R.S. Mallhi

Minimal residual disease detection using flow cytometry: Applications in acute leukemia

Minimal residual disease (MRD) describes disease that can be diagnosed by methodologies other than conventional morphology, and includes molecular methods (like polymerase chain reaction (PCR)) or flow cytometry (FCM). Detection and monitoring of MRD is becoming the standard of care, considering its importance in predicting the treatment outcome. MRD aids in identifying high-risk patients and hence therapy can be intensified in them while deintensification of therapy can prevent long-term sequelae of chemotherapy in low-risk category. FCM is considered as a less labor-intensive and faster MRD technique as compared to PCR although it has its own share of disadvantages. Current immune-based methodologies for detection of MRD depend on establishing leukemia-associated aberrant immunophenotype (LAIP), at diagnosis or relapse and use this information at specified time points for detection of MRD, or apply a standardized panel of antibody combinations for all MRD cases, in a different-from-normal approach. This review highlights MRD detection by FCM and its application in acute leukemia.

Drug-induced immune hemolytic anemia (Direct Antiglobulin Test positive).

Drug-induced immune hemolytic anemia occurs rarely (1 in 1 million population).1 It is an uncommon finding characterized by a sudden decrease in hemoglobin after treatment with the putative drug. To date, about 100 drugs have been implicated in causing a positive Direct Antiglobulin Test (DAT) and/or hemolytic anemia. The most common drugs associated with this, are penicillin and its derivatives, cephalosporins (cefotetan, ceftriaxone etc.), methyldopa, β-lactamase inhibitors and quinidine. Drug antibodies fall into two types: drug-independent (autoantibodies) and drug-dependent (“penicillin type” or “immune complex type”). Some drugs cause non-immunologic protein adsorption onto drug-treated red blood cells (RBCs).1–3 All these mechanism are associated with positive DAT which may lead to hemolytic anemia.

Antiphospholipid syndrome: A diagnostic challenge

The antiphospholipid syndrome (APS) is an acquired autoimmune thrombophilic disorder that is characterized by thrombosis (venous, arterial and microvascular) and obstetric morbidity due to a diverse family of antibodies against phospholipid-binding proteins present in plasma. The term antiphospholipid antibody is actually a misnomer as the antibodies are not against the phospholipid per se, but target the plasma protein co-factors, which bind to anionic PLs. The exact etiology has not been elucidated and is multifactorial. The initial guidelines for the diagnosis of APS were laid down in Sapporo, 1999, which were subsequently revised as the Sydney Consensus Conference criteria in 2006. Major changes were the inclusion of β2GPI as independent laboratory criteria, addition of ischemic stroke and transient cerebral ischemia as established clinical criteria and the requirement of repeating the test after 12 weeks. The laboratory tests recommended are coagulation assays, which study the effect of lupus anticoagulant on the clotting time and immunological assays, mostly ELISAs to detect IgG and IgM antibodies against cardiolipin and/or β2 glycoprotein I. For the diagnosis of APS, at least one clinical criterion and one laboratory criterion should be present. Limitations pertaining to the standardization, reproducibility and robustness of the currently recommended diagnostic tests still remain. Despite elaborate guidelines and syndrome defining criteria, the diagnosis of APS still remains a challenge. A greater interaction between the clinicians and the laboratory professionals is necessary for arriving at the correct diagnosis as a misdiagnosis of APS can have grave consequences.

Presence of Irregular Antibody (Anti-c) in a Multitransfused Cardiac Surgery Patient

Multi transfusion of blood and its components in cardio- vascular surgeries still remains a standard practice despite various advances in blood saving practices. Amongst the complications of blood transfusion, the formation of alloantibodies and autoantibodies against red blood cell antigens is one problem that frequently confounds the blood transfusion services [1]. Among such antibodies are alloantibodies against Rhesus (Rh) blood group antigens. Fifty-eight antigens belonging to Rh system have been discovered till date [2]. However the common problems revolve around five principal antigens that are—D, E, e, C and c and their corresponding antibodies, anti-D, anti-E, anti-e, anti-C and anti-c. Anti-c is clinically the most important Rh antibody after anti-D [2]. Anti-c is an important cause of delayed hemolytic transfusion reactions (DHTR) and hemolytic disease of fetus and newborn (HDFN) [2]. One such case of anti-c seen in our transfusion services is presented below.

The Possible Advantages of Cryoprecipitate Prepared From Fresh Frozen Plasma From Blood Stored for 24 Hours

BACKGROUND To compare the coagulation-factor profile of cryoprecipitate produced from fresh frozen plasma from whole blood (WB) stored for 24 hours at room temperature (24CP) with that of standard cryoprecipitate (CP). METHODS We collected 80 units of WB from healthy volunteers, of which 20 units were of each blood group. Each unit of blood was divided into 2 parts. One part was used for preparation and quality-control evaluation of CP within 8 hours of collection; the other part was stored at room temperature for 24 hours and then subjected to CP preparation. Coagulation studies were carried out on each batch of CP after production. Fibrinogen, Factor VIII (FVII), and von Willibrand factor (vWF) were measured, and the blood groups were determined. We used the Students t-test to perform comparisons and considered results to be significant at P < .005. RESULTS Overall, all 3 clotting factors were increased in 24CP compared with CP, with a statistically significant increase in the level of FVIII. Blood group AB had significantly increased levels of fibrinogen and vWF in 24CP compared with CP. CONCLUSION Our study showed that 24CP has equal or greater levels of coagulation factors compared with CP. His indicates that our alternate approach for preparation of CP may enable more efficient use of blood collected in satellite blood collection centers and during blood drives.