SID	acquired/secondary immunodeficiency
ATG	antithymocyte globulin
CMV	cytomegalovirus
EBV	Epstein–Barr virus
GC	glycoprotein C1
Conditioning	myeloablative (MAC) or reduced intensity (RIC)
GvHd	graft-versus-host disease
HBV	Hepatitis B virus
HBs	surface Hepatitis B antigen
HCV	Hepatitis C virus
HHV	Human Herpesvirus
HSCT	hematopoietic stem cell transplantation
HSV	Herpes Simplex Virus
IgGSD	IgG subclass deficiency
PC	long-lived plasma cells
MBC	the memory B lymphocytes
PAMPs	pathogen-associated molecular patterns
PAD	primary antibody deficiency
RAI	relative avidity index
SIgAD	selective immunoglobulin A deficiency
SOT	solid organ transplant
TLR	Toll-Like receptor
THI	transient hypogammaglobulinemia of infancy
VZV	Varicella Zoster Virus;
WMDA	WORLD MARROW DONOR ASSOCIATION
B2M	β2-microglubulin
Drug	i.e., MEL, indicates melphalan, BU, busulfan; Flu, fludarabine CY cyclophosphamide