Immunological recovery in TB/HIV co-infected patients on antiretroviral therapy: implication for TB preventive therapy
Abstract
Background
Understanding the immune
response to combination antiretroviral therapy (cART) is
essential for a clear approach to tuberculosis (TB) preventive
therapy. We investigated the immunological recovery in
cART-treated HIV-infected patients developing TB compared to
those who remained free of TB.
Methods
We extracted data of
HIV-infected patients from a multicenter cohort for the HIV
clinical surveillance in Germany. No patients included in our
study had TB at the beginning of the observation. Using a
longitudinal mixed model, we assessed the differences in the
mean change of biomarkers (CD4+ cell count, CD8+ cell count,
CD4:CD8 ratio and viral load) since cART initiation in patients
who remained free of TB vs. those developing TB. To detect the
best-fit trajectories of the immunological biomarkers, we
applied a multivariable fractional polynomials model.
Results
We analyzed a total of
10,671 HIV-infected patients including 139 patients who
developed TB during follow-up. The highest TB incidences were
observed during the first two years since cART initiation (0.32
and 0.50 per 100 person-years). In an adjusted multivariable
mixed model, we found that the average change in CD4+ cell count
recovery was significantly greater by 33 cells/μl in patients
who remained free of TB compared with those developing TB. After
the initial three months of cART, 65.6% of patients who
remaining free of TB achieved CD4+ count of ≥400 cells/μl,
while only 11.3% of patients developing TB reached this
immunological status after the three months of cART. We found no
differences in the average change of CD8+ cell count, CD4:CD8
ratio or viral load between the two-patient groups.
Conclusion
All HIV-infected patients
responded to cART. However, patients developing TB showed
reduced recovery in CD4+ cell count and this might partly
explain the incident TB in HIV-infected patients receiving cART.
These findings reinforce the importance of adjunctive TB
preventive therapy for patients with reduced recovery in CD4+
cell count.
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Source:
BMC Infectious Diseases
