Measles IgM Antibodies Research Articles

A Seroepidemiological Study of Measles: Some Practical Implications for Measles Immunization Program, Kingdom of Saudi Arabia

It was hypothesized that the recent outbreaks of measles in a geographically defined area of Al-Qassim might reflect significant changes in the epidemiology of measles and cast doubt upon the real protective value of measles vaccines. Therefore, the two objectives of this research were to study some epidemiological parameters of cases of measles (n=993) and the current immunological status of immunized children (n=2810). The crossmatched data about measles patients were collected on an official proforma and 3 mL of blood were extracted from each child for determining the measles IgG and IgM antibodies. The results showed that female patients were significantly overrepresented (51.3%). The majority of patients encountered at primary health care centers (PHCCs) (81.3%) were more than five years of age (76.5%). Among nonvaccinated measles cases, 54.9% (n=402) were from rural/desert areas. The measles vaccine failure rate was 26.3%. The results of the surveyed children showed that 2% of them were not vaccinated. The measles IgM levels were detected significantly in recently vaccinated females (n=29/51, 56.9%). The measles IgG positivity unaffected by age, sex, and residence was found in 87.4% of children. A significant portion of children from rural/desert areas were not vaccinated (n=44/57, 77.2%). Though there were apparently high seroconversion rates in children under two years of age following Edmonston-Zagreb vaccine, overall it did not achieve any statistical significance when compared with seroconversion rates in all children following Schwartz vaccine. We conclude that besides at age six months, and MMR containing measles vaccine at 12 months, children at school entry (six years) should also be considered for measles vaccination.

Measles Vaccine Immunogenicity in 6- Versus 15-Month-Old Infants Born to Mothers in the Measles Vaccine Era

The low titer of measles antibody in infants of mothers with vaccine-induced immunity may allow immunization against measles before 15 months of age. Six- and 15-month-old infants born to mothers < or = 30 years of age with no history of measles were recruited. Infants enrolled at 6 months of age were immunized with monovalent measles vaccine (Attenuvax), and maternal serum and infant pre- and postvaccination sera were obtained. Those enrolled for primary vaccination at 15 months of age received either Attenuvax (N = 12) or M-M-RII (N = 3). Six-month-old infants were revaccinated with M-M-RII at 15 months of age; pre- and postrevaccination sera were again obtained. Three antibody assays were used: a measles neutralizing assay (NT) and two enzyme immunoassays (EIA) for measles IgG and measles IgM. Among primary vaccinees, 14 of 19 infants aged 6 months (74%) developed NT antibody, as did 15 of 15 infants aged 15 months (100%). The reciprocal geometric mean titer of 6-month-old seroresponders was 23.3, significantly lower than that of the 15-month-old primary vaccinees (87.7, P < .001). Primary seroconversion rates by EIA were 53% for 6-month-old infants and 100% for those aged 15 months. Revaccination of infants who had received Attenuvax at 6 months of age resulted in 100% NT positivity; the geometric mean titer rose to equal that of the group given primary immunization at 15 months of age. Measles IgM antibody was detected in 10 of 14 infants tested 1 month after primary vaccination at 15 months, but was not detected in any of the revaccinated infants after the second dose at 15 months of age (P < .001). 1) Immunization with measles vaccine in infants born to vaccine-immune mothers at 6 months of age induced NT antibody in 74% of infants. 2) Revaccination of prior 6-month-old vaccinees at 15 months resulted in antibody titers equivalent to 15-month-old vaccinees. 3) Lack of an IgM response following revaccination suggests that even seronegative infants may be primed to respond on re-exposure to measles.

Measles IgM antibodies in cerebrospinal fluid and serum in subacute sclerosing panencephalitis

Using a direct enzyme-linked immunosorbent assay (ELISA), we examined serum and cerebrospinal fluid (CSF) from six patients with subacute sclerosing panencephalitis (SSPE) and control subjects for presence of measles-virus-specific IgM antibodies. All samples from the SSPE patients contained demonstrable titers of measles antibodies. The levels of measles IgM antibodies were higher in CSF diluted 1:5 than in serum diluted 1:50, reflecting a local production of IgM antibodies in the central nervous system. Antibody titers remained constant over the course of SSPE in three of the patients followed for three to six months. The IgM ELISA had high sensitivity as well as specificity and was not complicated by false-positive reactions owing to the presence of rheumatoid factor.

