RESUMO
AIMS: The introduction of clearly defined histopathological criteria for a standardised evaluation of the periprosthetic membrane, which can appear in cases of total joint arthroplasty revision surgery. METHODS: Based on histomorphological criteria, four types of periprosthetic membrane were defined: wear particle induced type (detection of foreign body particles; macrophages and multinucleated giant cells occupy at least 20% of the area; type I); infectious type (granulation tissue with neutrophilic granulocytes, plasma cells and few, if any, wear particles; type II); combined type (aspects of type I and type II occur simultaneously; type III); and indeterminate type (neither criteria for type I nor type II are fulfilled; type IV). The periprosthetic membranes of 370 patients (217 women, 153 men; mean age 67.6 years, mean period until revision surgery 7.4 years) were analysed according to the defined criteria. RESULTS: Frequency of histopathological membrane types was: type I 54.3%, type II 19.7%, type III 5.4%, type IV 15.4%, and not assessable 5.1%. The mean period between primary arthroplasty and revision surgery was 10.1 years for type I, 3.2 years for type II, 4.5 years for type III and 5.4 years for type IV. The correlation between histopathological and microbiological diagnosis was high (89.7%), and the inter-observer reproducibility sufficient (85%). CONCLUSION: The classification proposed enables standardised typing of periprosthetic membranes and may serve as a tool for further research on the pathogenesis of the loosening of total joint replacement. The study highlights the importance of non-infectious, non-particle induced loosening of prosthetic devices in orthopaedic surgery (membrane type IV), which was observed in 15.4% of patients.
Assuntos
Artroplastia de Quadril/efeitos adversos , Artroplastia do Joelho/efeitos adversos , Reação a Corpo Estranho/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Artroplastia de Quadril/métodos , Artroplastia do Joelho/métodos , Feminino , Reação a Corpo Estranho/classificação , Reação a Corpo Estranho/etiologia , Células Gigantes de Corpo Estranho/patologia , Tecido de Granulação/patologia , Articulação do Quadril/patologia , Humanos , Articulação do Joelho/patologia , Masculino , Pessoa de Meia-Idade , Falha de Prótese , Infecções Relacionadas à Prótese/complicações , Infecções Relacionadas à Prótese/patologia , ReoperaçãoRESUMO
The lysosomal enzymes N-acetylglucosaminidase (N-ACGA) and beta-galactosidase (beta-gal) are involved in cellular collagen metabolism and may, therefore, be markers of fibrosis in idiopathic interstitial pneumonias, such as idiopathic pulmonary fibrosis (IPF). N-ACGA and beta-gal were analyzed in the bronchoalveolar lavage fluid (BALF) of patients with the histologic pattern of usual interstitial pneumonia (UIP, n=10) and controls (n=9). Cellular distribution in BALF as well as the concentration of TGF-beta a well-known mediator of fibroblast matrix deposition were correlated to the enzyme activities in both groups of patients. We found that both, N-ACGA (UIP: 25.2 nmol/l s +/- 3.4; controls: 73 nmol/l s +/- 1.3) and beta-gal (UIP: 4.7 nmol/l s +/- 0.5; controls: 2.4 nmol/l s +/- 0.3) were elevated significantly in BALF of patients with IPF compared to that of control patients (P<0.003). This increase was paralleled by an increase in neutrophils (IPF: 17.9% +/- 21.8; controls: 5.4% +/- 6.3; P=0.03) and eosinophils (IPF: 2.0% +/- 1.5; controls: 0.2% +/- 0.45; P=0.002) in BALF fluid. In addition, N-ACGA activity correlated closely with lung function (FVC, TLC, and DLCO), transforming growth factor-beta (TGF-beta) in BALF (r=0.77, P=0.008) and activated lymphocytes (r=0.66, P=0.0021). Our findings suggest that measurement of lysosomal enzymes such as N-ACGA may represent a useful indicator of fibrotic activity in IPF.
