In vitro synthesis of IgM rheumatoid factor by lymphocytes from patients with essential mixed cryoglobulinemia.

Peripheral blood mononuclear cells (PBMC) from patients with Essential Mixed Cryoglobulinemia (EMC) were studied for their ability to synthesize polyclonal IgM and rheumatoid factor (RF) IgM in vitro. Our results indicate: that EMC-PBMC produce smaller amounts of polyclonal IgM but higher quantities of IgM-RF than normal PBMC after pokeweed mitogen (PWM) or Staphylococcus aureus activation, so that the IgM-RF to total IgM ratio is significantly greater in EMC than in normal cultures; that enriched EMC-B lymphocytes display a significantly higher spontaneous synthesis of IgM-RF than normal B lymphocytes and that the IgM-RF B cell clones are receptive to T cell regulation. Taken together these findings suggest an expansion of B cell clones committed to IgM RF production and the presence in peripheral blood of differentiated B lymphocytes capable of secreting IgM-RF in EMC.     

Antineutrophil cytoplasmic antibodies (ANCA)

Antineutrophil cytoplasmic antibodies (ANCA) are a sensitive and specific marker for ANCA-associated systemic vasculitis. Using indirect immunofluorescence on ethanol-fixed neutrophils, two major fluoroscopic patterns can be recognised: a diffuse cytoplasmic staining (C-ANCA), and a perinuclear/nuclear staining (P-ANCA). In patients with vasculitis, more of 90% of C-ANCA are directed against proteinase 3 (PR3-ANCA) whereas approximately 80-90% of P-ANCA recognise myelperoxidase (MPO-ANCA). Although C-ANCA (PR3-ANCA) is preferentially associated with Wegener's granulomatosis (WG), and P-ANCA (MPO-ANCA) with microscopic polyangiitis (MPA), idiopathic necrotising crescentic glomerulonephritis (iNCGN) and Churg-Strauss syndrome (CSS), there is not absolute specificity. Between 10-20% of patients with classical WG show P-ANCA (MPO-ANCA), and even a larger percentage of patients with MPA or CSS have C-ANCA (PR3-ANCA). Furthermore, it should be stressed that approximately 10-20% of patients with WG or MPA (and 40-50% of cases of CSS) have negative assay for ANCA. The best diagnostic performance is obtained when indirect immunofluorescence is combined with PR3 and MPO-specific ELISAs. ANCA with different and unknown antigen specificity are found in a variety of conditions other than AASV, including inflammatory bowel diseases, other autoimmune diseases, and infections where their clinical significance is unclear. ANCA levels are useful to monitor disease activity but should not be used by themselves to guide treatment. A significant increase in ANCA titres, or the reappearance of ANCA, should alert the clinicians and lead to a stricter patient control.     

Early response to immunosuppressive therapy predicts good renal outcome in lupus nephritis: Lessons from long‐term followup of patients in the Euro‐Lupus Nephritis Trial

Objective

In the Euro‐Lupus Nephritis Trial (ELNT), 90 patients with lupus nephritis were randomly assigned to a high‐dose intravenous cyclophosphamide (IV CYC) regimen (6 monthly pulses and 2 quarterly pulses with escalating doses) or a low‐dose IV CYC regimen (6 pulses of 500 mg given at intervals of 2 weeks), each of which was followed by azathioprine (AZA). After a median followup of 41 months, a difference in efficacy between the 2 regimens was not observed. The present analysis was undertaken to extend the followup and to identify prognostic factors.

Methods

Renal function was prospectively assessed quarterly in all 90 patients except 5 who were lost to followup. Survival curves were derived using the Kaplan‐Meier method.

Results

After a median followup of 73 months, there was no significant difference in the cumulative probability of end‐stage renal disease or doubling of the serum creatinine level in patients who received the low‐dose IV CYC regimen versus those who received the high‐dose regimen. At long‐term followup, 18 patients (8 receiving low‐dose and 10 receiving high‐dose treatment) had developed permanent renal impairment and were classified as having poor long‐term renal outcome. We demonstrated by multivariate analysis that early response to therapy at 6 months (defined as a decrease in serum creatinine level and proteinuria <1 gm/24 hours) was the best predictor of good long‐term renal outcome.

Conclusion

Long‐term followup of patients from the ELNT confirms that, in lupus nephritis, a remission‐inducing regimen of low‐dose IV CYC followed by AZA achieves clinical results comparable with those obtained with a high‐dose regimen. Early response to therapy is predictive of good long‐term renal outcome.

     

Long-term renal injury in ANCA-associated vasculitis: an analysis of 31 patients with follow-up biopsies.

