56 CA titers typically range between 512 and 32000. DAT is always positive for C3d.[3] and [56] Most
reported patients have been adults, and AIHA typically occurs during the second or third week after the febrile illness has started.56 In most published cases the PD0325901 ic50 onset has been sudden with pallor, jaundice and, sometimes, prostration. Intravascular hemolysis, as evidenced by hemoglobinuria, has been reported in several patients. In general, the prognosis is good and the hemolytic complication is self-remitting within 4–6 weeks, although a lethal course has been described in one patient.[55] and [56] A number of case reports have been published on CA mediated AIHA in infectious mononucleosis with confirmed Epstein–Barr virus (EBV) etiology.[57], [58], [59] and [60] As compared to M. pneumoniae pneumonia, however, infectious mononucleosis is an infrequent cause of AIHA, accounting for approximately 1% of the cases. [1] and [2] Conversely, the frequency of clinically significant hemolysis in EBV infections is unknown but probably low. Hospital-based data have indicated check details that hematological complications, being generally mild and including several manifestations
other than AIHA, occur in 25–50% of patients with EBV infection. 59 Since patient selection will influence such figures and most individuals with infectious mononucleosis are not hospitalized, the frequency is probably much lower among patients with EBV-infection in the community. CA found in EBV-infections are polyclonal and almost invariably specific for the i-antigen.[57], [60] and [61] The immunoglobulin class may be either IgM or IgG.60 Rheumatoid factor-like IgM-IgG complexes have also been reported to act as CA in single cases.60 In most published reports, DAT has been positive for C3d only. Anti-i titers are usually modest, typically at 256–512, and the hemolytic anemia is transient and generally mild.60 Several authors have reported on transient CAS mediated
by anti-i autoantibodies following cytomegalovirus (CMV) infection.[60] and [61] Rarely, CA-mediated hemolysis has been described in adenovirus infections, influenza A, varicella, rubella, Legionella pneumophilica pneumonia, Celecoxib listeriosis and pneumonia caused by Chlamydia species. [11], [60], [62], [63], [64] and [65] We observed a slight, transient CAS in an otherwise healthy 23 year old man two weeks after a Chlamydia pneumoniae pneumonia. Severe CAS with a prolonged course and cryoglobulin activity of the CA has been reported following Escherichia coli lung infection. 22 Autoantibody specificities in these rare cases have included anti-I, anti-i and anti-Pr. Cold-antibody AIHA with infectious etiology typically involves a young adult or adolescent with M. pneumoniae pneumonia or infectious mononucleosis. Anemia or hemoglobinuria in such patients should immediately raise the suspicion of secondary AIHA.