title: Mannose-binding lectin deficiency is not associated with increased risk for polyomavirus nephropathy.
abstract: BACKGROUND
  Polyomavirus associated nephropathy (PVAN) affects up to 10% of kidney transplant recipients and is a major risk factor for graft loss. Mannose-binding lectin (MBL) is an important recognition molecule of the innate immune system, and its deficiency has been associated with susceptibility to various infections. In transplantation, on the other hand, high MBL levels have been associated with increased tissue damage in ischemia-reperfusion models and poorer graft and patient survival in solid organ transplant patients. To investigate the relation between MBL and BK virus infection, post-transplant (post-Tx) MBL levels were determined in a cohort of de novo kidney transplant patients with and without BK viremia.
  
  
  METHODS
  41 de novo kidney transplant patients with high (n=16, group 1) or low level BK viremia (n=25, group 2) and 64 patients without BK viremia (group 3) were included. In every patient, functional MBL levels were determined at 1-3 time points (days 30, 90 or 180) post-Tx using an MBL oligomer ELISA.
  
  
  RESULTS
  MBL levels remained unchanged between days 30 and 180 post-Tx independent of BKV viremia. Frequencies of MBL deficiency (<500 ng/mL) and MBL levels were not significantly different between the 3 groups. However, group 2 patients showed a trend towards lower MBL serum levels compared to group 1 patients, notably in patients without acute rejection (p=0.076).
  
  
  CONCLUSIONS
  MBL deficiency was not associated with higher risk for BK viremia. In contrast, we hypothesize that BK virus replication in patients with low MBL levels might imply lower risk for progression towards PVAN compared to patients with high MBL levels. This view is supported by recent data demonstrating local complement activation in BK nephropathy.
authors.affiliation: Department of Nephrology and Intensive Care, Charité Campus Virchow, Augustenburger Platz 1, 13353 Berlin, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Liman
authors.forename: Nina
authors.initials: N
authors.lastname: Babel
authors.forename: Thomas
authors.initials: T
authors.lastname: Schachtner
authors.forename: Nadine
authors.initials: N
authors.lastname: Unterwalder
authors.forename: Julian
authors.initials: J
authors.lastname: König
authors.forename: Jörg
authors.initials: J
authors.lastname: Hofmann
authors.forename: Petra
authors.initials: P
authors.lastname: Reinke
authors.forename: Peter
authors.initials: P
authors.lastname: Nickel
mesh_terms: D000328:Adult; D001739:BK Virus; D003167:Complement Activation / Q000276:immunology; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000097:blood* / Q000276:immunology / Q000821:virology*; D016030:Kidney Transplantation; D008297:Male; D037601:Mannose-Binding Lectin / Q000097:blood* / Q000172:deficiency / Q000276:immunology; D008875:Middle Aged; D027601:Polyomavirus Infections / Q000097:blood* / Q000276:immunology; D012307:Risk Factors; D014766:Viremia / Q000276:immunology / Q000821:virology
chemical_list: D037601:Mannose-Binding Lectin