However, in a later study, the same investigators classified sarcoidosis patients as those with or who had developed pulmonary fibrosis within 4 years compared to those with self-limiting or Lofgren's syndrome and found that a haplotype of single nucleotide polymorphism (SNP) variants affecting TLR1, TLR6 and TLR10 genes (which can act as co-receptors with TLR2) were absent in the fibrotic group [37]. Here, TLR2 is linked to sarcoidosis.