Introduction
Autoimmune disorders are common in patients with primary immunodeficiency diseases. However, the prevalence of autoimmunity is low in patients with X-linked agammaglobulinemia. Clinical case
A 14-yo boy diagnosed with X-linked agammaglobulinemia (2019), with low levels of IgG, less than 2% of B lymphocyte count, absent BTK expression, and two pathogenic variants in BTK (first variant in a splice site mutation in Intron 13/14: TAG>GTCAA, second variant was a 2 bp insertion in exon 14, causing a truncated protein p.Trp395Ilefs*8). He started with icteric tinge, hepatosplenomegaly, high grade fever, generalized edema and weight loss. Laboratory work-up showed elevated liver enzymes, no infections detected, negative autoimmune serologies (ANA, anti-mitochondrial, ANCAs, anti-LKM1 and anti-smooth muscle), cholangioresonance ruled out sclerosing cholangitis. Subsequently, a liver biopsy showed: T lymphocytes infiltration, predominantly with CD3+, CD5+ and CD7+, mild atypia, polymorphonuclear leukocytes were also observed without finding the presence of microorganisms and absence or only sporadic B lymphocytes with CD 20+ (less than 1%) that cross the limiting plate, findings compatible with a diagnosis of autoimmune hepatitis. He was on regular IVIG, dose was increased to 1 gr/kg/month and phenobarbital, ursodeoxycholic acid, azathioprine, hydroxychloroquine, and prednisone were added to treatment. Three months after starting treatment, liver function tests normalized. The patient developed portal hypertension and has been treated for esophageal varices. Discussion
An association of X-linked agammaglobulinemia with autoimmune hepatitis is very uncommon. This would suggest different mechanisms of autoimmunity that have not yet been fully elucidated, mainly driven by T-cells given the absence of B-cells and antibodies in this disease. Liver biopsy plays a pivotal role in patients with abnormal liver function without clear explanation.