Geraldine Cambridge

B-cell targeting in rheumatoid arthritis and other autoimmune diseases

B-cell-targeted therapy for autoimmune disease emerged from theoretical proposition to practical reality between 1997 and 1998, with the availability of the B-cell-depleting monoclonal antibody rituximab. Since then, a score of autoantibody-associated disorders have been treated, with most convincing evidence of efficacy seen in subjects with rheumatoid arthritis. Several classes of B-cell-targeted agent are now under investigation. From the outset, a major goal of B-cell targeting has been the re-establishment of some form of immunological tolerance. In some subjects, the observed improvement of disease for years following therapy fuels hope that this goal might ultimately be achievable.

Clinical outcome in 22 patients with rheumatoid arthritis treated with B lymphocyte depletion

Objectives: To obtain evidence for dose response and to extend evidence of safety and efficacy for B lymphocyte depletion in rheumatoid arthritis. Methods: Twenty two patients with rheumatoid arthritis received a total of 29 treatments with five different combinations of rituximab (RTX), cyclophosphamide (CP), and/or high dose prednisolone (PR) on an open basis as follows; cohort I: RTX 1400 mg/m2, CP 750×2+PR; cohort II: RTX 300–700 mg/m2, −CP±PR); cohort III: RTX 600–700 mg/m2, CP 750×2+PR; cohort IV: RTX 1200 mg/m2, CP 750×2−PR; cohort V: RTX 500 mg/m2, CP 750×2+PR. American College of Rheumatology (ACR) criteria of improvement at six months were chosen as the primary outcome measure. Disease activity scores and total duration of improvement and of B cytopenia were also recorded. Results: No major adverse events attributable to treatment were seen. ACR grades of improvement at six months were as follows: cohort I: ACR70×3, ACR50×2; cohort II: ACR20×1, ACR0×3; cohort III: ACR70×6, ACR50×2, ACR20×2; cohort IV: ACR70×2, ACR50×2, ACR20×1, ACR0×1; cohort V: ACR0×4. Conclusions: B lymphocyte depletion in rheumatoid arthritis has so far proved to be safe and associated with major improvement with protocols including RTX 600 mg/m2 or more and CP, but not with more limited protocols. These observations provide an initial basis for the design of formal trials of B cell depletion and other B cell directed treatments, including a phase II controlled trial now in progress.

A retrospective seven-year analysis of the use of B cell depletion therapy in systemic lupus erythematosus at University College London Hospital: the first fifty patients.

OBJECTIVE To describe the 6-month clinical outcome and the long-term safety profile of B cell depletion therapy (BCDT) in 50 patients with active systemic lupus erythematosus (SLE), who were nonresponsive or poorly responsive to conventional immunosuppression. METHODS All except 4 of 50 patients with active SLE received 1 gm of rituximab, 750 mg of cyclophosphamide, and 100-250 mg of methylprednisolone, administered on 2 occasions 2 weeks apart, to achieve B cell depletion. Clinical outcome was assessed using the British Isles Lupus Assessment Group (BILAG) activity index and serial serologic measurements of disease activity. Remission was defined as a change from a BILAG A or B score to a C or D score in every organ system. Partial remission was a change from a BILAG A or B score to a C or D score in at least 1 system, but with the persistence of 1 score of A or B in another system. No improvement was defined as a BILAG A or B score that remained unchanged after treatment. RESULTS Of the 45 patients available for followup at 6 months, 19 patients (42%) achieved remission, and 21 patients (47%) reached partial remission after 1 cycle of BCDT (mean followup 39.6 months). BCDT resulted in a decrease in median global BILAG scores from 12 to 5 (P < 0.0001) and median anti-double-stranded DNA antibody titers from 106 to 42 IU/ml (P < 0.0001), and an increase in the median C3 level from 0.81 to 0.95 mg/liter (P < 0.02) at 6 months. Five serious adverse events were observed. CONCLUSION BCDT is an effective treatment for patients with active SLE whose disease has failed to respond to standard immunosuppressive therapy. Although the safety profile of BCDT is favorable, ongoing monitoring is required.

Do self‐perpetuating B lymphocytes drive human autoimmune disease?

Normal immunological memory is thought to be underpinned by T lymphocytes. However, in rheumatoid arthritis there are indications that T‐lymphocyte control has been subverted by self‐perpetuating B lymphocytes. Potential mechanisms in other autoimmune states are less clear, but a number of observations suggest that misappropriation of immunological memory by B lymphocytes may be a common feature of human autoantibody‐associated disease. Put simply, autoantibodies drive their own production. If so, the availability of safe B‐lymphocyte‐depleting agents provides a potential means for reversal of autoimmunity.

