{"id":1650,"date":"2018-09-13T12:34:19","date_gmt":"2018-09-13T12:34:19","guid":{"rendered":"http:\/\/edren.org\/ren\/?page_id=1650"},"modified":"2025-08-29T13:47:47","modified_gmt":"2025-08-29T13:47:47","slug":"bk-virus","status":"publish","type":"page","link":"https:\/\/edren.org\/ren\/handbook\/transplant-handbook\/infection-prophylaxis-and-treatment\/bk-virus\/","title":{"rendered":"BK Virus"},"content":{"rendered":"<p><span style=\"font-family: georgia, palatino, serif;\">BK and JC are two polyoma viruses that are not associated with symptomatic infection in immunocompetent individuals, but are commonly acquired and lie dormant. They may\u00a0 cause significant disease in immunosuppressed patients. JC virus has only very rarely been reported to cause renal disease, and the brain disease that it can cause is extremely rare in renal patients. Kidney infection by BK virus is a well recognised problem though. Published evidence of BK nephropathy is almost completely limited to renal transplantation.<\/span><\/p>\n<p><span style=\"font-family: georgia, palatino, serif;\"><strong><span style=\"color: #993300;\">BK virus (BKV)<\/span><\/strong> infects more than 80% of individuals by early childhood, and persists in epithelium of kidney, ureters and bladder. Viruria is common following renal transplantation, and testing for this is not helpful. Viraemia is less common, and sometimes (not always) associated with nephritis.<\/span><\/p>\n<p><span style=\"font-family: georgia, palatino, serif;\"><strong><span style=\"color: #993300;\">BKV associated nephropathy (BKVAN) <\/span><\/strong>is a tubulointerstitial nephritis that has often been mistaken for rejection, and carries a high risk of graft failure. There generally are no extra-renal symptoms or signs to suggest viral infection. The risk of BKVAN is highest in the first year after transplant. Occasionally it occurs later.<\/span><\/p>\n<h3><span style=\"color: #993300;\"><strong><span style=\"color: #993300;\">Screening and diagnosis<\/span><\/strong><br \/>\n<\/span><\/h3>\n<p><span style=\"font-family: georgia, palatino, serif;\">BKVAN is almost always associated with significant viraemia, making screening by PCR of blood potentially useful. Our protocol is to screen:<\/span><\/p>\n<ul style=\"list-style-type: disc;\">\n<li><span style=\"font-family: georgia, palatino, serif;\">First year after renal transplantation: Monthly for 6 months, at 1, 2, 3, 4, 5, and 6 months, then 3 monthly, at 9 and 12 months. 90% of cases have occured by 7 months in our cohort.<\/span><\/li>\n<li><span style=\"font-family: georgia, palatino, serif;\">Thereafter, six monthly testing at 18, 24 and 30 months &#8211; then stop, so a total of 2.5 years of surveillance.<\/span><\/li>\n<li><span style=\"font-family: georgia, palatino, serif;\">Indication testing could obviously occur after this routine surveillance period.<\/span><\/li>\n<li><span style=\"font-family: georgia, palatino, serif;\">The laboratory will not process a request if &lt;4 weeks has elapsed since the previous result (unless that sample had a positive result).<\/span><\/li>\n<li><span style=\"font-family: georgia, palatino, serif;\">In the event of a first positive result, a follow up test in &lt;4 weeks (but not &lt; than 2 weeks) is warranted. In this instance, it should be specified on the clinical information that this is a follow up of a positive result to ensure the request is processed.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-family: georgia, palatino, serif;\">Diagnosis of BKVAN requires a renal biopsy, but the diagnosis may often be presumed if graft dysfunction is present in the context of a significant viral load. We increasingly do not biopsy to confirm BKVAN as the treatment is generally similar for BK viraemia and BKVAN and thorough screening means we generally detect BK infection in the early stages of it&#8217;s trajectory.<\/span><\/p>\n<p>&nbsp;<\/p>\n<h3><strong><span style=\"color: #993300;\">Management: reduction of immunosuppression<\/span><span style=\"color: #993300;\"><br \/>\n<\/span><\/strong><\/h3>\n<p><span style=\"font-family: georgia, palatino, serif;\">Reduction in immunosuppression is the cornerstone of BKV management. However there is no clear consensus on the viral load above which therapy should be altered but above 1,000 iu \/ ml (approximatley 10,000 copies \/ ml) appears to corrleate well with BKVAN.<\/span><\/p>\n<p><span style=\"font-family: georgia, palatino, serif;\">The most robust data supports initially reducing or stoppping the antimetabolite (generally MMF), with later reductions in tacrolimus if viraemia or nephropathy persists. Other options include switching tacrolimus for cyclosporine or even sirolimus.<\/span><\/p>\n<ul style=\"list-style-type: disc;\">\n<li><span style=\"font-family: georgia, palatino, serif;\">Corticosteroids are generally continued at the same dose, as other agents are reduced<\/span><\/li>\n<li><span style=\"font-family: georgia, palatino, serif;\">Renal function and BKV levels should be monitored 2-4 weekly<\/span><\/li>\n<li><span style=\"font-family: georgia, palatino, serif;\">Check Donor Specific Antibodies (DSA) if the anti-metabolite is stopped for more than 4 weeks<\/span><\/li>\n<\/ul>\n<p><span style=\"font-family: georgia, palatino, serif;\"><strong><span style=\"color: #993300;\">After viral clearance<\/span><\/strong> &#8211; many practitioners see BK viraemia as a sign of over-immunosuppression and do not routinely return to previous dose of anti-metabolite. It may be necessary to balance this with perceived immunological risk, monitoring viral load.