Assuntos
Acetilglucosaminidase/análise , Líquido da Lavagem Broncoalveolar/química , Fibrose Pulmonar/enzimologia , beta-Galactosidase/análise , Biomarcadores/análise , Líquido da Lavagem Broncoalveolar/citologia , Estudos de Casos e Controles , Volume Expiratório Forçado , Humanos , Contagem de Leucócitos , Pessoa de Meia-Idade , Monitorização Fisiológica , Fibrose Pulmonar/sangue , Fibrose Pulmonar/fisiopatologia , Estatísticas não Paramétricas , Fator de Crescimento Transformador beta/análise , Capacidade VitalAssuntos
Neoplasias/mortalidade , Adulto , Biópsia , Estudos Transversais , Etiópia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/patologiaRESUMO
OBJECTIVE: To investigate the association between immunohistopathological and morphological features of synovitis in rheumatoid arthritis and the amounts of collagen degradation products pyridinoline and deoxypyridinoline in the synovial tissue and in body fluids in order to discover potential markers of erosive disease. METHODS: Histopathological analysis of synovial tissue samples from 22 patients with RA was performed according to the histopathologic scoring system of RA synovitis by P. Stiehl. Accordingly, the samples were (a) classified into type I synovitis, type II synovitis, or undifferentiated synovitis and were (b) characterized for local features of disease activity, including basic activity and actual activity. The contents of pyridinoline and deoxypyridinoline were measured in the synovial tissue, the synovial fluid, serum and urine by HPLC analysis. RESULTS: The amounts of pyridinoline in synovial tissue samples characterized by type II synovitis were 1.7-fold and 2.7-fold higher compared with those with type I synovitis and undifferentiated synovitis, respectively. In contrast, the content of deoxypyridinoline was not different between the histopathologic types of synovitis. At the same time, increased amounts of pyridinoline, but not deoxypyridinoline, were detected in synovial tissue samples with basic activity or actual activity grade II compared with synovial tissue samples with basic activity or actual activity grade I. The concentrations of both collagen degradation products in the synovial fluid, serum and urine did not differ between patients when they were analyzed either for histopathologic types of synovitis or local disease activity. CONCLUSION: The amount of cartilage collagen degradation product pyridinoline in synovial tissue is positively correlated with the histopathological grading of local disease activity. Furthermore, the increased amounts of pyridinoline in synovial tissue samples with type II synovitis suggest a more erosive course of RA in patients with this type of synovitis.
Assuntos
Aminoácidos/análise , Artrite Reumatoide/patologia , Sinovite/patologia , Adulto , Idoso , Artrite Reumatoide/imunologia , Linfócitos B/imunologia , Linfócitos B/patologia , Cartilagem Articular/imunologia , Cartilagem Articular/patologia , Estudos de Coortes , Colágeno/análise , Progressão da Doença , Feminino , Humanos , Macrófagos/imunologia , Macrófagos/patologia , Masculino , Pessoa de Meia-Idade , Membrana Sinovial/imunologia , Membrana Sinovial/patologia , Sinovite/classificação , Sinovite/imunologia , Linfócitos T/imunologia , Linfócitos T/patologiaRESUMO
The "rhagocyte" (Delbarre) was defined with the aid of own results and results from the literature as an unity of structure and function of phagocytic cells in synovial fluids. Rhagocytes are an ubiquitous phenomenon in most cases of inflammation in joints detectable with nonspecific methods and are not a specific sign for the diagnosis of rheumatoid arthritis. The inclusion bodies of rhagocytes were demonstrated as immunoglobulin complexes with fixation of complement (IgG/IgM/C) by means of the immunofluorescence technique. In these specific preparations the rhagocyte has an importance as rheumatoid arthritis cell (R.A. cell) as defined by Hollander. --A definition of the rhagocyte and a description of histochemical results is given in a synopsis of characteristical properties of inclusion body cells. Moreover, a representation of the morphogenesis and value of the rhagocytes in a concept of the pathogenesis of rheumatoid arthritis, the in vitro and in vivo reproduction of rhagocytes and its value for the diagnosis in diseases of joints is given.
Assuntos
Líquido Sinovial/citologia , Complexo Antígeno-Anticorpo , Artrite Reumatoide/patologia , Proteínas do Sistema Complemento/análise , Humanos , Corpos de Inclusão , FagocitoseRESUMO
The importance of immunologic factors in the local defense against myobacterial disease derives from different mechanisms of action. These may be characterized as follows: mycobacteria act as antigens or antigenic fragments to cause local sensitization, activation, and proliferation of T-lymphocytes leading to the formation of giant cells of Langhans' type. Antibodies play a role only as opsonines and are not directly responsible for the destruction of the invading organisms. Lymphokines on the other hand activate connective tissue cells and thereby contribute to the walling of infection and the development of scar tissue.
