Dr Veena Singh

Immunoglobulin levels vs. age

Innate and adaptive immunity

Immunologic defects(1) T cell

(2) B cell

(3) Macrophage

(4) Complement

Primary immunodeficiencyInherited genetic defects in the immune cell

development or function or inherited deficiency in a particular immune molecule

Secondary immunodeficiencyLoss of previously functional immunity due to

infection, toxicity, radiation, splenectomy and malnutrition

When to suspect immunodeficiency ?

Very frequent infectionsVery severe infectionsFamily historyUnusual clinical presentation Unusual microorganism at unusual site

Additional clues..>8 ear infections per year>2 serious sinus infections per year>2 months treatment with poor result Requirement of iv antibiotics Failure to thrive with or without diarrhea

Common clinical featuresRecurrent respiratory tract infectionsSevere bacterial infectionPersistent infection with incomplete responsePersistent sinusitis/mastoiditisFTT/Growth retardationDiarrhea/malabsorption

Occasionally presentLymphadenopathyHepatosplenomegalyRecurrent meningitisPyodermaDeep infections: osteomyelitis, cellulitis

Detailed historyUpto 6 monthsHistory of newborn seizures, cardiac anomalyDelayed cord detachment, recurrent infectionDiarrhea, pneumonia, oral thrush, FTTBloody stools, draining ears, eczema

6 months to 5 yearsPersistent thrush, nail dystrophy,

endocrinopathiesShort stature, fine hair, severe varicellaOculocutaneous albinism with recurrent

infectionLymphadenopathy, dermatitis, pneumonia

Examination Clinically-BCG scar absentwasted, stunted, malnourishedSkin eczema present, hypopigmented patches Oral thrush, nail fungal infectionAbsence of tonsils and lymph nodesRespiratory system-b/l ronchi , wheeze,

crepts

Initial immunologic testing of the child with recurrent infections Complete blood count,differential,ESRLymphocyte,neutrophils,platelets,Howell jolly bodies,ESR Screening tests for B-cell cefectsIgA, if abnormal IgG, IgM measurementIsohemagglutininsAntibody titres to tetanus, diphtheria,

H.influenzae

Cont…. Screening test for Tcell defectAbsolute lymphocyte countCandida albicans intradermal test Screening test for phagocytic cell defectAbsolute neutrophil countRespiratory burst assay Screening test for complement

deficiencyCH50

Laboratory tests to assess immune function(1) T cell: Enumeration (flow cytometry),

functional assays (mitogen response, DTH skin tests)

(2) B cell: Enumeration, circulating antibody levels

(3) Macrophage: Enumeration, functional assays (nitroblue tetrazolium)

(4) Complement: Direct measurement of complement components, complement hemolysis assay

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