Rhesus D Variants among Pregnant Women in the Northern Nigeria

CHAPTER ONE

INTRODUCTION

• BACKGROUND

The Rhesus blood group system is one of the most polymorphic and immunogenic systems of blood group antigens known in humans. This blood group system is comprise of numerous antigens, principally among them is ‘’RHD’’, ‘’RhC’’, “Rhc”, “RhE” and “Rhe” antigens (Flegel, 2007; Sell et al., 2013).

The Rh factor is a term used to describe the presence of the D antigen, the first antigen that was identified belonging to the Rh blood group system (Huang, 2013), on the surface of erythrocytes. The common potent Rh antigens reside on the RH polypeptides, whose expression is controlled by the RHD and RHCE genes, linked in tandem on chromosome one. The RHD produces the D antigen and RHCE produces the alleles Ce, ce, cE and CE compound antigens. There are about 300 allelic forms of the RHD and RHCE genes named at the molecular level. This polymorphism is due to various pattern of genomic diversification at the RH locus. The predominant mechanism of diversification at the RH locus is coding nucleotide changes and genomic rearrangement through homologous recombination.

The D antigen is clinically the most important because of its high immunogenicity and polymorphism. It has a prevalence rate of about 85% in Caucasians and about 95% in blacks (Daniels et al., 2007; Poole and Daniels, 2007). The RHD negative phenotype is characterised by high molecular diversity between serologic and molecular methods. It accounts for the incidence of alloimmunization due to pregnancy or blood transfusion, despite the numerous red cell antigens (Delaney et al., 2016; Egbor, Fellow and Knott,

2012). Most red cell alloimmunization is attributed to antigens “D” “C”, “c”, “E”, “K”, and “Jk”a (Evers et al., 2016; Flegel et al., 2016). Alloimmunization in mothers is caused by pregnancy, blood transfusion, abortion, ectopic pregnancy, amniocentesis (iatrogenic) and foeto-maternal haemorrhage (Nour, ARamy and Ali, 2011).

The absence of the D antigen designates RH negative status on human erythrocytes; its molecular basis is divided into deletion and non-deletion types. Vast majority of Caucasians with the phenotype have a total deletion of the RHD gene. The non-deletion type occurs commonly in Africans, Japanese and other Asians (Huang, 2013). There  are genomic alterations of three types that silence the D antigen expression in RH negative subjects who carry either a partial or completely intact RHD (Avent et al., 2006; Flegel, 2011). The weak D (DU) phenotype is associated with various forms of mutations that affect the quantity and quality of D antigen (Daniels, 2013; Singleton et al., 2016). Most of these mutations are novel missense mutation that results in a single amino acid substitution that resides on either transmembrane domains or cytoplasmic portion of the protein. Partial D phenotype typifies a loss and/ or an alteration of one or more of D epitopes within the context of entire D protein. They often show weakened D expression making it difficult to differentiate between partial D and weak D (Denomme et al., 2005).

Due to the density and epitope expression of the D antigen on the red cell surface, the phenotypes commonly observed are normal D positive, weak D, partial D, DEL and D negative (Ye et al., 2014). Expression of weak D and partial D is attributed to variants of antigens and a large number of alleles of RHD gene (Rizzo et al., 2012). The weak D

phenotype is due to quantitative expression of the D antigen epitopes whiles that of the partial D is due to qualitative expression of antigenic epitopes of the D antigen.

The discovery of the Rh blood group system was an insight into the instances of the haemolytic disease of the foetus and new-born (HDFN). HDFN is perpetuated by foeto- maternal rhesus antigens incompatibility (Rouillac-Le Sciellour et al., 2007). HDFN occurs as result of the immune-mediated destruction of red cells antigens of a  foetus that are not usually found on maternal red cells ( (Fasano, 2016). The common antibody produced is immunoglobulin G (IgG). The trans placental transfer of IgG antibodies attacks foetal RHD antigens leading to their destruction (Fasano, 2016). Other RH  blood group antigens that can cause alloimmunization include antigen C, E, c and e (Shao et al., 2010). Antibodies directed against epitopes of these antigens can cause alloimmunization through transfusion or pregnancy. The antibodies often encountered in Africa are anti-c, anti-C, anti-e and anti-D (Ngoma et al., 2016).

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A COMPARATIVE ASSESSMENT OF VISION IN INFANTS AND CHILDREN

The testing of vision in infants and children has been treated separately from the testing of adults because infants and children often cannot be tested with the same materials and techniques as adults.

