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 Table of Contents  
Year : 2015  |  Volume : 4  |  Issue : 1  |  Page : 9-12

Swine flu (H1N1 infection): An autoimmune endocrine condition in pregnant females

1 Post Doctoral Study, University of Mumbai, Mumbai, Maharashtra, India
2 Mario Lioni Hospital (AMIL), Rio de Janeiro, Brazil
3 Roby Institute, Austin, Texas, USA
4 University of Texas, Austin, Texas, USA
5 Central Hospital of the Brazilian Army, Rio de Janeiro, Brazil
6 School of Dentistry, State University of Rio de Janeiro, Rio de Janeiro, Brazil

Date of Web Publication13-Jan-2015

Correspondence Address:
Shilpa Shah
Aniket, Prarthna Samaj Road, Vile-parle (East), Mumbai - 400 057
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2278-344X.149206

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Background: H1N1 infection tends to be more severe in pregnant than nonpregnant women. It is not known whether this is due to hormonal changes during pregnancy and/or immune responses to hormones. Aims: Whether the effect of pregnancy on responses to the H1N1 pandemic is mediated by the effects of immune responses to hormones resulting in anti-hormone antibody production requires investigation. Settings and Design: A prospective study was designed, and H1N1-infected pregnant women were recruited from the Intensive Care Unit of a hospital during the period 2009-2010. Materials and Methods: Differences in the levels of anti-estrogen and anti-progesterone antibodies were determined in H1N1-infected pregnant patients and healthy pregnant and healthy non-pregnant women, using the Enzyme-Linked Immunosorbent Assay technique. Statistical Analysis: Statistical Package for the Social Sciences 16.0 (SPSS inc, Chicago, USA) software was used for all statistical procedures. Results: Pregnant women showed nonsignificant trends for higher immunoglobulin G (IgG) and IgM anti-estrogen-antibodies as compared to the healthy non-pregnant women. IgG, IgM, and IgE anti-progesterone-antibodies were also higher in pregnant women than in nonpregnant women, with marginally significant effects for IgG and IgE. H1N1 infection was associated with increased anti-estrogen IgG and IgA relative to healthy pregnant females. Conclusion: Findings about elevated anti-estrogen and anti-progesterone antibodies might improve our understanding of higher susceptibility of pregnant females to swine flu, and thereby lead to better management of this disease.

Keywords: Antibodies, estrogen, H1N1, pregnancy, progesterone

How to cite this article:
Shah S, Marcello B, Russell R, Patricia R, Richard R, Patricia S, Eduardo T. Swine flu (H1N1 infection): An autoimmune endocrine condition in pregnant females. Int J Health Allied Sci 2015;4:9-12

How to cite this URL:
Shah S, Marcello B, Russell R, Patricia R, Richard R, Patricia S, Eduardo T. Swine flu (H1N1 infection): An autoimmune endocrine condition in pregnant females. Int J Health Allied Sci [serial online] 2015 [cited 2023 Mar 22];4:9-12. Available from: https://www.ijhas.in/text.asp?2015/4/1/9/149206

  Introduction Top

H1N1 flu pandemic reported a high mortality rate among infected pregnant women. [1],[2],[3] Hormonal environment during pregnancy contributes to suppression of cell-mediated immunity while mediating a systemic change toward T-cell type 2 (Th2) dominance, which increases the risk for autoimmune disease [4],[5],[6] and susceptibility to some intracellular pathogens including viruses, bacteria, and parasites. [7],[8],[9],[10],[11] Whether the effect of pregnancy on responses to the H1N1 is mediated by the effects of hormones on immune responses requires investigation. The current research investigates antibodies to estrogen and progesterone in pregnant women suffering from swine flu.

  Materials and methods Top

A prospective study was carried out at Hospital Moacy dor Carmo, Duque de Caxias, Rio-de-Janeiro, Brazil and was approved by the institutional review board of Universidad do Grande Rio, Duque de Caxias, Rio-de-Janeiro, Brazil. Mario Lioni Hospital and Sergio Franco Laboratory, Brazil at Rio-de-Janeiro provided the medical supplies for this study. H1N1 infected pregnant women were recruited from the Intensive Care Unit of Hospital Moacyr do Carmo, Duque de Caxias and Xerém Maternity at Rio-de-Janeiro, Brazil. Swine flu is prevalent only during an outbreak of H1N1 virus infection and it is not perennially prevalent. It was for this reason of uncertainty that it was difficult to decide an ideal sample size. [12] The criteria for recruitment were hospitalized pregnant women with clinical symptoms of flu, a positive ELISA test report for H1N1, and doctor's diagnosis of swine flu. Control pregnant women and non-pregnant women were randomly recruited from those attending Xerém Maternity, Duque de Caxias, Rio de Janeiro, Brazil over the period of 2009-2010. Our study involved eight pregnant women aged 18-51 with confirmed swine flu diagnosis. 10 age-matched healthy nonpregnant women and eight age-matched healthy pregnant women served as controls.

