Activated phosphoinositide 3-kinase δ syndrome presenting with gut-associated T-cell lymphoproliferative disease

Area of Science:

• Immunology
• Genetics
• Pediatrics

Background:

• Recurrent respiratory infections and gastrointestinal symptoms in childhood can indicate primary immunodeficiency.
• T-cell lymphoproliferative disease (T-cell LPD) is a rare condition affecting immune cell function.

Observation:

• A 13-year-old male presented with chronic diarrhea, abdominal pain, and bloody stools, alongside a history of frequent respiratory infections.
• Colonoscopy revealed T-cell LPD, with laboratory findings of T-lymphocytopenia, elevated IgG, and poor antibody response.

Findings:

• The patient was diagnosed with activated PI3Kδ syndrome (APDS) based on combined immunodeficiency and T-cell LPD.
• Genetic testing identified a heterozygous PIK3CD gene mutation (c.1573 G > A, p.Glu525Lys), confirming the diagnosis of APDS.

Implications:

• This case underscores the importance of considering APDS in pediatric patients with combined immunodeficiency and T-cell LPD.
• Targeted therapies and allogeneic hematopoietic stem cell transplantation are crucial for managing APDS and its associated complications.