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Biochemical and cellular characteristics of pleural fluid from two patients with pleuropulmonary tularemia and 39 patients with tuberculous pleurisy were compared. High pleural fluid concentrations of adenosine deaminase, lysozyme, and beta 2-microglobulin occurred in both diseases. As is the case with tuberculous pleural effusions, pleural fluid in tularemia showed an abundance of lymphocytes, predominantly CD4-positive T lymphocytes. The similar pleural fluid findings suggest analogous local pathogenetic mechanisms in tularemia and tuberculosis. In the diagnostic evaluation of a lymphocyte-rich exudative pleural effusion with a high adenosine deaminase concentration, a possible cause to consider is tularemia.

We studied the in vivo effect of long-term doxycycline treatment combined with NSAID on human interstitial collagenases, other matrix metalloproteinases, serine proteinases, tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) and lactoferrin from saliva and serum during the course of acute reactive arthritis (ReA). Collagenase activity and serine proteases (elastase-like, cathepsin G-like and trypsin-like activities) of saliva (n = 10) and gelatinase, lactoferrin and TIMP-1 of saliva (n = 10) and serum (n = 10) samples before and after 2 months doxycycline treatment, combined with NSAID, were studied by quantitative SDS-PAGE assay, ELISA assay and by spectrophotometric assay. The cellular source and molecular forms of salivary collagenase were characterized by immunoblotting using specific antisera. We found that activities of total and endogenously active interstitial collagenase reduced significantly. The salivary collagenase was found to originate from neutrophils. No fragmentation of either pro 75-kD and active 65-kD MMP-8 was detected after 2 months doxycycline treatment. However, during 2 months doxycycline and NSAID treatment no reduction of salivary and serum gelatinase, lactoferrin and TIMP-1-levels and salivary serine protease activities were detected. The in vivo inhibition of collagenase (MMP-8) activity during long-term doxycycline therapy in human saliva containing inflammatory exudate of ReA patients may contribute to the reduced tissue destruction observed in recent clinical and animal model studies in arthritides during long-term doxycycline/tetracycline treatment.

A human lymphocyte culture protocol was used to identify the biocompatibility pattern of fine particulate ultra-high molecular weight polyethylene. Polyethylene did not cause an increase in lymphocyte DNA synthesis as assessed by the 3H-thymidine incorporation method on culture Days 1, 3, nor 5. As analyzed with monoclonal activation markers, the polyethylene dependent expression of major histocompatibility complex (MHC) class II antigen as well as interleukin-2 receptor (CD25) was virtually nonexistent. An apparent increase in the amount of CD11b positive monocytes/macrophages from 7% +/- 2% to 22% +/- 6% was recorded. Samples of pseudocapsules of the totally replaced hips (THR) obtained at revision operations for aseptic loosening of cementless prostheses with polyethylene lining of the acetabular component, were obtained from ten patients for immunopathologic studies. In seven cases the prostheses consisted of chromium-cobalt-molybdenum steel alloy and in three cases of titanium. Revisions were performed on average 4.6 years (range, 2.5-7) after insertion of the prostheses. The predominant cell in the lining cell layer of the periprosthetic cavity was in each case the CD11b, CD68, and nonspecific esterase positive but endogenous peroxidase-negative macrophage. Proline 4-hydroxylase positive fibroblasts dominated the stroma that was also inhabited by usually perivascular mononuclear cell infiltrations of mainly CD11b/CD68 phenotype with occasional CD4-positive cells. Only few mononuclear cells were activated CD25 positive T cells or CD19-positive B-lymphocytes. In titanium-based THRs, the cytoplasm of the macrophages contained a large number of small metallic particles, although this phenomenon was not seen in chromium-cobalt-molybdenum steel-based THRs. Fine particulate ultra-high molecular weight polyethylene is immunologically relatively insert. Nevertheless, it causes a clear foreign body type of phenomenon in vitro. The loosening of cementless acetabular components was associated with CD11b- and CD68-positive macrophage reaction in the pseudocapsular tissue. In any case, there is no clinical or experimental evidence to suggest that the use of cementless THR prostheses with polyethylene sockets would prevent an adverse biologic host response.

