Immune complexes and abnormal liver function in haemophilia

Plasma protein variations in hemophiliacs receiving factor replacement therapy

OBJECTIVE

Post transfusion manifestations and its affiliated factors are vital to understand in a disease like hemophilia where multi-transfusions are given to the patients.

METHODS

To investigate the implications of factor replacement therapy on plasma proteins, 52 hemophiliacs and 68 carrier females were examined for 12 plasma proteins using various electrophoretic techniques.

RESULTS

Severe hemophiliacs showed raised levels ( p< 0.05) of a2 M, IgG and Albumins where values were found to be 4.78 +/- 0.865 g/l, 21.48 +/- 3.38 g/l, 66.26 +/- 11.92 g/l respectively at 95% confidence intervals however, controls and carriers showed trivial variations.

CONCLUSION

Juxtaposing the dissimilarities of 12 plasma proteins in carriers, controls and hemophiliacs, it has been gleaned that factor replacement therapy do play role when seen in severe hemophiliacs with raised levels.

The Impact of Clotting Factor Concentrates on the Immune System in Individuals With Hemophilia

All reported studies to date, whether comparative or not, have shown a tendency toward a slower decrease in CD4+ numbers in patients receiving very high-purity agents with the rapidity in fall-off being affected by level of CD4+ numbers (low CD4+ numbers decreasing more rapidly), age (older persons showing more rapid CD4+ cell fall-off), and anti-HIV therapy. Clearly, these observations need to be extended in numbers, and the high-purity agents should also be similarly compared with the very high-purity therapies.

Liver dysfunction in haemophilia

Liver function was studied in 139 of 291 haemophiliacs known to a single Regional Haemophilia Centre including patients with classical haemophilia, Christmas disease and von Willebrand's disease. In 57 patients, six-monthly liver function tests over a five year period were also available. Thirty-nine of the 139 patients had had jaundice or hepatitis and 56 had a positive test for HBsAb in the blood although few of these had had an identifiable clinical illness. Fifty-eight haemophiliacs had elevated serum aminotransferases at the time of study, but the five year review revealed only six patients who had had persistently abnormal results, although none had clinically evident liver disease. Liver dysfunction was unrelated to a history of hepatitis, to a positive HBsAb test, or to age, type of haemophilia, factor level or frequency of factor replacement treatment. Abnormalities of liver function in haemophilia appear to be unrelated to past or present hepatitis B infection in most cases and may not be related to any single transmitted infectious agent.

A functional defect in the early phase of the immune response observed in patients with hemophilia A

In search of a functional immunological defect in patients with hemophilia A, we investigated the early phase of the immune response and found a deficiency in the monocyte-T cell interaction after in vitro exposure to a bacterial antigen. T-cell proliferation in response to Escherichia coli-pulsed autologous monocytes was significantly (P less than 0.025) reduced in hemophiliacs [mean dpm +/- SEM (n = 25): 9036 +/- 2600] as compared to healthy controls [mean dpm +/- SEM (n = 24): 17,812 +/- 2985]. This functional defect was expressed in a severe form (antigen-induced monocyte-T cell interaction less than or equal to 2000 dpm) in both HTLV III antibody-positive and -negative patient populations. Significantly decreased T-helper/T-suppressor-cell ratios (mean dpm +/- SEM: patients 1.47 +/- 0.13; controls 2.04 +/- 0.11; P less than 0.001)--but without a concomitant reduction in the absolute number of T-helper cells--could also be observed.

Changes in plasma haptoglobin and alpha-2-macroglobulin in hemophiliacs receiving factor replacement therapy

Plasma proteins were studied in 84 patients with hemophilia A, who were receiving factor replacement therapy. Compared with age-matched controls, 63 patients (75%) had subnormal haptoglobin and 58 (69%) had elevated alpha-2-macroglobulin. Causes for depressed haptoglobin were sought by correlating ABO blood types, liver function tests, factor VIII procoagulant levels, and intensity of yearly exposure to clotting factor products. Subnormal haptoglobin levels in chronically transfused patients may relate in part to hemolysis from AB incompatability. However, depressed haptoglobin levels were also found in group O hemophiliacs without other evidence of hemolysis. Most patients lacked evidence of active liver disease, making synthetic deficiency unlikely. There was close correlation between depressed haptoglobin and severity of clotting factor deficiency. The degree of alpha-2-macroglobulin elevation correlated with severity of procoagulant deficiency but not with intensity of clotting factor replacement therapy. Since alpha-2-macroglobulin plays a major role in the catabolism of fibrinogen, elevated levels may represent a compensatory increase in response to exogenous fibrinogen contained in the clotting factor concentrates. Alternatively, since alpha-2-macroglobulin has potent immunosuppressive properties, the elevation may represent a response to transfused alloantigens. Whatever the underlying cause, it is likely the elevations are due to endogenous production rather than to transfusions since clotting factor concentrates contain minimal amounts of alpha-2-macroglobulin.