Blood samples were obtained from all study subjects by venipuncture, and serum was separated. Antibodies to progesterone and estrogen were measured at Immunosciences Lab., Inc., Beverly Hills, CA, USA using the Enzyme-Linked Immunosorbent Assay technique. [13] Statistical data analysis was carried out using Statistical Package for the Social Sciences 16.0 (SPSS inc, Chicago, USA) software. Only two groups were compared at a time, and an independent-samples Student's t-test was performed to determine statistical significance, without the assumption of equal variances and without corrections for multiple testing. The distributions were moderately skewed (skewness of up to 3.0), but parametric tests such as the t-test are considered appropriate in this situation. [14]

  Results Top

[Table 1] and [Table 2] show the levels of anti-estrogen and anti-progesterone antibodies in healthy nonpregnant controls, healthy pregnant women, and pregnant women suffering from swine flu. Pregnant women showed trends for higher immunoglobulin G (IgG) and IgM anti-estrogen antibodies as compared to the healthy nonpregnant women, but these trends were not statistically significant. IgG, IgM, and IgE anti-progesterone-antibodies were also higher in pregnant women than in non-pregnant women, with marginally significant effects for IgG and IgE. When the levels of all anti-progesterone antibodies were averaged, the levels were significantly higher in healthy pregnant women than in healthy nonpregnant controls (P = 0.013). When all anti-progesterone and all anti-estrogen antibodies were averaged, the difference between healthy non-pregnant woman and healthy pregnant woman was again significant (P = 0.018).
Table 1: Anti-estrogen-antibodies

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Table 2: Anti-progesterone-antibodies

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Comparing pregnant women suffering from swine flu with healthy pregnant women, we find elevated IgG and IgA anti-estrogen-antibodies in the H1N1 infected women. [Table 2] shows only a nonsignificant trend for elevated IgG and IgA anti-progesterone antibodies in the infected women compared to the healthy pregnant women, but unexpectedly, we also observe a borderline significant (P = 0.084) reduction of anti-progesterone IgE.

The degree of specificity in the formation of antibodies to estrogen and progesterone can be estimated by observing the correlation between anti-estrogen and anti-progesterone antibodies within each immunoglobulin class. [Table 3] shows the results. Healthy nonpregnant women had a tendency for elevations in anti-estrogen antibodies to occur together with anti-progesterone-antibodies in the same immunoglobulin class except IgE. In healthy pregnant women, anti-estrogen antibodies tend to be elevated together with anti-progesterone-antibodies in the IgG and IgM classes but not in IgA and IgE. In H1N1-infected pregnant women, elevations in anti-estrogen antibodies, usually, occurred together with anti-progesterone-antibodies in the same immunoglobulin class except IgE.
Table 3: Correlation between anti-estrogen and anti-progesterone antibodies in different antibody classes, with statistical significance level (P value) in parentheses

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A further matter is the specificity of the antibody response across immunoglobulin classes. [Table 4] shows the correlations separately for the three clinical groups. In healthy nonpregnant women, the only highly significant result is a strong correlation between the IgA and IgM antibodies for estrogen. Those who have high anti-estrogen IgA also have high anti-estrogen IgM. A trend in the same direction for anti-progesterone antibodies does not reach statistical significance. There are no significant correlations for healthy pregnant women, but for the H1N1-infected women there are significant correlations between the levels of IgG and IgA antibodies, both for progesterone and estrogen.
Table 4: Correlations between antibody levels (measured as OD405) in the four immunoglobulin classes

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  Discussion Top

Estrogens affect both innate and adaptive immune function. Estradiol has dose-dependent effects, with low doses enhancing and high doses reducing proinflammatory cytokine production. Low estradiol concentrations promote helper T-cell type 1 (Th1) responses and cell-mediated immunity and high concentrations of estradiol augment helper Th2 responses and humoral immunity. Elevated levels of estradiol during pregnancy may increase humoral immunity and lower cell-mediated immunity. While lower cell-mediated immunity might aggravate susceptibility to some infections, higher humoral immunity might favor autoimmunity, including higher levels of antibodies to progesterone and estrogen in our pregnant study females compared to nonpregnant controls. [15] This could explain the greater severity of swine flu in pregnant females. Another estrogen that affects the functioning of the immune system is estriol, which is produced during pregnancy by the placenta. When estriol levels are high, inflammatory responses and the symptoms of Th1-mediated autoimmune diseases-including multiple sclerosis-are reduced. [16],[17]