Production of monoclonal antibodies to human IgM for assay of viral IgM antibodies

Monoclonal antibodies to human IgM were produced by fusing the Sp 2/0-Ag 14 line of mouse myeloma cells with spleen cells from BALB/c mice immunized with purified human IgM. From 6 clones which secreted antibody to human IgM, the one which produced the highest levels of antibody and grew relatively rapidly was selected for expansion and production of immune reagents for viral IgM antibody assays. Mouse ascitic fluids produced with this clone of cells had antibody titers for human IgM of 1 × 10 −10 by indirect enzyme immunofluorescence assay (EIFA). The monoclonal antibodies were found to belong to subclass 1 of murine IgG, and their specificity was shown to be directed against the Fab portion of the μ chain of human IgM. Antibodies from murine ascitic fluid conjugated with horseradish peroxidase were shown to be suitable for assay of measles IgM antibody by indirect immunoperoxidase staining. Antibodies conjugated with alkaline phosphatase could be used in an indirect EIFA for determination of measles IgM antibodies; use of monoclonal conjugates in this system eliminated the nonspecific activity observed in tests utilizing polyclonal anti-μ reagents. Further, the monoclonal antibodies were highly satisfactory for use in a ‘capture’ system for viral IgM antibody assays. The availability of monoclonal antibodies to human IgM overcomes problems with specificity, consistency and supply which have previously hindered development and standardization of viral IgM antibody assays.

Measles virus-specific IgM antibodies and IgM-class rheumatoid factor in serum and cerebrospinal fluid of subacute sclerosing panencephalitis patients

Serum and cerebrospinal fluid (CSF) from 20 subacute sclerosing panencephalitis (SSPE) patients were analyzed with solid-phase radioimmunoassays designed to detect measles virus-specific IgM antibodies and IgM-class rheumatoid factor (RF). Serum and CSF from patients 1 to 16 did not contain measles IgM antibodies or elevated levels of RF. Serum from all and CSF from two of the remaining four patients were apparently measles IgM positive. RF levels were elevated, however, in serum from two and in serum and CSF from another of these four patients. Testing after removal of IgG or RF revealed that patient 17 had both measles IgM and elevated levels of RF in serum, and measles IgM in CSF. Reactivation of measles IgM synthesis was detected in the blood of patient 18. The serum of patient 19 and the serum and CSF of patient 20 contained only elevated levels of RF. The implications of these results are twofold. First, although measles IgM is found in some SSPE patients, it is not found consistently enough to be a marker for the chronic measles virus infection in these patients. Second, the possible interfering presence of RF must be taken carefully into account in any study of IgM antibody persistence.

Solid-phase radioimmunoassay determination of virus-specific IgM antibody levels in a follow-up patients with naturally acquired measles infections.

The question of the exact disappearance time or possible persistence of measles-specific IgM antibodies after naturally acquired measles virus infections was studied with a sensitive solid-phase radioimmunoassay (RIA) method. A total of 30 patients were analyzed with follow-up times varying from 4.5 to 8 months; all were measles IgM positive in the first serum specimen obtained after the onset of rash. In 29 of 30 patients, the measles IgM declined to undetectable levels by approximately 90 days. The remaining patient developed postmeasles encephalitis, however, and was found to have a prolonged measles IgM antibody response. For comparison, the measles-specific IgG response was also studied and was found to develop only slightly later than the IgM response, with levels then remaining high and stable up to 8 months later. Although apparent measles IgM antibodies were found in 1 of 64 nonmatched adult controls, they were due to the presence of high levels of IgM-class rheumatoid factor. The data presented indicate that measles IgM antibodies begin to decline soon after the onset of rash and reach negative levels 1 to 3 months later; in complicated infections, however, measles IgM antibody synthesis may not terminate normally.

Measles IgM response during reinfection of previously vaccinated children

Measles IgM antibody was found in the convalescent sera from five of seven childrenwith a primary measles infection, but in only two of seven previously vaccinated children with clinical measles, and in none of seven previously vaccinated children who were revaccinated with attenuated measles virus. Since specific IgM antibody is characteristic of a primary immune response to measles virus, the absence of IgM indicates that some children are experiencing a reinfection despite a primary antigenic stimulus by the vaccine.

SEROLOGICAL CONFIRMATION OF MEASLES IN CHILDREN ADMITTED WITH CLINICAL DIAGNOSIS OF MEASLES.

Objective: To determine the frequency of IgM antibodies in clinically diagnosed cases of measles.Design: Cross-sectional, descriptive studyPlace and duration: Department of Pediatrics, Saidu Group of Teaching Hospital, Saidu Sharif, Swat(from 1st Jan 2010-31 Dec 2011).Patients and method: A total of 150 patients of measles clinically diagnosed were enrolled for the study.Detailed history, demographic profile and vaccination status were recorded. Blood samples were collectedfrom all subjects for measles serology by observing WHO protocol.Results: Out of 150 patients, 57% (86) were male and 43% (64) were female with mean age of 38.28±30.99months. Out of these 150 patients, 66% (99) were positive for measles IgM antibodies, while 34% (51) werenegative for measles IgM. Out of 51 measles negative patients 11.8% (6) were positive for rubella.Conclusion: Diagnosing measles on clinical features alone is reasonable but not specific and IgM may beused to confirm the diagnosisKey words: Measles, IgM antibodies, children, vaccination status