Objectives: The biocompatibility of total hip replacement prostheses and methylmethacrylate cement which is used for fixation of the prosthetic components has been subject to debate for three decades., Methods: We have studied the host response to total hip replacement prostheses in a number of clinical and experimental investigations., Results: Methylmethacrylate cement is immunologically relatively inert while it causes, in in vitro experiments and in vivo, a foreign body type of reaction. In cementless prostheses, the wear of polyethylene which is used for lining of the acetabular component causes a similar foreign body type of reaction., Conclusion: Ultimately, the total hip prosthesis cannot be made invisible to the host system. The host response can be controlled and reduced, but not eliminated by technical improvement and development of more biocompatible materials.

We studied the composition of the fluid in joint cavity of the hip joint in primary osteoarthritis (OA) from samples obtained at primary total hip replacement (THR) operations (N = 21) and in the THR pseudojoint, where the samples were obtained in revision operations for the common type of prosthesis loosening (N = 17). Protein concentrations differed little in both groups (31.8 +/- 1.9 mg/ml vs 34.4 +/- 1.9 mg/ml, p < 0.01), which suggests similar transcapillary flow in the degenerative hip joint and THR pseudojoint. Hyaluronate was found in OA joint fluid and in the fluid from the THR pseudojoint (2.21 +/- 0.23 mg/ml vs 0.43 +/- 0.04 mg/ml, p < 0.005) and high performance liquid chromatography (HPLC) analysis, calibrated using laser light scatter analyzed molecular weight standards, disclosed the low molecular weight nature of the OA synovial fluid compared to the THR pseudojoint fluid (1.12 +/- 0.84 x 10(6) vs 2.63 +/- 1.13 x 10(6) Da, NS). This suggests that THR arthroplasties cause an adaptive tissue response and formation of fibroblast-like B type lining cells able to synthesize and secrete hyaluronate.

We studied tissue samples of noninfected delayed union or nonunion of diaphyseal bones in 10 patients immunopathologically and neuroimmunologically 4 to 25 months after the primary injury. Samples mostly consisted of vascularized connective tissue of varying density with the proline-4-hydroxylase-containing fibroblast as the major cell type. Most inflammatory cells were CD4 T-lymphocytes and their number was always twice that of the CD8 positive cells. Staining for CD11b positive monocyte/macrophages showed in all samples positive cells scattered in the connective tissue stroma with perivascular enrichments. Mast cells were absent or very rare. Our findings suggest that delayed union and nonunion tissue consists of vascularized connective tissue, which mostly contains 5B5 fibroblasts, CD11b macrophages and vascular endothelial cells with only few immigrant recently recruited monocytes or lymphoid cells. Almost all resident cells seem to be involved in tissue remodeling as suggested by their content of fibroblast-type MMP-1 and its proteolytic activator MMP-3 or stromelysin. The most striking finding was the paucity or total lack of peripheral innervation, which may have to do with the nonunion of the fracture.

Coracoacromial ligament and periligamentous fatty and loose connective tissue obtained during Neer's acromioplasty in patients with chronic painful rotator cuff tendinitis/impingement syndrome was studied for possible signs of inflammatory involvement and for the presence of neuropeptide-containing nerves, using routine histology and immunoperoxidase staining. No accumulations of inflammatory cells were found in the tissues studied. The dense ligamentous tissue proper was practically aneural, as was seen in staining for the generalized neuronal markers protein gene product 9.5 and synaptophysin. In contrast, the periligamentous fatty and loose connective tissue was innervated. Almost all nerves in such tissue contained C-flanking peptide of neuropeptide Y, whereas substance P, calcitonin gene-related peptide, and vasoactive intestinal peptide-containing nerves were not found at all or were extremely rare. This suggests that the coracoacromial ligament is not a target of irritative inflammation. In the periligamentary sheath, nerves containing markers for the C-type nociceptive pain fibers were practically absent and all local nerves were postganglionic sympathetic vaso-regulatory nerves.

