Diagnosis of severe combined immunodeficiency

Abstract

Early diagnosis of severe combined immunodeficiency (SCID) is important to enable prompt referral to a supraregional centre for bone marrow transplantation before the occurrence of end organ damage secondary to infective complications. This review outlines clinical, microbiological, and immunopathological clues that aid the diagnosis of SCID and emphasises the multidisciplinary approach needed to diagnose and treat these infants.

Figure 1 Chest radiograph of infant with severe combined immunodeficiency (SCID) showing absence of thymus, hyperinflated lungs, and interstitial pneumonitis secondary to Pneumocystis carinii pneumonia and parainfluenzae type 3 infection.

Figure 2 Infant with Omenn's syndrome, showing alopecia, erythroderma, and varicella zoster lesions.

Figure 3 Pneumocysts demonstrated by silver staining of alveolar tissue from a lung biopsy.

Figure 4 Lymph node biopsy in Omenn's syndrome (courtesy of B Angus). (A) Haematoxylin and eosin stained preparation. Note the absence of germinal centres and the replacement of the paracortex by a diffuse infiltrate of large cells with abundant pale cytoplasm. (B) Immunostaining for S100 protein. Note the positive labelling of almost all the cells in the cortex. This indicates infiltration of the node by a population of interdigitating reticulum cells .