Immunodeficiency Diseases

The term immunodeficiency covers a group of disorders of specific immune responses, neutrophil, macrophage and natural killer cells functions, as well as defects in the compliment system that lead to impaired resistance to microbial infections. 

 Classification – These diseases are crudely classified into primary and secondary types.

1) Primary immunodeficiency diseases (exceedingly rare)

-  These disorders usually manifest in early childhood and are almost always genetically determined. Though, some overlap exists  primary immunodeficiency diseases are further divided into: 

Deficiencies of antibody (B – cells) immunity.

        Eg.  Infantile X-linked agammaglobinmea 

Transient hypogammaglobulinmea of infancy 

Deficiencies of cell mediated (T-cell) Immunity

T-cell deficiencies are difficult to trace as T-cells affects B – cell functions

Eg.  Di George’s syndrome: 

Combined T-cell and B-cell deficiencies

  Eg Severe combined immunodeficiency disease (SCID). 

 2) Secondary immunodeficiencies States

These immunodeficiency states may be acquired secondary to various disease processes or drug effects

-  Protein deficiency

Lack of protein leads to cell mediated immunity and hypocomplementamia

-  Hematologic malignancies

Leukemia and lymphomas where normal functioning cell replaced by neoplastic ones here both humeral and cell mediated immunity are impaired

-  Acute viral infection

Especially infectious mononucleosis and misels cause temporary impairment of cell-mediated immunity

-  Chronic renal failure

Probably due to toxic effects of accumulated metabolites that affects both B and T-cell functions

-  Iatrogenic

Steroids etc for organ transplants, cytotoxic drugs or radiotherapy for the treatment of malignancies.

-  Splenctomy

After staging operations of lymphomas or traumatic spleen rupture Splenectomy leads to a characteristic immunodeficiency in which the patient is susceptible to infections by phylogenic bacteria especially pneumococal pneumonia.

-  Acquired immunodeficiency syndrome (AIDS)

As a prototype example of secondary immunodeficiency states.

References

Bezabeh ,M. ; Tesfaye,A.; Ergicho, B.; Erke, M.; Mengistu, S. and Bedane,A.; Desta, A.(2004). General Pathology. Jimma University, Gondar University Haramaya University, Dedub University.