HSPD1 and chlamydia infectious disease: This serum sample also had IgG1 antibodies to C. trachomatis HSP60 (2006 = 17.7 μg/ml and 2010 = 36.4 μg/ml) and to C. pneumoniae (2006 = 30 μg/ml and 2010 = 23.7 μg/ml), indicating an ongoing or recent Chlamydia infection.