Progesterone suppresses innate immune responses. [18] Elevated concentrations of progesterone during pregnancy inhibit the development of Th1 immune responses that could potentially lead to fetal rejection, but also promote Th2 immune responses. [19],[20] Our study findings of higher levels of anti-progesterone antibodies in healthy and swine flu infected pregnant females, especially in the IgG class, can possibly be explained by the progesterone-induced activation of Th2-mediated immunity during pregnancy. [4],[5],[6] The formation of autoantibodies to progesterone itself appears to be one element in this progesterone-promoted immune response. Elevated antibody titers during normal pregnancy can be attributed to a general activation of Th2-mediated immunity, but the formation of hormone antibodies in H1N1 infection could be a very specific immune response. It is interesting to mention that total IgG2 are enhanced in a Th1-dependent manner, and pregnant women with severe 2009 H1N1 were reported to have lower levels of total IgG2 than healthy pregnant women or women with only moderate H1N1 disease. [21] Elevated specific IgG antibodies to both estrogen and progesterone in our study subjects could be a Th2-dependent specific immune response.

The results of this study raise important observations. One result is a tendency for pregnant women to have elevated antibody titers to progesterone. This supports the notion that B-cell mediated autoimmunity, which is stimulated by Th2 cells, is increased during pregnancy in a nonspecific way that includes elevations of IgG, IgM, and/or IgE. In addition, the elevated levels of estrogen and progesterone during pregnancy are likely to favor the formation of antibodies to these hormones. This raises the possibility of anti-hormone antibodies endangering pregnancy by tying up the hormones. This possibility needs to be investigated by determinations of the anti-hormone antibodies in difficult pregnancies and pregnancies ending in miscarriage, and in women suffering recurrent miscarriages. [22] Furthermore, the possibility that anti-hormone antibodies can impair female fertility needs to be investigated in future studies.

Infection with H1N1 during pregnancy tends to be associated with higher titers of the hormone antibodies in the IgG and IgA classes but lower antibodies in the IgM and IgE classes. The class of immunoglobulin which forms the antibodies is regulated by cytokines. Swine flu is speculated to cause a c ytokine storm, or hypercytokinemia, which is a potentially fatal immune reaction consisting a positive feedback loop between cytokines and immune cells, with highly elevated levels of various cytokines usually associated with cell-mediated immunity but also commonly linked to the pathogenesis of autoimmune/inflammatory diseases. [9] These mechanisms need to be explored to understand how specific classes of antibodies are raised in coordination.

Results of this study [Table 3] indicate that although antibodies against steroid hormones are specific, there is a possibility of cross-reaction between estrogen and progesterone. Future studies are needed to investigate whether the same cross-reacting antibodies bind both estrogen and progesterone or whether two separate antibodies are formed, one specific for estrogen and the other specific for progesterone.

Such correlation between IgA and IgM against estrogen in non-pregnant females and correlation between IgA and IgG against estrogen and progesterone [Table 4] in swine flu suffering pregnant females could possibly be indicative of a syndrome. For example, increased serum IgA and IgM against lipopolysaccharide of enterobacteria is a characteristic finding in chronic fatigue syndrome. [23] Swine flu suffering females had a coordinated response of IgM and IgE for progesterone but not estrogen. Nonsignificant trends in the same direction are also seen in the healthy nonpregnant and healthy pregnant groups.

The study had to be concluded with small sample size as once the H1N1 epidemic got over even after a wait for an extensively long period there were no subjects that could meet the criteria for recruitment. Nevertheless, the study finding is important indicating autoimmune endocrine modality for the disease. If this study gets attention of clinicians then it can have multiple applications not only for swine flu or flu in general, but may be also for other disease conditions in pregnant women. The study shows that antibodies against estrogen and progesterone can be demonstrated in clinical samples and that the levels of these antibodies can be different in different clinical conditions. Findings of the current research about anti-estrogen and anti-progesterone antibodies can improve our understanding of swine flu and other morbidities caused by intracellular infections, and thereby lead to better management of these conditions. Determination of these antibodies can be of assistance for prognosis, therapy as well as follow-up like in other autoimmune endocrine conditions. It can also help with a better understanding of pregnancy complications that may be related to the presence of anti-hormone antibodies.

  Acknowledgments Top

The authors thank Professor Dr. Gerhard Meisenberg, Ross University School of Medicine, Dominica; Professor Marcello Mendes, Mario Lioni Hospital, Rio-de-Janeiro, Brazil; and Ms. Dorothy Dreux, CALM International, Brazil.

  References Top

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  [Table 1], [Table 2], [Table 3], [Table 4]

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