TNF and susceptibility to pneumonia measurement: Morales-García et al.[5] compared Mexican influenza A patients and matching, co-inhabiting controls and found that single nucleotide polymorphisms (SNPs) in the TNF and LTA genes contributed to developing the disease, with an OR as high as 27 (95% CI 3–1248) for rs361525*AA in TNF. This allele was also found to be associated with influenza A in Greek patients, and in particular with those developing pneumonia (OR 3.74, 95% CI 1.06–13.25)[6].