MPO and pneumococcal infection: Notably, both studies on Mycobacterium tuberculosis infection identified apolipoprotein B, although one also identified apolipoprotein E and the S100 calcium binding protein A8.45, 47 Similarly, both studies involving Streptococcus pneumoniae infection identified myeloperoxidase, although one also identified lactotransferrin, and the other identified S100 calcium binding protein A9, cathelicidin antimicrobial peptide, ceruloplasmin, and cystatin C.42, 44 The two studies investigating Trypanosoma sp.