B cell depletion therapy in systemic lupus erythematosus: long-term follow-up and predictors of response

Objectives: To describe the long-term clinical outcome and safety profile of B cell depletion therapy (BCDT) in patients with systemic lupus erythematosus (SLE). It was also determined whether baseline parameters can predict the likelihood of disease flare. Methods: 32 patients with refractory SLE were treated with BCDT using a combination protocol (rituximab and cyclo-phosphamide). Patients were assessed with the British Isles Lupus Assessment Group (BILAG) activity index, and baseline serology was measured. Flare was defined as a new BILAG ‘A’ or two new subsequent ‘B’s in any organ system. Results: Of the 32 patients, 12 have remained well after one cycle of BCDT (median follow-up 39 months). BCDT was followed by a decrease of median global BILAG scores from 13 to 5 at 6 months (p = 0.006). Baseline anti-extractable nuclear antigen (ENA) was the only identified independent predictor of flare post-BCDT (p = 0.034, odds ratio = 8, 95% CI 1.2 to 55) from multivariable analysis. Patients with low baseline serum C3 had a shorter time to flare post-BCDT (p = 0.008). Four serious adverse events were observed. Conclusion: Autoantibody profiling may help identify patients who will have a more sustained response. Although the long-term safety profile of BCDT is favourable, ongoing vigilance is recommended.

B cell depletion therapy in systemic lupus erythaematosus: relationships among serum B lymphocyte stimulator levels, autoantibody profile and clinical response

Objective: To assess the relationships between serum B lymphocyte stimulator (BLyS) levels, autoantibody profile and clinical response in patients with systemic lupus erythaematosus (SLE) following rituximab-based B cell depletion therapy (BCDT). Methods: A total of 25 patients with active refractory SLE were followed for ⩾1 year following BCDT. Disease activity was assessed using the British Isles Lupus Assessment Group (BILAG) system, and serum levels of BLyS and autoantibodies to dsDNA and extractable nuclear antigens (ENA) measured by ELISA. Serum immunoglobulins and anti-dsDNA antibodies were assessed for expression of the 9G4 idiotope (indicating VH4–34 germline gene origin). Results: Following BCDT, all patients depleted in the peripheral blood and improved clinically for ⩾3 months. Pre-BCDT BLyS levels were quantifiable (median 1.9 ng/ml) in 18/25 patients and rose in most patients at 3 months post-BCDT (median 4.15 ng/ml). Nine patients, all with quantifiable pre-BCDT serum BLyS, experienced a disease flare within 1 year. This group of patients was more likely to harbour anti-Ro/SSA antibodies (odds ratio 1.76; p = 0.06) with higher serum levels (p = 0.0027; Mann–Whitney U test). Serum levels of anti-ribonucleoprotein (RNP)/Sm were also higher in this group (p<0.05). Expression of VH4–34 by serum immunoglobulins and anti-dsDNA antibodies had no predictive value for the length of clinical response. Conclusions: Patients with SLE with an expanded autoantibody profile and raised BLyS levels at baseline had shorter clinical responses to BCDT. This may reflect a greater propensity to, and degree of, epitope spreading in such patients and suggests that treatment regimens beyond BCDT may be necessary to induce long-lasting clinical remissions in these individuals.

Induction of tumor necrosis factor α production by adhered human monocytes: A key role for Fcγ receptor type IIIA in rheumatoid arthritis

OBJECTIVE: Small IgG rheumatoid factor immune complexes may provide the trigger for macrophage-derived tumor necrosis factor alpha (TNFalpha) production in rheumatoid arthritis. Immune complexes may bind to any of 3 IgG Fc receptors (FcgammaR). Therefore, the ability of monocyte-derived macrophages to produce TNFalpha was examined following ligation of each of the 3 human FcgammaR, using murine monoclonal antibodies (mAb) to each receptor as a model for small immune complexes. METHODS: Adhered human monocytes expressing all 3 FcgammaR were incubated with murine anti-FcgammaR mAb directed against FcgammaRI, FcgammaRII, or FcgammaRIII. Supernatants were collected at various time points and tested for the presence of TNFalpha and interleukin-1alpha (IL-1alpha) by enzyme-linked immunosorbent assay. RESULTS: The anti-FcgammaRIII mAb induced adhered human monocytes to release TNFalpha. However, F(ab)2 and Fab fragments of the anti-FcgammaRIII mAb failed to induce TNFalpha production. TNFalpha was undetectable following incubation with the anti-FcgammaRI or anti-FcgammaRII mAb. Furthermore, blocking FcgammaRI or FcgammaRII had no effect on the levels of TNFalpha released in response to the anti-FcgammaRIII mAb. Of the 3 anti-FcgammaR mAb, only anti-FcgammaRIII induced IL-1alpha production from adhered human monocytes, and this was inhibited by the presence of a neutralizing anti-TNFalpha mAb. CONCLUSION: This study suggests a dominant role for FcgammaRIIIA in the induction of both TNFalpha and IL-1alpha production by human macrophages in rheumatoid arthritis following receptor ligation by small immune complexes. The signaling of TNFalpha production may require the ligation of either 3 FcgammaRIIIA receptors or only 2 FcgammaRIIIA receptors, where one interaction must involve binding via an Fc domain. In addition, IL-1alpha production following FcgammaRIIIA ligation appears to be dependent on the presence of TNFalpha.

