Clinical Utility of QuantiFERON-Cytomegalovirus Test in Management of Kidney Transplant Recipients

• Indeterminate result of QuantiFERON-cytomegalovirus (QF-CMV) is associated with increased incidence of CMV disease.
• Indeterminate QF-CMV test result indicates risk of severe infectious complications.
• QF-CMV appears to be a useful tool in identifying patients with impaired immunity.

Immune monitoring of cytomegalovirus (CMV) – specific T-cells responses has become an additional tool in the CMV risk assessment of kidney transplant recipients (KTRs). Some data demonstrated a potential use of QuantiFERON-CMV assay (QF-CMV) in stratifying CMV risk before transplantation, at the end of prophylaxis and during pre-emptive strategy. High risk for CMV disease was also reported in KTRs with indeterminate QF-CMV results in which both mitogen and CMV antigen responses were absent.Twenty-five KTRs in the first year after kidney transplantation (KT), including 17 KTRs after CMV infection treatment (CMV-KTR), were studied by QF-CMV assay.Positive QF assay (QF+) was present in 16 of 25 (64%) of KTRs, negative (QF−) in 5 of 25 (20%), and indeterminate (QF0) in 4 of 25 (16%). The QF0 patients, in comparison to the combined group of QF+ and QF−, presented an increased incidence of CMV disease (4 of 4 [100%] vs. 7 of 21 [33.3%]; P < .05) and severe infectious complications such as sepsis, and systemic mycosis (4 of 4 [100%] vs. 6 of 21 [29%]; P < .02). Of 17 CMV-KTRs, 11 of 17 (64.7%) were QF+, 2 of 17 (11.8%) were QF−, and 4 of 17 (23.5%) were QF0. The incidence of CMV disease and severe infectious complications was not different among these groups. CMV-KTRs with interferon-γ <3.5 IU/mL vs. >3.5 IU/mL in mitogen tube, irrespective of QF-CMV status, showed an increased incidence of CMV disease (8 of 9 [88.9%] vs. 3 of 8 [37.5%]; P < .05) and severe infectious complications (8 of 9 [88.9%] vs. 2 of 8 [25%]; P < .02).In conclusion, indeterminate result of QF-CMV or interferon-γ <3.5 IU/mL in mitogen tube seems to be related to impaired immunity. The QF-CMV assay appears to be a useful tool in clinical practice, identifying the group of KTRs with increased risk of infectious complications who may benefit from immunosuppression reduction and maintenance of antiviral prophylaxis.