Abstract
Background:
In sub-Saharan Africa, the Human Herpesvirus 8 (HHV-8) is endemic but with disparities between regions and population studied. Although the virus remains mostly latent, there is some evidences that blood transfusion may represents one of the transmission way for this virus. Here, we evaluated HHV-8 seroprevalence among blood donors in Mali.
Materials and Methods:
This cross-sectional study recruited blood donors from the Blood Transfusion Center at Gabriel Touré Hospital, Bamako. Serum was used for the detection of latent HHV-8 IgG directed against LANA-1 by an indirect immunofluorescence assay (IFA). HIV-1, HBV, HCV and Treponema pallidum were also screened.
Results:
HHV-8 seroprevalence was 10.4% in Malian blood donors. None of the socio-demographic characteristics were associated with HHV-8 infection, although there is a tendency of a higher HHV-8 seroprevalence among participants living in Bamako than those not living there. One individual had co-infection HHV-8/HBV, another HHV-8/HCV while another had HCV and Treponema pallidum. None has been tested positive for HIV infection.
Conclusion:
This intermediate seroprevalence in Malian blood donors suggests that the risk of HHV-8 transmission by transfusion should be considered. Further investigations are needed to assess impact of HHV-8 in polytransfused patients residing in an endemic area for this virus.
Keywords: HHV-8, Seroprevalence, Blood donors, Transfusion, IFA, Mali
INTRODUCTION
Human herpesvirus 8 (HHV-8), also known as Kaposi’s sarcoma associated herpesvirus (KSHV), causes several neoplastic diseases and is responsible of all forms of KS. HHV-8 infection is not ubiquitous, but endemic in Sub-Saharan Africa, some parts of Eastern Europe and Mediterranean. HHV-8 seroprevalence varies between different populations and it is commonly found in human immunodeficiency virus (HIV)-positive individuals and men who have sex with men (MSM) 1,2. The exact route of transmission is still very much debated. Some studies report that saliva is implicated as the main vehicle of transmission in sub-Saharan children; others, on the other hand, support the hypothesis of horizontal transmission in adulthood 2,3. It should be noted that, HHV-8 can be transmitted by blood transfusion. Ensuring good haemovigilance remains a major public health problem in sub-Saharan Africa and more particularly in low-income countries on the African continent 4. Various studies provide strong evidence of HHV-8 transmission by blood transfusion in sub-Saharan Africa. A Ugandan study carried out on patients receiving transfusion; tested for anti-HHV-8 antibodies pre- and post-transfusion, showed that 43% received blood seropositive for HHV-8 and seroconversion risk was significantly higher in recipients of HHV-8 seropositive blood 5. In addition, this area is described as highly endemic for this virus. Some sub-region countries reported HHV-8 seroprevalences in blood donors of 14%, 22% and 57% in Burkina-Faso, Central African Republic and Tanzania, respectively 2,6,7. In Mali, HHV-8 studies in blood donors are almost absent while the most dreaded post-transfusion infections are viral in origin. We investigated the prevalence of antibodies directed against HHV-8 latent associated nuclear antigen 1 (LANA-1) by use of an indirect immunofluorescence assay (IFA) in blood donors from Bamako and its periphery.
MATERIALS AND METHODS
This cross-sectional study included 229 parental and voluntary non-remunerated blood donors, without clinical evidence of Kaposi Sarcoma recruited from November 2019 to January 2020 at the Blood Transfusion Center at Gabriel Touré Hospital in Bamako, Mali. After collecting socio-demographic characteristics, serum was collected for HIV-1, HBsAg, HCV and syphilis screening in Bamako blood bank laboratory. The detection of HHV-8 antibodies directed against LANA-1 Immunoglobulin G (IgG) by IFA using the BC- 3 cell line infected with HHV-8 but not with Epstein Barr virus (Figure 1 and Supplementary Figure 1) was performed as previously described in the virology department of the Pitié-Salpêtrière Hospital, Paris, France 8. This technique uses unstimulated cells (sensitivity 80 – 85%, specificity nearly 100%). Samples reactive at a 1:50 dilution were considered positive (Figure 1, A and C, Supplementary Figure 1, A, B, C and F). Note that, the term “equivocal HHV-8 serology result” was used when after twice tests in some patients, we had an indeterminate result, i.e. ambiguous, fluorescent slide on reading (Figure 1, B and Supplementary Figure 1, D). Continuous variables were described with median and interquartile range [IQR] and categorical variables as numbers and percentages. GraphPad software was used to perform nonparametric tests, Mann–Whitney U test for quantitative data, Fisher exact t test for qualitative data. Confidence interval was 95% (95%CI) and p < 0.05 was considered significant.
