*Purpose: Anti-thymocyte globulin (ATG) induction causes profound and long-lasting lymphocyte depletion, with CD4+ reconstitution lagging behind other subsets. While absolute CD4 count is the preferred monitoring parameter for disease progression and immune function in HIV (+) patients, lymphocyte-depleting induction may render it unreliable as a marker in HIV (+) transplant recipients. CD4 percentage (%CD4) of lymphocytes could be a reasonable alternative. Herein we describe the pattern of absolute CD4 count and %CD4 recovery following ATG induction.

*Methods: We performed a single-center review of HIV (+) kidney transplant recipients from 2007 to 2017. Patients with lymphocyte subset data available at our institution were included. Recovery at 1 year post-transplant was defined according to AIDS definitions established by the CDC, as an absolute CD4 count ≥200 cells/µL and CD4 percentage ≥14%.

*Results: A total of 25 HIV(+) patients were identified, of which 9 with CD4 monitoring were included. Mean age was 48±8 years, 6 male, 5 African American, and 6 deceased donor kidney transplants. All patients received ATG induction followed by maintenance immunosuppression with tacrolimus, mycophenolate mofetil, and prednisone. At 1 year, 8 (89%) had an absolute CD4 count ≥200 and 8 (89%) had %CD4 ≥14%. Individual patient trends are depicted in Figure 1. Absolute CD4 count and %CD4 recovery were discordant in 2 cases; 1 patient had recovery of CD4 count but not %CD4, whereas the other had %CD4 recovery but not absolute CD4 count. Median times to recovery of absolute CD4 count and %CD4 were 168 (IQR 56-177) and 53 (IQR 18-110) days, respectively (Figure 2). No breakthrough HIV viremia occurred; there was one case of HSV esophagitis but no other opportunistic infections. There were no graft losses or patient deaths at 1 year.

*Conclusions: These data suggest that although adequate recovery of both absolute CD4 count and %CD4 were observed following ATG induction, discordance between the values may exist. Furthermore, %CD4 may recover earlier than absolute counts. To our knowledge, this is the first study to assess the role of monitoring %CD4 in HIV (+) transplant recipients. Understanding lymphocyte reconstitution and the utility of %CD4 monitoring requires further investigation.

« Back to 2019 American Transplant Congress