Search

Streptococcus pneumoniae is a common pathogen responsible for pulmonary infections and the leading cause of mortality and morbidity in patients with particularly B cell immunodeficiencies. Antibody production is the principal protective immune response against S. pneumoniae and measurement of the production of antipolysaccharide antibodies is important in the evaluation of B cell deficiencies. We quantified serotype-specific immunoglobulin G antibodies against seven common pneumococcal serotypes before and three weeks after unconjugated vaccine in 416 patients with recurrent respiratory tract infections; fifty-five (13%) of whom showed impaired antibody response. We could evaluate 41 of these 55 patients for their particular clinical features. Specific antibody deficiency, was diagnosed in 10 of these patients, common variable immunodeficiency in 18, ataxia telangiectasia in 10 and other antibody deficiencies in 7 (transient hypogammaglobulinemia in 4, IgG subclass deficiency in 1, partial and selective IgA deficiency in 1) patients. Evaluation of the antibody response to polysaccharide antigens should be considered early on in patients with recurrent respiratory infections and required particularly for the diagnosis of specific antibody deficiency and the decision of the appropriate treatment approaches.

Mendelian susceptibility to mycobacterial disease (MSMD) is characterized by infections with weakly virulent mycobacteria (BCG and environmental mycobacteria), M. tuberculosis, Salmonella, candida and some other intracellular microorganisms. Nine different genetic defects have been defined to cause MSMD and IL-12Rβ1 deficiency is the most common form. We present here the clinical and genetic features of 18 patients with IL12Rβ1 deficiency diagnosed by surface expression of IL-12Rβ1 and Sanger's sequencing. Seventeen patients showed classical presentation (infections with BCG, salmonella and candida) while one patient experienced recurrent leishmaniasis. In all patients the percentage of activated lymphocytes with surface expression of IL12Rβ1 was < 1% indicating that it is an effective method for the screening of these patients. Three recurrent mutations were responsible for 85% of our families. Prognosis was good in patients, in whom specific antimicrobial therapy was given before dissemination occurs, as well as prophylactic antimicrobial treatment when needed and IFN-γ therapy for severe infectious episodes.

Defects in genes that have role in apoptotic pathways result in development of Autoimmune Lymphoproliferative Syndrome (ALPS) and ALPS related disorders. Germline and somatic FAS mutations, FASL and CASP10 mutations constitute other genetic defects in ALPS. Patients who fulfill ALPS diagnostic criteria and do not have any identified known disease causing mutations are classified as ALPS-unknown or ALPS phenotype and comprise about one third of all patients. CASP8, NRAS and KRAS gene mutations were reported for ALPS related diseases. We performed DNA sequence analysis in 25 unrelated patients with probable ALPS for FAS, FASL and CASP8 gene defects. Pathogenic mutations could not be found in the FAS, FASL and CASP8 genes. However, we found that the frequencies of SNPs rs2234978 and rs1045487 of FAS and CASP8 genes were significantly higher in the patients. Our results suggest that CASP8 and FAS gene polymorphisms in particular, may contribute to the susceptibility to development of ALPS phenotype.