Table 4. Molecular defects found in some... | American Society of Hematology

Table 4.

Molecular defects found in some patients considered to have CVID

Defect type	Result
Underlying B-cell defects
Defective B-cell cytoplasmic second messengers (Btk)¹²¹	X-linked agammaglobulinemia
Deletions in immunoglobulin genes¹²²
Underlying T-cell defects
Defective T-cell surface receptors (CD40L)¹²³	CD40L deficiency
Defective T-cell cytoplastic second messengers (lck, SAP)124 125	X-linked lymphoproliferative disease, SCID (forme fruste)
Defective cell cycling, DNA repair enzymes¹²⁶	Ataxia-telangiectasia, Nijmegen breakage syndrome
Defective purine salvage pathway metabolism¹²⁷	ADA, PNP deficiency

Defect type	Result
Underlying B-cell defects
Defective B-cell cytoplasmic second messengers (Btk)¹²¹	X-linked agammaglobulinemia
Deletions in immunoglobulin genes¹²²
Underlying T-cell defects
Defective T-cell surface receptors (CD40L)¹²³	CD40L deficiency
Defective T-cell cytoplastic second messengers (lck, SAP)124 125	X-linked lymphoproliferative disease, SCID (forme fruste)
Defective cell cycling, DNA repair enzymes¹²⁶	Ataxia-telangiectasia, Nijmegen breakage syndrome
Defective purine salvage pathway metabolism¹²⁷	ADA, PNP deficiency

SCID indicates severe combined immunodeficiency; ADA, adenosine deaminase; and PNP, purine nucleoside phosphorylase. For explanation of other abbreviations, see Tables 1 and 3.