Assuntos
Tuberculose Pulmonar/imunologia , Formação de Anticorpos , Antígenos de Bactérias/imunologia , Humanos , Imunidade Celular , Imunoglobulinas/metabolismo , Pulmão/imunologia , Linfocinas/fisiologia , Ativação de Macrófagos , Muramidase/metabolismo , Mycobacterium tuberculosis/imunologia , Fagocitose , Tuberculoma/imunologiaRESUMO
With an own histological classification of rheumatoid arthritis (RA) in synovial membranes (SM) of two main types: type I (B-lymphocytic and plasma cellular, local non-destructive, better prognosis); type II (T-lymphocytic, macrophacytic, local destructive, worse prognosis) and type III as a mixed one we examined whether there is a relation between special adhesion molecules and any of this histological types. 32 fresh cryo-conserved RA-SM (type I, II, III; n = 9, 11, 12, respectively) were investigated immunohistochemically using the APAAP method in order to obtain the expression of LFA-1, VCAM-1, CD44 and E-selectin. Positive cells were counted morphometrically within six histological areas: lining layer, subintimal, perivascular, lymphatic follicles, perifollicular and interstitial. Type II showed a significant higher expression than type I for LFA-1 in lining layer and subintimal II (65%; 53% vs 0%; 32%); for VCAM-1 in subintimal, perifollicular, perivascular and interstitial areas (61%, 54%, 58%, 61% vs 6%, 8%, 5%, 6%). In lining layer and lymphatic follicles no significant difference between both types was detected. CD44 and E-selectin: No statistical differences could be found. RA-SM type II shows high expression of LFA-1 and VCAM-1, this is related to a higher destructive process.
Assuntos
Artrite Reumatoide/genética , Antígeno-1 Associado à Função Linfocitária/genética , Molécula 1 de Adesão de Célula Vascular/genética , Especificidade de Anticorpos , Artrite Reumatoide/classificação , Artrite Reumatoide/imunologia , Artrite Reumatoide/patologia , Selectina E/genética , Humanos , Imuno-Histoquímica , Antígeno-1 Associado à Função Linfocitária/análise , Pessoa de Meia-Idade , Modelos Imunológicos , Membrana Sinovial/imunologia , Membrana Sinovial/patologia , Molécula 1 de Adesão de Célula Vascular/análiseRESUMO
In 1967, Pekin, Malinin and Zvaifler described macrophages with one or more phagocytized granulocytes. These authors declared these cell phagocytes as a characteristic cytologic sign of Reiter's syndrome. Because we could observe this phenomenon in other joint diseases, too, we studied systematically different inflammable and non-inflammable joint effusions for the diagnostic value of these cells. We counted 1,000 cells in each joint effusion and determined the numbers of phagocytizing and the numbers and sorts of phagocytized cells and heterophagic vacuoles with cell fractions, respectively. We concluded that, beside the Reiter's syndrome, other inflammatory joint diseases had these cell changes, too, especially joint effusions in juvenile rheumatoid arthritis. In the other cases we found a reduced number of phagocytizing and phagocytized cells only. Cell phagocytes, including synovial lining cells, are obviously characteristic for early phases of chronic inflammatory or transitory joint diseases with joint effusions. However, cell phagocytes are not a proof for the diagnosis of Reiter's syndrome in joint effusions.
Assuntos
Hidrartrose/patologia , Artrite Juvenil/patologia , Artrite Reativa/patologia , Humanos , Macrófagos/patologia , FagocitoseRESUMO
Fifty surgically removed synivial membranes from large joints of patients with rheumatoid arthritis were examined histologically from 10 different areas. The diagnostic reliability and the histologically graded basic and actual activity were estimated. All 3 parameters differed considerably within the individual synovial membrane. To assess the diagnostic value of synovial needle biopsies the results were compared with those of simulated biopsy cylinders. The morphological results gained from the biopsy cylinders were much poorer, showing that needle biopsies are limited diagnostic value.
