Intraarticular injection of arthritogenic factor causes mast cell degranulation, inflammation, fat necrosis, and synovial hyperplasia

Arthritis resembling human rheumatoid arthritis is produced in rats either by immunization with type II collagen or injection of complete Freund's adjuvant. The development of arthritis in both models may be mediated by a T cell-derived, type II collagen-specific protein that has been termed arthritogenic factor. Here, the morphologic changes produced after intraarticular injection of this factor were determined. T cell lines were derived from type II collagen-immunized rats. Arthritogenic factor was isolated from culture supernatants by affinity chromatography on type II collagen-conjugated Sepharose and injected into rat knees. The synovium covering the infrapatellar fat pad was examined by light and electron microscopy at 6 hours to 7 days after injection. By 6 hours, the synovium and fat pad were edematous and heavily infiltrated with neutrophils and a few mononuclear cells. Fibrin was present in the synovium and joint space. Most mast cells had partially degranulated. By 24 hours, the infiltrate became primarily mononuclear and fewer neutrophils were seen. Fat necrosis and edema occurred in the subsynovium. By 48 hours and 7 days, the synovium was hyperplastic, some fibrin persisted, and macrophages were present. Control knees, injected with material obtained from T cell lines established with the antigen, ovalbumin, and subjected to type II collagen affinity chromatography, had less fibrin deposition, milder cellular infiltrates, and less mast cell degranulation than knees injected with arthritogenic factor. These studies suggest that arthritogenic factor stimulates acute cellular infiltration and mast cell secretion which is followed by fat necrosis, synovial hyperplasia, and mononuclear cell infiltration.

Detection of arthritogenic factor in adjuvant arthritis

An evocation of arthritis by an Ag-specific lymphokine has recently been considered with the description of arthritogenic factor (AF) in rats with collagen arthritis. Because rats with CFA-induced arthritis also exhibit T cell reactivity to native type II collagen, T cell lines specific for this protein were established from CFA-injected rats. Supernatant material from these lines contained a type II collagen-binding lymphokine with functional and biochemical attributes identical with those described for AF, i.e., it was a 65-kDa species cross-reacting immunoprotein possessing the ability to incite an erosive, proliferative synovitis when injected into the knee joint of naive recipients. Similarities were also observed with HPLC and on two-dimensional gels. Lymph node cells from rats with arthritis created by injection of the synthetic adjuvant, CP-20,961 failed to produce AF, suggesting that this material is not a ubiquitous concomitant of inflammatory arthritis in the rat. Test injections into sites contiguous with the ear cartilage plate and into fibroblast-lined s.c. pouches suggested that cartilage was a requisite for the induction of inflammation by AF. These data identify a potentially shared effector pathway in the collagen and adjuvant models. The presence of AF in two frequently used models further supports the hypothesis that Ag-specific lymphokines can create autoimmune disease.

Detection of arthritogenic factor in adjuvant arthritis

An evocation of arthritis by an Ag-specific lymphokine has recently been considered with the description of arthritogenic factor (AF) in rats with collagen arthritis. Because rats with CFA-induced arthritis also exhibit T cell reactivity to native type II collagen, T cell lines specific for this protein were established from CFA-injected rats. Supernatant material from these lines contained a type II collagen-binding lymphokine with functional and biochemical attributes identical with those described for AF, i.e., it was a 65-kDa species cross-reacting immunoprotein possessing the ability to incite an erosive, proliferative synovitis when injected into the knee joint of naive recipients. Similarities were also observed with HPLC and on two-dimensional gels. Lymph node cells from rats with arthritis created by injection of the synthetic adjuvant, CP-20,961 failed to produce AF, suggesting that this material is not a ubiquitous concomitant of inflammatory arthritis in the rat. Test injections into sites contiguous with the ear cartilage plate and into fibroblast-lined s.c. pouches suggested that cartilage was a requisite for the induction of inflammation by AF. These data identify a potentially shared effector pathway in the collagen and adjuvant models. The presence of AF in two frequently used models further supports the hypothesis that Ag-specific lymphokines can create autoimmune disease.