Subacromial bursal tissue was studied in 12 patients operated on for painful (10 patients with constant pain and 2 patients with pain on motion) rotator cuff tendinitis/impingement syndrome. The Neer acromioplasty technique was used. Six patients had moderate inflammatory changes and one had a slight inflammation. In three of the five remaining patients, the subacromial bursa did not show any signs of inflammatory involvement, but patients experienced pain at rest and at night, reflecting clinical inflammation in tissues other than the bursa. The two patients with pain only on strain did not show inflammation of the bursa. Immunohistochemical typing of the bursal tissue disclosed a typical chronic mononuclear cell infiltrate consisting mainly of CD2-positive T lymphocytes (50-80% of all inflammatory cells), accompanied by less frequent CD11b (C3bi receptor)-positive monocyte/macrophages (10-40%). The relative paucity of plasmablasts/plasma cells expressing PCA-1 suggests this to be an inflammatory rather than an immune response. Active involvement of some of the local cells is suggested to be the source of algogenic and hyperalgesic substances contributing to pain in chronic shoulder pain syndromes.

In order to study the role of interleukin-6 (IL-6) in inflammatory disease we monitored plasma levels of IL-6 and acute phase proteins such as C-reactive protein (CRP) and renin substrate (RS) in patients with reactive arthritis (ReA), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE). Venous plasma samples were collected: (1) during the acute phase or exacerbation of the disease, and (2) several months latter during convalescence. Increased mean [95% confidence intervals (CI)] levels of plasma IL-6 were observed in patients with ReA both in the acute phase and later, 229 (177 to 280) ng/l and 197 (134 to 260) ng/l respectively (P less than 0.001 as compared to controls). The corresponding plasma IL-6 levels in RA patients were 283 (223 to 340) ng/l and 183 (151 to 226) ng/l, respectively (P less than 0.001 as compared to controls). Plasma IL-6 levels in SLE patients were not increased. Plasma RS levels were increased in all patient groups, but no significant correlation to IL-6 or CRP levels was observed, whereas plasma IL-6 and CRP levels showed a positive correlation in ReA and RA patients.

Tissue lesions from eight patients with recurrent oral ulcers (ROU) were subjected to detailed immunohistopathologic studies. In five patients, a specimen of an unaffected area from the opposite site was obtained. The main inflammatory cells in situ were CD3 positive T lymphocytes, with CD4 cells forming approximately half (range 30-60%) and CD8 cells 20% (range 10-30%) of all cells. CD19 positive B lymphocytes formed 5-12% of all cells. Furthermore, 45% (range 15-65%) of all lymphoid cells had signs of previous antigenous contact and had helper/inducer CDw29 type. Suppressor/inducer CD45R cells formed only about 20% (range 7-50%) of all cells. Although this observation suggests involvement of antigen as a causative and/or triggering stimulus, elements of a non-specific inflammatory response were observed as well. Endogenous peroxidase-positive neutrophils were present at the ulcer site, and were occasionally observed intravascularly and in the extracellular matrix in areas characterized by inflammatory mononuclear cell infiltrates. Although the proportion of endogenous peroxidase-positive, recently recruited monocytes was low, CD11b and nonspecific esterase-positive mature tissue macrophages formed about 14% (range 5-35%) of all inflammatory cells in situ, particularly at the periphery of the lymphoid cell infiltrates. Mast cells were also observed in all samples studied, forming 2-5% of inflammatory cells in the richly vascularized connective tissue beneath the basement membrane. In the specimens from clinically unaffected areas, inflammatory cells were rare. Our observations stress the multifaceted nature and participation of multiple effector systems in the local tissue pathogenesis of ROU.

Interleukin-1 (IL-1) stimulates fibroblast-mediated hyaluronate (HA) synthesis in vitro. In the present study the degree of polymerization of such HA was studied using HPLC (high performance liquid chromatography) with a size exclusion column combined with 125I-HABP assay used to measure the HA concentration in various HA molecular weight fractions separated using HPLC. IL-1 stimulated HA was more polydisperse than that produced by resting fibroblasts with a molecular weight varying from more than 4 x 10(6) daltons to less than 7.1 x 10(3) daltons. This IL-1 effect may contribute to the low molecular weight HA produced by freshly explanted arthritic synovial tissue and to the low viscosity of arthritic synovial fluid in vivo.

