Prevalence of anti-neutrophil cytoplasmic antibodies (ANCA) in juvenile chronic arthritis.

OBJECTIVE: Sera from 66 children with active JCA of oligoarticular, polyarticular or systemic onset, 13 sera from patients in disease remission, 15 sera from patients with reactive arthritis, and 11 from Lyme arthritis patients were tested for the presence of anti-neutrophil cytoplasmic antibodies (ANCA) in order to evaluate their diagnostic significance in JCA. RESULTS: ANCA were found in 21% (14/66) of the active JCA sera, all showing an atypical pANCA staining pattern using indirect immunofluorescence on ethanol fixed granulocytes. 71% of these sera also showed antinuclear antibodies (ANA) on HEp-2 cells. By additional staining on paraformaldehyde fixed granulocytes to exclude staining artefacts due to ethanol fixation, 2 of the pANCA positive sera showed cytoplasmic staining. In no case did we find nuclear fluorescence suggesting a true cytoplasmic localization of the involved antigens. All ANCA positive sera were negative for anti-MPO and anti-LF antibodies. ANCA prevalence in our study group did not correlate with the disease subgroup, disease duration or other clinical characteristics. However, we found ANCA only in active disease. CONCLUSION: Our data suggest that the diagnostic importance of ANCA in JCA is restricted to only a few JCA patients. In these cases, however, ANCA positivity supports the diagnosis of JCA. Further studies are needed to substantiate this finding, as well as possible subgroup specificities. Standardized techniques of granulocyte fixation and antigen specific tests are needed to produce comparable results in different study groups.

Cytokine-independent progression of immunoglobulin production in vitro by B lymphocytes from patients with systemic lupus erythematosus.

B lymphocytes from patients with systemic lupus erythematosus (SLE) secreted high levels of immunoglobulin spontaneously when cultured in vitro. Addition of the cytokines interleukin-2, interleukin-4 and interleukin-6 either alone or in combination failed to augment spontaneous immunoglobulin synthesis. Percoll-separated low-density SLE B lymphocytes matured into immunoglobulin-secreting cells also independent of exogenous interleukins. During maturation these cells became enlarged and less dense, and began to express CD23. This was in contrast to normal B cells, which did not secrete immunoglobulin spontaneously but synthesized IgM after interleukin stimulation. These results indicate that in vitro immunoglobulin synthesis by SLE B cells is already initiated in these cells and progresses independently of further stimulatory manoeuvres.

Low-dose methotrexate in systemic onset juvenile chronic arthritis.

Twelve children with severe systemic juvenile chronic arthritis, all requiring high dose corticosteroids, have been admitted to a pilot study to evaluate the effect of low-dose methotrexate (mean dose: 8.5 mg/M2) on disease activity over a 6 month period. Definite improvement occurred in 4 children, allowing reduction of the steroid dose in 2 cases. Two children showed an acute flare of disease activity during the treatment period and in three, steroids had to be increased. Overall, side effects were rare with a rise in transaminases only occurring once. MTX blood levels taken on 14 occasions in 8 children documented absorption in all cases with a mean level of 3.45 x 10(-7) mol/l on a mean dose of 9 mg/M2. Low-dose MTX appears to be a safe drug in the short term treatment of severe systemic JCA with beneficial effect in about a third of patients. Long-term controlled trials will be needed to evaluate its role in the treatment of systemic disease as well as side effects.