HLA Class I, II, and III Polymorphism in Italian Patients With Sarcoidosis: Discussion

Though available data are too scant to draw a worldwide map of HLA-sarcoidosis associations, some results of our investigation seem to be in agreement with literature findings. We confirm suggestions of European investigators about MHC association witH sarcoidosis: HLA-B8 appears to be positively related to the disease in whites (Table 2). These data could not be confirmed in West Indian or Japanese patients, the latter belonging to a population where B8 is a very rare antigen. It is known that HLA-B8,DR3 antigens may be linked to disorders with an immunologic basis and that HLA-B8,DR3 positive individuals may undergo the development of diseases with an autoimmune component. Both these observations fit the current concepts on the pathogenesis of sarcoidosis. We cannot draw any conclusion in our series about a possible association of HLAr prognosis, as others have previously published, since at the moment of the preparation of this manuscript, most of our patients have not reached a sufficient follow-up period. canadianfamilypharmacy

When the role of MHC in a particular disease is analyzed, it is of great interest to consider various clinical features of patients. For this reason, in this work we extended the analysis of the relationship of sarcoidosis-HLA region genes adding other disease aspects, such as sex of patients, age of onset, radiologic stage, and extrapulmonary localizations.
In agreement with epidemiologic data, the mean age of our patients was 36.08 years. The two subsets of patients, under and over the average, seem to be characterized by different genetic markers (Table 3 and “Results” section). We demonstrate that HLA-A3,B35,CW4,C4BQ0 phenotypes and DR5 are associated with early onset of sarcoidosis. This strengthens the hypothesis of the existence within the HLA region of a genetic accelerating factor, which leads to anticipating the age of onset of the disease. This finding adds further evidence to our previous ones about the implication of DR5 phenotype in the juvenile form of certain autoimmune diseases such as rheumatoid arthritis, vitiligo, alopecia areata, and Hashimotos thyroiditis, as some of us reported elsewhere. It is interesting to underline that even among a series of Japanese patients with sarcoid, DR5 was found to be associated with early onset of the disease, but in that case there was a positive association with good outcome.

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