Assuntos
Artrite Reumatoide/diagnóstico , Biópsia por Agulha , Membrana Sinovial/patologia , Estudos de Avaliação como Assunto , Humanos , Sinovite/diagnósticoRESUMO
By means of the migration inhibition test, the influence of the synovial fluid of rheumatoid arthritis patients on normal blood lymphocytes was investigated. There was the hypothesis that the migration inhibitory factor is already formed in the synovial membrane of rheumatoid arthritis patients. In 35 cases a migration inhibition could be demonstrated, in 3 cases the migration of normal lymphocytes remained uninfluenced, in 6 cases a migration enhancement occurred. The demonstration of the rheumatic factor in the synovial fluids used was partly positive, partly negative. Especially the demonstration of a migration enhancement--this phenomenon could be reproduced repeatedly--cannot yet be interpreted unequivocally and requires further investigations.
Assuntos
Artrite Reumatoide/imunologia , Fatores Inibidores da Migração de Macrófagos/farmacologia , Líquido Sinovial/fisiologia , Inibição de Migração Celular , Humanos , Linfócitos/fisiologiaRESUMO
In a survey in a general part the differential-diagnostic approach in the establishment of cytological findings of the arthrocentesis for the judgment of the normal and pathologically changed synovial fluid are described. Especially the differential-diagnostic possibilities by constellations of the findings from determination of the total number of leucocytes, the differential cell picture and the determination of the individual signs characteristic for a disease are demonstrated. A special part deals with the assessment of the cytologic findings of the arthrocentesis for the diagnosis, the local and general judgment of the activity and the judgment of the therapeutic success of medicamentous and operative measures in rheumatoid arthritis with the help of the cytology of the puncture of a joint.
Assuntos
Artrite Reumatoide/diagnóstico , Artropatias/diagnóstico , Líquido Sinovial/citologia , Cristalização , Diagnóstico Diferencial , Contagem de Eritrócitos , Granulócitos , Humanos , Imunoglobulina G/análise , Contagem de Leucócitos , Monócitos , NeutrófilosRESUMO
Rheumatoid arthritis (RA) is an inflammatory disease of the synovial membrane, which results in the destruction of joints by inflammatory pannus. The synovial membrane shows proliferation and cellular infiltrates on microscopy with signs of chronic and acute inflammation. Macrophages are thought to play a central role in the pathogenesis of RA. We examined synovial membrane specimens of 21 RA patients using morphological, immunohistological and enzyme histochemical methods for number and distribution of macrophages. We were able to identify 41.5 +/- 8.8% of lining cells as macrophages, depending on the method used. In abundant diffuse lymphocellular infiltrates, 23.4 +/- 11.1% of mononuclear cells were macrophages. In addition, most cells in the region of tumorlike proliferation and a stromal population of fibroblastlike cells were detected by macrophage markers. Although cell number in synovial membrane increases drastically, we did not find correlations between the relative amount of macrophages in these regions and basic activity. Basic activity includes proliferative reaction as well as lymphoplasmacellular and mononuclear infiltration--both signs of an immunopathological process. In contrast, using enzymes or activation markers, there was a clear correlation. We consider that a constant high percentage of macrophages in RA synovial membrane is present regardless of any actual inflammatory process.
Assuntos
Artrite Reumatoide/patologia , Macrófagos/patologia , Membrana Sinovial/patologia , Adulto , Humanos , Pessoa de Meia-IdadeRESUMO
Rheumatoid-Arthritis (RA) is a systemic disease with chronic joint inflammation caused by complex immune mechanisms. Aim of our study was the analysis of the distributions of macrophages and neutrophils at the cartilage-pannus junction in order to assess the possible functional relationship of both cell types in cartilage damage. We used 39 samples of synovectomies from patients suffering from RA. The samples were stained by histological (Hematoxilin-Eosin, HE), enzymehistological (Naphtol-ASD) and immunohistochemical (Peroxidase-antiperoxidase, alkaline phosphatase-antialkaline phosphatase) techniques and examined by light microscopy. Lysozyme alpha-1-antitrypsin and alpha-1-antichymotrypsin were stained with peroxidase-antiperoxidase-technique, the monoclonal antibody for macrophages CD 68 were used in alkaline phosphatase-antialkaline phosphatase technique. We found a clear domination of macrophages at the cartilage-pannus junction compared to the number of neutrophils. Over 90% of the analyzed cells were identified as macrophages, which were presumably activated macrophages. The macrophages accumulated directly underneath the erosion front and infiltrated the cartilage. The cartilage showed erosions with clear infiltrations by macrophages. We conclude that this distribution is a clear sign of active cartilage destruction by macrophages and emphasize their role in perpetuation of the rheumatoid inflammation.
