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[Severe combined immune defect. Presentation of exfoliative dermatitis with eosinophilia and lymphadenopathy]
S Vossbeck1, C Knobloch, B Heymer
1Abteilung Pädiatrie II, Universität Ulm.
Insights
Omenn syndrome in infants with severe combined immunodeficiency (SCID) presents with maternal or host T cells. The study found no clinical differences, suggesting T cell-induced inflammation causes Omenn syndrome in SCID.
Area of Science:
- Immunology
- Pediatrics
- Genetics
Background:
- Severe combined immunodeficiency (SCID) is a group of rare genetic disorders characterized by profound defects in cellular and humoral immunity.
- Omenn syndrome is a specific SCID variant presenting with autoimmune-like symptoms, including exfoliative dermatitis, alopecia, hepatosplenomegaly, and eosinophilia.
Observation:
- Nine infants with SCID and Omenn syndrome were studied, exhibiting characteristic immunological abnormalities.
- A key observation was the presence of mature T cells in peripheral blood, which were of maternal origin in 5 patients and host origin in 4.
- Clinical, laboratory, and histopathological parameters were analyzed and compared between the two patient groups.
Findings:
- No significant clinical or laboratory differences were detected between infants with maternal versus host T cells.
- Histopathological analysis of skin biopsies and lymph nodes revealed dense infiltrates of lymphocytes, histiocytes, and eosinophils in both groups.
- The sole distinguishing factor identified was the presence or absence of maternal T cells.
Implications:
- The findings suggest that Omenn syndrome in SCID is triggered by a T cell-mediated inflammatory response.
- This reaction is hypothesized to be similar to, but distinct from, a graft-versus-host reaction.
- Understanding this mechanism could inform therapeutic strategies for SCID and related inflammatory conditions.
Background:
We report on 9 infants with severe combined immunodeficiency (SCID), who additionally showed signs of Omenn syndrome with an exfoliative dermatopathy, alopecia, enlarged lymph nodes, a hepatomegalia and a striking blood eosinophilia. The immunological evaluation revealed the characteristic abnormalities of SCID with cellular and humoral immunodeficiency. All patients however had the unusual finding of mature T cells in the peripheral blood. By HLA typing these cells were noted to be of maternal origin in 5 patients. In the other 4 patients the T cells were of host origin. We asked for additional differences between both patient groups.
Method:
Both patient groups were analyzed and compared with regard to case histories, clinical, laboratory and histopathological parameters.
Results:
No clinical or laboratory differences could be detected. The histomorphologic analysis of patients with or without maternal T cells was identical. The skin biopsies showed dense cell infiltrations of lymphocytes, histiocytes and eosinophils, in the enlarged lymph nodes the latter two cell types predominated. Therefore the only difference between the 2 patient groups was the presence or absence of maternal T cells.
Conclusion:
Since the Omenn syndrome is found in association with maternal as well as patient derived T cells, we postulate that the peculiar symptoms of this syndrome are the result of a T cell induced inflammatory reaction, similar but not identical to a graft versus host reaction, occurring on the basis of an inborn SCID.