Interpretative Information

Clinical Utility

The CMV inSIGHT™ T Cell Immunity Panel measures the strength of T cell responses to Cytomegalovirus (CMV) specific antigens. It evaluates and reports the activity of CD4 and CD8 T cell responses independently.  Effective T cell immunity against CMV is a factor in controlling CMV viral latency.  CMV can affect patients with weakened immune systems and is a common risk factor in patients following solid organ or hematopoietic stem cell transplant.

About Cytomegalovirus

Cytomegalovirus, also known as human herpesvirus 5, is a highly ubiquitous, double-stranded DNA virus in the Betaherpesvirinae subfamily. Following primary infection, CMV establishes a lifelong latent infection, which may reactivate in both immunocompetent and immunocompromised individuals. Clinically significant CMV infection frequently develops in immunocompromised patient populations (e.g. hematopoietic stem cell transplantation, solid organ transplant and HIV). A frequent complication after transplantation, CMV infection may cause a series of direct and indirect effects that lead to increased incidence of graft rejection, opportunistic infections, and decreased allograft and patient survival. CMV reactivations have also been reported to occur frequently in critically ill immunocompetent patients and are associated with prolonged hospitalization or death. T cell responses, both CD4+ and CD8+ T cells, are vital components of CMV immune control.  The monitoring of CMV-specific T cell responses utilizing intracellular cytokine staining may aid in the detection of patients at increased risk of CMV disease after transplantation and may be useful in guiding prophylaxis and preemptive therapies. 

Procedure

Whole blood is stimulated with SEB, CMV antigens, or left unstimulated as a negative control and incubated at 37ºC. During the incubation Brefeldin A is added, causing the interferon (IFN)-gamma to be retained inside the cell. Following the stimulation phase, cells are recovered, stained for surface markers (CD3, CD4, CD8, CD69) and intracellular IFN-gamma, and analyzed by flow cytometry.