<prompt> PNH is associated with a deficiency of :DAFMIRLGPI Anchored proteinAplastic Anemia and PancytopeniaAll of the above  <response>: Answer is D All of the above PNH is associated with a deficiency of GPI anchored proteins including DAF and MIRL PNH is associated with a deficiency of GPI Anchored proteins DAF CD55 and MIRL CD59 are the most impoant GPI Anchored proteins that may be deficient in PNH. Since option D allows us to select all the above options and we are not forced to select one single best protein Option D becomes the answer of choice. Glycosvl phosphatidvlinositol GPI anchored proteins and PNH PNH is primarily associated with a deficiency of GPI anchored proteins on hemotopoetic cells All proteins that are deficient in PNH are GPI Anchored and all GPI anchored proteins that are expressed by hematopoietic cells are deficient in PNH - Wintrobes The most impoant GPI anchored proteins that are causally related to PNH are the complement regulatory proteins that result in abnormal susceptibility of erythrocytes to complement mediated lysis. GPI Anchored complement regulatory proteins Decay accelerating factor DAF -- CD 55 Membrane Inhibitor of Reactive Lysis MIRL -- CD59 However several other GPI anchored proteins may be deficient in PNH and currently the list of proteins deficient in PNH numbers more than 20 GPI Anchored Proteins Deficient in PNH Cellular prion protein Leukocyte alkaline phosphatase - CD66b formerly CD67 Acetylcholinesterase - CD66c Decay accelerating factor DAF, CD55 - p50-80 Membrane inhibitor of reactivity lysis MIRL, CD59 - CD24 FcyRlllb CD16b - CD48 Lymphocyte function-associated antigen 3 LFA-3, CD58 - Thy-1 CD90 Endotoxin-binding protein CD14 - CD109 Campath 1 CD52 - CD157 5-ectonucleotidase CD73 - GP500 Urokinase plasminogen activator receptor CD87 - GP175 JMH-bearing protein CD108 - Folate receptor 