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INTRODUCTION

Pelvic Inflammatory Disease (PID) refers to an inflammatory condition in the female reproductive system above the internal os of the cervix. It can be due to a bacterial, fungal or viral infection though bacterial infection is more common.

Organisms that are notable in PID conditions are, Neisseria gonorrhoeae and Chlamydia trachomatis, even normal vaginal flora can be involved. The infection can be due to a single species of organisms or a co- infection of many different organisms.

World Health Organisation (WHO) estimates that worldwide over 340 million new cases of four curable STIs ( gonorrhoea, chlamydia, syphilis, and trichomoniasis) occurred in 1999 in men and women age 15-49. In sub-Saharan Africa, the WHO Global programme estimated the prevalence of STIs at 208 million cases, with an annual incidence of 65 million (WHO, 1995)

32 Prevalence of PID in Nigeria is high, particularly among young adults. A study done in Port Harcourt, Nigeria put the prevalence among undergraduates at 11%. 5 Prasad et al24 in a similar study reported a prevalence of 14% among young women in India.

A study in 1994 in hospitals showed that 10 percent of out-patient attendees were due to STIs (Roseberry et al., 1994). Another population study in a community trial in Rakai, Uganda, found a prevalence of 15.6% for HIV, 9.4% for syphilis, 25.0 % for trichomoniasis, 1.1% for gonorrhoea, 2.2% for chlamydia and 51.2% for bacterial vaginosis, at a baseline control group (Wawer etal., 1999).

According to data from the Mulago STD clinic, the prevalence of HIV among STD clients remains much higher than in the general population. While the HIV prevalence has stabilised around 6.4% in the general population since 2000, among STD clients it has remained high, ranging between 19 and 23.7% (MOH, 2003b).

There are limitations and constraints associated with making an etiological diagnosis based on laboratory evidence, apart from research settings, most of the diagnosis and management of STD patients is based on the syndromic approach.

PID could be a result of an untreated sexually transmitted disease, abortion childbirth, miscarriage or post pelvic operations. It can be diagnosed using laparoscopy, pelvic scans and histology smears. However there are other conditions that have to be considered when diagnosing the disease and they include appendicitis, ectopic pregnancy, hemorrhagic or ruptured cyst and twisted cyst.

PID can be cured but its effects can be permanent hence early treatment and regular screening of individuals at a high risk of STIs is important since gonococcal infections are asymptomatic. Treatment generally involves antibiotic therapy and the drugs are given either orally or intravenously. Untreated or late treated PID has serious complication such as infertility, ectopic pregnancy chronic abdominal pain.

Prevention strategies include avoiding STIs and early treatment of the symptoms for any STI or PID which include; pain during intercourse, abnormal vaginal discharge and fever.

PROBLEM STATEMENT

In general, infertility can be attributed to the female partner one third of the time, the male partner one third of the time, and both partners in the remaining one third. This approximation emphasizes the importance of evaluating both members of the couple before instituting therapy (William’s gyaenecology).

In Uganda the rate of infertility is high and the most probable cause is risky behaviours which people always engage in, this has led to people acquiring different infections which have led to P.I.D , a disease people hardly know anything about.

Early identification of the disease is a major preliquisite to prevention and controlling of the disease, however with the various myths and inadequate information about the disease many people are at a high risk.

JUSTIFICATION

According to the 2004-05 Uganda HIV/AIDS Sero-Behavioural Survey, the prevalence of STIs and related risk behavior was high. In the same survey, only 9 percent of women and 15 percent of men reported condom use during the preceding 12 months, 14 percent of youth age 15-24 reported started having sex before age15. Sixty-three percent of females and 47 percent of males 18-24 years had had sex before age 18, and only 29 percent of females and 33 percent of males used a condom at initiation of sex. Multiple sexual partners were common and No table of figures entries found.reported multiple sexual partners

Despite the above troubling information there has not been any reported study in Uganda on the awareness of PID among the youth. This research will therefore serve to add knowledge on the awareness of this debilitating disease that has great impact on both the spread of HIV and infertility.

AIMS AND OBJECTIVES

Determine the status Assessing level of awareness on causes and prevention of pelvic inflammation disease

SPECIFIC OBJECTIVES

1. 1. To evaluate the knowledge of the students about the PID
   2. To identify the predisposing factors to PID among the students
   3. To identify the prevention approaches of PID

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