In summary, the genetics of the innate immunity and specifically the variants of human SP-A1 and SP-A2 affect survival after K. pneumoniae infection in a sex-, gene-, and variant-specific manner with females showing a better survival than males: (a) Gene-specific survival: co-ex = SP-A2 > SP-A1 > KO (male and female together); (b) Variant-specific survival co-ex (6A2/1A0) = 1A0 > 1A3 = 6A2 > 6A4 (male and female together); (c) Treatment with exogenous SP-A1 or SP-A2 before and/or at the time of infection improves survival significantly. This evidence concerns the gene SFTPA1 and infection.