efb. In acute-phase samples 27% of patients showed positive antibody levels against Clf and 10% showed positive levels against Efb, while in convalescent-phase samples 63% (26 of 41) showed a positive serology against Clf and 49% (20 of 41) showed a positive serology against Efb. Antibody levels against Efb were significantly lower in the acute-phase sera than in sera from healthy individuals (P = 0. 002). An antibody response against Clf was most frequent in patients suffering from osteitis plus septic arthritis and from endocarditis (80% positive). The antibody response against Efb appeared to develop later in the course of disease. A possible biological effect of measured antibodies was demonstrated with the help of an inhibition ELISA, in which both high-titer and low-titer sera inhibited the binding of bacteria to fibrinogen. In conclusion, we have demonstrated in vivo production of S. aureus fibrinogen binding proteins during deep S. aureus infections and a possible diagnostic and prophylactic role of the corresponding serum antibodies in such infections.

[Experimental studies of polymorphonuclear leukocyte on mandibular bone infection model in rabbit]

Polymorphonuclear leukocytes (PMN) play important roles in the prevention of infection at an early stage. We studied the function of these leukocytes using rabbit models of mandibular bone infection to evaluate the conditions which could not be reproduced in human beings Streptococcus milleri NCTC7331 and Bacteroides fragillis NCTC9343 were inoculated into the mandibular bone of rabbits using the Satoh-Heimdahl method, to produce supposed multiple infection models. Rabbits inoculated with these bacteria were used as a test group, and animals with surgically induced inflammation were used as a control group. We compared the number of leukocytes, the function of PMN, and histopathologic findings. 1) The number of leukocytes increased after treatment, reached a perk on day 3, gradually diminished later, but remained slightly higher than the baseline level on day 7, with persistence of inflammation in both groups. 2) Adhesiveness, ability to migrate and NBT reduction, were accelerated in both groups. 3) These functions of PMN accelerated more in the test group because the bacteria inoculated induced stronger inflammatory reactions and activated a series of infection defense mechanisms in the hosts. 4) Histopathologic examination after treatment showed invasion of inflammatory cells, predominantly leukocytes, in both groups, but heavier and more extensive infiltration in the group treated with the bacteria. All measurements were higher in the test group than the control group. These results showed that in the test group, causative or accompanied microorganisms activated the host's infection defense mechanisms and accelerated the functioning of PMN at an acute stage of infection.

Histopathological and serological progression of experimental Staphylococcus aureus arthritis

In a newly developed mouse model of Staphylococcus aureus arthritis the kinetics of joint destruction and serological manifestations as well as the clinical course of arthritis and osteitis were studied. Almost all mice developed histopathological signs of arthritis upon a single intravenous injection of 10(7) S. aureus LS-1 cells. There was rapid joint destruction, with synovial hypertrophy already visible, within 24 h after injection of the bacteria. Cartilage and/or bone erosions were seen in a majority of the mice within 72 h. Extra-articular manifestations, especially signs of bone infection, were also found soon after inoculation of the bacteria. Tail osteitis was frequent (50% of the mice) but appeared later than arthritis. Polymorphonuclear cells prevailed in the early joint lesions and were also common in the extra-articular manifestations. Within 3 days, mononuclear cells were also seen in the inflamed synovium, gaining a dominant position 3 weeks after the start of the disease. Serum interleukin-6 levels were already increased within 6 h after bacterial injection and remained elevated throughout the course of arthritis. Serum tumor necrosis factor levels were increased within 24 h. There was a tremendous induction of immunoglobulin production, especially of the immunoglobulin G1 isotype. This was paralleled by the production of specific antibodies to S. aureus (cell walls and toxin), as well as autoantibodies (rheumatoid factors and anti-single-stranded DNA antibodies), all predominantly of the immunoglobulin G isotype. The type and magnitude of the immunoglobulin G response together with the elevated interleukin-6 levels speak in favor of both antigen-specific and polyclonal B-cell activation during S. aureus arthritis. This study points out important similarities between our new model of S. aureus arthritis and human S. aureus arthritis. This resemblance will enable controlled studies of pathogenetic mechanisms of septic arthritis as well as therapeutic and prophylactic approaches.

[Immunostimulation with ibuprofen in chronic osteitis. An experimental study]

The present investigation shows that chronic posttraumatic osteitis is associated with markedly elevated prostaglandin E2 (PGE2) serum levels. Synthesis of PGE2 is inhibited by nonsteroidal antiinflammatory drugs, such as ibuprofen, which block cyclooxygenase. Osteitis patients showed significantly decreased PGE2 serum levels during treatment with ibuprofen (1200 mg/day). In addition, a significant increase in soluble interleucin-2 receptor serum levels was observed. PGE2 has significant immunosuppressive effects on cell-mediated immunity. On the other hand, soluble interleucin-2 receptor is a reliable indicator of immune system activation. Ibuprofen seems to be a potent immunostimulating agent for the treatment of chronic posttraumatic osteitis, which is characterized by depression of cell-mediated immunity.

