Prevalence of IgG subclasses (IgG1/IgG3) in Antenatal Alloimmunized Women: Experience in a Tertiary Hospital in South India

Jui, Choudhuri (2015) Prevalence of IgG subclasses (IgG1/IgG3) in Antenatal Alloimmunized Women: Experience in a Tertiary Hospital in South India. Masters thesis, Christian Medical College, Vellore.


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OBJECTIVE: To study the prevalence of IgG subclasses (IgG1 and IgG3) in antenatal alloimmunized women in South India and to correlate it with occurrence and severity of Hemolytic Disease of Fetus and Newborns (HDFN). METHODOLOGY: 85 antenatal women with a positive antibody screen were included in this study, irrespective of parity and period of gestation. The antibodies were identified and IgG subclass (IgG1/ IgG3) was determined using the “DAT IgG1/IgG3 ID card from DiaMed Gmbh, BIO-RAD which utilizes the column agglutination technique. These pregnancies were followed up to see the outcome. The newborn was identified to “have or not have HDFN” using the DAT test and further categorized into Mild/ Moderate/Severe HDFN based on the modality of treatment required. The prevalence of IgG1/IgG3 subclasses was calculated in the alloimmunized antenatal. The categorical data including disease IgG subclass, severity of HDFN and correlation with DAT strength was calculated using Pearson’s chi square test. The severity of HDFN was correlated with the IgG (IgG1 and IgG3) subclasses and antibody titre levels in maternal serum using the univariate and binary logistic regression analysis. RESULTS AND CONCLUSION: The prevalence of IgG subclasses in our study was found to be, 20% for IgG1, 4% for IgG3, 25% for IgG1+ IgG3, 51% had neither IgG1 and/or IgG3. Among the 57 newborns at risk of HDFN, we found a highly significant difference between disease severity and absence / presence of IgG1/IgG3 – either singly or in combination (p<0.001). Assessing disease severity in low and intermediate antibody titre level groups showed a significant difference with more severe disease in those with IgG1 and / or IgG3 as compared to those who were negative for both these subclasses (p<0.001). The binary logistic regression analysis showed the odds of severe HDFN to increase an additional seven times stepwise , the lowest being in patients with neither IgG1/IgG3, to having either one of them, to having both these subclasses together (p<0.05, CI between 1.5-31.89). DAT was positive in 37 of 57 babies. Severity of HDFN was significantly associated with increasing DAT strength (p<0.001). We conclude that the presence of IgG1/IgG3 subclass impacts significantly on the severity of HDFN. This effect continues to be significant even when titres are low. These mothers therefore require closer antenatal monitoring, and babies in this group require closer follow up to allow for appropriate and timely intervention. A stronger DAT reflects as HDFN with greater severity. This study identified the significance of IgG subclass as an independent prognostic marker for HDFN which can easily be incorporated into routine clinical practice.

Item Type: Thesis (Masters)
Uncontrolled Keywords: IgG subclasses (IgG1/IgG3) ; Antenatal Alloimmunized Women ; Tertiary Hospital ; South India.
Subjects: MEDICAL > Immunohaematology Blood Transfusion
Depositing User: Punitha K
Date Deposited: 04 May 2018 16:47
Last Modified: 04 May 2018 16:47

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