Assuntos
Artrite Reumatoide/imunologia , Cartilagem Articular/imunologia , Macrófagos/imunologia , Neutrófilos/imunologia , Antígenos CD/análise , Antígenos de Diferenciação Mielomonocítica/análise , Artrite Reumatoide/patologia , Cartilagem Articular/patologia , Contagem de Células , Humanos , Técnicas Imunoenzimáticas , Ativação de Macrófagos/imunologia , Macrófagos/patologia , Neutrófilos/patologia , Membrana Sinovial/imunologia , Membrana Sinovial/patologiaRESUMO
The tissue around X 5 CrNiMo 18.10-steel implantates with different surfaces was examined in 72 guinea-pigs. Aside from controls, these animals were preoperatively sensibilized against chromium and nickel. The results can be summarized since the histologic findings showed no different peculiarities. The authors describe an intussusception of the implantate in connective tissue which evidently depends on time and surface. Further the spreading of alien material in the surrounding of the implantate, and morphologic findings are reported. The morphologic evidences are described and discussed in detail, since they are interpreted as signs of cell-mediated immune reactions. The presence of lymphocytes, lymphoblasts, histiocytes (mostly carrying alien material), and granulocytes, as well as proliferations at the arterioles suggest an overlapping of immune reactions.
Assuntos
Hipersensibilidade a Drogas/imunologia , Metais , Animais , Cromo/análise , Colágeno , Implantes de Medicamento , Fibroblastos , Granulócitos/imunologia , Cobaias , Histiócitos/imunologia , Imunidade Celular , Linfócitos/imunologia , Músculos/análise , Músculos/irrigação sanguínea , Músculos/patologia , Níquel/análiseRESUMO
Findings are presented within the synovial effusion of a 55-year-old man with numerous, macroscopically visible, brownish-blackish rods of a length from 3 to 5 mm. The combined cytologic as well as histologic results of synovial fluid investigations, including the investigation of a synovial fibrin clot, led to the diagnosis of ochronosis. Similar findings were described previously two times only. The morphologic diagnosis ochronosis was proved to be well founded by the subsequent investigation of the patient's urine. Hints are also given for diagnosis of ochronotic synovial effusions.
Assuntos
Articulação do Joelho , Ocronose/patologia , Osteoartrite/patologia , Líquido Sinovial/citologia , Sinovite/patologia , Cartilagem Articular/patologia , Fibrina/metabolismo , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Based on two case reports the inherent problems of diagnosis and treatment of this rare tumor are discussed. The importance of a complex immunohistologic and immunochemical analysis of the monoclonal immunoglobulin produced by the tumor is emphasized. Determining the serum level of the immunoglobulin is decisive for establishing the necessary treatment strategy. Apart from the tumor-specific aftercare by a specialist, these patients always require additional treatment at an immunology clinic.
Assuntos
Neoplasias Mandibulares , Plasmocitoma , Feminino , Humanos , Imunoglobulinas/análise , Masculino , Neoplasias Mandibulares/sangue , Pessoa de Meia-Idade , Plasmocitoma/sangueRESUMO
Clinical studies suggest prognostic relevance of p16INK4A in nonsmall cell lung cancer (NSCLC) while conflicting results for p53 have been published. However, the importance of the apoptosis regulating gene BAX, a downstream regulator of p53, on the prognosis of NSCLC is unknown. The present study investigated the prognostic relevance of BAX with respect to the status of p53 and P16INK4A in 61 patients with advanced NSCLC. Protein expression of BAX, p53 and p16INK4A was investigated retrospectively by immunohistochemistry. Tumour deoxyribonucleic acid (DNA) was screened for p53 mutations by single strand-conformation polymorphism polymerase chain reaction (PCR) and BAX frameshift mutations by fragment length analysis. Patients with positive BAX protein expression had a significantly longer median survival (14 months) than those patients without BAX expression (6 months, p=0.0004). In contrast, p53 status did not influence prognosis. Patients with p161NK4A negative tumours had a significantly shorter survival (4 months) than those with p16INK41 protein expression (15 months, p=0.0001). Furthermore, the loss of p16INK4A protein expression correlated strongly with the pressure of distant and advanced lymph-node metastases. The best survival was seen in a subgroup of 20 patients with positive p16INK4A expression and intact BAX (p=0.0002). The results of the present study suggest that the loss of BAX and p16INK4A expression are independent markers for poor prognosis in nonsmall cell lung cancer. The study suggests that multimarker analysis of genes involved in apoptosis may be useful for determining individual therapy and for identifying targets for gene-replacement therapy. This should be assessed in a prospective study with a larger cohort of patients.
