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Arterial stiffness indexes and serum cytokine levels in seronegative spondyloarthritis: relationships between stiffness markers and metabolic and immunoinflammatory variables: comments on the article by Tuttolomondo et al

study. The mean (± sd) age of the patients was 74 ± 4.7 years. Four patients were affected by CPPD according to our gold standard. In three out of these four patients, CPP crystal deposition was also found in the synovial membrane whereas none of the patients affected by OA alone presented with CPP in the synovial membrane. From the morphological viewpoint, the synovial membrane of patients affected by CPPD presented with large fibrous areas with shrunken or flat villi and reduced stromal vessels. Villi were diminished in number and devoid of epithelium. In one case residual hypertrophic but not proliferating synoviocytes were observed. In another case lymphocytes and giant cells containing phagocytized crystals were identified. By contrast, the synovial membrane of patients affected by OA alone appeared well represented and in some slides proliferating, with numerous and well-formed villi. The stromal layer presented increased vascularity without, or with only slight, evidence of fibrosis. Lymphoplasmacellular infiltrates of medium/severe grade were present in all the patients affected by OA, organized in clusters or in some cases in follicles. (Figure 1). Synovial membrane morphology in late-stage OA has been described previously by other authors (5, 6), who found similar patterns to our series of patients. However, to the best of our knowledge, this is the first study to investigate the histology of the synovial membrane in patients with CPPD. The link between the two diseases is not clear and generally CPPD is considered as a consequence of OA that does not affect the clinical and radiological outcome if compared to OA alone, as testified by the classification of the disease, which includes an asymptomatic form of CPPD with OA (1). These results suggest that different pathogenetic pathways could be involved in the course of the two diseases that could lead to different phenotypical patterns and outcomes in the two groups of patients. Further studies are necessary to confirm these preliminary data and to better explore the histological and phenotypical associations of the two diseases as well as the pathogenetical pathways.