Attenuation of collagen arthritis and modulation of delayed-type hypersensitivity by type II collagen reactive T-cell lines

T-cell lines were established from the lymph node cells of syngeneic Louvain (LOU) rats previously immunized with native chick type II collagen (CII) emulsified in incomplete Freund's adjuvant. The CII lines proliferated in vitro to type II collagen but not to type I collagen, ovalbumin (OV), or PPD. Control lines, developed from LOU rats immunized with OV emulsified in complete Freund's adjuvant, were OV specific because they did not respond to other antigens in vitro. CII line cells could adoptively transfer delayed-type hypersensitivity (DTH) but did not induce IgG antibody production to collagen. Moreover, the intravenous administration of 2 X 10(7) CII line cells prevented the subsequent induction of collagen arthritis following immunization and suppressed DTH to collagen without affecting antibody responses in the recipients. Spleen cells, but not sera, from these resistant rats decreased CII line reactivity in vitro. OV or irradiated CII lines had no effect on clinical or immunologic parameters in this model. These findings demonstrate protection from arthritis afforded by T-cell line transfer and suggest that the phenomenon results from down-regulation of the recipients' cellular immunity to collagen.

An arthritogenic lymphokine in the rat

A type II collagen-specific arthritogenic lymphokine has been identified in the rat. Arthritogenic factor (AF) is a 65 kD protein generated in vitro by T cells from rats with collagen arthritis, and it induces an erosive, proliferative synovitis when injected into the knee joint of syngeneic naive recipients. Complement does not appear to be required. These data identify a potential T cell-mediated effector mechanism in this model, and suggest that AF may function in other inflammatory synovial diseases.

Effect of antithymocyte serum on collagen arthritis in rats: evidence that T cells are involved in its pathogenesis

To assess the role of T cells in collagen arthritis, a heterologous T cell-specific antiserum (ATS) was administered intraperitoneally to female Wistar-Furth rats. ATS treatment on Day -1, 1, 3, and 5 and immunization with native chick type II collagen on Day 0 resulted in a decreased incidence of arthritis (5 of 19, 26%) compared to immunized rats given either nonimmune heterologous serum on these days (20 of 25, 80%) or ATS injected on Day 5, 7, 9, and 11 (17 of 20, 85%) (P less than 0.001 for both comparisons). The early-ATS protocol also was associated with a delayed onset and reduced disease severity in the few rats in this group that did develop arthritis. Both delayed-type hypersensitivity (DTH) and serum IgG antibody titers to native type II collagen, measured on Day 10, were decreased significantly (P less than 0.002) in rats administered ATS beginning on Day -1 compared to the other two groups. These data suggest that T cells contribute to the inception of collagen arthritis and that their critical function occurs within the first 5 days after immunization.

Total lymphoid irradiation therapy in refractory rheumatoid arthritis. Fifteen- to forty-month followup

Twelve patients with refractory rheumatoid arthritis were treated with total lymphoid irradiation (TLI) to a total cumulative dose of 3,000 rads. Post-TLI morbidity/mortality included 8 patients with xerostomia, 4 with weight loss of greater than 10 kg, 3 with loss of 4 or more teeth, 3 with herpes zoster, 4 with bacterial infection that was fatal in 2, 3 with hypothyroidism, 1 with cutaneous vasculitis, and death from myocardial infarction in 1 patient and cardiorespiratory arrest in another. Ten of the patients were reevaluated 15-40 months (mean +/- SE, 30 +/- 2) after completion of TLI, and significant improvement was noted in several disease parameters including number of swollen joints, duration of morning stiffness, and 50-foot walking time. Blood lymphopenia and a decrease in helper T cells (T4) were also noted. These data suggest that changes in immunoregulation induced by TLI can produce longlasting alterations in rheumatoid arthritis, although adverse effects may limit its efficacy.