Serum hyaluronate was monitored in volunteer patients with rheumatoid arthritis who were mobilized on day 1 at 7 am, but stayed at rest in bed on day 2 until mobilized at 11:30 am. 125I-hyaluronate binding protein assay disclosed a normal morning peak on day 1 but not on day 2. Instead, on day 2 transiently high hyaluronate levels were seen after 11:30 am. This suggests that joint mobilization affects serum hyaluronate. The morning peak may depend on the accumulation of hyaluronate in immobilized joints at night and its mobilization in the morning. High performance liquid chromatography with a size exclusion column used for fraction collection with 125I-hyaluronate binding protein assay showed that the serum hyaluronate in the morning peak is of relatively low molecular weight when compared to synovial fluid hyaluronate. This difference may be due to degradation of synovial fluid hyaluronate before its clearance into the blood stream.

In three patients a mechanically well-fixed Mathys Ceros 80 (Ha) hydroxyapatite-coated acetabular component was revised 2, 5 and 13 months after total hip replacement due to component malposition. In each case there was a thin cellular connective tissue membrane between hydroxyapatite and bone, the main cell type being fibroblast with only occasional giant cells. Immunohistological analysis revealed some MHC locus II antigen positive cells that were identified as monocytes. No interleukin-2 receptor positive cells were found. Under clinical cyclic loading conditions there does not seem to be chemical fixation or bony ingrowth into the hydroxyapatite coated prosthesis component. In human lymphocyte cultures, hydroxyapatite (Interpore 200, particle diameters 15-40 microns) did not cause an increase in lymphocyte DNA synthesis as assessed by the 3H-thymidine incorporation method on culture days 1, 3 and 5. As analysed with lymphocyte activation markers, the hydroxyapatite-dependent expression of MHC locus II antigen was modest and differed significantly (P less than 0.05) from that in culture medium only on day 3. Hydroxyapatite induced only a slight interleukin-2 receptor expression that did not differ from culture medium on days 1, 3 and 5. CD4 and CD8 positive lymphocytes as well as monocytes were not seen attached to hydroxyapatite particles during the culture days. Our findings suggest that hydroxyapatite is an immunologically inert implant material.

In this study, lysozyme mRNA in labial salivary glands has been localized with in situ hybridization technique using 35S-labeled hen lysozyme cDNA (cDNALZM) as a hybridization probe in normals and in patients with Sjögren's syndrome, 35S-DNALZM:mRNA hybrids were detected only in acinar serous cells, although lysozyme was identified in ductal cells using immunohistochemical techniques. Our results suggest that the serous acinar cells are the only site of lysozyme synthesis in small salivary glands. The presence of lysozyme in ductal cells may be a result of reabsorption from the saliva or concentration from the blood or surrounding tissues.

Herpes simplex virus (HSV) antigens were sought in 15 biopsy specimens from both lesional mucosa and clinically healthy looking oral mucosa between attacks in patients with erythema multiforme (EM). Four of the eight biopsy specimens obtained from lesional EM mucosa stained positively with HSV-1-and/or HSV-2-specific antisera applied in direct immunoperoxidase staining. Of the 16 tissue specimens used as controls, two displayed positive staining with HSV-1 and/or HSV-2. Five of the seven biopsy specimens from macroscopically healthy oral mucosa obtained between attacks from patients with recurrent EM stained positively with HSV-1 and/or HSV-2. Of the six tissue specimens used as controls, three stained positively. Most of the local inflammatory mononuclear cells belonged to the T cell series, mainly to the CD-4 subset. A small proportion of the local T cells were blast transformed as assessed by CD-25 expression and [3H]thymidine incorporation. This, together with the findings showing a lower degree of activation in the biopsy from macroscopically healthy looking mucosa between attacks suggest an active role of the cell-mediated immune response in the genesis of oral lesions in EM. The persistence of HSV antigens, and the well-established role of HSV as a precipitating factor in recurrent EM, suggest that HSV may be involved, but since HSV seems to be present in other mucosal lesions as well as in clinically healthy mucosa, quite frequently an additional, hitherto unknown factor must be present in order that EM may occur.

