SCID (OMENN SYNDROME)

Soon after birth10 loose bowel movements a day

17th dayRash: legs entire body Hospital admission

Hospital examinationPurulent eye dischargeNormal eardrumsLymph node (-)

Blood test diff count: Eosinophils 56% (N: <5%)Monocyte 23% (N: 10%)Neutrophils 5%Lymphocytes 6% (N: 50%)

During admissionEnlarged lymph nodesAbscess drained: S. aureus & C. albicansOral thrush

Immunologist consulted

Ricardo Reis: Male, 7 years old Normal birth history Parents have three normal children but have had two previous death after similar

rash complaint after 1 month old.

Further examinationLow IgG, IgM and IgA: (-)Very high IgE (7200 IU/ml N: <50 IU/ml)

X-RayThymic shadow (-)Normal cor/pulmonale

Immunological examinationBlood test

Absent B-cellsScarce T cells

Poor respond to CD3 monoclonal antibody

FACS AnalysisNo reaction to CD19All lymphocytes are CD3+

90% coexpressed CD45RO

65% coexpressed MHC II80% CD4+15% CD8+

Low T-cell repertoire

As these tests were carried out, Ricardo died of PCP.

IMMUNOLOGICAL BACKGROUND

Omenn syndrome: a variant of SCID

Mutant RAG-1 or RAG-2 genes no V(D)J recombination

No B cells Non-functioning T cells Oligoclonal population

of self-reactive T cells Inflammation

Conclusion: Entire adap-tive immunity affected

IMMUNOLOGICAL BACKGROUND

Place of RAG-1&2 in the differentiation of lymphocytes:

CLINICAL ASPECTS

SCID Extremely vulnerable to infections

Omenn Syndrome Erythrodermia, chronic diarrhea, (opportunistic)

infections, failure to thrive, lymphadenopathy, hepatosplenomegaly

Lab: Eosinophilia, low Ig’s but high IgE, absence B-cells, low T-cell count.

Complications: Vaccines, infections (pneumocystis jiroveci) lethal

DIAGNOSIS

Blood test: B- and T-cells (and markers), leukocytes, immunoglobulins

Symptoms: failure to thrive, diarrhea, swollen lymph nodes, inflammation of the skin, low T-cell levels and no B-cells

DD: Other SCID types: X-linked severe combined

immunodeficiency (X-SCID), Adenosine deaminase deficiency

Hyper IgE syndrome (Job syndrome) Histiocytosis

MANAGEMENT

Isolation Bone marrow transplantation

DISCUSSION

QUESTIONS?