<\/span><\/p>\n<p><span style=\"font-family: georgia, palatino, serif;\">This protocol has been used in Edinburgh, though use of alternative therapies is now rare (see below):<\/span><\/p>\n<p><a href=\"http:\/\/edren.org\/ren\/wp-content\/uploads\/2020\/02\/BKvirus.png\"><img loading=\"lazy\" decoding=\"async\" class=\" wp-image-3866 aligncenter\" src=\"http:\/\/edren.org\/ren\/wp-content\/uploads\/2020\/02\/BKvirus.png\" alt=\"\" width=\"573\" height=\"398\" srcset=\"https:\/\/edren.org\/ren\/wp-content\/uploads\/2020\/02\/BKvirus.png 561w, https:\/\/edren.org\/ren\/wp-content\/uploads\/2020\/02\/BKvirus-300x209.png 300w, https:\/\/edren.org\/ren\/wp-content\/uploads\/2020\/02\/BKvirus-150x104.png 150w\" sizes=\"auto, (max-width: 573px) 100vw, 573px\" \/><\/a><\/p>\n<h3><strong><span style=\"color: #993300;\">Alternative agents for BKVAN<\/span><\/strong><\/h3>\n<p><span style=\"font-family: georgia, palatino, serif;\">These are all unproven and generally not indicated.<\/span><\/p>\n<ul style=\"list-style-type: disc;\">\n<li><span style=\"font-family: georgia, palatino, serif;\"><strong><span style=\"color: #993300;\">IVIG<\/span><\/strong> &#8211; contain anti-BKV neutralising antibodies, but there is no robust evidence that it alters the course of nephritis.<\/span><\/li>\n<li><span style=\"font-family: georgia, palatino, serif;\"><strong><span style=\"color: #993300;\">Leflunomide <\/span><\/strong>&#8211; has both immunosuppressive and antiviral activity. The therapeutic dose is uncertain and liver and bone marrow toxicity may occur. There are other significant side effects. There is no good evidence from clinical studies to support its use.<\/span><\/li>\n<li><span style=\"font-family: georgia, palatino, serif;\"><strong><span style=\"color: #993300;\">Cidofovir<\/span><\/strong> &#8211; has modest in vitro antiviral activity agains BKV, but is itself nephrotoxic. Currently there is only very weak justification for using it or related compounds<\/span>.<\/li>\n<\/ul>\n<h3><strong><span style=\"color: #993300;\">Concomitant BKVAN and acute rejection<\/span><\/strong><\/h3>\n<p><span style=\"font-family: georgia, palatino, serif;\">This is a difficult diagnosis to be convinced about, as histologically TCMR and BKVAN can look very similar, unless vascular or microcirulatory injuries are present. The treatment is unclear and should be directed against the predominant lesion if that can be determined. Current viral load (and viral load trajectory) and DSA may help support the decision. IVIg may have a role.<\/span><\/p>\n<h3><strong><span style=\"color: #993300;\">Retransplantation<\/span><\/strong><\/h3>\n<p><span style=\"font-family: georgia, palatino, serif;\">Retransplantation after graft loss from BKVAN has generally been successful, in the context of viraemia that has resolved.<\/span><\/p>\n<h3><strong><span style=\"color: #993300;\">Further info<\/span><\/strong><\/h3>\n<ul style=\"list-style-type: disc;\">\n<li><a href=\"http:\/\/edren.org\/ren\/edren-info\/bk-virus-nephropathy\/\">Info for patients about BKV<\/a> (Edren)<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><span style=\"font-size: 12pt;\">Paul Phelan<\/span><\/p>\n<p><span style=\"font-size: 12pt;\">Screening frequency updated at June 5th 2025 protocol meeting &#8211; PP<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>BK and JC are two polyoma viruses that are not associated with symptomatic infection in immunocompetent individuals, but are commonly acquired and lie dormant. They may\u00a0 cause significant disease in immunosuppressed patients. JC virus has only very rarely been reported to cause renal disease, and the brain disease that it\u2026<\/p>\n<p> <a class=\"continue-reading-link\" href=\"https:\/\/edren.org\/ren\/handbook\/transplant-handbook\/infection-prophylaxis-and-treatment\/bk-virus\/\"><span>Continue reading<\/span><i class=\"crycon-right-dir\"><\/i><\/a> <\/p>\n","protected":false},"author":2,"featured_media":0,"parent":1628,"menu_order":135,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_lmt_disableupdate":"no","_lmt_disable":"","footnotes":""},"class_list":["post-1650","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/edren.org\/ren\/wp-json\/wp\/v2\/pages\/1650","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/edren.org\/ren\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/edren.org\/ren\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/edren.org\/ren\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/edren.org\/ren\/wp-json\/wp\/v2\/comments?post=1650"}],"version-history":[{"count":24,"href":"https:\/\/edren.org\/ren\/wp-json\/wp\/v2\/pages\/1650\/revisions"}],"predecessor-version":[{"id":6667,"href":"https:\/\/edren.org\/ren\/wp-json\/wp\/v2\/pages\/1650\/revisions\/6667"}],"up":[{"embeddable":true,"href":"https:\/\/edren.org\/ren\/wp-json\/wp\/v2\/pages\/1628"}],"wp:attachment":[{"href":"https:\/\/edren.org\/ren\/wp-json\/wp\/v2\/media?parent=1650"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}