Assuntos
Biomarcadores Tumorais/análise , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Inibidor p16 de Quinase Dependente de Ciclina/análise , Neoplasias Pulmonares/mortalidade , Proteínas Proto-Oncogênicas c-bcl-2 , Proteínas Proto-Oncogênicas/análise , Idoso , Idoso de 80 Anos ou mais , Carcinoma Pulmonar de Células não Pequenas/química , DNA de Neoplasias/análise , Feminino , Humanos , Imuno-Histoquímica , Neoplasias Pulmonares/química , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Prognóstico , Proteínas Proto-Oncogênicas/genética , Estudos Retrospectivos , Taxa de Sobrevida , Proteína Supressora de Tumor p53/análise , Proteína X Associada a bcl-2RESUMO
Endothelin (ET) is a broncho- and vasoconstrictive cytokine, but it also possesses proinflammatory and mitogenic activity. It is suggested to be involved in the pathogenesis of fibrotic lung diseases. We analyzed the concentration of ET 1 in the bronchoalveolar lavage (BAL) fluid in 95 patients with different lung diseases, among them 41 patients with interstitial lung diseases (13 fibrosing alveolitis in systemic sclerosis (FASS), 9 idiopathic pulmonary fibrosis (IFP), 8 sarcoidosis (S), 6 occupational lung disease (OLD), 5 other alveolitidies A), 27 patients with pneumonia, and 8 patients with chronic obstructive pulmonary disease (COPD). A heterogeneous group of 19 patients served as controls. The median ET concentration was 3.3 pg/ml. Significantly higher concentration was found in patients with FASS (5.8 pg/ml), IPF (5.0 pg/ml), and S (5.1 pg/ml) compared with OLD (2.8 pg/ml), A (1.9 pg/ml), COPD (1.5 pg/ml), and the control group (2.5 pg/ml). In pneumonia, the elevated ET concentration (4.1 pg/ml) was accompanied by a high alveolocapillary leakage. When normalized to BAL albumin concentration, only FASS presented with significantly elevated ET/albumin in the BAL compared with the control group (134.5 vs. 56.l pg/mg, p < 0.05). There were no correlations between ET and BAL differential cell count or pulmonary function tests. In current smokers, ET in BALF was significantly higher compared with non- or ex-smokers (3.9 vs. 2.0 pg/ml, p < 0.01), but not so the ET/albumin ratio (65.0 vs. 62.5 pg/mg). In summary, ET in the BAL is differentially expressed in distinct inflammatory and interstitial lung disease. Consistently high concentrations are found in FASS and elevated ET concentration could be discussed in IPF, sarcoidosis, and pneumonia. ET concentration in BAL is influenced by current smoking habits.
Assuntos
Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/citologia , Endotelinas/biossíntese , Pneumopatias/metabolismo , Adulto , Idoso , Albuminas/análise , Biomarcadores/análise , Feminino , Alemanha/epidemiologia , Humanos , Pneumopatias/etiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fibrose Pulmonar/etiologia , Testes de Função Respiratória , Fumar/efeitos adversosRESUMO
The effect of D-penicillamine on experimental allergic arthritis in rabbits (16 with arthritis and 15 controls) was investigated. After 40 days of treatment with D-penicillamine (intravenous) the arthritis had receded to a large extent. At the same time a maturation inhibition of the hematopoietic marrow had occurred in all the treated arthritic and control animals. The results suggest that D-penicillamine affects fast proliferating cells, to which the precursors of immunologically active cells in the synovial membrane also belong.