fall bb week 4

cold allab

IgM ab IS XM, only sig at 37 C, Anti-P1 -M -N -Lewis -Lua, variable and dosage, incub below rt 4 C to enhance

resolving cold alloab Interference

Id IS rxn not carried through AHG, if still react at 37 could be sig, 0.01 M DTT to plasma and retest with saline dilution control (if control stays reactive but DTT not reactive sig IgM)

avoiding detecting cold ab

omit IS/37 C phase readings on routine ab screens

neutralization tech

soluble form of ag (Le H I P1 Sda or Ch/Rg) is added to pt plasma to inhibit specific ab, if ab binds the soluble ag it can no longer agglu ag-pos rbc

dilution control

plasma + saline in equal vol to neutralizing reagent, must remain reactive to prove neg result due to true neutralization not just simple dilution

neutralization of Anti-Le (a-b+)

control 1+, neutralization 0, lewis ab is neutralized

control 1+, neutralization 1+, lewis ab is not neutralized or diluted

control 0, neutralization 0, lewis ab is prob diluted

anti H inhibited by

saliva from a secretor containing H substance (Le [a-b-][a-b+] donors)

anti-I inhibited by

human milk

anti-Lea inhibited by

saliva containing Lea sub (Le a+b- and a-b+ donors)

anti-Leb inhibited by

saliva from secretor Le a-b+

anti-P1 inhibited by

hydatid cyst fluid, pigeon egg white

anti-Sda inhibited by

pooled human urine, guinea pig urine

anti- Ch/Rg, I, i, Inb, and Kn inhibited by

pooled human plasma

autoab rxn

pos with all reagent, donor, self rbc, ac and DAT

remove auto ab to detect alloab

prewarm and absorption

AIHA autoimmune hemolytic anemia

cold IgM, warm IgG, mixed both, PCH IgG biphasic hemolysin

cold autoab

IS, ac and DAT pos, C3, mild anemia, mycoplasma pneumoniae, mono, anti I, H, IH, cold panel to ID

cold panel

ab screening cells, group O cord cells (I neg), auto cells, A1/A2/B cells (per pt ABO type)

anti-i

uncommon cold autoab bc most adults are i-

anti-I

most common cold autoab, react with all cells except cord

anti-HI and anti-Ha

more common cold autoab in A1 than A1B, react best with O and A2 cells bc have most H ag

anti-Pr

very rare cold autoab, pathogenic due to high titer and high thermal amplitude

nonpathogenic cold agglu

polyclonal, low titer, no rxn above 30 C, rxn increases as temp decreases, elutes spontaneously when warming to 37 C

pathogenic cold agglu

monoclonal, high titer at 4 C, can react at temp as high as bt (wide thermal amplitude), sig hemolysis, can cause CAS

cold agglu syndrom CAS mech

IgM binds its ag (i or I) on rbcs in cooler areas of body (extremities), recruits C1, C4, C2, C3b deposit on rbc marking for extravascular phagocytosis, cells escaping removal warm IgM dissociates, C3b cleaved to C3d detected by anti-C3 in DAT

CAS population

primary idiopathic, 2ndary acute- myco pneum, infec mono (anti-i), viral disease in kids, 2ndary chronic- elderly, lymphoma, CLL, waldenstrom macroglobulinemia

CAS symptoms

worsen with temp decrease, raynauds (acrocyanosis, numbness, pain in extremidies), weak, pale, weight loss, jaundice, hemoglobinuria

CAS lab findings

anemia, high retics, low haptoglobin, high LDH, pos DAT with C3, IgM autoab titer over 1000 at 4 C

monospecific anti-IgG AHG

avoids cold autoab rxn, poly would detect complement

PEG, enzymes gel, solid-phase

enhance autoab rxn, use 22% bovine albumin or saline method to avoid cold autoab

prewarm

6-7 drops of pt plasma, 1 drop of cells in diff tubes, dry bath 37 C for 5-10 min, wash with the warm saline, add 2 drops of mono anti-IgG AHG centrifug and read

prewarm limitation

may reduce rxn of weak sig ab (vel), cannot eliminate unidentified ab, false neg if AHG contain IgM component prewarmed

cold autoabsorption procedure

incub washed pt rbcs and plasma for 1 hr 4 C, mix and check for agglu every 15 min, if aggly centrifuge remove plasma re incub or new set of washed rbc, continue until no agglu, test plasma with rRBCs, check sc to confirm removal

cold panel/screen process

confirm cold autoab first, incub at rt or 4 C at IS, anti-I most common, anti-i, IH, H in A1 or A1B, rarely anti-Pr if cells react equally but not with enzyme cells

autoadsorption

pts own rbc remove autoab from plasma so underlying alloab can be detected, only use if not transfused in last 3 months

allogeneic differential adsorption

known phenotyped rbc remove autoab from plasma so underlying alloab can be detected, needed if pt was recently transfused

rabbit erythrocyte stroma RESt

adsorbs cold IgM ab, usually anti-I, carries ag similar. to I IH and H, useful when pt has been recently transfused, not used for reverse grouping or XM bc has B ag and adsorb anti-B, can absorb other sig IgM ab

adsorbed plasma when removing cold autoab

retested against previously reactive cells to confirm complete adsorption and reveal any alloab

PCH

least common AIHA, acute transient self limiting, caused by biphasic hemolysin (donath-landsteiner ab) an IgG with anti-P specificity, IgG binds rbc and partially activates complement in cold extremities

PCH complement

full complement activation (C5-9) and hemolysis only after warming to 37 C (core of body), ab dissociates from cells at warmer temp DAT pos with C3

PCH primary pop

idiopathic, chronic disease in the elderly

PCH 2ndary pop

following viral infec in kids (mumps, measles, varicella), historically associated with tertiary syphilis

PCH symptoms

fever, chills, malaise, pallor, jaundice, back pain, abdominal cramps, anemia can be life threatening (condition is usually self limiting within days- few weeks)

PCH lab findings

rapid anemia, hemoglobinemia, hemoglobinuria (red-brown urine), high retics aniso poik hemophagocytosis, DAT pos with C3 IgG alr dissociated

PCH donath-landsteiner test

pt serum + rbc incubate at 4 C, warm to 37 C until clot forms or serum removal to avoid losing ab before testing, hemolysis after warming confirms biphasic hemolysin

CAD cold agglu disease

IgM, anti-I (sometimes anti-i rarely Pr) specificity, DAT pos with C3 (IgM dissociates when warming), titer over 1000 4 C, extravascular hemolysis, chronic- elderly and lymphoproliferative disease

PCH summary

IgG biphasic hemolysin (anti-P specificity donath Landsteiner), Dat pos with C3 (igG dissociates warming), titier under 1:64, intravascular hemolysis, acute self limiting in kids post viral

transfusion with CAS

no interference when finding compatible blood, in-line blood warmer to keep transfused cells above the temp of reactivity

transfusion with PCH

P-neg blood is rare and not required (autoanti-P only reacts in cold temp), keep pt warm, consider in-line blood warmer

mixed AIHA

patho cold and warm auto ab, DAT pos with anti-IgG and anti-C3, eluate- warm reactive IgG autoab, IgM thermal amplitude extends to 30 C, must reduce reactivity of both

paroxysmal nocturnal hemoglobinuria PNH

not ab mediated, confused with PCH, intrinsic rbc genetic defect in PIGA gene reducing GPI anchor expression, protective proteins CD55 CD59 cannot bind to rbcs, lysis by complement

paroxysmal nocturnal hemoglobinuria PNH lab and symptoms

DAT neg, ab screen neg, red/dark urine, fatigue, dyspney, thrombosis