Antigen-specific suppression of collagen arthritis by adoptive transfer of spleen cells

Wistar-Furth (W-F) rats were given 10(9) syngeneic spleen cells, suspended in Hanks' balanced salt solution (HBSS), intravenously on Day 0 to investigate the mechanisms involved in antigen-specific suppression of collagen arthritis. These cells were pooled from W-F donors which had been injected iv on Days -21, -14, and -7 with rat red blood cells (RBC) coupled with glutaraldehyde to either native chick type II collagen, denatured type II collagen, or native type I collagen. All recipients were immunized with an emulsion of native type II collagen in incomplete Freund's adjuvant on Day 1 to induce collagen arthritis. There was a decreased incidence of arthritis, by clinical and radiographic assessments, in rats receiving spleen cells from donors previously administered native type II collagen-coupled RBC compared to those given spleen cells obtained from donors treated with denatured type II or native type I collagen-coupled RBC [18 of 30 (60%) arthritic vs 20 of 20 (100%) and 19 of 20 (95%) arthritic, for the three groups, respectively, P less than 0.01 for both comparisons]. The incidence of arthritis in 35 rats administered HBSS iv 1 day prior to immunization (83%) and 10 immunized rats given no iv injections (100%) was also significantly higher (P less than 0.05) than the incidence in the antigen-relevant experimental group. Hemagglutinating antibody titers and delayed-type hypersensitivity (DTH) to collagen were lower in the recipients of cells from donors administered native type II collagen-coupled RBC, whereas IgG antibody titers to collagen were unaltered. These results demonstrate that passively transferred spleen cells can attenuate collagen arthritis and sensitization in an antigen-specific manner.

Trichosporon cutaneum endocarditis: a sequela of intravenous drug abuse

A 42-year-old abuser of intravenous drugs developed fulminant aortic insufficiency necessitating a prosthetic valve replacement. Trichosporon cutaneum was isolated from the surgical specimen. The patient received a total of 3,195 g of amphotericin B, and 148 g of 5-fluorocytosine during his four-month hospitalization. He manifested no additional signs of persistent fungal infection, but died one year later from an intracerebral hemorrhage.

Structural Evidence for an Unblocked VHI Sub-Subgroup of Human Heavy Chains

The N-terminal amino acid sequence of an unblocked human heavy chain of an IgGκ paraprotein from patient Tho is reported. This unblocked VH sequence belongs to the VHI subgroup and has striking structural homology to an unblocked VHI sequence previously reported for the IgGκ paraprotein isolated from the serum of patient Bro. Direct sequence comparison of the Tho and Bro proteins reveals complete structural identity in 25 of the N-terminal 27 residues, with unique amino acid substitutions shared at the N-terminus and positions 16, 18, and 24. This remarkable sequence homology suggests that the two VH sequences represent examples of an unblocked VHI sub-subgroup.

The Tho and Bro sequences possess an ala-glu-val basic triplet at positions 9 to 11 in common with the other previously reported VHI proteins which help to further establish this sequence triplet as a recognizable VHI subgroup-specific region. Moreover, in this regard, the unblocked sequences of Tho and Bro emphasize the importance of extending an unblocked VHI sequence beyond positions 9 to 11 before a subgroup assignment can be determined.

Structural evidence for an unblocked VHI sub-subgroup of human heavy chains

The N-terminal amino acid sequence of an unblocked human heavy chain of an IgGK paraprotein from patient Tho is reported. This unblocked VH sequence belongs to the VHI subgroup and has striking structural homology to an unblocked VHI sequence previously reported for the IgGK paraprotein isolated from the serum of patient Bro. Direct sequence comparison of the Tho and Bro proteins reveals complete structural identity in 25 of the N-terminal 27 residues, with unique amino acid substitutions shared at the N-terminus and positions 16, 18, and 24. This remarkable sequence homology suggests that the two VH sequences represent examples of an unblocked VHI sub-subgroup. The Tho and Bro sequences possess an ala-glu-val basic triplet at positions 9 to 11 in common with the other previously reported VHI proteins which help to further establish this sequence triplet as a recognizable VHI subgroup-specific region. Moreover, in this regard, the unblocked sequences of Tho and Bro emphasize the importance of extending an unblocked VHI sequence beyond positions 9 to 11 before a subgroup assignment can be determined.