The Influence of Portal Pressure on the Discordance Between Absolute CD4+ Cell Count and CD4+ Cell Percentage in HIV/Hepatitis C Virus–Coinfected Patients

TO THE EDITOR—We read the articles by Hull et al [1] and Claassen et al [2] with interest. The authors have demonstrated that a discordance between absolute CD4 cell count and CD4 cell percentage is common in both human immunodeficiency virus (HIV)/hepatitis C virus (HCV)–coinfected and HIVinfected patients and that it is associated with end-stage liver disease and surrogate markers of liver fibrosis, such as aspartate aminotransferase to platelet ratio index and liver stiffness measured by transient elastography. On the basis of the association of CD4 cell discordance with thrombocytopenia, leukopenia, and splenomegaly in HIV-uninfected patients [3], Hull et al speculated that CD4 cell discordance might be attributed to portal hypertension–induced splenic sequestration of lymphocytes. We would like to report our own complementary data on the relationship between portal pressure and CD4 cell discordance in HIV/HCVcoinfected patients screened for inclusion in a prospective trial [4]. Portal pressure was assessed through measurement of the hepatic venous pressure gradient (HVPG) in 97 HIV/HCV-coinfected patients with compensated liver disease. In accordance with the definitions used by Hull et al, CD4 cell counts were considered concordant when the absolute CD4 cell count matched the corresponding CD4 cell percentage determined in HIV-infected individuals (<100 cells/μL, <7%; 100–199 cells/μL, 7%–13%; 200– 299 cells/μL, 14%–20%; 300–399 cells/μL, 21%–27%; 400–499 cells/μL, 28%–34%; >500 cells/μL, >35%). Higher CD4 cell percentages than expected from the absolute CD4 cell counts were referred to as high discordance, while lower CD4 cell percentages than expected from the absolute CD4 cell counts were referred to as low discordance. Patient characteristics were as follows: 76% were male, mean age was 37.3 ± 9.7 years, 72% were on combined antiretroviral therapy, mean absolute CD4 cell count was 519 ± 261 cells/μL, mean CD4 cell percentage was 28.6 ± 10.4%, mean HVPG was 4.8 ± 3.8 mm Hg, and 19% had cirrhosis. High and low CD4 cell discordance was observed in 18% and 38% of patients, respectively, whereas 44% of patients had concordant CD4 cell counts. There was a tendency toward a higher prevalence of high CD4cell discordance in patients with high portal pressure (≤5 mm Hg, 15% vs 6–10 mm Hg, 22% vs ≥11 mm Hg, 29%; P = .651). In contrast, low CD4 cell discordance was observed more frequently in patients with low portal