Table 4.
Changes in T cells, B cells, and immunoglobulins during normal pregnancy.
| Component | Main findings | References |
|---|---|---|
| T cells | ||
| Total levels | Lower levels of T cells during pregnancy than before pregnancy. | 149 |
| No differences in the absolute total lymphocyte count and the percentage of total T cells during the first, second, and third trimesters. | 147, 148 | |
| Subsets | No difference in the percentages of T helper [CD4+] and T suppressor [CD8+] cells during the first, second, and third trimesters. | 147, 148 |
| No significant changes in the percentage of CD4+ cells, CD8+ cells, nor CD4+/CD8+ ratio at any stage of pregnancy. | 150 | |
| Lower number of T helper cells and cytotoxic T cells in third and first trimesters of pregnancy, respectively, compared to pre-pregnancy. Higher number of suppressor T cells (CD8+CD11b+) in the first trimester, compared to pre-pregnancy. | 149 | |
| Pregnancy is associated with a Th-2 or anti-inflammatory state. | 151–155 | |
| A progressive shift from Th1 cell responses to Th2 cell responses initiated early in pregnancy. | 1, 156 | |
| Lower plasma IL-2 levels (indicative of CD4+ Th1 cells) in the post-partum period when compared to all trimesters. | 157 | |
| Lower percentage of Th1 cells (CD4+ cells producing IFN-γ) in the third trimester compared to the first trimester and no changes in the percentage of Th2 (CD4+ cells producing IL-4) was observed. | 158 | |
| No change in the proportion of Th1 or Th2 cells during pregnancy. No differences in the percentage of CD3+CD8−IFN-γ+ cells (Th1 phenotype) across gestation. No change in the percentage of resting CD4+ T-cells expressing CXCR3 (associated with Th1 cells) and CCR4 (associated with Th2 cells) during different stages of pregnancy. | 159 | |
| Increase in the numbers of IFN-γ and IL-4 secreting cells as pregnancy progressed compared with postpartum | 160 | |
| No change in the ratio of Th17 cells to CD4+ T cells during all stages of pregnancy compared to that of healthy non-pregnant women. | 161 | |
| Function | Reduced PHA-Stimulated T lymphocytes proliferation in pregnant women at various times throughout gestation compared with those from non-pregnant controls. | 162 |
| Decreased lymphocyte proliferation to mitogenic stimulation in the first, second and third trimesters as compared to non-pregnant women. | 147 | |
| Decreased in IL-2 and IFN-γ production and increased in production of IL-4 and IL-10, during normal pregnancy in response to antigen- and mitogen stimulation. | 163 | |
| The ability of T cells to form colonies varied during pregnancy. | 164 | |
| B cells | ||
| Total B cells | Lower numbers and/or frequency of total B cells in pregnant women compared to post-partum levels or to healthy non-pregnant women. | 149, 150, 165–175 |
| No changes in absolute levels of total B cells during the entire course of pregnancy. | 165, 176, 177 | |
| Decrease in the absolute levels of total B cells during the entire course of pregnancy. | 149, 168 | |
| Subsets of B cells | Lower frequency or total levels of CD5+ B cells during pregnancy, at delivery or early in the postpartum period. | 149, 165, 169, 173 |
| Lower absolute counts of transitional B cells, unswitched memory B cells, resting memory B cells, and plasmablasts during the third trimester than in non-pregnancy. | 174, 178 | |
| Markers of B cell activation and function | No difference in the percentage of activated B cells during the three trimesters compared to non-pregnant women. | 178 |
| Lower soluble CD23 levels in pregnant women during the 3rd trimester than in non‐pregnant women. | 179 | |
| Higher B cell activating factor levels during their third trimester than in non‐pregnant women. | 179 | |
| Loss of responsiveness of B cells to mitogens and infectious agents during the course of normal human pregnancy. | 180 | |
| Immunoglobulins | ||
| Total IgG levels | No significant changes in total IgG levels during pregnancy. | 181–183 |
| Decreased total IgG levels during pregnancy, especially in late pregnancy. | 179, 184–189 | |
| Subclass levels | Higher IgG1 levels in the three trimesters when compared to non-pregnant women. Higher IgG3 levels in the second trimester, when compared to non-pregnant women. No differences in IgG2 and IgG4 levels in any trimester as compared to non-pregnant women. |
178 |
| Glycosylation | Increase in galactosylation and sialylation of the Fc portion of IgG. | 190–192 |
| High and similar levels of fucosylation of Fc portion of IgG during pregnancy. | 190, 192 | |
| No changes in glycosylation in the Fab portion of IgG during pregnancy. | 190 | |
| Asymetric IgG | Increase in asymmetric IgG antibodies in pregnancy with maximum increase in the second trimester. | 193, 194 |
| IgA | ||
| Total levels | No significant change in IgA levels during pregnancy. | 166, 182, 183, 186, 189 |
| Higher IgA levels in the first trimester as compared to second or third trimester. | 187 | |
| Higher IgA levels in the first trimester compared to non-pregnant women. | 178 | |
| Lower IgA levels in the third trimester as compared to non-pregnant women. | 179 | |
| IgM | ||
| Total levels | No changes total IgM levels during the course of pregnancy. | 166, 182, 184, 186 |
| Decrease in IgM levels in the second and third trimester when compared to first trimester. | 181, 185, 187 | |
| Increase in total IgM levels during late-third (36-42 WG) compared with early-third (27-33 WG) trimester. | 185, 195 | |
| Increase in total IgM levels in the first trimester as compared to non-pregnant women | 178 | |
| No difference in IgM levels in the third trimester compared to non-pregnant women. | 179 | |
| IgE | ||
| Total levels | No change in IgE levels during the course of pregnancy. | 178 |
IFN-γ, Interferon- γ; Th, T helper; PHA, Phytohemagglutinin; IgG, immunoglobulin G; Fc, fragment crystallization; IgA, immunoglobulin A; IgM, immunoglobulin M; IgE, immunoglobulin E.