Immunodeficient t-cell primaryD89.9

Group of rare diseases that are the result of genetic disorders of the T-cellular immune system. Because of the central immunoregulatory functions of the T cells, there is always a humoral immune defect, so that functionally, these are combined immune defects. The common feature of these pathogenetically heterogeneous diseases is a pronounced susceptibility to infections (see below: opportunistic infections) as well as a tendency to develop malignancies and autoimmunological complications. Most of these prognostically extremely unfavorable diseases can be cured by bone marrow transplantation.

The classification of T-cellular immunodeficiency syndromes is initially based mainly on clinical findings and immunological, disease-specific abnormalities that result from morphological, functional and phenotypic examinations of the lymphatic system, among others. The possibility of defining the underlying defects at the molecular level increasingly allows a classification according to pathogenetic aspects.

T-cellular immunodeficiency syndromes can occur in association with other, very rare, non-immunological diseases. Rarely only are they due to an isolated T-cell defect.

• Wiskott-Aldrich syndrome: thrombocytopenia, eczema; combined, progressive immunodeficiency
• Ataxia teleangiectatica (Louis-Bar-Syndrome - G11.3): Progressive cerebellar ataxia, telangiectasia, progressive combined immunodeficiency.
• Bloom syndrome: dwarfism, skeletal abnormalities, facial erythema, combined immunodeficiency.
• DiGeorge syndrome: cardiovascular abnormalities, facial dysmorphia, hypoparathyroidism/tetany, thymic hypoplasia; variable T-cell functions.
• Chronic mucocutaneous candidiasis (B37.2): Heterogeneous group of diseases characterized by persistent candidiasis of the skin and skin-related mucous membranes. Often associated with polyendocrinopathy (e.g. APECED syndrome)
• hyper- IgE syndrome

• The main symptom is the early occurrence of infectious complications, whereby opportunistic pathogens (see below: infections, opportunistic) are characteristic as triggers. The course of the disease is almost always characterized by a progressive deterioration. Particularly frequent are observed:
• Therapy-resistant fungal infections (especially in the area of the oral mucosa).
• Chronic intestinal infections with failure to thrive that cannot be influenced.
• Recurrent infections in the respiratory tract with signs of obstruction and dyspnoea.
• Acute interstitial pneumonia (often Pneumocystis carinii).
• The dermatological picture corresponds to an acute graft-versus-host disease with maculo-papular exanthema, diffuse alopecia. At maximum expression, image of toxic epidermal necrolysis (TEN).

T cells are absent or markedly decreased.

Exception: Omenn syndrome (SCID with eosinophilia): Blood count: Mostly lymphopenia, often eosinophilia and thrombocytosis; hypo-dysgammaglobulinemia.

HLA typing: Detection of foreign, e.g. maternal T cells.