Tiny study aims to Fine-Tune antibody therapy for rare immune disorders

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria:Confirmed Diagnosis: Diagnosis of primary antibody immunodeficiency based on clinical presentation and laboratory evidence of impaired antibody production. Diagnoses should align with standard criteria (e.g., ESID/IUIS diagnostic criteria). Laboratory Evidence: Documented quantitative deficiency in serum immunoglobulins, defined as reduced IgG, IgA, and/or IgM levels below the age-adjusted lower limit of normal, and/or demonstrated poor specific antibody response to vaccines. Age: Patients aged between 5 and 50 years (inclusive) at the time of screening. Treatment Status: Currently receiving or scheduled to initiate regular immunoglobulin replacement therapy. Consent: Provision of written informed consent by the patient or their legal guardian, along with documented assent from pediatric participants where developmentally appropriate. \- Exclusion Criteria:Secondary Immunodeficiency: Presence of other severe comorbidities that may affect immune function. This specifically includes secondary causes of hypogammaglobulinemia, such as active malignancies, protein-losing enteropathy, nephrotic syndrome, or untreated HIV infection. Other PIDs: Confirmed diagnosis of primary immunodeficiency disorders other than predominantly antibody deficiency. Confounding Medications: Use of systemic immunosuppressive or targeted immunomodulatory drugs within 3 months prior to enrollment. Patients on stable immunoglobulin replacement therapy are exempt from this exclusion. Acute Confounding Illness: Presence of active, severe, uncontrolled infections at the time of baseline blood sampling that, in the investigator's clinical judgment, would transiently distort baseline immune subset profiling. Pregnancy/Lactation: Current pregnancy or breastfeeding, due to the physiological alterations in maternal immune subsets. \-