Primary antibody deficiencies (PADs) are frequent primary immunodeficiencies in humans, characterized by hypogammaglobulinemia, defects in production of specific antibodies, and recurrent infections. Information about PADs is quickly developing, leading to improved diagnoses and efficient disease management. This study is a review of the pathogenesis, diagnosis, clinical manifestations, and management of PAD disorders such as agammaglobulinemia, common variable immunodeficiency, monogenic defects associated with hypogammaglobulinemia, class switch recombination deficiencies, selective IgA deficiency, subclass immunoglobulin isotypes deficiencies, specific antibody deficiency, and transient hypogammaglobulinemia. 

Background/Objectives: Hyper-immunoglobulin M (HIgM) syndrome is a primary immunodeficiency disease in which impaired immunoglobulin class-switch recombination causes normal or high levels of serum IgM versus low or undetectable serum levels of class-switched immunoglobulins.
Methods: The diagnoses of all patients with HIgM in familial cases were evaluated based on genetic testing. Since this syndrome can present with either infectious diseases, malignancies, or autoimmune diseases, all medical complications were recorded in the index patients and relatives.
Results: Surprisingly, the evaluation identified a family with 3 males suffering from CD40 ligand deficiency, and each one had different autoimmune manifestations, including Guillain-barre syndrome and pauciarticular and polyarticular juvenile rheumatoid arthritis.
Conclusions: Based on the results, it is hypothesized that other genetic modifying factors or environmental parameters affecting epigenetics may have a significant role in the presentation of autoimmunity in CD40 ligand deficiency.

Background: Lipopolysaccharide-responsive beige-like anchor protein (LRBA) deficiency is a rare genetic primary immunodeficiency (PID) disease caused by mutation in the LRBA gene. The most important symptoms in patients include autoimmunity, recurrent infections, hypogammaglobulinemia, and enteropathy.
Methods: A total of 19 LRBA patients were enrolled in this longitudinal study. All recorded data for clinical presentation, demographic information, laboratory and gastrointestinal findings were collected.
Results: In this study, 11 females and 8 males (from 16 unrelated families) with LRBA deficiency were evaluated. The most common gastrointestinal symptoms were gastroenteritis, chronic or bloody diarrhea with abdominal pain, vomiting, anorexia, and FTT. The most important pathologic finding was colitis that was seen in 4 patients. Gastritis, esophagitis, gastroesophageal reflux disease, celiac-like disease, and normal upper endoscopy were documented equally in 2 patients. Also seen was enteritis in 3, proctitis, ileitis, and cryptitis in 1, and villous atrophy in 3 of the LRBA patients.
Conclusion: A variety of gastrointestinal conditions may be the most frequent complications in patients with LRBA deficiency.