Polyomavirus BK neutralizing activity in human immunoglobulin preparations. Transplantation. 2010;89:1462-1465. [PMID: 20568674 DOI: 10.1097/tp.0b013e3181daaaf1]

Evaluating the impact of pre-transplant desensitization utilizing a plasmapheresis and low-dose intravenous immunoglobulin protocol on BK viremia in renal transplant recipients

BACKGROUND

A correlation exists between polyomavirus BK (BKV) viremia in renal transplant recipients (RTR) and the degree of immunosuppression. However, the impact of pre-transplant desensitization on the incidence of BKV viremia is unknown.

METHODS

This retrospective study evaluated living-donor RTR between January 2004 and December 2008 receiving routine BKV viral load monitoring. Patients were divided into those who underwent pre-transplant desensitization (n = 20) and those who did not (n = 71). The primary endpoint was the incidence of BKV viremia at 1 year post transplant.

RESULTS

All demographic data were similar, except for more female patients (65% vs. 36.6%; P = 0.0392) in the desensitized group. More desensitized patients had a previous transplant (75% vs. 12.7%; P < 0.0001) and were more likely to be induced with basiliximab (75% vs. 35.2%; P = 0.0021). Following transplantation, antibody-mediated rejection (AMR) rates were highest in the desensitized group (55% vs. 1.4%; P < 0.0001). The incidence of BKV viremia at 1 year post transplant was significantly higher in desensitized patients (45% vs. 19.7%; P = 0.0385). Desensitization was also associated with a higher prevalence of BKV viremia at any time post transplant (50% vs. 22.5%; P = 0.0245), polyomavirus-associated nephropathy (20% vs. 2.8%; P = 0.0198) and BKV-related allograft loss (10% vs. 0%; P = 0.0464). Also of note, in a subgroup analysis of only our desensitized patients, it did not appear that development of AMR significantly impacted the incidence of BKV viremia in these individuals.

CONCLUSIONS

This analysis reveals that pre-transplant desensitization significantly increases the risk for BKV viremia and nephropathy.

Native kidney BK virus nephropathy associated with chronic lymphocytic leukaemia

BK virus nephropathy (BKVN) is a well-recognized complication of renal transplantation. Several cases of native kidney BKVN following other solid organ or bone marrow transplants have been reported. We describe a patient with chronic lymphocytic leukaemia who presented with deteriorating renal function with no history of solid organ or bone marrow transplantation. Renal biopsy demonstrated tubular injury characteristic of viral infection, confirmed as BK virus by immunohistochemistry and elevated serum BK viral titres. Treatment with leflunomide reduced serum viral titres and stabilized renal function. This is the first biopsy-proven case of native kidney BKVN in a patient with no previous transplantation history.

Incidence and outcomes of BK virus allograft nephropathy among ABO- and HLA-incompatible kidney transplant recipients

BACKGROUND AND OBJECTIVES

ABO-incompatible kidney transplant recipients may have a higher incidence of BK virus allograft nephropathy (BKVAN) compared with ABO-compatible recipients. It is unclear whether HLA-incompatible recipients share this risk or whether this phenomenon is unique to ABO-incompatible recipients. DESIGN, SETTING, PARTICIPATION, MEASUREMENTS: This study analyzed adult incompatible kidney transplant recipients from 1998 to 2010 (62 ABO-incompatible and 221 HLA-incompatible) and identified patients in whom BKVAN was diagnosed by biopsy (per protocol or for cause). This was a retrospective analysis of a prospectively maintained database that compared BKVAN incidence and outcomes between ABO- and HLA-incompatible recipients, respectively. BKVAN link to rejection and graft accommodation phenotype were also explored. The Johns Hopkins Institutional Review Board approved this study.

RESULTS

Risk for BKVAN was greater among ABO-incompatible than HLA-incompatible patients (17.7% versus 5.9%; P=0.008). Of BKVAN cases, 42% were subclinical, diagnosed by protocol biopsy. ABO-incompatibility and age were independent predictors for BKVAN on logistic regression. C4d deposition without histologic features of glomerulitis and capillaritis (graft accommodation-like phenotype) on 1-year biopsies of ABO-incompatible patients with and without BKVAN was 40% and 75.8%, respectively (P=0.04). Death-censored graft survival (91%) and serum creatinine level among surviving kidneys (1.8 mg/dl) were identical in ABO- and HLA-incompatible patients with BKVAN (median, 1399 and 1017 days after transplantation, respectively).

CONCLUSIONS

ABO-incompatible kidney recipients are at greater risk for BKVAN than HLA-incompatible kidney recipients. ABO-incompatible recipients not showing the typical graft accommodation-like phenotype may be at heightened risk for BKVAN, but this observation requires replication among other groups.

Infectious complications in kidney-transplant recipients desensitized with rituximab and intravenous immunoglobulin

BACKGROUND AND OBJECTIVES

Rituximab and intravenous Ig (IVIG) are commonly used for desensitization of HLA and blood group-incompatible (ABOi) transplants. However, serious infections have been noted in association with rituximab administration. In this study, we retrospectively compared infectious outcomes in those who received rituximab plus IVIG for HLA or ABOi transplants (RIT group) with a group of nonsensitized, ABO-compatible transplant recipients (non-RIT group).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients undergoing kidney transplantation at Cedars-Sinai Medical Center were included in the analysis. A total of 361 patients were identified. All received antimicrobial prophylaxis and viral surveillance. The primary outcome was infection.

RESULTS

Overall patient survival was 97 and 96%, and graft survival was 91 and 89% in the RIT and non-RIT groups, respectively, after an average follow-up of 18 months. There were equal rates of bacterial (34.7% versus 39.1%), viral (21.8% versus 25.1%), fungal (5.9% versus 5.2%), and serious infections (22.9% versus 25.5%) in the RIT and non-RIT groups respectively. Urinary tract infection was the most common infection, accounting for 50% of all bacterial infections. Cytomegalovirus viremia was nonsignificantly more common in the nonrituximab-treated group (15.2% versus 10%), whereas BK viremia was marginally more frequent in the rituximab-treated group (10.6% versus 5.8%). There were no graft losses caused by BK-associated nephropathy. There were two deaths in each group related to infection (1%).

CONCLUSION

Rituximab does not increase infection risk when used with intravenous Ig for desensitization.

The BK virus in renal transplant recipients-review of pathogenesis, diagnosis, and treatment

The BK virus, a DNA virus from the Polyomavirus group, represents an opportunistic infection of immunosuppressed transplant recipients. Though the virus was discovered approximately 40 years ago, the emergence of BK virus nephropathy since 1995 onwards, with associated high graft loss rates, has revolutionized renal transplantation medicine. Kidney transplant professionals realized that the consequences of over-immunosuppression were as severe as the consequences of under-immunosuppression and we entered the era of immunosuppressive minimization. Despite this recognition, the optimal testing type for BK virus infections and frequency of testing are hotly debated. Similarly, optimal treatment strategies remain sources of intense controversy. The authors review the current strategies of screening, diagnosis, and possible treatment, and also review the amount and quality of evidence in favor or against. Similarities and differences between cytomegalovirus, Epstein-Barr virus, and BV virus, the three major viral infections in kidney transplantation, are highlighted.