Constitutional mismatch repair deficiency

Other antibody deficiencies 

Similar to the patients with X-linked agammaglobulinemia (XLA), hyper IgM syndrome, common variable immune deficiency (CVID), and specific antibody deficiency (SAD), individuals with less common antibody deficiencies usually present with upper respiratory infections or infections of the sinuses or lungs, typically with organisms like Streptococcus pneumoniae and Haemophilus influenzae. Laboratory studies show low immunoglobulins and/or deficient specific antibody production. Many of these disorders also include abnormalities in the cells responsible for generating or maintaining an antibody response. The patients often improve with antibiotics but get sick again when these are discontinued. The cornerstone of therapy for antibody deficiency disorders is immunoglobulin (Ig) replacement therapy.