Haemolysin test for characterization of immune ABO antibodies.

BACKGROUND & OBJECTIVES: Antibodies with haemolytic properties are common within the ABO system. These lytic antibodies are immunoglobulin G (IgG) and in high titres cause haemolysis during blood transfusion. Information on Immunoglobulin types and concentration of ABO haemolysins in Indian population is lacking. The present study was undertaken to know the usefulness of haemolysin test for characterization of immunoglobulin class of ABO antibodies. METHODS: Serum samples from 187 O group blood donors were screened for A and B haemolysins. Thirty five samples were treated with dithiothretiol (DTT) for characterization of Ig class. Antibody titre was compared with grade of haemolysis. RESULTS: Of the 51 strongly haemolytic serum samples, 32 (62.8%) had IgG titres of > or = 64 after treatment with DTT. There was significant association (P<0.05) between grade of haemolysin and anti B IgG titre. INTERPRETATION & CONCLUSION: Haemolysin test was found to be a useful screening test to identify group O donors with high levels of IgG anti A and/or anti B for blood transfusion purposes.

Clinically significant autoantibodies--a case report.

Auto antiA1 and anti H was found in the serum of a patient admitted in this hospital for intracardiac repair of Ventricular Septal defect (VSD). Blood was grouped as A1 positive with discrepant cell and serum grouping due to auto anti A1 and anti H. No blood units were compatible for the patient. 17 A1, 3 A2 and 8 O group blood units were crossmatched and found incompatible at 37 degrees C and A2 and O at 25 degrees C--as the patient required surgery at hypothermia. Surgery was postponed. Antibody status was reviewed after 4 months. The thermal amplitude of auto anti H had changed by then but there was no change in auto anti A1. Surgery was done using A2 group blood.

Profile of transfusion transmissible infections and associated risk factors among blood donors of Kerala.

Blood transfusion is an important mode of transmission of infections to the recipient. The aim of the study was to assess the prevalence of transfusion transmissible infections and the possible risk factors among blood donors. During the study period (1994-99) donor samples were screened for HBsAg, HIV, HCV and Syphilis. The relevant donor history was examined to identify the risk factors leading to transfusion transmissible infections. The prevalence of infection was 3.1% among donors, with HBsAg constituting 1.3%, HCV 1.4%, HIV 0.2% and RPR 0.2%. In a classification based on occupation, class III donors (drivers, Businessmen & men in uniform) showed a significantly higher incidence of transfusion transmissible infections for HIV (0.38%) and Syphilis (0.36%). Health care workers constituted only a small fraction of the study; prevalence of infections was low among them. History of jaundice or hospitalization was not associated with higher incidence of seropositivity. Seropositivity for HIV is relatively low compared to similar studies conducted in other regions of the country. This finding is attributed to the pre donation counseling in donor selection. An important outcome of the study is that Class III donors form a high-risk group for transfusion transmissible infections.

Detection of high risk pregnancies with relation to ABO haemolytic disease of newborn.

IgM and IgG anti A and anti B antibody status of 100 antenatal O group mothers (who had non O group husbands) were studied. Of these, 3 mothers had an IgM anti A antibody levels ranging from 1:512 to 1:2048 and IgG ranging from 1:1204 to 1:2048, IgM anti B ranging from 1:128 to 1:512 and IgG anti B ranging from 1:256 to 1:512. All these mothers had A + ve children and all these children suffered from ABO haemolytic disease of newborn (HDN). A 4th mother had an IgM anti A titre of 1:64 and IgG anti A titre of 1:16. The titre of IgM anti B in this mother was 1:512 and that of IgG 1:1024. The child was A + ve and did not suffer from ABO haemolytic disease of newborn.

Compatibility problems after intravenous immunoglobulin--a case report.

Serious incompatibility was noted in a patient diagnosed as acute Guillain Barre syndrome treated with intravenous immunoglobulin. Patient had positive direct and indirect antiglobulin test and the auto control was negative. There was no clinical signs of hemolysis. Patient's blood group was O D positive and cross matched several units of ABO compatible D positive and D negative blood. Only one unit was compatible. These findings suggest that the particular intravenous immunoglobulin contained a mixture of saline and immune antibodies having different specificity. As the number of patients getting treated with intravenous immunoglobulin is on the rise more and more compatibility problems should be anticipated and should be borne in mind during serological testing and evaluation.

Para Bombay phenotype--a case report.

Bombay phenotype is peculiar in that red cells are not agglutinated by antisera A, B or H; while serum contains anti A, B and H. Existence of modifying genes at independent loci with variable expression of ABO genes is postulated. We report here a case of partial suppression where antigens could be detected by elution tests and unlike classical Bombay type, normal amount of appropriate blood group substances were present in saliva. This case of para Bombay phenotype was detected as a result of discrepancy in cell and serum group ng. This highlights the importance of both forward and reverse grouping in ABO testing.

Morphological & ultrastructural changes of platelet concentrates stored in PVC bags.

To assess the effect of storage bags on platelets, we studied the morphological and ultrastructural changes of samples drawn from platelet concentrates (PC) prepared and stored in triple, poly vinyl chloride (PVC) bags, manufactured in India. Using the scanning electron microscopy, we demonstrate formation of long pseudopods, and interaction through these to form aggregates. When platelets were stored at 23 +/- 2 degrees C, morphological changes were severe compared to the deleterious effects when kept at 22 +/- 0.5 degrees C. Ultrastructural analysis also showed that maintenance of discoid shape and prevention of granule secretion could be improved by storing the platelets at 22 +/- 0.5 degrees C. Significant degree of platelet fragmentation took place when the storage temperature was high. The morphology score done for platelets stored at both 22 +/- 0.5 degrees C and 23 +/- 2 degrees C showed that preservation of discoid shape was better with the former.

Biochemical lesions of platelets stored as concentrates in PVC bags.

Acid-base status of platelet suspension during storage is a measure of the gas permeability of the bag material. To assess the efficacy of the bags available in our market to store platelets, we compared biochemical lesions of platelets stored in an Indian polyvinyl chloride (PVC) triple bag against a Japanese PVC bag standardized for 5 days platelet storage. Platelet concentrates prepared in both control and test PVC bags were stored for 72 h. Two ml samples were drawn 1 h after preparation, and then at 24 h intervals, for analysis. Our data show that the mean pH value in the test bags was maintained above 6.5. However, the CO2 tension was high and O2 tension was low. We also analyzed malondialdehyde (MDA) formation which is a measure of arachidonic acid metabolism, and seemed to be unaffected in stored platelets. Lactate dehydrogenase (LDH) was not released into the plasma excessively and hence significant platelet lysis was absent during storage. Hypotonic shock response (HSR) of platelets stored in both test and control bags was comparable, indicating the possibility of satisfactory post-transfusion recovery.