Comment to: Cluster analysis for clinical sarcoidosis' phenotyping

We have read and appreciated the commentary by M. d'Alessandro to our manuscript entitled “Cluster analysis for clinical sarcoidosis’ phenotyping” published in European Journal of Internal Medicine [ ]. We agree that phenotyping sarcoidosis patients is important for clarifying prognosis and therapeutic approaches. Since ethnicity, sex, genetic background, environmental exposures or socioeconomic status may play an important role in sarcoidosis, several attempts have been previously published showing a wide range of phenotypic variability. The aim of our investigation was to distinguish clinical phenotypes of sarcoidosis in our Spanish population by combining traditional signs and symptoms [ ]. It is evident that sarcoidosis population in Spain is mostly Caucasian, where approximately half of them present in the form of Löfgren's syndrome typically. In accordance with M. D'Alessandro, the six phenotype clusters emerged in our study may not apply in other racial groups such as the African-American or Japanese populations, with poor presence of Löfgren's syndrome, and cannot be generalized. For the same reason, phenotypic classification in such African-American or Japanese populations cannot be generalized in our population. This is why we believe that our results may help the clinical approach of sarcoidosis among European populations, in which Caucasians are represented in large proportion. In this regard, further studies assessing biological markers and genotypes may help each area or country to choose what clinical phenotype classification better suits its population characteristics and disease process.