Antiperinuclear factors are present in polyarthritis before ACR criteria for rheumatoid arthritis are fulfilled.

OBJECTIVE: To show that antiperinuclear factor (APF) may be useful for the diagnosis of rheumatoid arthritis at a time when the American College of Rheumatology (ACR) criteria are not yet fulfilled. METHODS: Testing for APF-IgG (1:100 threshold) and rheumatoid factors (RF) was done in 60 patients with polyarthritis of recent onset during a three year follow up. RESULTS: At the end of the study, 21/40 rheumatoid arthritis were positive for RF and 31/40 for APF, including 18/40 cases (45%) in which ACR criteria were not yet fulfilled. CONCLUSIONS: APF are useful in the diagnosis of early rheumatoid arthritis.

Impact of using stored cells for immunofluorescence detection of antiperinuclear factor on sensitivity of the method for the diagnosis of rheumatoid arthritis.

Antiperinuclear factor is as sensitive as (0.75 to 0.80) and more specific than (0.94 to 0.97) rheumatoid factor for the diagnosis of rheumatoid arthritis. Although three groups found similar performance characteristics using the assay technique described by Youinou, lower sensitivities have also been reported. To clarify these discrepancies, we investigated each parameter of the assay, including storage time of the oral mucosa cells used as the substrate. Even when the slides were frozen, titers fell by one dilution within the first week and by two dilutions within two weeks after sampling. This decline seemed related to storage rather than to freezing: slides kept at 4 degrees C yielded an apparent three-dilution fall in titers after one week and were unevaluable after longer storage times. Successive freeze-thaw cycles did not influence results when the assay was done on the day the cells were sampled and fixed. Titers in sera stored at -25 degrees C remained unchanged or decreased by no more than one dilution during the first 18 months but declined thereafter. These data emphasize the need for performing the assay on the same day or, at the latest, on the day after fixation of the slides. That this precaution was taken should be specified in the "Methods" section of articles on antiperinuclear factor detection.

Absence of antineutrophil cytoplasmic antibodies in giant cell arteritis.

OBJECTIVE: To determine the prevalence of antineutrophil cytoplasmic antibodies (ANCA) in patients with active giant cell arteritis (GCA). METHODS: 23 patients with GCA were selected according to ACR 1990 criteria. Sera were harvested in all patients at an active stage of the disease and during followup (1 to 3 sera/patient for a total of 50 sera). ANCA positivity was searched for by indirect immunofluorescence (IIF) and enzyme linked immunosorbent assay (ELISA) using a neutrophil extract, and antigen specificity was determined by proteinase 3 (PR3), lactoferrin (LF) and myeloperoxidase (MPO) ELISA: RESULTS: Only 1/23 patients exhibited reactivity in IgG ANCA ELISA and IIF, with borderline anti-MPO reactivity in ELISA which was not inhibited by preincubation with MPO in the liquid phase, and no reactivity in Western blot analysis. Specificity could not be demonstrated in another patient who had positive IgG ANCA ELISA but negative ANCA IIF and negative antigen specific ELISA: All other patients were ANCA negative. CONCLUSION: As our patients with GCA did not exhibit typical ANCA when validated antigen specific assays were used, careful laboratory controls and clinical evaluation would seem essential in cases of apparent ANCA positivity.

Rat long-term bone marrow culture as a model for transient production of multinucleated giant cells into suspension culture fraction and for steady mineralization process of adherent stromal cells.

Under in vitro conditions rat bone marrow stromal cells induced into osteogenic differentiation by beta-glycerophosphate, exogenous ascorbic acid and dexamethasone are able to produce a mineralized matrix. Here we describe adult rat long-term bone marrow cultures (LTBMC), deprived of these substances. Mineralization process in stromal adherent cells occurred after 1 month of incubation and was proved by means of X-ray electron microprobe. The high content of sulfur in the extracellular matrix surrounding the mineralized nodules suggests non-distrophic pathway of Ca/P deposition. During the first 2 weeks of incubation the extensive production of multinucleated tartrate-resistant acid phosphatase (TRAP) positive and TRAP negative giant cells occurred into the suspension fraction of the cultures. Rat LTBMC may serve as a model for the investigation of differentiation of osteoblastic progenitors and their interactions with multinucleated TRAP positive cells.

[Purulent pleurisy caused by anaerobic bacteria. Apropos of 2 observations]. / Les pleurésies purulentes à germes anaérobies. A propos de deux observations.

Purulent pleural effusions due to anaerobic organisms secondary to infections of the pulmonary parenchyma are complications which often occur following the inhalation of organisms from the buccal cavity. The most commonly found organisms belong to the endogenous anaerobic flora of Veillon. Rapid encystment of the pleural collection is suggestive of this diagnosis. Treatment consists of drainage of the cavity associated with specific antibiotics.