The immunomodulatory T4/T8 ratio was studied in the total and activated lymphocyte populations by a method combining visualisation of 3H-thymidine incorporating blasts with autoradiography (AR) with simultaneous identification of the respective lymphocyte subsets using monoclonal antibodies in avidin-biotin-peroxidase complex (ABC) staining. In rheumatoid arthritis synovial fluid the activated T4/T8 ratio (calculated from T cells in the S phase of the cell cycle) was significantly different from the total T4/T8 ratio (calculated for all the T cells) (0.45 +/- 0.05 versus 0.69 +/- 0.05, P less than 0.01). Similarly, the activated and total T4/T8 ratios were also significantly different in the phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cell cultures at days 3 and 5.

Skin biopsies from 6 patients with Jessner's lymphocytic infiltration (JLI) were studied using monoclonal antibodies in peroxidase staining, on some occasions combined with [3H]thymidine incorporation visualized by autoradiography. Ninety-one +/- two percent of all inflammatory mononuclear cells in situ were T11-positive T lymphocytes, whereas B lymphocytes were few. Forty-nine +/- nine percent of cells were Ia-positive, suggesting involvement of T cells in the local pathogenetic mechanisms, but interleukin-2 receptor-carrying cells as well as [3H]thymidine-incorporating cells accounted for less than 2% of all inflammatory cells, suggesting that T blasts account for only a small minority. Similarly, PCA-1 plasma cells were few in situ, there was no immunoglobulin or complement deposition at the dermal-epidermal junction and serum antinuclear and anti-DNA antibodies as well as complement levels were normal, and no visceral involvement was revealed during the survey period. According to our findings, JLI of the skin seems to be sufficiently distinctive to be appreciated as an entity. T lymphocytes in JLI do not seem to proliferate in the site of inflammation but are merely accumulated from the circulation.

The state of lymphocyte activation in tuberculous pleural effusions was studied. The proportion of cells at and beyond the G1 phase of the cell cycle displaying interleukin-2 receptor, transferrin receptor or gp 40/80 glycoprotein in avidin-biotin-peroxidase complex (ABC) staining was 6 +/- 2 percent, 8 +/- 3 percent, and 14 +/- 4 percent of all pleural fluid mononuclear cells, respectively. These findings imply that only a fraction of pleural fluid lymphocytes is activated in tuberculosis. The proportion of autoradiographically visualized 3H-thymidine incorporating blasts at the S phase of the cell cycle was 1.2 +/- 0.3 percent. This phenomenon further confirms the impression that, in spite of activation, most of the pleural fluid mononuclear cells are resting cells. The T4/T8 ratio in the functionally active blast cell population determined by a double labeling method combining ABC staining with autoradiography was similar to the total T4/T8 ratio (2.3 +/- 0.7 vs 2.7 +/- 0.8, p greater than 0.05) calculated for all pleural fluid mononuclear cells.

The current study evaluated the activation of T-cell mediated cellular immune response in the oral lesions in lichen planus (OLP). Analysis was made of the ultramorphology, lymphocyte activation marker expression, DNA synthesis, and gamma-interferon production of the inflammatory cells in OLP lesions. According to these four different aspects of lymphocyte activation, only a minor fraction, 5% at the most, of all T-cells in situ were activated. This minor fraction, however, not the resting T-cells without these signs of activation, may decide the outcome of the local immune-inflammatory process in OLP. Of the inflammatory cells in situ, however, 81 +/- 5% were Ia positive. This finding may be the result of an Ia inducing capacity of the gamma-interferon produced locally by the activated T-cells.

