Immunogenicity of 13-valent pneumococcal conjugate vaccine among children with underlying medical conditions

BACKGROUND

Streptococcus pneumoniae is a leading cause of vaccine-preventable disease in children under 5years. Immunocompromised children and those with underlying diseases are at increased risk of severe complications from vaccine-preventable infections. We studied the humoral immune response to the 13-valent pneumococcal conjugate vaccine (PCV13) in children with HIV-infection, kidney or lung disease and compared this to the response in healthy control children.

METHODS

Children aged 12-71months with underlying conditions including HIV-infection and those with kidney and lung diseases (at-risk children), and a healthy control group were vaccinated with PCV13. The at-risk children received two doses of PCV13 and the controls received one dose. Serotype-specific antibodies for all PCV13 serotypes were measured by a luminex-based enzyme immunoassay at baseline and post-vaccination.

RESULTS

After the first PCV13 dose, the fold-increase in serotype-specific antibody geometric mean concentrations (GMCs) from baseline and the percentage of participants with ≥4-fold-increase in antibody concentrations was similar between the control and at-risk children. GMCs were, however, lower for three of the 13 serotypes in HIV-infected children, higher for serotype 6B in children with kidney disease and higher for serotypes 6B and 14 in children with lung disease. After second vaccine dose HIV-infected children had an increase in GMCs from post-first dose for nine serotypes but the percentage of participants with ≥4-fold-increase from baseline was similar post-second dose compared to post-first dose except for serotypes 6A and 19F. In children with kidney or lung diseases the immune responses after second vaccine dose were similar to post-first dose. Attenuated responses were observed for serotypes 3 and 19A in all study-groups, which was especially pronounced in the at-risk groups.

CONCLUSION

All study-groups mounted an immune response to PCV13, with the at-risk groups having responses that were mostly similar to the control children.

A review of Takayasu's arteritis in children in Gauteng, South Africa

We have reviewed 31 patients with Takayasu's arteritis followed at two pediatric nephrology units in Gauteng, South Africa over a 15-year period. There were 25 black patients, 4 white, and 2 of mixed race. The mean age at diagnosis was 8.42+/-3.59 (range 2.4-14.5, median 8) years. The most common presenting sign was hypertension, followed by cardiac failure, bruits, and absent pulses. The Mantoux test was strongly positive in 27 patients (90%, control population 5%). Markers of activity included a raised erythrocyte sedimentation rate (23 patients) or Gallium single photon emission tomography (positive in 12 of 16 patients). Angiography revealed type II (abdominal aorta) and III (arch plus abdominal aorta) lesions to be most common (11 in each group). All patients received antituberculous therapy and most low-dose aspirin for its antithromboxane effect. Corticosteroids and further immunosuppression were used to control disease activity. We added total lymphoid irradiation (TLI) or cyclophosphamide. Twenty-six patients in all received further immunosuppression, with 13 patients in each group. Results were similar in the two groups, with similar pre- and posttherapy systolic blood pressures and creatinine clearances. Two patients in each group relapsed, 3 died in the TLI group and 2 in the cyclophosphamide group. Surgical intervention, usually in the quiescent phase, consisted mainly of renal autotransplantation. Because of the problems with TLI and 2 patients with papillary carcinoma of the thyroid with long-term follow-up, we no longer use TLI. We have shown that with active medical and surgical intervention the aggressive course of this disease in children can be modified.

Variants of alpha 1-proteinase inhibitor in black and white South African patients with focal glomerulosclerosis and minimal change nephrotic syndrome

OBJECTIVE

To determine the prevalence and biochemical characteristics of certain alleles of alpha 1-proteinase inhibitor in black and white South African patients with two common types of pathology causing the nephrotic syndrome.

DESIGN

A cross sectional study of black and white patients with focal glomerulosclerosis (FGS) or minimal change disease (MCNS) and black and white controls.

SETTING

The patients were drawn from the Paediatric Nephrology Units at the Johannesburg and Baragwanath Hospitals and the controls were drawn from the South African Blood Transfusion Service and the Paediatric Nephrology Clinic in Johannesburg.

