Defects in humoral immunity

main symptoms of primary immunodeficiencies.

defects, mainly affecting the humoral immunity make up about 70% of all primary IDS and include conditions such as common variable immunodeficiency (CVID), agammaglobulinemia, selective deficiency of subclasses of IgG, selective IgA deficiency, as well as some other (rare) condition.

Laboratory diagnosis of these diseases is based on the identification of reduction or absence of one or several classes of immunoglobulins in the serum at relatively normal rates of T-cell immunity.The number of B-lymphocytes can be normal (selective IgA deficiency), reduced (common variable immunodeficiency) or zero (agammaglobulinemia).

most typical clinical manifestations of humoral IDS are repeated, long-term recurrent bronchopulmonary infections, and infections of the skin, intestinal and systemic infections.Typically, the infectious syndrome debut in these patients after 6-12 months of life, during the complete catabolism of maternal IgG.

are encapsulated bacteria rarel

y highlighted other types of bacteria, viruses (especially characteristic of enterovirus infection), fungi, mycoplasma and protozoa (see. Table below) The most frequently isolated pathogens in these patients.Pulmonary infection in patients with agammaglobulinemia and CVID not receiving replacement therapy, often lead to the formation of bronchiectasis.In most cases, defects in humoral immunity viral infection without singularities occur in connection with the normal function of T-lymphocytes.Often in patients with humoral IDS marked hypoplasia of the tonsils and lymph nodes.

selective immunoglobulin A deficiency

significant reduction in serum IgA notes with an average frequency of 1 in 500-700 people.Presumably the defect is a result of lack of maturation IgA-producing lymphocytes.

criterion for diagnosis is a decrease in serum immunoglobulin A than 7 mg / dL in children older than 4 years.

most characteristic manifestations of IgA-selective deficit - an infection of upper respiratory tract and bronchopulmonary tract, as well as allergic and autoimmune conditions.Allergic and autoimmune syndromes occur without any special features that distinguish them from similar conditions in individuals with a normal amount of immunoglobulin A in serum.Bronchopulmonary tract infections occur a mild and rarely becomes chronic.In general, the disease has a good prognosis.

specific therapies selective IgA deficiency exists.Treatment of allergic and autoimmune diseases in IgA-deficient patients do not differ from those in patients without this immunodeficiency.There are reports of coping with infectious syndrome in patients with selective IgA deficiency on the background of IgG-containing drugs replacement therapy.

agammaglobulinemia agammaglobulinemia is typical, and the most severe disease with selective deficiency of antibody production.The described genetic defects lead to a breach of the various stages of maturation of B-lymphocytes.The disease is inherited as an X-linked (Bruton's Disease), and autosomal recessive.

diagnosis criterion is a reduction in serum IgG concentration of less than 2 g / l in the absence of IgA, IgM and circulating B-lymphocytes.

The main clinical manifestations include recurrent bacterial infections of the respiratory tract (bronchitis, pneumonia, sinusitis, purulent otitis), gastrointestinal (enterocolitis), rarely - skin.Patients are highly susceptible to enteroviruses which may cause them to severe encephalitis.Nature often occurring skleredemo- dermatomiozitopodobnogo syndromes and is not well understood, most likely, they have enterovirus etiology.

Common Variable Immune Deficiency

term "common variable immune deficiency" (CVID) is used to describe a group have not yet differentiated syndromes.All of them are characterized by defective antibody synthesis.The prevalence of CVID ranges from 1:50 000 to 1: 200 000.

Currently CVID classified by WHO experts in primary immunodeficiencies group c violation of antibody, but revealed much evidence of the defeat of the T-lymphocytes.Thus, the decrease in immunoglobulin production, probably due to the violation of T cell regulation of their synthesis, t. E. CVID is largely a combined immunodeficiency.

Diagnosis is based on a significant reduction of the three, at least - the two major classes of immunoglobulins (IgA, IgG, IgM) in normal or more reduction in the number of circulating B cells, as well as violations of specific response.Before the diagnosis is necessary to rule out other well-known causes of agammaglobulinemia.

Infectious manifestations of CVID are characteristic for the entire group of humoral defects.In this group of patients with common chronic infection Giardia lamblia.

Among patients with CVID unusually high incidence of lymphoreticular and gastrointestinal cancers.In contrast, X-linked agammaglobulinemia, a third of patients with CVID marked splenomegaly and / or diffuse lymphadenopathy.There are non-caseating granulomas resembling those of sarcoidosis.In addition, patients with CVID are subject to various autoimmune disorders as gemotsitopeny (pernicious anemia, hemolytic anemia, thrombocytopenia, neutropenia), arthritis and others.

Hyper-IgM-syndrome

syndrome is a group of genetically heterogeneous diseases with similar clinical (and laboratory) displays.The molecular basis of the syndrome are disorders path CD40 receptor interaction on B-lymphocytes with CD40-ligand on T cells, leading to impaired synthesis IgM switching to other classes of immunoglobulins.In 70% of cases the disease is inherited X-linked, in the other - an autosomal recessive.

main criterion for setting giperIgM syndrome diagnosis is a sharp decrease in serum IgG and IgA concentrations in normal or high IgM.The number of circulating T and B lymphocytes are usually normal.Nevertheless, in most varieties of manifestations of the disease, characteristic of dysfunction of cellular immunity (see. Below).

Clinically hyper-IgM-syndrome is characterized by repeated, sometimes difficult occurring infections.In the first place there are lesions of the respiratory tract, presented sinusitis, bronchitis and pneumonia caused by, in particular, and conditionally pathogenic flora (Pneumocyctis carinii).

serious problem with hyper-IgM-syndrome are gastrointestinal disorders.Cryptosporidiosis is one of the reasons for inadequate inflammatory response to the development of ulcerative lesions of the gastrointestinal tract, and sclerosing cholangitis, often leading to chronic liver failure.Many patients with this syndrome are identified certain hematological disorders (hemolytic anemia, neutropenia, thrombocytopenia), and autoimmune disorders such as arthritis, glomerulonephritis.Often there is hyperplasia of the lymph nodes and tonsils are often revealed hepatosplenomegaly.For these patients, the disease characterized by neoplastic.

Magazine "Difficult patient» №2-2007.

article is provided by a charitable foundation to help children with impaired immunity "Sunflower".

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