Repeated B cell depletion in treatment of refractory systemic lupus erythematosus

Objectives: To report the clinical outcome and safety profile of repeated B cell depletion in seven patients with refractory systemic lupus erythematosus (SLE). Methods: Since June 2000, seven patients with refractory SLE had repeated cycles of B cell depletion (18 cycles in total, up to three cycles per patient) because of disease relapse. The clinical response (assessed by the British Isles Lupus Activity Guide (BILAG) activity index), duration of B cell depletion, and adverse events in these patients was reviewed. Results: Four patients (Nos 1, 2, 3, 6) had three cycles of treatment and three (Nos 4, 5, 7) had two cycles. Four of the seven patients (Nos 1, 3, 5, 6) improved. The mean global BILAG scores dropped from 15 to 6 at 5–7 months. The median duration of clinical response and B cell depletion was 13 months and 6 months, respectively. After the third cycle, 2/4 patients (Nos 1 and 2) improved. The median duration of clinical benefit was 12 months. Most patients tolerate re-treatment very well. Conclusion: Re-treatment with B cell depletion of patients with severe SLE is safe and may be effective for 6–12 months on average.

Antineutrophil antibodies in familial inflammatory bowel disease.

BACKGROUND/AIMS Antineutrophil cytoplasmic antibodies have been reported to occur more frequently in healthy first-degree relatives of patients with ulcerative colitis than in healthy controls. The aim of this study was to determine their prevalence in families in which more than one member was affected with inflammatory bowel disease. METHODS With use of an indirect immunofluorescence method, 168 affected members and 197 unaffected first-degree relatives in 56 such families were studied. RESULTS Antibodies were detected in 46% of patients with ulcerative colitis without a positive family history and in 44% of those within families with several affected members. There was no evidence of clustering of antibodies in particular families. Within families in which both ulcerative colitis and Crohns disease coexisted, antibodies were detected primarily in patients with ulcerative colitis. Antibodies were seldom present (3%) in those patients with Crohns disease, whether they were familial or nonfamilial cases. Similarly, antibodies were seldom present (3%) in controls or the unaffected first-degree relatives of patients with inflammatory bowel disease. CONCLUSIONS Antineutrophil cytoplasmic antibodies are associated with ulcerative colitis, and their presence is not increased in the first-degree relatives of patients with ulcerative colitis. They are more likely to be a consequence of the disease than a subclinical genetic disease marker.

Differential distribution of Fc gamma RIIIa in normal human tissues and co-localization with DAF and fibrillin-1: implications for immunological microenvironments.

FcγRIIIa is a cytokine‐inducible IgG Fc receptor implicated in the activation of macrophages by imm_une complexes. Differential expression of FcγRIIIa by macrophages in different tissues may therefore modulate local imm_une responsiveness. FcγRIIIa expression in normal human tissues was assessed semiquantitatively using microdensitometry. Synovial intimal, serosal, alveolar, salivary gland and placental macrophages, Kupffer cells, and macrophages in mechanically stressed dermis expressed high levels of FcγRIIIa. Less consistent expression was seen in skeletal muscle and lymphoid organs. No significant expression was observed in brain, thyroid, spine, intestine, myocardium, prostate, uterus, flexor forearm dermis, uterus, or kidney. Staining for FcγRIII was also observed on extracellular matrix, and co‐localized with both complement decay‐accelerating factor and fibrillin‐1. It is proposed that differential levels of both cellular and extracellular FcγRIIIa, by modulating the response to imm_une complexes, may contribute to relative tissue susceptibility to infection and autoimm_une disease.