Which of the following immunodeficiency disorders is characterized by a deficiency of immunoglobulin A (Ig

Explanation: The correct answer is b. Persistent fever and night sweats. Fever and night sweats are common clinical manifestations of immunodeficiency disorders. The immune system's inability to fight off infections can lead to recurrent fevers and night sweats as the body tries to combat pathogens.

Incorrect choices:

a. Hyperactivity and restlessness are not typical clinical manifestations of immunodeficiency disorders. These symptoms are more commonly associated with conditions affecting the central nervous system.

c. Weight gain and increased appetite are not typical clinical manifestations of immunodeficiency disorders. They may be seen in conditions like hypothyroidism or hormonal imbalances.

d. Elevated blood pressure is not a common clinical manifestation of immunodeficiency disorders. It may be seen in conditions like hypertension or cardiovascular disorders.

Explanation: The correct answer is c. Common variable immunodeficiency (CVID) is characterized by a deficiency or absence of B cells, leading to a reduced ability to produce antibodies and an increased susceptibility to infections.

Incorrect choices:

a. DiGeorge syndrome is a disorder caused by a genetic defect resulting in the underdevelopment of the thymus and parathyroid glands, leading to T cell deficiency.

b. Severe combined immunodeficiency (SCID) is a severe form of immunodeficiency that affects both B and T cells, leading to a complete absence or dysfunction of the immune system.

d. Wiskott-Aldrich syndrome is a rare X-linked genetic disorder characterized by a triad of symptoms, including eczema, low platelet count, and immunodeficiency. It primarily affects T cells and platelets, not B cells.