DNA synthesis in prolyl 4-hydroxylase (PH; EC 1.14.11.2) positive fibroblasts in situ in synovial tissue was studied using an autoradiography-avidin-biotin-peroxidase complex (ABC) double labeling. Fibroblasts in monolayer culture and in situ in synovial tissue were PH positive, whereas freshly isolated peripheral blood lymphocytes, monocytes, dendritic cells and granulocytes were PH negative. In rheumatoid arthritis (RA) 37 +/- 3 (22-56)% of all DNA synthesizing cells in situ were PH containing fibroblasts, whereas all DNA synthesizing cells in patients with meniscus lesion were PH positive. In both conditions, more than half of the self-replicating fibroblasts were located in the lining cell layer. This is probably not an artifact caused by insufficient penetration of 3H-thymidine because most of the DNA synthesizing lymphocytes were deep down in the synovial stroma. In RA 51 +/- 8 (17-88) PH positive fibroblasts in the S phase of the cell cycle were observed/3 mm2 synovial tissue, whereas the corresponding figure in meniscus patients was only 1 +/- 1 (0-5) (p less than 0.01). This suggests that the local fibroblasts in RA are activated, probably as a result of various fibroblast growth factors produced locally as a result of the inflammatory synovitis. In RA however, less than 1% of all local fibroblasts were self-replicating in situ, whereas labeling indices over 5% were not uncommon in RA synovial fibroblast cultures. This finding suggests that uncontrolled fibroblast proliferation is regulated in vivo by negative feedback mechanisms.

An immunoperoxidase-autoradiography double labeling method for analysis of lymphocyte activation markers and DNA synthesis is described. For this study expression of MHC locus II coded Ia antigen, interleukin-2 receptor, transferrin receptor and gp 40/80 glycoprotein was analyzed using monoclonal antibodies in avidin-biotin-peroxidase complex staining combined with visualization of [3H]thymidine incorporation by autoradiography. Compared to spontaneous [3H]thymidine incorporation assay information is obtained at single cell level. In contrast to blast indexes calculated from MGG stained preparates, information on the expression of various functional cell surface structures as well as DNA synthesis is also obtained. Double-assay for lymphocyte phenotype and DNA synthesis by flow cytometry might be preferred to light microscopy, but the widespread use of immunoperoxidase staining and autoradiography may make this new kind of approach more easily available. Other advantages worth considering are the possibility of transporting, staining and counterstaining as microscope slides and the permanent nature of the documentation and morphological information obtained. In our experience, this method seems to be useful for studying resting peripheral blood lymphocytes as well as mitogen and antigen induced changes in the lymphocyte activation state.

The occurrence of MHC class I antigens and microbial antigens derived from the triggering infection of the diseased joints in reactive arthritis (ReA) seems to set the stage for local immune activation. In this report activated lymphocytes are demonstrated by using an avidin-biotin-peroxidase complex (ABC) method combined with autoradiography that identifies DNA synthesis and, thus, activation. Most of the activated T lymphocytes in reactive arthritis were found to belong to the CD8 suppressor/cytotoxic T-lymphocyte subset. In striking contrast, the majority of the activated T lymphocytes detected in rheumatoid arthritis (RA) synovial fluid belonged to the CD4 helper/inducer subset. These findings agree well with the assumption that CD8-positive cells identify the foreign antigen in the context of class I antigens, whereas CD4-positive cells are found to be associated with the recognition of MHC locus II coded HLA antigens.

Activation state and proliferation of lymphocytes of 6 patients with definite multiple sclerosis in clinical remission were studied. Lymphocytes carrying MHC class II coded Ia antigen, glycoprotein gp 40/80 and interleukin-2 receptor were significantly higher in patients with MS in remission than in normal healthy controls. The entrance of T cells into the G1 and S phase of the cell cycle was studied using [3H]thymidine autoradiography in combination with immunocytochemistry (cell markers). The proportion of T cells in the S phase of the cell cycle in the peripheral blood was similar in the MS patient and in the control group.

Biopsy specimens from mixed connective tissue disease (MCTD) and discoid lupus erythematodes (DLE) skin lesions were stained with monoclonal antibodies to differentiation and activation antigens. In addition, the blast cells were studied by combining autoradiography with immunoperoxidase staining. In both disease conditions most of the inflammatory cells in situ were positive for T11 antigen, the CD4/CD8 ratio being low. Only a few of the cells were pan-B positive B cells. The expression of various activation antigens did not differ significantly between MCTD and DLE biopsy specimens; the number of T9, Tac, and 4F2 antigen carrying cells was relatively low, whereas Ia-positive cells were more numerous. 3H-Thymidine incorporating T blasts comprised less than 1% of all inflammatory cells. T4 and T8 marker-carrying blast cells were present in about equal proportions. These findings suggest that Ia antigen-expressing T cells are important from the pathogenetic point of view in both MCTD and DLE. Because the local proliferation of T cells was extremely low according to the lack of interleukin-2 receptor and OKT9 markers and 3H-thymidine incorporation, it seems probable that most of the T cells are recruited from the circulation to the site of the inflammation.

