Table 2. Secondary causes of hypogammaglobulinaemia^[4,13].

Drug-induced	Antimalarial agents
	Captopril Phenytoin, carbamazepime Anti-CD20 mAbs: Rituximab Glucocorticoids Sulfasalazine
Single gene and other defects	Ataxia telangiectasia AR forms of SCID and other combined immunodeficiency Hyper IgM syndromes Transcobalamin II deficiency and hypogammaglobulinaemia X-linked agammaglobulinemia X-linked Lymphoproliferative disorder (EBV-associated) X-linked SCID
Chromosomal abnormalities	Chromosome 18q-syndrome Monosomy 22 Trisomy 8 Trisomy 21
Infectious diseases	HIV EBV Congenital infections with CMV/rubella/Toxoplasma
Malignancies	Chronic lymphocytic leukaemia Non-Hodgkin lymphoma Monoclonal gammopathy
Other systemic disorders causing excessive loss of immunoglobulins	Nephrotic syndrome Severe burns Lymphangiectasia Protein-losing enteropathy

mAbs = monoclonal antibodies

AR = autosomal recessive

SCID = severe combined immune deficiency

EBV = Epstein-Barr virus

CMV = cytomegalovirus