BACKGROUND: We reported previously that in renal disease in relation to antineutrophil cytoplasm auto-antibodies (ANCA)-associated vasculitis, renal outcome correlates better with the percentage of normal glomeruli than with separate active lesions. This may imply that glomeruli, once affected by necrotizing and crescentic lesions, are irreversibly damaged. We quantified and evaluated the course of renal lesions in the present study. METHODS: We retrospectively analysed 31 patients with renal disease in relation to ANCA-associated vasculitis, all treated with immunosuppressive drugs. In all patients, a renal biopsy was performed at diagnosis. A follow-up biopsy was performed in all patients on the indication of a suspected renal relapse, after a mean interval of 31 months. RESULTS: The mean percentage of normal glomeruli in the renal biopsy did not change over time (29% in the initial and 30% in the follow-up biopsy). The mean percentage of glomeruli with crescents, however, significantly decreased from 57 to 30% (P<0.001). The percentage of glomerulosclerosis significantly increased from 12 to 39% (P<0.001). The data were independent of diagnosis, gender, age, time interval between the biopsies, and treatment. CONCLUSIONS: This is the first study to quantify glomerular changes between two time points in patients with renal vasculitis. Our results suggest that, on average, no new glomeruli are recruited into the active disease process. The sum of the percentage of crescentic and sclerotic glomeruli in the initial biopsies is larger than the percentage of sclerotic glomeruli in the follow-up biopsies. Thus, therapy seems not only to prevent normal glomeruli from being recruited into the active disease process for a certain time, but seems also to allow part of the active lesions to revert into a normal phenotype, although another part of the active lesions will be transformed to a chronic phenotype.     

Renal manifestations associated with hepatitis C virus

Among the several types of chronic glomerulonephritis (GN) described in association with hepatitis C virus (HCV) infection, cryoglobulinemic glomerulonephritis is by far the most frequent. It is usually associated with type II cryoglobulinemia with IgM k rheumatoid factor. It is a membranoproliferative GN, which shows some distinctive histologic features (intraglomerular monocyte infiltration, intraluminal thrombi due to massive precipitation of cryoglobulins, renal vasculitis), has a chronic course with acute recurrent episodes that can be controlled by corticosteroids more than by antiviral therapy (interferon alpha). More controversial is the association with type I non-cryoglobulinemic membranoproliferative GN, which has been found in some series from the USA and Japan but not in others. The demonstration of HCV antibodies and/or HCV-RNA in other types of chronic glomerulonephritis is usually reported in a small minority of cases suggesting the possibility of a coincidental finding more than an etiologic factor.     

HLA–DRB4 as a genetic risk factor for Churg‐Strauss syndrome

Objective

To explore the association between HLA alleles and Churg‐Strauss syndrome (CSS), and to investigate the potential influence of HLA alleles on the clinical spectrum of the disease.

Methods

Low‐resolution genotyping of HLA–A, HLA–B, and HLA–DR loci and genotyping of TNFA −238A/G and TNFA −308A/G single‐nucleotide polymorphisms were performed in 48 consecutive CSS patients and 350 healthy controls.

Results

The frequency of the HLA–DRB1*07 allele was higher in the CSS patients than in controls (27.1% versus 13.3%; χ² = 12.64, P = 0.0003, corrected P [P_corr] = 0.0042, odds ratio [OR] 2.42, 95% confidence interval [95% CI] 1.47–3.99). The HLA–DRB4 gene, present in subjects carrying either HLA–DRB1*04, HLA–DRB1*07, or HLA–DRB1*09 alleles, was also far more frequent in patients than in controls (38.5% versus 20.1%; χ² = 16.46, P = 0.000058, P_corr = 0.000232, OR 2.49, 95% CI 1.58–3.09). Conversely, the frequency of the HLA–DRB3 gene was lower in patients than in controls (35.4% versus 50.4%; χ² = 7.62, P = 0.0057, P_corr = 0.0228, OR 0.54, 95% CI 0.35–0.84). CSS has 2 major clinical subsets, antineutrophil cytoplasmic antibody (ANCA)–positive, with features of small‐vessel vasculitis, and ANCA‐negative, in which organ damage is mainly mediated by tissue eosinophilic infiltration; analysis of HLA–DRB4 in patients categorized by different numbers of vasculitic manifestations (purpura, alveolar hemorrhage, mononeuritis multiplex, rapidly progressive glomerulonephritis, and constitutional symptoms) showed that its frequency strongly correlated with the number of vasculitis symptoms (P for trend = 0.001).

Conclusion

These findings indicate that HLA–DRB4 is a genetic risk factor for the development of CSS and increases the likelihood of development of vasculitic manifestations of the disease.