Primary Immunodeficiency Disorders medical comic

This comic sorts inborn immune defects by which part of the defence force has dropped the ball — antibodies, T cells, both, or phagocytes — and shows how the pattern of infections points to the defect. It covers the classic syndromes examiners ask about, then contrasts them with secondary, acquired immunodeficiency.

For MBBS, NEET-PG, FMGE, NEXT and USMLE revision.

Primary immunodeficiency disorders: what the comic covers

High-yield points

The type of infection is a clue: antibody defects give recurrent pyogenic bacterial infections; T-cell defects give viral, fungal and opportunistic infections; phagocyte defects give catalase-positive bacteria and fungi.
X-linked (Bruton's) agammaglobulinaemia blocks B-cell maturation, so B cells and all immunoglobulins are absent after maternal IgG wanes.
Common variable immunodeficiency usually presents later, with low immunoglobulins despite B cells present.
Selective IgA deficiency is the commonest primary immunodeficiency; it causes mucosal infections and risks anaphylaxis to blood products.
DiGeorge syndrome (22q11 deletion) gives thymic aplasia with T-cell deficiency, hypocalcaemia and heart defects.
Severe combined immunodeficiency (SCID) removes both T- and B-cell function and presents in infancy with severe infections.
Wiskott–Aldrich syndrome (X-linked) combines eczema, thrombocytopenia and recurrent infections; ataxia telangiectasia is a DNA-repair defect.
Chronic granulomatous disease (NADPH oxidase defect) fails to kill catalase-positive organisms; Chediak–Higashi syndrome shows giant granules in phagocytes.

Mnemonics from the comic

Chronic granulomatous disease: CGD shoots blanks at catalase cats.

Quick questions

Which is the most common primary immunodeficiency?

Selective IgA deficiency. Many people have no symptoms; others get recurrent sinus, lung and gut infections and can react to IgA in blood products.

Why do patients with chronic granulomatous disease get catalase-positive infections?

Their phagocytes lack NADPH oxidase and cannot make their own hydrogen peroxide. Catalase-negative bacteria supply peroxide the cell can use, but catalase-positive organisms such as S. aureus, Aspergillus and Serratia destroy it.

What is the triad of Wiskott–Aldrich syndrome?

Eczema, thrombocytopenia with small platelets, and recurrent infections, in an X-linked recessive pattern.

Is this comic free to read?

The first pages are free to preview. Members read the full comic, and you can sign up free to read one comic in full.