Liver fibrosis increases risk of discordance in CD4 cell count and percentage in HIV-positive people

Michael Carter
Published: 09 April 2012

Liver fibrosis is associated with discordance between CD4 cell counts and percentages in HIV-positive people, according to US research published in the online edition of Clinical Infectious Diseases. The association was especially marked for patients with a total lymphocyte count below 1200 cells/mm3.

The investigators believe their findings have clinical significance. “From a practical standpoint, our findings suggest a relatively simple approach could be for clinicians to evaluate CD percentage in addition to CD4 number whenever a patient’s total lymphocyte count is below 1200 cells/mm3.”

Separate research also published in the online edition of Clinical Infectious Diseases and reported here on aidsmap.com showed that discordance between CD4 cell count and percentage was common in patients with HIV and hepatitis C-co-infection and was associated with important markers of liver disease.

In resource-rich settings, CD4 cell counts are routinely measured in HIV care. Decisions on when to start antiretroviral therapy are partly guided by CD4 cell count and the test is central to monitoring disease progression.

The number of CD4 cells is usually correlated with CD4 cell percentage – the proportion of lymphocyte cells which are CD4 cells.

However, it is well known that CD4 cell count can fall in the context of infections. Research conducted in patients with hepatitis C mono-infection has shown that CD4 cell count and percentage can be discordant in patients with more advanced liver disease.

Investigators from the US ALIVE study wanted to see if liver fibrosis was associated with discordance between CD4 cell count and percentage.

A total of 287 people took part in the study. Their median age was 48 years, 94% were black, 65% were men and 43% reported injecting drug use in the previous six months. There was a high prevalence of hepatitis C-co-infection (data not supplied).

Only 47% of participants were taking antiretroviral therapy. Median CD4 cell count was 282 cells/mm3 and median CD4 cell count percentage was 22%. An undetectable viral load was present in 55% of patients.

Liver fibrosis was assessed using Fibroscan. Significant fibrosis was defined as a liver stiffness score of or above 9.3 kPa and was present in 31% of patients.

Concordance between CD4 cell count and percentage was observed in 47% of participants. Low discordance (a lower CD4 cell percentage than would be expected for a given CD4 cell count) was present in 19% of individuals, and 34% had high discordance (a higher CD4 cell percentage than would normally be associated with a CD4 cell count).

The risk of high discordance was significantly increased for patients with significant fibrosis (odds ratio [OR] = 1.69; 95% CI, 0.95-2.96). The risk was further increased for patients with significant fibrosis and a total lymphocyte count below 1200 cells/mm3 (OR = 2.66; 95% CI, 1.11-6.40).

Low discordance was associated with antiretroviral therapy (OR = 2.53; 95% CI, 1.27-5.06).

“Accurate evaluation of immune status in HIV-infected persons is critical to assessing HIV disease progression, for determining when to initiate therapy and for monitoring therapeutic responses,” comment the authors. “In this study… we identified a high degree of discordance between CD4 cell number and CD4 percentage.”

They emphasise the association between this discordance and liver fibrosis, especially in people with a low total lymphocyte count. “These data suggest that liver disease-related lymphopenia may contribute to CD4 number/percentage discordance.”

The authors conclude, “Clinicians may need to consider incorporating CD4 percentage into the decision-making process of providing appropriate care to HIV-infected patients with underlying liver fibrosis.”

Reference

Claassen CW et al. Discordance between CD4+-lymphocyte counts and percentages in HIV-infected persons with liver fibrosis. Clin Infect Dis, online edition, 2012.

Hepatitis information

For more information on hepatitis visit infohep.org.

Infohep is a project we're working on in partnership with the European Liver Patients Association (ELPA).

Visit infohep.org >

Related news selected from other sources

More editors' picks on CD4 count >