title: Association of BK Virus Titers With Lymphocyte Count in Renal Transplant Patients.
abstract: OBJECTIVE
  Regular screening for the BK virus (BKV) is recommended for early intervention in renal transplant patients. Identification of predictors for the development of BK viremia would improve their monitoring. We performed a retrospective study investigating whether the lymphocyte count may be a predictor of BKV development in renal transplant patients.
  
  
  METHODS
  We retrospectively analyzed 268 renal transplant patients who were followed in our clinic from January 2011 to August 2014. The viral loads of BKV in blood detected by quantitative real-time polymerase chain reaction test were performed according to relevant guidelines. We also retrospectively monitored lymphocyte count, creatinine, immunosuppressive drug doses, and tacrolimus/cyclosporine/mTor inhibitors levels during the same time as BKV screening. Demographic and other clinical data were extracted from patients' files. The calculation of correlation coefficients and receiver operating characteristics (ROC) curve analysis were performed.
  
  
  RESULTS
  Overall, 16 patients (5.9%) who experienced BKV-DNA positivity were included the study. Mean age of patients was 38.2 ± 12.8 years. All patients received steroid and calcineurin inhibitors (CNIs). Mycophenolate mofetil/mycophenolic acid (MMF/MPA) was administered to 14 patients. BKV-DNA was found in 64 of the 88 (72.7%) plasma samples. The lymphocyte count on the first day of positive BKV-DNA test was significantly lower than in those with negative BKV-DNA results (1700/μl vs 2400/μl, respectively; P = .009). Its AUC of the ROC curve was 0.77 (P = .012). The optimal cutoff point for lymphocyte count was 1900/μl, and sensitivity and specificity for predict BKV positivity were 75% and 78.57%, respectively. We also found that lymphocyte count negatively correlated with the first detectable BKV titers (r = -0.438; P = .015). However, there is no relation between CNI/mTOR inhibitor levels, MMF/MPA doses, lymphocyte count, and all BKV-titers.
  
  
  CONCLUSIONS
  Decreased lymphocyte count may be a predictor for preceding BKV viremia. Clinicians should be more careful in terms of the decreased lymphocyte count in case of BKV replication in renal transplant patients.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, School of Medicine, Marmara University, Istanbul, Turkey. Electronic address: arzuvelioglu@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Velioglu
authors.affiliation: Department of Medical Microbiology, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: B
authors.initials: B
authors.lastname: Aksu
authors.affiliation: Division of Nephrology, Department of Internal Medicine, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: E
authors.initials: E
authors.lastname: Asicioglu
authors.affiliation: Division of Nephrology, Department of Internal Medicine, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: H
authors.initials: H
authors.lastname: Arıkan
authors.affiliation: Department of Urology, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: I
authors.initials: I
authors.lastname: Tinay
authors.affiliation: Department of General Surgery, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: S
authors.initials: S
authors.lastname: Yardimci
authors.affiliation: Department of General Surgery, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: C
authors.initials: C
authors.lastname: Yegen
authors.affiliation: Division of Nephrology, Department of Internal Medicine, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: S
authors.initials: S
authors.lastname: Tuglular
authors.affiliation: Division of Nephrology, Department of Internal Medicine, School of Medicine, Marmara University, Istanbul, Turkey.
authors.forename: C
authors.initials: C
authors.lastname: Ozener
mesh_terms: D000328:Adult; D000368:Aged; D001739:BK Virus / Q000502:physiology*; D065095:Calcineurin Inhibitors / Q000627:therapeutic use; D016572:Cyclosporine / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage; D016030:Kidney Transplantation / Q000009:adverse effects*; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D009173:Mycophenolic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives; D027601:Polyomavirus Infections / Q000097:blood* / Q000821:virology; D060888:Real-Time Polymerase Chain Reaction; D012189:Retrospective Studies; D013256:Steroids / Q000627:therapeutic use; D016559:Tacrolimus / Q000008:administration & dosage; D014412:Tumor Virus Infections / Q000097:blood* / Q000821:virology; D019562:Viral Load; D014766:Viremia / Q000821:virology; D014779:Virus Replication; D055815:Young Adult
chemical_list: D065095:Calcineurin Inhibitors; D007166:Immunosuppressive Agents; D013256:Steroids; D016572:Cyclosporine; D009173:Mycophenolic Acid; D016559:Tacrolimus