Peter Priftakis

Association between a High BK Virus Load in Urine Samples of Patients with Graft-Versus-Host Disease and Development of Hemorrhagic Cystitis after Hematopoietic Stem Cell Transplantation

ABSTRACT BK virus (BKV) load in urine alone or in combination with acute graft-versus-host disease (GVHD) was correlated to development of hemorrhagic cystitis (HC). BKV load in combination with acute GVHD discriminated the best, while BKV and viral load alone, but not GVHD, still showed predictive ability for HC.

BK-viruria and haemorrhagic cystitis are more frequent in allogeneic haematopoietic stem cell transplant patients receiving full conditioning and unrelated-HLA-mismatched grafts

The influence of conditioning regimen, donor background and HLA matching on development of BK virus (BKV)-associated haemorrhagic cystitis (HC) was examined in 175 allogeneic haematopoietic stem cell transplant (HSCT) patients, undergoing 179 HSCT events. Twenty-seven patients presented late-onset HC, and BK viruria was verified in 23/27 HC events. Seventy-one (40%) HSCTs were performed with myeloablative conditioning (MC), 108 (60%) were performed with reduced intensity conditioning (RIC), 66 (37%) were performed with a related donor (RD) grafts and 113 (63%) with an unrelated donor (URD) graft. BK viruria was more common during HC, than non-HC events, after MC as compared to RIC (both P<0.001), and with an HLA-mismatched donor (P<0.01). By multivariate logistical regression analysis, independent risk factors for HC were BKV (OR 6.7; 95% CI 2.0–21.7; P=0.001), MC (OR 6.0; 95% CI 2.1–17.3; P<0.001) and URD (OR 3.4; 95% CI 1.1–10.6; P=0.03). However, when analysing HSCT performed with URD or RD grafts separately, BKV (OR 8.5; 95% CI 1.8–19.3; P=0.004) and MC (OR 5.9; 95% CI 1.3–11.3; P=0.009) increased the risk for HC only with a URD, but not with an RD graft.

BK virus (BKV) quantification in urine samples of bone marrow transplanted patients is helpful for diagnosis of hemorrhagic cystitis, although wide individual variations exist

BACKGROUND Hemorrhagic cystitis (HC) in allogeneic bone marrow transplanted (BMT) patients is associated with BK virus (BKV) reactivation manifested as BK viruria. However, since 77-90% of all adult BMT patients excrete BKV, viral reactivation alone cannot be responsible for HC. Recently, a significant overrepresentation of C-->G mutations in the Sp1 binding site in the non-coding control region (NCCR) of BKV was shown to be present in HC patients and absent in non-HC patients. OBJECTIVES We aimed to investigate if this mutation resulted in excessive BKV excretion in HC patients. STUDY DESIGN A Real-Time PCR was developed and used to quantify BKV in urine samples from 21 patients with HC, with and without the mutations, as well as from patients without HC. RESULTS Quantification of BKV was successful in 18 of 21 urine patients (six with and six without C-->G mutations) and six patients without HC. A mean of 3.0 x 10(6) BKV copies/microl was detected in urine samples of HC patients with C-->G mutations, compared to a mean of 1.5 x 10(6) BKV copies/microl in HC patients without C-->G mutations and a mean of 1.0 x 10(6) BKV copies/microl in patients without HC. The obtained differences were however not statistically significant, due to one individual non-HC patient with an extremely high BKV copy number. Nevertheless, while 50% of the samples in the HC groups expressed 1 x 10(6) copies/microl or more, only one of the samples in the non-HC group contained a virus quantity higher than 5 x 10(5) copies. CONCLUSIONS Although we could not confirm that the C-->G mutations in the Sp1 site of BKV were responsible for an increased viral load in patients with HC, our data suggest that levels of BKV above 10(4) copies/microl may indicate a risk for HC.

Overrepresentation of point mutations in the Sp1 site of the non-coding control region of BK virus in bone marrow transplanted patients with haemorrhagic cystitis

BACKGROUND Haemorrhagic cystitis (HC) in allogeneic bone marrow transplanted (BMT) patients is associated with reactivation of BK virus (BKV) manifested as BK viruria. However, it has been suggested that BKV reactivation alone is not responsible for HC, since BKV can be detected in the urine of 50-90% of all adult BMT patients. OBJECTIVES In the present study, we analysed if BK viruses with specific mutations in the non-coding control region (NCCR) or in the region encoding the major capsid protein (VP1) were more frequently associated to the appearance of HC in BMT patients. STUDY DESIGN The NCCR and the region encoding VP1 of BKV excreted in the urine from 25 BMT patients, 16 with and nine without HC, were sequenced by an ABI Prism Big Dye terminator cycle sequencing ready reaction kit. RESULTS AND CONCLUSIONS A statistically significant (P=0.019) overrepresentation of C to G mutations within the NCCR Sp1 binding site was observed in 7/16 (43%) patients with HC (six cases at position 249 (P=0.035) and one case at position 251), as compared with 0/9 (0%) of the patients without HC. Major differences were not observed in the VP1 sequences of patients with and without HC. BKV WW and WWT-variants as well as BKV subtype I were most commonly encountered in both groups of patients. In conclusion, C to G point mutations, within the BKV NCCR Sp1 binding site, were significantly more common in patients with HC, suggesting that these mutations may be indicative for the clinical diagnosis of HC and could influence the virulence of the virus.

Increased risk of gastrointestinal acute GVHD following the addition of melphalan to busulfan/cyclophosphamide conditioning

Risk factors associated with the development of aGVHD in the gastrointestinal tract have not been studied in depth. We retrospectively assessed 25 pediatric patients with MDS and JMML and compared the treatment outcome of two different conditioning regimens. Seventeen children (68%) underwent conditioning with busulfan (Bu), cyclophosphamide (Cy), and melphalan (Mel) and eight children (32%) with Bu and Cy. Gastrointestinal aGVHD stages II–IV (day 0–100) were observed in 47% (eight of 17) of the patients in the BuCyMel group and in none (0 of 8) in the BuCy group (p < 0.05). In patients who developed gastrointestinal aGVHD stages III–IV, a 24‐h variation in the Bu concentration with a nighttime peak was noted. HC and liver aGVHD stages II–IV were observed in 47% (eight of 17) and 35% (six of 17) after BuCyMel conditioning and in 0% (0 of 17) and 12.5% (one of eight) after BuCy conditioning. The overall survival rate was 53% (nine of 17) in the BuCyMel group and 62.5% (five of eight) in the BuCy group. In conclusion, the addition of melphalan to the BuCy conditioning regimen resulted in severe gastrointestinal complications and did not improve overall survival.