Immune reconstitution inflammatory syndrome

Immune Reconstitution Inflammatory Syndrome

Immune Reconstitution Inflammatory Syndrome (IRIS) is a condition observed in some patients who are undergoing treatment for immunodeficiency, particularly in the context of HIV/AIDS and other conditions that lead to severe immunosuppression. IRIS is characterized by an exaggerated inflammatory response to opportunistic infections or other antigens as the immune system begins to recover.

Pathophysiology

IRIS occurs when the immune system, previously weakened by disease or treatment, begins to recover and mounts an inflammatory response against existing infections or antigens. This response can lead to a worsening of symptoms or the unmasking of previously subclinical infections. The underlying mechanism involves the rapid restoration of pathogen-specific immune responses, which can lead to tissue damage and clinical deterioration.

Types of IRIS

IRIS can be broadly classified into two types:

• Paradoxical IRIS: This occurs when there is a worsening of symptoms of a known infection after the initiation of antiretroviral therapy (ART) or other immune-restorative treatments.
• Unmasking IRIS: This occurs when a previously undiagnosed infection becomes clinically apparent after the initiation of ART or immune recovery.

Risk Factors

Several factors can increase the risk of developing IRIS, including:

• Low CD4 cell count at the start of ART
• High viral load
• Rapid immune recovery
• Presence of opportunistic infections such as tuberculosis, cytomegalovirus, or cryptococcal meningitis

Clinical Presentation

The clinical manifestations of IRIS vary depending on the underlying infection or antigen involved. Common symptoms include:

• Fever
• Lymphadenopathy
• Respiratory symptoms
• Neurological symptoms

The severity of IRIS can range from mild to life-threatening, depending on the organs involved and the extent of the inflammatory response.

Diagnosis

Diagnosing IRIS involves a combination of clinical evaluation, laboratory tests, and imaging studies. Key diagnostic criteria include:

• Recent initiation of ART or immune-restorative therapy
• Clinical deterioration despite virological and immunological improvement
• Exclusion of other causes of clinical worsening

Management

Management of IRIS involves:

• Continuing ART to maintain immune recovery
• Treating the underlying opportunistic infection
• Using anti-inflammatory medications, such as corticosteroids, in severe cases

Prognosis

The prognosis of IRIS varies depending on the underlying infection and the patient's overall health. With appropriate management, most patients experience resolution of symptoms and continue to benefit from immune recovery.

Also see

• HIV/AIDS
• Opportunistic infection
• Antiretroviral therapy
• Cytomegalovirus
• Cryptococcal meningitis