Figure 1: Indirect Immunofluorescence assay for the qualitative detection of HHV-8 IgG antibodies directed against the LANA-1 protein.
The positivity for HHV-8 antibodies is revealed by the presence of dots in the nucleus. (A) positive sample at 1:50 dilution; (B) indeterminate result sample at 1:50 dilution (equivocal HHV-8 serology): ambiguous result, hyper fluorescence on reading; (C) strongly positive sample at the 1:50 dilution; (D) negative sample at 1:50 dilution.
RESULTS AND DISCUSSION
We showed that 10.4% of this population of apparently healthy blood donors in Mali had HHV-8 antibodies. None of them had clinical evidence of KS. The socio-demographic characteristics, the geographical setting and HIV-1, HBsAg, HCV and syphilis (Treponema pallidum) screening of the 229 blood donors are described in Table 1. The median age was 29 [IQR, 23–35] years. The majority of blood donors were male (58%), residing in Bamako (89%), attending the center for a parental blood donation (99%) and more than two-thirds have reached primary school or less (69%). None of the socio-demographic characteristics tested were associated with HHV-8 infection, although there is a tendency of a higher HHV-8 seroprevalence among participants living in Bamako than those not living there. One individual had co-infection with HHV-8 and HBV, another with HHV-8 and HCV while another had one with HCV and Treponema pallidum. None has been tested positive for HIV infection. Consistent with previous studies in Burkina-Faso, Central African Republic and Tanzania, this blood donor population is young and predominantly male 2,6,7. The 8 (4%) blood donors with equivocal HHV-8 serology results were excluded in our seroprevalence estimation. This is the first study to investigate HHV-8 seroprevalence in blood donors in Mali showing a moderate seroprevalence around 10%. Many samples had negative HHV-8 serology (Figure 1, D and Supplementary Figure 1, E). This seroprevalence is relatively close to that has been reported in blood donors population in Burkina Faso 7. However, other studies carried out in blood donors from the sub-region report high prevalence of up to 57% 2,6. Differences in assays used, ethnic groups of the sampled populations, cultural practices (pre-masticating baby food, use of medicinal herbs), environmental factors (volcanic soil, exposure to iron) and geographic location of these countries in the area described as the KS belt could be the reason for observed differences in HHV-8 seroprevalence 9–11. However, since the majority of transfusions are whole blood, the presence of HHV-8 in the peripheral compartment does not exclude its transmission, even in the absence of clinical symptoms. Especially since the Malian recommendations in terms of transfusion safety do not prescribe leukodepletion steps while HHV-8 is mostly latent in B lymphocytes.
