CD8A and onchocerciasis: In addition, CTLA-4 expression was also shown to be up-regulated in filarial infected individuals [53–55] but within this study expression levels of CTLA-4 on CD4+ and CD8+ T cells was equal between Mp MF- and Mp MF+ individuals, suggesting that M. perstans specifically induce immunomodulatory mechanisms which might be different from those observed in onchocerciasis or lymphatic filariasis.