High IgG reactivity in the majority (16 of 23 patients) of COPD patients to various regions of MID, UspA1, and UspA2 is similar in distribution to that of the healthy adult population. The acute (A, C, and E)- and convalescent (B, D, and F)-phase sera that were directed against different regions of the outer membrane proteins MID (A and B), UspA1 (C and D), and UspA2 (E and F) showed little changes. Each symbol represents the average of two separate IgG ELISAs performed independently. The longer horizontal bars represent median values.