High-grade fever and pancytopenia in an adult patient with common variable immune deficiency.

Fever of unknown origin in patients with common variable immune deficiency (CVID) can be caused by variety of infectious, autoimmune, or malignancy-related etiologies. We present a 52-year-old man with history of CVID, who presented with 3 weeks of persistent high-grade fevers. During admission, he developed severe pancytopenia with shock and multiorgan failure. An extensive workup was performed for typical and atypical infections, autoimmune pathologies, and malignancy. His peripheral blood smear showed marked anisocytosis and poikilocytosis with elevated atypical lymphocytes. Flow cytometry showed markedly elevated CD8 counts, with abnormal CD4/CD8 ratio. Monospot test was negative but real-time polymerase chain reaction showed high Epstein-Barr virus load. Initial clinical suspicion was high for bacterial infections including pneumonia and acute sinusitis complicated by bacteremia and sepsis. Hematologic malignancy was also high on the differentials because of presence of rapidly progressive pancytopenia. The final diagnosis in this case illustrates a rare but potentially fatal disease that can present in CVID patients with persistent fevers and pancytopenia and can be refractory to standard treatment regimen. Because allergy and immunology physicians commonly treat CVID patients, they should be aware of this disease condition including pathophysiology, clinical presentation, laboratory workup, and treatment options.