![]() ![]() Serum levels of all immunoglobulins are low or nearly undetectable, and there is an absent antibody response to vaccinations. Initial laboratory tests to be performed include a complete blood count with differential, quantitative serum immunoglobulin levels (IgG, IgA, and IgM), and serum specific antibody titers in response to immunization such as against tetanus or diphtheria. The diagnosis of XLA comprises clinical suspicion by history, especially family history, and physical examination followed by laboratory and genetic tests. Growth charts may show evidence of failure to thrive especially in older children.Īn accurate diagnosis of XLA is important, not just for the sake of treatment but also to ensure proper genetic counseling for the individual and the family. On physical examination, the absence of tonsils, chronic cough, chronic rhinitis, post-nasal drip, and clubbing can be seen. Even without a positive family history, signs hinting towards an evaluation for a primary immunodeficiency include recurrent infections, atypical infections, and unusually severe infections requiring hospitalization in a young male. Proper family history for frequent hospitalizations or deaths in boys at an early age can hint towards XLA well before symptoms of infections manifest. However, it is important to note that infections are relatively common, and knowing when to suspect XLA is key. The average age at diagnosis for patients with a family history of XLA is 2.6 years of age, while those without a positive family history are diagnosed only at 5.4 years of age on average. However, this effect wanes by six months of age, which is when the first signs of disease become apparent. During the third trimester of pregnancy, maternal IgG transfers to the fetus protecting the neonate from early infections. The classical clinical presentation is of a young boy, who is aged between 3 months to early adulthood, with recurrent bacterial infections. However, with the increasing use of intravenous immunoglobulin in these patients, the incidence has decreased to a few isolated cases. Thus, there is an increased propensity to develop enteroviral infections, manifesting as meningoencephalitis, hepatitis, or dermatomyositis-like infections. Ĭertain enteroviruses also are protected by the humoral immunity from replication in the gastrointestinal tract and subsequent spread to the central nervous system. ![]() Recurrent otitis media is the most common type of infection seen before diagnosis in these patients. Thus Streptococcus pneumoniae, Haemophilus influenzae type B, Streptococcus pyogenes, and the Pseudomonas species are some of the common causative organisms. Encapsulated pyogenic bacteria are usually the culprits because they are opsonized by antibodies as a defense mechanism. The deficiency of immunoglobulins results in absent antibody responses and increases the tendency to develop bacterial infections. ![]() Immunoglobulin-secreting plasma cells also are absent, resulting in deficiency (hypogammaglobulinemia) or absent (agammaglobulinemia) immunoglobulins. Thus there is a failure of B cell development in affected individuals. BTK plays a role in the maturation of Pro-B-Cells to Pre-B-cells. ![]()
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