ABSTRACT
The genetic variability of the human herpesvirus 8 (HHV-8) strains circulating in the populations living in the Maghreb region, an endemic area for HHV-8 and associated Kaposi's sarcoma, remains largely unknown. We have thus analyzed the genetic variation of the complete K1 gene of HHV-8 in a series of 35 viral strains, originating from 28 Moroccan patients with classic, AIDS-associated or iatrogenic Kaposi's sarcoma lesions. All but one of the 35 strains belonged to the large C molecular subtype. Furthermore, high genetic diversity within the C subtype was observed in the 35 sequenced HHV-8 K1 genes, with strains belonging to several and distinct subgroups highly supported from a phylogenetically viewpoint (e.g., C3, C7, C'' and C5). Considering these newly identified Moroccan viral strains in the context of 189 complete K1 genes, we were able to characterized, using the Simplot program, two main groups of recombinant chimeric K1 genes, either intertypic (C5) or intratypic (C7). In addition, the genetic characterization of the host maternal gene pool, through the analyses of mtDNA variation, did not provide evidence for any association between a particular human ethno-geographic background (i.e., North African vs. sub-Saharan African vs. West Eurasian linages) and any HHV-8 strain because both C' and C'' strains were randomly distributed among the different patients' population backgrounds.
Subject(s)
Genes, Viral , Molecular Epidemiology , Sarcoma, Kaposi/epidemiology , Sarcoma, Kaposi/virology , Viral Proteins/genetics , Acquired Immunodeficiency Syndrome/complications , Adult , Aged , Aged, 80 and over , DNA, Mitochondrial/genetics , Female , Gene Pool , Genetic Variation , Humans , Male , Middle Aged , Morocco/epidemiology , Phylogeny , Polymorphism, Genetic , Population/genetics , Recombination, Genetic , Sequence Analysis, DNA , Viral Proteins/classificationABSTRACT
AIMS: The Maghreb region is considered to be an endemic area for classical Kaposi's sarcoma (KS) but the few published reports have focused on clinical descriptions. We report here the clinical, virological and pathological features of 26 KS cases, including 17 classic forms, eight epidemic forms and one case of post-transplant KS. METHODS: Evidence of human herpesvirus (HHV)-8 infection was detected by serology, immunohistochemistry and polymerase chain reaction. RESULTS: Antibodies directed against HHV-8 latent nuclear antigen (LNA-1/ORF73) were present in sera from all 26 KS cases and the ORF26 HHV-8 gene fragment was amplified from the tumour DNA of all patients. KS lesions that met the classical criteria for KS (spindle cells, positive endothelial markers) and were immunostained with the anti-LNA-1 marker, demonstrated typical granular intranuclear labelling of the spindle cells in all but one case of KS, in which very few spindle cells were present. Furthermore, whereas LNA-1 staining was largely confined to spindle cells in the late nodular stage, it was also observed in endothelial cells forming the walls of slit-like vessels in early patch-stage lesions. CONCLUSION: This study confirms that Morocco is an endemic area for classical KS, which remains the most frequent type of KS in this country, and emphasises the value of the LNA-1 marker for the early diagnosis of KS lesions.