Measurements of human herpesvirus 8 viral load in blood before and after leukoreduction filtration

Human Herpesvirus 8 in Australia: DNAemia and Cumulative Exposure in Blood Donors

Human herpesvirus 8 (HHV-8), the causative agent of Kaposi’s sarcoma, multicentric Castleman’s disease and primary effusion lymphoma, predominantly manifests in immunocompromised individuals. However, infection in immunocompetent individuals does occur. The prevalence of HHV-8 exposure in blood donors from non-endemic countries ranges between 1.2% and 7.3%. Nothing was known about the prevalence in Australian blood donors. Therefore, this study investigated the active and cumulative exposure of HHV-8 in this cohort. Plasma samples (n = 480) were collected from eastern Australian blood donors and were tested for HHV-8 DNA by qPCR, and for HHV-8 antibodies by two different ELISAs. Samples initially positive on either ELISA were retested in duplicate on both, and on a mock-coated ELISA. Any samples positive two or three out of the three times tested on at least one ELISA, and repeat negative on the mock-coated ELISA, were assigned as repeat positive. None of the 480 samples tested contained HHV-8 DNA. Serological testing revealed 28 samples (5.83%; 95% CI: 3.74−7.93%) had antibodies to HHV-8. There was no difference (p > 0.05) in seropositivity between sex or with increasing age. This is the first study to show serological evidence of cumulative HHV-8 exposure and no HHV-8 DNAemia within a select blood donor population in Australia. Our molecular and serological data is consistent with published results for blood donors residing in HHV-8 non-endemic countries, which shows the prevalence to be very low.

Infiltrating Kaposi sarcoma presenting as acute kidney injury: An unexpected consequence of deliberate hepatitis C-positive organ transplantation

Kaposi sarcoma (KS) following kidney transplantation can result from recipient reactivation of latent human herpesvirus 8 (HHV-8) infection or activation of donor-acquired HHV-8 infection. Post-transplant KS typically manifests with cutaneous pathology, but rare cases of renal allograft involvement have been reported. We describe two cases of donor-derived HHV-8 infection in two hepatitis C (HCV) viremia-negative transplant recipients who each received a kidney from a donor with HCV viremia. One recipient did not develop KS while the other presented with acute kidney injury caused by extensive KS infiltration of the renal parenchyma and metastatic disease. This report reviews the literature for cases of KS involving the renal allograft and highlights an unexpected consequence of deliberate HCV-positive organ transplantation.

Donor-derived human herpesvirus 8 and development of Kaposi sarcoma among 6 recipients of organs from donors with high-risk sexual and substance use behavior

Kaposi sarcoma (KS) can develop following organ transplantation through reactivation of recipient human herpesvirus 8 (HHV-8) infection or through donor-derived HHV-8 transmission. We describe 6 cases of donor-derived HHV-8 infection and KS investigated from July 2018 to January 2020. Organs from 6 donors, retrospectively identified as HHV-8-positive, with a history of drug use disorder, were transplanted into 22 recipients. Four of 6 donors had risk factors for HHV-8 infection reported in donor history questionnaires. Fourteen of 22 organ recipients (64%) had evidence of posttransplant HHV-8 infection. Lung recipients were particularly susceptible to KS. Four of the 6 recipients who developed KS died from KS or associated complications. The US opioid crisis has resulted in an increasing number and proportion of organ donors with substance use disorder, and particularly injection drug use history, which may increase the risk of HHV-8 transmission to recipients. Better awareness of the risk of posttransplant KS for recipients of organs from donors with HHV-8 infection risk could be useful for recipient management. Testing donors and recipients for HHV-8 is currently challenging with no validated commercial serology kits available. Limited HHV-8 antibody testing is available through some US reference laboratories and the Centers for Disease Control and Prevention.

Transfusion-transmitted cytomegalovirus: behaviour of cell-free virus during blood component processing. A study on the safety of labile blood components in Switzerland

BACKGROUND

Nowadays, most blood products are leukocyte-reduced. After this procedure, the residual risk for transfusion transmitted cytomegalovirus (TT-CMV) is mostly attributed to cell-free viruses in the plasma of blood donors following primary infection or viral reactivation. Here, objectives are: 1) to study the behaviour of cell-free CMV through the blood component processing; 2) to determine the anti-CMV seroprevalence, the level of viremia, the window-period in blood donor population; and 3) to identify cases of TT-CMV in bone marrow transplant (BMT) recipients.

MATERIALS AND METHODS

Cell-free CMV was injected into blood bags originating from regular donors. Blood components were processed according to either the CompoSelect^® or the CompoFlow^® (Fresenius Kabi AG) techniques. Samples were analysed at each step for presence of virus DNA using quantitative polymerase chain reaction (PCR). The anti-CMV seroprevalence in our donor population was taken from our donor data system. The viremia was assessed in pooled plasmas samples from routine donations by quantitative PCR. Medical charts of 165 BMT anti-CMV seronegative recipients/anti-CMV seronegative donors who received CMV-unscreened blood products were reviewed.

RESULTS

Cell-free CMV passes without any decrease in viral load through all stages of blood processing. The anti-CMV seroprevalence was 46.13%. Four DNA positive samples out of 42,240 individual blood donations were identified (0.009%); all had low levels of viremia (range 11-255 IU/mL). No window-period donation was identified. No TT-CMV was found.

DISCUSSION

Cell-free CMV remains a concern with current blood component processing as it passes through all the processes. However, since low levels of CMV DNA were identified in the donations tested, and no BMT recipients had TT-CMV, the residual threat of TT-CMV after leukocyte reduction appears to be very low.

Seroprevalence of HHV-6 and HHV-8 among blood donors in Greece

Background

Herpes viruses infection transmitted through healthy but infected blood donors pose a danger to herpes-naive immunocompromised recipients. The risk of transfusion-related HHV-8 transmission is different in endemic and not endemic areas. HHV-6 and HHV-8 seroprevalence and viral load among blood donors have been reported from different countries. The aim of our study was to assess the seroprevalence of HHV-8 and HHV-6 in volunteer blood donors from Greece which is unknown.

Findings

Serum samples from 179 healthy blood donors were tested for the presence of IgG antibodies against HHV-6 and HHV-8 with ELISA. None of the 179 donors of Greek origin tested was positive for HHV-8. HHV-6 seropositivity was assessed in 160 blood donors’ samples and was found to be 78.75% (126/160). The HHV-6 seroprevalence did not differ either between males and females or among different decade age groups.

Conclusions

The fact, that no blood donor was positive for HHV-8 IgG antibodies indicates that the risk for transfusion related HHV-8 transmission in Greece, if any, is negligible and does not warrant broad testing for HHV-8. Definitely further studies are needed, in order to clarify the potential risk of HHV-6 transmission.