Circulating levels of CD4⁺ T lymphocytes in hemophilic LTNPs (A). Two peculiar infected hemophiliacs have been included (B). Patient no. 9 showed relatively stable levels of CD4⁺ T cells over the last 4 years, whereas patient no. 8 has demonstrated a LTNP-like profile up to 11 years since infection, when both the CD4 count and clinical condition have begun to deteriorate (long-term progressor).