BTLA and B-cell chronic lymphocytic leukemia: Diplotype analysis including two polymorphisms, rs1982809 and 2705511, revealed that BTLA mRNA expression levels in T cell subpopulation of CLL patients possessing predisposing rs1982809G+ and 2705511C+ alleles (n = 20) were significantly lower than mRNA expression levels in homozygotes [AA]/[AA] (n = 7) for these two SNPs (0.007 ± 0.011 vs. 0.016 ± 0.01, p = 0.036).