Identification of differentially expressed genes in trabecular bone from the iliac crest of osteoarthritic patients.

OBJECTIVE: Osteoarthritis (OA) is clinically characterized by degeneration of the joints and has been traditionally considered a primary disorder of articular cartilage, with secondary changes in the subchondral bone. The increased bone mass and generalized changes in bone quality observed in osteoarthritic patients suggest that OA may be a primary systemic bone disorder with secondary articular cartilage damage. The iliac crest is a skeletal site distant from the affected joint, with a minimal load-bearing function. To provide evidence that OA is a systemic disorder, we searched for differentially expressed genes in the iliac crest bone of patients suffering from hip OA. MATERIAL AND METHODS: Gene expression levels between bone samples collected at surgery from the iliac crest of patients undergoing total hip arthroplasty for primary OA and younger donors, who were undergoing spinal arthrodesis, were investigated by means of oligonucleotide microarrays. To verify data detected by microarrays technology, Real Time Reverse Transcription-Polymerase Chain Reaction (RT-PCR) assays were performed with specimens from osteoarthritic patients and donors, as well as from elderly donors who were undergoing arthroplasty for subcapital femoral neck fracture. RESULTS: The microarray analysis surveyed 8327 genes and identified 83 whose expression levels differed at least 1.5-fold in the OA group (P<0.005). Comparisons between Real Time RT-PCR data from OA and the two donor groups indicated differential expression of genes involved in bone cell functions in the group of OA patients. The genes identified, including CCL2, FOS, PRSS11, DVL2, AKT1, CA2, BMP6, OMD, MMP2, TGFBR3, FLT1, BMP1 and TNFRS11B, have known roles in osteoblast or osteoclast activities. CONCLUSIONS: The data from this study identify a set of genes, closely related to bone cell functions, in which differential regulation in osteoarthritic bone distant from the diseased subchondral bone might underlie the etiopathogenesis of OA as a generalized bone disease.

The diagnostic interpretation of basophil activation test in immediate allergic reactions to betalactams.

BACKGROUND: Basophil activation by allergens, including drugs, has been used to determine sensitivity and to study IgE recognition and cross-reactivity. OBJECTIVE: We sought to determine the sensitivity and specificity of a basophil activation test (Basotest) in patients with immediate allergic reactions to betalactams, with a later comparison between patients who were selective (those recognizing the culprit drug excluding benzylpenicillin (BP)) and cross-reactors (those recognizing several penicillin determinants including BP). METHODS: Basotest to different haptens was performed in 70 patients with immediate allergic reactions to betalactams, classified into three groups: (A) skin test positive independently of CAP/RAST immunoassay value, (B) skin test negative and CAP/RAST positive, and (C) skin test and CAP/RAST negative but drug provocation test positive. Basotest was carried out by flow cytometry following the manufacturer's instructions using different betalactam determinants and results expressed as a stimulation index. RESULTS: Of the 70 patients, 34 (48.6%) were positive to Basotest (sensitivity: 48.6%), 31 (44.3%) to CAP/RAST and 46 (65.7%) to either one or the other. Considering the different groups, Basotest was positive in 50.9% of patients in Group A, 60% in Group B and 14.3% in Group C. The specificity was 91.3%. Positivity to the haptens was 28.6% to amoxicillin (AX), 21.7% to BP, 20% to benzylpenicilloyl-poly-l-lysine, 12.5% to ampicillin and 2.2% to minor determinant mixture. In patients with cephalosporin reactions, Basotest to the culprit cephalosporin was positive in 77.7%. There were differences between the two reactor groups in the sensitivity of Basotest (selective to AX=50%, cross-reactors=28.6%; chi(2)=10.809, P=0.004) and in the CAP/RAST (selective to AX=28.6%, cross-reactors=61.9%; chi(2)=8.944, P=0.011). CONCLUSIONS: The sensitivity of Basotest is similar to immunoassays (CAP/RAST). Sensitivity is improved when used in combination. Although further studies are required, Basotest results for cephalosporin allergy seem very promising. This technique does not help differentiate between selective reactors and cross-reactors.

Skin test evaluation in nonimmediate allergic reactions to penicillins.

BACKGROUND: Nonimmediate reactions (NIR) to aminopenicillins (AP) are frequent. Although patch testing (PT) and intradermal testing (IT) are used for diagnosis, comparative results have never been adequately performed. We compared PT and IT in subjects with NIR to AP. METHODS: Twenty-one subjects with NIR to AP and positive IT were re-evaluated. Skin tests were performed with amoxicillin (AX) and ampicillin (AM) at different concentrations in petrolatum, 50, 25, and 5% w/w, for PT and in saline, 20, 2, and 0.2 mg/ml for both PT and IT. Skin biopsies from the site of the positive response were studied with haematoxylin-eosin and immunohistochemistry. RESULTS: In the re-evaluation, one case was IT and PT negative and was excluded; 20 were IT positive and 18 PT positive for both AX and AM. Decreasing concentrations of AP induced a reduction in positivity in both methods when diluted in saline, but not when mixed in petrolatum (PT only). With both PT and IT, immunohistochemical studies showed a perivascular mononuclear infiltrate with CD4 and CD8 memory cells expressing perforin and granzyme B. CONCLUSIONS: Both tests appear valuable for the diagnosis of NIR to AP. However, IT diagnosed more patients than PT. The vehicle (saline or petrolatum) had no influence on the response, although in the former the concentration was critical. The immunohistochemical analysis showed skin infiltrates compatible with a T-cell drug reaction.