Neutrophil chemotaxis in patients with pustulotic arthro-osteitis

The chemotactic response of peripheral blood polymorphonuclear leukocytes (PMNs) to N-formyl-methionyl-leucyl-phenylalanine was determined in four groups of persons (I) 19 patients with pustulosis palmoplantaris (PPP) and skeletal disorder (pustulotic arthro-osteitis); (II) 15 patients with a similar anterior chest wall involvement, but no PPP; (III) 9 patients with PPP, but without skeletal involvement, and (IV) 69 healthy adults (controls). The chemotactic activity of PMNs was found to be significantly increased in groups I-III, and patients with a similar osteoarthropathy, but no PPP compared with the controls. Furthermore the patients with pustulotic arthrosteitis had enhanced chemotactic activity compared with the patients with PPP only. This indicates that both skeletal involvement and PPP are somehow related to the function of PMNs. Colchicine was found of benefit in 2 of 3 group I, and in 6 group II patients, and it normalized their PMN chemotaxis.

[Effect of intestinal resection on the behavior of mononuclear subpopulations in Crohn disease]

The literature data about the distribution of mononuclear cells in Crohn's disease are still contradictory. In 50 surgical C.D. patients, clinically classified corresponding to the Crohn's Disease Activity Index (CDAI), the T-lymphocytes and their subsets helper-T- and suppressor-T-lymphocytes (TH/TS) were therefore determined by use of monoclonal antisera, the B-lymphocytes by F(a b)-anti human Ig and the macrophages by uptake of latex microparticles. 37 C.D. patients underwent diseased bowel removal. Blood was drawn from the Crohn-draining mesenteric vein for analysis. Further investigations were performed at the 10th p. op. day as well as after an average period of 7 months (2-18). In comparison the mononuclear cell distribution was examined in 14 patients suffering from chronic osteitis and in 14 patients without any inflammatory disease as controls. C.D. patients showed preoperatively a significantly decreased TH/TS-ratio as well as a significantly increased proportion of macrophages. There was a lymphocytopenia in the peripheral differential blood count. Whereas the distribution of mononuclear subpopulations in the mesenteric blood was identical to the peripheral blood, significant lymphocytosis in the differential blood count of mesenteric blood was found. On the 10th p. op. day the TH/TS-ratio rose almost up to normal, which continued during the follow-up period. The macrophages remained constantly increased in all stages of investigation although during the follow-up none of the patients had signs of disease recurrence. Osteitis patients showed a similar distribution as C.D. patients, even if the changes compared to controls were not as distinct. The proportion of B-lymphocytes was the same in all groups examined. The individual TH/TS-ratios and proportions of macrophages of C.D. patients did not correlate to their clinical data. The changes within the T-cell-subpopulations seem to reflect less M. Crohn's disease itself than its inflammatory complications. Further studies have to be undertaken concerning the impact of the constant increase in macrophages, even after resection of the Crohn bearing bowel segment.

Osteitis condensans ilii or sacro-iliitis?

Eight patients with a radiological diagnosis of Osteitis condensans ilii (OCI) had clinical features similar to those of 8 patients with sacro-iliitis (SI). The X-ray appearances may be very difficult to differentiate on standard films and discrimination between the two conditions has to be made from a combination of clinical and radiological findings. The term OCI should be regarded with suspicion when applied to young people with a history of backache.

[Bone and joint infection. Role of immune deficiences. Interest of serology and immunology in the diagnosis (author's transl)]

Although bone and joint infections do not seem to be more frequent in patients with immune deficiences than in normal subjects, it seems paradoxically that an immune deficiency is relatively frequent during fully diagnosed bone and joint infections : the discrepancy between the two types of data is not easy to explain. Serology and immunology laboratories give little information in the etiological diagnosis of bone and joint infections, with the exception of perhaps gonococcal infections (search for anti-gonococcal antibodies by immunofluorescence). staphylococcal infections (pasteurella, yersinia, tularemia and brucella infections). In most cases, although the abnormalities observed are due to infection of the organism by the germ, they have nothing characteristic of the bone and joint localisation itself.

HLA B27 in patients with seronegative spondarthritides

We investigated the pattern of genetic susceptibility to rheumatic diseases in Indians by means of HLA analysis. HLA B27 was present in more than 90% of cases included under the broad category or seronegative spondarthritides. In this respect our data resembled results reported for Caucasian populations. In our population, however, the phenotypic frequency of HLA B27 was low as reported from Japan.

Comparison of osteitis condensans ilii and ankylosing spondylitis in female patients: clinical, radiological and HLA typing characteristics

A study comparing 12 patients with ankylosing spondylitis (AS) to 25 with osteitis condensans ilii (OCI), referred to a rheumatic disease center, was carried out to determine whether OCI represents a varient of AS in women. In the group with OCI, chronic lumbodorsal pain was present in 9, 36%, a 'fibrositis' syndrome in 6, 24%, and 16, 64% had recurrent episodes of polyarthralgia. A definite arthritis with effusion developed in 10 patients, 40%. No patient with OCI had iritis or colitis, whereas 4 patients with AS had iritis and four had colitis. Radiographs of the spine showed no evidence of spondylitis in the OCI group. Of the 25 patients with OCI, only 2, 8% were HLA B27 positive compared with 11 of 12 patients with AS, 92%. These results suggest that OCI is not a variant of AS in women.