Background: Pathologic similarities between sarcoidosis (SA) and tuberculosis (TB) suggest M. tuberculosis antigen(s) as causative agents. It seems likely that in the genetically different predisposed hosts, the same antigen(s) may cause the development of sarcoid or tuberculous Th1 response. AIM AND MATERIALS/METHODS: To test a difference in haplotypes associated with both diseases, we compared the distribution of DRB1, DQA1 and DQB1 alleles in 45 SA patients, 62 TB patients and in 143 healthy volunteers, using a PCR-SSP method.
Results: Our results revealed that DRB1*03/*11, DQB1*02, DQA*0501 in Stage I of SA with Löfgren's syndrome (Ls) and DRB1*15, DQA1*0102/*0103 in Stage II of SA were more common, whereas DQA1*0102 (Ls) and DRB1*16/*04/*08, DQB1*03/*04/*05/*06, DQA1*0301 (Ls, Stage II) were less common than in the controls. Nevertheless, after Bonferroni correction, only DRB1*04, DQB1*02/*03/*05/*06, DQA1*0102/*0301/*0501 differed significantly. In TB group, DRB1*16/*14, DQB1*05, DQA1*0303 were more frequent and DRB1*11, DQB1*02, DQA1*0201/*0505 less frequently present as compared to the controls, but frequency of DRB1*16, DQB1*02/*05 and DQA1*0303/*0505 only was significantly different after correction. After correction in both Stages of SA, DRB1*11 was more common and DRB1*16/*04/*14, DQB1*03/*05, DQA1*0301/0302/*0303 were less frequent than in the TB group. DQB1*02, DQA1*0201/*0501 (Ls) and DRB1*15/*13 (Stage II) were more frequently present in SA than in TB, but after correction, only DRB1*15, DQB1*02, DQA1*0501 were significantly different.
Conclusions: We identified associations of HLA class II alleles in SA and TB with expression pattern specific and different for each group. In most cases, in SA patients frequency of HLA class II alleles occurrence is opposite to the frequency in TB patients.