Table 1:
Sociodemographic and medical data according to HHV-8 serological status in the 229 blood donors recruited
| Characteristics | Total | HHV-8 seropositive | HHV-8 seronegative | P value | ||
|---|---|---|---|---|---|---|
|
|
||||||
| No. (%) | No. | % | No. | % | ||
| All | 229 | 23 | 10.4 | 198 | 89.6 | |
| Age, | ||||||
| median (IQR), years | 29 (23–35) | 32 (25–37) | 28 (23–35) | 0.24 | ||
| Age group, years | ||||||
| 18–30 | 138 (60.3) | 11 | 47.8 | 124 | 62.6 | 0.25 |
| 31–40 | 60 (26.2) | 9 | 39.1 | 50 | 25.3 | |
| 41–50 | 28 (12.2) | 2 | 8.7 | 22 | 11.1 | |
| > 50 | 3 (1.3) | 1 | 4.4 | 2 | 1 | |
| Gender | ||||||
| Male | 133 (58.1) | 12 | 52.2 | 115 | 58.1 | 0.65 |
| Female | 96 (41.9) | 11 | 47.8 | 83 | 41.9 | |
| Education level | ||||||
| None | 99 (43.2) | 8 | 34.8 | 84 | 42.4 | 0.47 |
| Primary | 60 (26.2) | 6 | 26.1 | 54 | 27.3 | |
| Secondary | 42 (18.3) | 5 | 21.7 | 36 | 18.2 | |
| Higher | 28 (12.2) | 4 | 17.4 | 24 | 12.1 | |
| Marital status | ||||||
| Single | 79 (34.5) | 8 | 34.8 | 70 | 35.4 | > 0.99 |
| Married | 150 (65.5) | 15 | 65.2 | 128 | 64.6 | |
| Geographical setting | ||||||
| Bamako | 203 (88.6) | 18 | 78.3 | 179 | 90.4 | 0.08 |
| Around Bamako | 26 (11.4) | 5 | 21.7 | 19 | 9.6 | |
| Type of blood donation | ||||||
| Parental donors | 226 (98.7) | 23 | 100 | 195 | 98.5 | > 0.99 |
| Volunteers donors | 3 (1.3) | 0 | 0 | 3 | 1.5 | |
| HIV-1 status | ||||||
| Positive | 0 | 0 | 0 | 0 | 0 | NC |
| Negative | 229 (100) | 23 | 100 | 198 | 100 | |
| HBsAg status | ||||||
| Positive | 22 (9.6) | 1 | 4.4 | 20 | 10.1 | 0.70 |
| Negative | 207 (90.4) | 22 | 95.6 | 178 | 89.9 | |
| HCV status | ||||||
| Positive | 6 (2.6) | 1 | 4.4 | 4 | 2 | 0.42 |
| Negative | 223 (97.4) | 22 | 95.6 | 194 | 98 | |
| T. pallidum status | ||||||
| Positive | 5 (2.2) | 0 | 0 | 4 | 2.02 | > 0.99 |
| Negative | 216 (94.3) | 22 | 95.6 | 187 | 94.4 | |
| Not specified | 8 (3.5) | 1 | 4.4 | 7 | 3.6 | |
HIV: Human Immunodeficiency virus 1; HBsAg: Hepatitis B surface antigen; HCV: Hepatitis C virus; IQR: Interquartile; No: number; NC: non calculated.
Our study has some limitations; (i) the relative low sensitivity of the indirect immunofluorescence test used leads to a possible underestimation of seroprevalence in our population, (ii) the patients included in our study were all asymptomatic to KS, thus the comparison of fluorescence intensity of serology, and in view of the HHV-8 quantification in peripheral compartment, between symptomatic and asymptomatic patients could not be study; (iii) finally, the sample size studied is limited and probably explains why the statistical results do not have rich significance.
In conclusion, this intermediate seroprevalence among blood donors in Mali suggests that the risk of transmission of HHV-8 by transfusion should be considered. Further studies are needed on the evaluation of HHV-8 transmission via blood transfusion in Africa, especially in children with homozygous sickle cell disease, who generally require several transfusions, and who live in an area of high HHV-8 seroprevalence.
Supplementary Material
The positivity for HHV-8 antibodies is revealed by the presence of dots in the nucleus. Positive sample at 1:50 dilution (A); strongly positive sample at the 1:50 dilution (B) (C); indeterminate result sample at 1:50 dilution (equivocal HHV-8 serology): ambiguous result, presence of small dots in the cytoplasm and fluorescence on reading (D); negative sample at 1:50 dilution (E); Positive control at 1:50 dilution (F).
ACKNOWLEDGEMENTS
We thank Privat Juthèce Malanda Kiminou and Jean-François Franetich for technical support.
FINANCIAL SUPPORT:
This work was supported by ANRS-MIE (Agence Nationale de Recherche sur le SIDA et les Maladies Infectieuses Emergentes) (Medical Virology AC43) and Fogarty International Center/ National Institutes of Health grant D43TW010350.
