Identification of the TNF (−308) gene polymorphism with ASPCR (A) and LTα (+252) gene polymorphism with PCR-RFLP (B). Genotypes were identified as homozygous, TNF1/1 or TNF2/2 if the single 184-bp fragment appeared exclusively in the F1-R1 or F1-R2 primer sets' reactions (A, lanes 1 and 2 and 3 and 4, respectively). Genotypes were identified as heterozygous, TNF1/2, if the 184-bp fragment appeared in both F1-R1 and F1-R2 primer sets' reactions (A, lanes 5 and 6). The 531-bp fragment, amplified with F1-R3primers, served as an internal control and competitor for the ASPCR. Lanes 1 through 3 on the (B) show the LTα (+252) polymorphic genotypes. The 368-bp fragment cleaved with Nco I (133- and 235-bp fragments) represented the LTα (5.5) allele, and that not cleaved represented the LTα (10.5) allele. Genotypes were identified as homozygous for LTα (10.5/10.5) if the single 368-bp fragment appeared (B, lane 1) and homozygous for LTα (5.5/5.5) if two 133- and 235-bp fragments were present (B, lane 2). The presence of noncleaved (368 bp) and cleaved fragments (133 and 235 bp) in the same sample identified the heterozygous genotype, LTα (10.5/5.5) (B, lane 3).