We studied the subsets of synovial fluid (SF) lymphocytes and their activation states in 4 subtypes of juvenile rheumatoid arthritis. The expression of lymphocyte differentiation antigens and activation markers (Ia and Tac) appeared to be similar in these subgroups. Tac + DNA-synthesizing T blasts represented, at most, 5% of all SF mononuclear cells. This finding was in clear contrast to the high proportion of Ia-positive SF mononuclear cells. There were no differences in Ia and Tac expression or DNA synthesis among the different juvenile rheumatoid arthritis subgroups. This finding suggests that the cell-mediated immune response may represent secondary features of the disease that are involved as a final common pathogenetic pathway.

The glycosaminoglycans (GAG) of plasma were assayed for uronic acid content in 13 female patients with systemic lupus erythematosus (SLE) and in healthy controls and compared with earlier results obtained in patients with rheumatoid arthritis (RA). The GAG were fractionated into a high charge "free" fraction known to contain chondroitin sulfate (CS) as a major and heparan-sulphate (HS) as a minor GAG and a low charge "bound" fraction known to contain low sulphated CS as the only GAG. The concentration of the free GAG was significantly increased in SLE (p less than 0.01); this increase was mainly due to the high concentrations of free GAG in patients with active disease. These patients also had an increased concentration of "bound" GAG (p less than 0.05). However, the plasma GAG concentrations did not correlate with the erythrocyte sedimentation rate, the binding of native DNA or the C4 concentration. Plasma proteoglycans and/or GAG are known to modulate certain immune functions. Whether the increase in free GAG reported here is somehow associated with the disturbed immunoregulation in SLE remains speculative.

Tritiated-thymidine incorporating cells in synovial tissue samples from ten patients with definite or classic rheumatoid arthritis (RA) were studied by combining two techniques. Tritiated-thymidine-labelled cells were seen in autoradiography and simultaneously the subtype of them was determined with immunoperoxidase staining using monoclonal antibodies. Tritiated-thymidine-labelled cells comprised 0.8 +/- 0.4% of all the inflammatory cells in RA synovial membrane. Of all 3H-thymidine-labelled cells 34 +/- 17% were positive for OKT8 and 19 +/- 8% for OKT4 monoclonal antibodies. OKM1-positive cells comprised 7 +/- 3% of all 3H-thymidine labelled cells, whereas only a few (3 +/- 4%) of them were positive for pan-B monoclonal antibody. This study emphasizes the importance of activated OKT8 lymphocytes in RA synovial membrane.

We analyzed lymphocyte activation state in vivo in lamina propria by applying a panel of monoclonal antibodies for cellular activation markers and by identifying different subsets of 3H-thymidine incorporating lymphoblasts by combining autoradiography with immunoperoxidase staining. In focal lymphoblastoid infiltrates 75 +/- 8% of all inflammatory cells displayed Ia, but lymphoid cells expressing 4F2 (40 +/- 6%) and T9 (14 +/- 3%) activation markers were less frequent. The expression of receptors for interleukin-2 (Tac) was particularly low (4 +/- 1%). There were very few 3H-thymidine incorporating cells (labeling index approx. 1%) and most of them belonged to the T cell series. T4+ blasts outnumbered T8+ blasts, and in this numerically minor subpopulation the activated T4/T8 ratio was 2.9 +/- 0.7. Our results suggest that, although a big part of the local inflammatory lymphocytes in Crohn's disease may be activated according to the expression of Ia and 4F2 activation markers, only a fraction of them possess interleukin-2 receptor and have been pushed to the S-phase of the cell cycle.

We studied the immunocytology of synovial fluid in purulent endoprosthetic infections using cell subtype-specific monoclonal antibodies in avidin-biotin-peroxidase complex staining. Two thirds of the monocytes were CD15-positive, whereas CD2-positive T lymphocytes only formed one third of all the mononuclear cells. The synovial fluid monocyte-activated T-cell ratio differed from findings in sterile inflammatory, reactive and rheumatoid arthritis.