ABREVIATIONS:
- HHV-8
Human Herpesvirus 8
- LANA-1
Latent Associated Nuclear Antigen 1
- IFA
Indirect Immunofluorescence Assay
- KSHV
Kaposi’s Sarcoma associated Herpesvirus
Footnotes
CONFLICT OF INTEREST STATEMENT
The authors have disclosed no conflicts of interest.
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are available from the corresponding author upon reasonable request.
References
- 1.Jary A, Leducq V, Desire N, et al. New Kaposi’s sarcoma-associated herpesvirus variant in men who have sex with men associated with severe pathologies. The Journal of Infectious Diseases. 2020;222(8):1320–1328. doi: 10.1093/infdis/jiaa180 [DOI] [PubMed] [Google Scholar]
- 2.Lidenge SJ, Tran T, Tso FY, et al. Prevalence of Kaposi’s sarcoma-associated herpesvirus and transfusion-transmissible infections in Tanzanian blood donors. International Journal of Infectious Diseases. 2020;95:204–209. doi: 10.1016/j.ijid.2020.04.018 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Mohammed ZB, Abdullah SF. Serodiagnosis of Human Herpesvirus-8 among Iraqi Blood Donors. Clinical Medicine. 7(2):6. [Google Scholar]
- 4.Kakisingi CN, Mukuku O, Matanda SK, et al. Profil épidémiologique et séroprévalence des donneurs de sang aux cliniques universitaires de Lubumbashi, République Démocratique du Congo. Pan Afr Med J. 2016;23. doi: 10.11604/pamj.2016.23.175.8480 [DOI] [Google Scholar]
- 5.Hladik W, Fowlkes AL, Banage F, Dondero TJ. Transmission of Human Herpesvirus 8 by Blood Transfusion. The New England Journal of Medicine. Published online 2006:8. [DOI] [PubMed] [Google Scholar]
- 6.Belec L, Cancre N, Hallouin M, Morvan J, Mohamed A, Gresenguet G. High prevalence in Central Africa of blood donors who are potentially infectious for human herpesvirus 8. Transfusion. 1998;38(8):771–775. doi: 10.1046/j.1537-2995.1998.38898375517.x [DOI] [PubMed] [Google Scholar]
- 7.Collenberg E, Ouedraogo T, Ganamé J, et al. Seroprevalence of six different viruses among pregnant women and blood donors in rural and urban Burkina Faso: A comparative analysis. J Med Virol. 2006;78(5):683–692. doi: 10.1002/jmv.20593 [DOI] [PubMed] [Google Scholar]
- 8.Marcelin A-G, Grandadam M, Flandre P, et al. Kaposi’s sarcoma herpesvirus and HIV-1 seroprevalences in prostitutes in Djibouti. J Med Virol. 2002;68(2):164–167. doi: 10.1002/jmv.10184 [DOI] [PubMed] [Google Scholar]
- 9.Crabtree KL, Wojcicki JM, Minhas V, et al. Risk Factors for Early Childhood Infection of Human Herpesvirus-8 in Zambian Children: The Role of Early Childhood Feeding Practices. Cancer Epidemiol Biomarkers Prev. 2014;23(2):300–308. doi: 10.1158/1055-9965.EPI-13-0730 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Dollard SC, Butler LM, Jones AMG, et al. Substantial regional differences in human herpesvirus 8 seroprevalence in sub-Saharan Africa: Insights on the origin of the “Kaposi’s sarcoma belt.” Int J Cancer. Published online 2010:7. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Montella M, Franceschi S, Geddes M, Arniani S, Cocchiarella G. Classic Kaposi’s sarcoma and volcanic soil in southern Italy. The Lancet. 1996;347(9005):905. doi: 10.1016/S0140-6736(96)91388-4 [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
The positivity for HHV-8 antibodies is revealed by the presence of dots in the nucleus. Positive sample at 1:50 dilution (A); strongly positive sample at the 1:50 dilution (B) (C); indeterminate result sample at 1:50 dilution (equivocal HHV-8 serology): ambiguous result, presence of small dots in the cytoplasm and fluorescence on reading (D); negative sample at 1:50 dilution (E); Positive control at 1:50 dilution (F).
Data Availability Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.