Equis ISSN 2398-2977

Blood: agammaglobulinemia

Contributor(s): Cody Coyne, Mark Holmes, Prof Derek Knottenbelt, Ruth Morgan, Vetstream Ltd

Introduction

  • Extremely rare immunologic disorder (5 case reports in the literature).
  • A form of transient agammaglobulinemia has been reported
  • Cause: caused by an absence of B-lymphocytes and thus a failure to produce immunoglobulins; may be inherited condition.
  • Signs: usually presents as persistent infections in male foals 2-6 months old.
  • Diagnosis: T-cell function is adequate and lymphocyte levels may be normal but B-lymphocytes, IgM and IgA are absent.
  • Treatment: supportive, antimicrobial therapy.
  • Prognosis: poor.

Pathogenesis

Etiology

  • Inherited sex-linked condition.

Pathophysiology

  • Absence of germinal centers and plasma cells   →   inability to produce mature B-lymphocytes resulting in minimal to no production of IgM and IgA.
  • Normal cell-mediated (T cell) immunity.
  • Fetal liver and bone marrow fail to produce B-lymphocytes   Blood: lymphocytes    →   secondary lymphoid organs are unable to synthesize and secrete immunoglobulins in response to challenge from foreign antigens presented by macrophages (plastic development of B-lymphocyte clones during organogenesis phase of embryological development).
  • Colostrum protects foals during the first few weeks of life but as maternal origin IgM and IgG concentrations begin to wane, foals become more vulnerable to infectious conditions.

Timecourse

  • Presents commonly at 2-6 months, when immunity from passive transfer of colostral immunoglobulins has waned.
  • Foals do not develop B-cells, resulting in a lack of IgA and IgM production. Affected cases therefore rely on cell-mediated immunity and the complement cascade to combat infectious organisms.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Baldwin J L et al (1991) Prevalence (treatment days) and severity of illness in hypogammaglobulinemic and normogammaglobulinemic foals. JAVMA 198 (3), 423-428 PubMed.
  • Clabough D L et al (1989) Comparison of four screening techniques for the diagnosis of equine neonatal hypogammaglobulinemia. JAVMA 194 (12), 1717-1720 PubMed.
  • McGuire T C et al (1983) Analysis of serum and lymphocyte surface IgM of healthy and immundeficient horses with monoclonal antibodies. Am J Vet Res 44 (7), 1284-1288 PubMed.
  • Liu I K (1980) Systemic diseases of the newborn foal. Vet Clin North Am Large Anim Pract (2), 361-375 PubMed.
  • Whitwell K E (1980) Investigations into fetal and neonatal losses in the horse. Vet Clin North Am Large Anim Pract (2), 313-331 PubMed.
  • Deem D A et al (1979) Agammaglobulinemia in a horse. JAVMA 175 (5), 469-472 PubMed.
  • Banks K L et al (1976) Absence of B lymphocytes in a horse with primary agammaglobulinemia. Clin Immunol Immunopathol (2), 282-290 PubMed.


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