1/1/2024 0 Comments X linked agammaglobulinemia![]() The association of XLA and scleroderma, dermatomyositis, and myositis is noted, but the explanation for this association is unknown. Mycoplasma pneumoniae, were shown to be associated with arthritis in XLA patients, similar to Mycoplasma-induced arthritis in otherwise healthy people. Recurrent infections with specific pathogens, e.g. In rheumatoid arthritis, methotrexate was used in therapy, but the clinical improvement was supported by an increased IgG level. There are suggestions for substitution in a higher dose (0.8 g/kg b.w.) to maintain a higher level of IgG than usual (about 8.0 g/l). The therapy of autoimmune disease in XLA patients is similar to patients without immunodeficiency, with one exception – regular substitution of immunoglobulins in XLA patients. It leads to uncontrolled proliferative potential of autoreactive T cells. Other studies suggested the occurrence of Th1 oriented diseases such as arthritis and diabetes type 1 in XLA patients due to T cell activation (in the absence of CD30 signaling) not deleted by the CD95-dependent cross-tolerance mechanism. From the study of XLA patients with rheumatoid arthritis the predominance of CD8+ T lymphocytes within infiltrations of synovial tissue and subcutaneous nodules indicated the role of these cells in the pathomechanism of rheumatoid erosive changes. One hypothesis suggested survival of self-reactive receptors on a few circulating B cells due to signaling by self antigens, which overcame the blocked signaling route through the btk mechanism. The occurrence of rheumatoid arthritis, dermatomyositis, and inflammatory bowel disease in XLA patients is difficult to explain. It is believed that this level is sufficient to prevent bacterial infections. Standard treatment of XLA patients is based on regular substitution of immunoglobulin (intravenous or subcutaneous form as home therapy), supporting a stable IgG level in serum (no less than 5.0-5.5 g/l). The study of T lymphocyte function showed a Th1 response as the T cell profile in XLA patients. The total number of T cells, the CD8 subpopulation and regulatory T cells were comparable to healthy controls. In these patients the study of T cells showed a low number of memory CD4 T cells (CD4+CD45RO and CD4+CD45RO+CXCR5+). ![]() Moreover, in a minority of patients, the lack of B lymphocytes (below 1% of peripheral blood mononuclear cells assayed with flow cytometry) is associated with a low number and reduced activation of NK cells. Recurrent bacterial infections, with a good response to antibiotics, are typical and, together with lack of tonsils in the boy, suggest agammaglobulinemia. The first symptoms of immunodeficiency are noted after 4 months of life, when the maternal IgG level decreases. X-linked agammaglobulinemia (XLA) is a primary humoral immunodeficiency caused by the btk mutation, leading to lack of B cells in the periphery and, in consequence, lack of immunoglobulins and specific antibody production.
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