RESULTS

There was a significant increase in the prevalence of the V allele in black patients with FGS (12%) as compared to black controls (1%) (p = 0.01). None of the white patients with FGS had the V allele but two out the five coloured (mixed race) patients had the V allele (20%). An increase in the prevalence of the S allele of alpha 1PI was found in white patients with FGS and MCNS (10%) as compared to white controls (2%). The plasma elastase inhibitory capacity (EIC) associated with the phenotypes (PI) M1 (Ala213)S, M1 (Ala213) V, and M1 (Ala213) M1 (Ala213) was significantly decreased as compared to the EIC associated with PI M1 (Val213) M1 (Val213) (p = 0.006, p = 0.004, and p = 0.025, respectively). Twelve of 13 patients with FGS and infected with tuberculosis had either the M1 (Ala213) V or F alleles and required transplantation owing to the severity of the disease. All of these patients were either black or coloured. However, eight of 12 patients with FGS who had the M1 (Ala213) V or S alleles but were PPD negative did not require transplantation.

CONCLUSION

It is possible that the combination of functionally less efficient alpha 1PI and an inflammatory challenge associated with an infection such as tuberculosis could predispose black and coloured nephrotic patients to more aggressive scarring in FGS.

Impact of tuberculosis in children with idiopathic nephrotic syndrome

Forty black South African children (mean age 4.7 +/- 2.6 years) with idiopathic nephrotic syndrome due to focal glomerulosclerosis (FSGS) were evaluated. Tuberculosis (TB) was found in 37.5% of children with FSGS (FSGS-TB) compared with 6% of a comparable group with minimal lesion nephrotic syndrome. No significant differences were found in the initial mean serum albumin, cholesterol, triglyceride and creatinine levels in FSGS-TB compared with children with glomerulosclerosis but without TB (FSGS-nonTB). The mean serum levels of C4, IgA and IgM were increased by 30%, 25% and 23%, respectively in children with FSGS-TB compared with FSGS-nonTB. Initial estimated creatinine clearance was similar in the two groups, but after a mean follow-up of 2.4 years, the mean estimated creatinine clearance of children with FSGS-TB was significantly reduced by 46% from the initial value, but remained stable in the FSGS-nonTB group. FSGS-TB children also had significantly increased requirements for renal replacement therapy compared with children with FSGS-nonTB. We conclude that TB infection is commonly associated with FSGS in black South African children; this may have deleterious effects on renal function.

Biochemical and serological characteristics of children with membranous nephropathy due to hepatitis B virus infection: correlation with hepatitis B e antigen, hepatitis B DNA and hepatitis D

Fourteen children with biopsy-proven membranous nephropathy associated with hepatitis B virus (HBV-MN) were evaluated biochemically and serologically and compared to 45 children with idiopathic nephrotic syndrome (INS). The mean ages of the two groups were similar (4.9 +/- 1.6 vs. 4.6 +/- 2.6 years). Serum albumin levels were similar in both groups, but serum cholesterol was significantly reduced in children with HBV-MN compared to INS. Serum C3 was also significantly depressed in children with HBV-MN compared to INS, but no differences in C4 levels were noted. Serum alanine transaminase as well as aspartate transaminase concentrations were significantly elevated in children with HBV-MN compared to those with INS, suggesting the presence of chronic hepatitis in children with HBV-MN. Hepatitis B surface and e antigens were present in serum of all children with HBV-MN, but only 54% had circulating HBV-DNA particles demonstrable in their serum. Serum C3 levels were higher in children with HBV-MN and circulating HBV-DNA, compared to those without circulating HBV-DNA. No other serological or biochemical differences occurred between these two groups. Glomerular deposition of IgG and C3 occurred in 91% of children with HBV-MN; but IgM deposition appeared to occur more frequently and with greater intensity in those children positive for circulating HBV-DNA. Antibody to delta antigen was negative in all children with HBV-MN. We conclude that biochemical and serological differences can be identified between HBV-MN and INS.(ABSTRACT TRUNCATED AT 250 WORDS)

Penicillin resistant pneumococcal peritonitis in nephrotic syndrome

Two infants with nephrotic syndrome who developed penicillin resistant pneumococcal peritonitis while receiving penicillin chemoprophylaxis are reported and the problems associated with prophylaxis against pneumococcal infection discussed. It is suggested that penicillin prophylaxis may be hazardous in an environment in which penicillin resistant pneumococci are prevalent.