Immune reconstitution reactions in human immunodeficiency virus-negative patients: report of a case and review of the literature

Abstract

Background: Immune reconstitution inflammatory syndrome (IRIS) is a phenomenon initially described in patients with human immunodeficiency virus. Upon initiation of combination antiretroviral therapy, recovery of cellular immunity triggers inflammation to a preexisting infection or antigen that causes paradoxical worsening of clinical disease. A similar phenomenon can occur in human immunodeficiency virus-negative patients, including pregnant women, neutropenic hosts, solid-organ or stem cell transplant recipients, and patients receiving tumor necrosis factor inhibitors.

Observations: We report a case of leprosy unmasking and downgrading reaction after stem cell transplantation that highlights some of the challenges inherent to the diagnosis of IRIS, especially in patients without human immunodeficiency virus infection, as well as review the spectrum of previously reported cases of IRIS reactions in this population.

Conclusions: The mechanism of immune reconstitution reactions is complex and variable, depending on the underlying antigen and the mechanism of immunosuppression or shift in immune status. Use of the term IRIS can aid our recognition of an important phenomenon that occurs in the setting of immunosuppression or shifts in immunity but should not deter us from thinking critically about the distinct processes that underlie this heterogeneous group of conditions.

Figure 1

Unmasking of occult leprosy. A, Ill-defined erythematous forearm plaque noted 6 days after transplant. B, Biopsy specimen revealed a perivascular and periadnexal lymphocytic infiltrate (hematoxylin-eosin, original magnification ×200). C, A retrospective Fite stain subsequently demonstrated many acid-fast bacilli consistent with the diagnosis of leprosy (original magnification ×400).

Figure 2

Leprosy type 1 reaction. A, Annular plaque on the arm. B, Indurated papules and plaques on the tragus. C, Biopsy specimen demonstrated a perivascular and periadnexal infiltrate of lymphocytes and foamy histiocytes (hematoxylin-eosin, original magnification ×200). A Fite stain (not shown) demonstrated many acid-fast bacilli.