Circulating immune complexes in haemophilia and von Willebrand's disease

Sera from 63 patients with haemophilia A, 21 with haemophilia B and 29 with von Willebrand's disease were screened for the presence of circulating immune complexes (CICs), serological markers of hepatitis A and B virus, autoantibodies and factor VIII or factor IX inhibitors. CICs were detected by the 125J Clq binding assay (ClqBA), the solid phase conglutinin assay (KgBSP) and the solid phase Clq assay (ClqSP). The incidence of CICs detected by the ClqBA and the ClqSP methods in haemophiliacs and in von Willebrand patients was higher than that observed in normal subjects, while the prevalence of CICs detected by the KgBSP method was not. The presence of CICs was not correlated with patient age, severity of disease, presence of hepatitis B virus serological markers, abnormal liver function tests or factor VIII inhibitors. A significant connection was demonstrated between CICs detected by the ClqBA method and replacement therapy when the dose administered over 1 year was over 20 000 U of factor VIII or IX concentrates. The high proportion of CICs in von Willebrand's disease, not connected with the replacement therapy or the presence of serological markers of hepatitis virus, is in agreement with the possibility that immune complexes may be related to the disease itself and independent, at least in part, of exogenous agents.

Abnormalities of the spleen and liver in patients with hemophilia

Previous studies have demonstrated functional and histologic abnormalities of the liver, and, more recently, splenomegaly in patients with hemophilia. Since these observations usually were derived from hemophiliacs who had received intensive replacement therapy, the question was posed as to whether the frequency of splenic and hepatic abnormalities was secondary to the amount of therapy utilized. In this study, a variety of tests were employed to evaluate spleen and liver size and function to determine if abnormalities in these organs correlated with the intensity of the transfusion program. The study group was comprised of 25 hemophiliacs (mean factor replacement-18,361 U/year; median factor replacement-12,920 U/year). Over 70% of our patients had elevations of aspartate and alanine aminotransferase. Immunoglobulin and complement levels were normal in most subjects. Ninety-six percent had evidence of exposure to hepatitis B virus. Liver-spleen imaging suggested significant hepatic abnormalities in most of the patients as evidenced by inhomogeneity of tracer uptake in the liver in 33% and relatively increased colloid uptake in the spleen in 90%. Splenomegaly (palpable spleen or enlargement on liver-spleen imaging) was detected in 40% of our patients, and tended to occur in the more frequently transfused patients. These findings indicate that significant abnormalities of the spleen and liver can occur in hemophiliacs who have received moderate amounts of replacement therapy and that liver-spleen imaging may be a useful method for monitoring the development of hepatic and splenic abnormalities.

Immune complexes in hemophilia

Circulating immune complexes (ICs), assayed by the L1210 enzyme-linked immunoassay, were detected in 48% of patients with hemophilia. A, 50% of patients with von Willebrand's disease, and in none of our patients with hemophilia B. Eighty-five % of the hemophilia A and B patients had mild to moderate disease with only one patient demonstrating a circulating inhibitor. No correlation was found between IC levels and hepatitis B infection, SGOT, disease severity, total quantity of factor VIII or IX infused, time interval from list infusion, or rheumatoid factor positivity. Although the nature of the ICs is not known, the similarity of IC levels between hemophilia A and von Willebrand's disease is discussed with regard to antibodies generated to non-procoagulant portions of the factor VIII molecule.

Viral exposure and abnormal liver function in haemophilia

Several studies have recently documented the presence of persistently abnormal liver function tests in asymptomatic haemophiliacs. While the aetiology is unknown it is possible that repeated exposure to agents transmitted in blood products may be important. This study has attempted to determine the prevalence of viral exposure and its relationship to liver function in this multitransfused group of individuals. The prevalence of viral antibodies with the exception of antibody to hepatitis B surface antigen (anti-HBs) and cytomegalovirus (CMV) was normal when compared to that in the general population. Hepatitis B surface antigen (HBsAg) was not detected, but anti-HBs was found in 83% of patients; 50% of patients had abnormal liver function. However, liver function tests were normal in all patients with mild haemophilia and were only rarely abnormal in patients who had no detectable antibody to CMV, Epstein-Barr virus (EBV), and HBsAg. This study demonstrates that multiple transfusions of blood products, that is, cryoprecipitate and factor concentrates, do not increase the risk of exposure to the viruses studied with the exception of hepatitis B virus.