title: A case of IgM deficiency with B cell deficiency detected by ABO discrepancy in a patient with acute osteomyelitis.
abstract: ABO discrepancy refers to an inconsistency between red cell and serum typings and has various causes, including hypogammaglobulinemia. IgM deficiency is a rare disorder that may accompany several conditions such as infection and autoimmune disorders. Here, we describe a case of IgM deficiency discovered during the evaluation of an ABO discrepancy in a 16-yr-old Korean boy. ABO blood grouping showed that while his cell type was O+, serum typing detected only anti-A (3+). Anti-B was not detectable at room temperature but was graded at 1+ at 4℃. ABO genotyping revealed an O/O genotype. His serum IgG, IgA, and IgM concentrations were 770 mg/dL (reference range: 800-1,700 mg/dL), 244 mg/dL (reference range: 100-490 mg/dL), and 13.5 mg/dL (reference range: 50-320 mg/dL), respectively. He was diagnosed with acute osteomyelitis on the basis of clinical presentation and imaging studies. The symptoms gradually improved within 3 weeks of treatment. However, the ABO discrepancy and IgM deficiency persisted even 6 months after recovery and lymphocyte subset analysis revealed CD19+ B cell deficiency. To the best of our knowledge, IgM deficiency detected by ABO discrepancy in a patient with acute osteomyelitis has not been reported before.
authors.affiliation: Department of Laboratory Medicine, Seoul Seonam Hospital, Ewha Womans University Medical Center, Seoul, Korea.
authors.forename: Chae Lim
authors.initials: CL
authors.lastname: Jung
authors.forename: Mi-Kyung
authors.initials: MK
authors.lastname: Cha
authors.forename: Byoung-Hyuk
authors.initials: BH
authors.lastname: Jun
authors.forename: Ki-Sook
authors.initials: KS
authors.lastname: Hong
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics; D000208:Acute Disease; D000293:Adolescent; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D001842:Bone and Bones / Q000000981:diagnostic imaging; D005838:Genotype; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007153:Immunologic Deficiency Syndromes / Q000150:complications / Q000175:diagnosis*; D007717:Knee / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D010019:Osteomyelitis / Q000150:complications / Q000175:diagnosis*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals
chemical_list: D000017:ABO Blood-Group System; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D019275:Radiopharmaceuticals
keywords: ABO discrepancy; Acute osteomyelitis; B cell deficiency; IgM deficiency