Mixed connective tissue disease. A clinico-serological study of 17 cases

Lymphocytic interstitial pneumonia in a patient with mixed connective tissue disease - A case report

Lymphocytic interstitial pneumonia (LIP) is an uncommon interstitial lung disease that is characterized by an interstitial infiltrate of lymphoplasmacytic cells. While idiopathic LIP appears to be extremely rare, most reported cases of LIP have been associated with coexisting immune derangements, particularly autoimmune diseases such as Sjögren's syndrome. In this report, we describe the presentation of LIP in a patient with underlying mixed connective tissue disease.

[Mixed connective tissue disease: prevalence and clinical characteristics in African black, study of 7 cases in Gabon and review of the literature]

The literature reports that mixed connective tissue disease seems more frequent in the black population and among Asians. This study aims to determine the prevalence of mixed connective tissue disease (MCTD) among connective tissue disorders and all rheumatologic pathologies in a hospital population in Gabon as well as to describe the clinical features of this disease. We conducted a retrospective study by reviewing the medical records of patients treated for mixed connective tissue disease (Kasukawa criteria) and other entities of connective tissue disorders (ACR criteria) in the Division of Rheumatology at the University Hospital in Libreville between January 2010 and December 2015. For each case of MCTD the parameters studied were articular and extra-articular manifestations, anti-U1RNP antibodies levels, patient's evolution. Over a period of 6 years, data were collected by medical records of 7 patients out of 6050 patients and 67 cases of connective tissue disorders, reflecting a prevalence of 0.11% and 10.44% respectively. the 7 patients were women (100%), with an average age of 39.5 years. Articular manifestations included: polyarthritis, myalgias, chubby fingers and Raynaud's phenomenon in 87.5%, 87.5%, 28.6% and 14% respectively. The 7 patients had high anti-U1RNP antibodies levels, ranging between 5 and 35N (N≤ 7 IU). A case of death due to pulmonary arterial hypertension (PAH) was certified. This is the largest case series of MCTD reported in Black Africa. The disease seems to be rare among the black Africans; the reason could be genetic. The demographic and clinical aspects appear similar to those in Caucasians, Asians and Blacks except for a low frequency of Raynaud?s phenomenon among Blacks.

Rheumatoid factor isotypes in mixed connective tissue disease

Mixed connective tissue disease (MCTD) is a connective tissue disorder that is often accompanied by various immunological abnormalities. In this study, we analyzed serum levels of rheumatoid factor (RF) isotypes in patients with MCTD and in normal controls to determine if any of these isotypes reflects the severity of the disease. IgM-RF, IgG-RF, and IgA-RF were positive in 48, 38, and 33% of the patients, respectively. The frequency of positive anti-SS-A antibody and decrease in white blood cell counts were significantly greater in patients with elevated IgA-RF levels than that in those with normal levels. These results suggest that the presence of RF isotypes can be regarded as one of the various immunological abnormalities of MCTD.

Pediatric-Onset Mixed Connective Tissue Disease

This article discusses the literature on pediatric-onset mixed connective tissue disease (MCTD) and adds 34 new cases. Although not benign, pediatric-onset MCTD carries less mortality than adult-onset disease.

Evaluation of interstitial lung disease in mixed connective tissue disease (MCTD)

OBJECTIVE

Interstitial lung disease (ILD) may be a characteristic, often serious, manifestation of mixed connective tissue disease (MCTD). In this retrospective study, the frequency and clinical picture of ILD were determined in patients with MCTD using two diagnostic tests: high-resolution computed tomography (HRCT) and inhaled aerosol clearance times of (99m)Tc-labelled diethylene-triamine pentaacetate ((99m)Tc-DTPA). In addition, pulmonary function, effects of therapy and a variety of immunoserological markers were also assessed.

METHODS

One hundred and forty-four consecutive patients with MCTD were selected from the clinic, irrespective of the presence or absence of ILD. All patients underwent a detailed clinical assessment, chest HRCT scanning, chest radiography, inhaled aerosol of (99m)Tc-DTPA clearance times, and all pulmonary function tests. Patients who had active ILD received corticosteroid (CS) or CS in combination with cyclophosphamide (CPH). All investigations were repeated after 6 months of immunosuppressive therapy.

RESULTS

Ninety-six out of 144 MCTD patients (66.6%) had active ILD, 75 of this group (78.1%) showed ground glass opacity, 21 patients (21.8%) ground glass opacity with mild fibrosis with HRCT. Forty-five patients with active ILD received 2 mg/kg/day CS for 6-8 weeks alone and 51 patients CS in combination with CPH (2 mg/kg/day). Six months later, after therapy, 67 out of 96 MCTD patients with ILD (69.8%) showed a negative HRCT pattern, ground glass opacity with mild fibrosis developed in 15 patients (15.6%), and fibrosis was detected in 13 patients (13.5%). Only one patient showed subpleural honeycombing. (99m)Tc-DTPA was rapid in all 96 MCTD patients with active ILD (28.7 +/- 8.2 min, normal value >40 min). After therapy the (99m)Tc-DTPA was normalized, 79 out of 96 patients (82.3%). Carbon monoxide diffusion capacity (DLCO) was reduced in 33 out of 96 MCTD patients with active ILD (34.3%), while there were no significant differences in the pulmonary function tests between the active versus inactive stage of ILD or versus patients without ILD. The sera of 96 MCTD patients with active ILD contained a high level of immune complexes (ICs), and the total haemolytic complement levels (CH50/ml U) decreased. After 6 months of therapy, the IC levels decreased and CH50/ml levels normalized (MCTD patients before and after active ILD: IC optical density = 355 +/- 227 vs 206 +/- 92, P<0.001; CH50/ml, 38.0 +/- 12.6 U vs 64.3 +/- 13.0 U, P<0.001).

CONCLUSIONS

HRCT is the gold standard for diagnosis of ILD. However, we used another method, (99m)Tc-DTPA, in order to compare this technique with HRCT. This latter technique has not been studied previously in MCTD. The elevated levels of IC and increased complement consumption indicated that IC-mediated alveolocapillary membrane damage and tissue injury might play a role in the pathogenesis of ILD in MCTD.

Anti-idiotype antibodies abrogate the tissue deposition of anti-RNP human autoantibodies injected into neonatal BALB/c mice

OBJECTIVE

The goals of the current work are: 1) to examine the epidermal deposition of anti-RNP IgG human autoantibodies in neonatal BALB/c mice; 2) to look for immunoregulatory effects of anti-idiotypes allowing one to inhibit the epidermal deposition of anti-RNP antibodies; and 3) to elicit antinuclear antibodies in adult BALB/c mice by internal images of anti-idiotypes.

MATERIALS AND METHODS

Anti-idiotype antibodies were produced with human anti-RNP IgG obtained by ion exchange chromatography; F(ab')2 fragments were recovered from pepsin digestion and were purified using Sephacryl S-300. F(ab')2 fragments were then used to immunize New Zealand rabbits.

RESULTS

The anti-RNP IgG recognized the 70 kDa protein and the A (31 kDa) and C (19 kDa) proteins, while the anti-idiotype antibody specifically recognized the light or heavy chain of the anti-RNP (Fab')2 fragments. Additionally, anti-idiotypes recognized the anti-RNP IgG from some sera, but not the IgG from other specificities or from normal IgG. When anti-RNP IgG was injected intraperitoneally into BALB/c mice it induced immune complex deposition in the epidermis and at the dermal-epidermal junction. Previous injection of anti-idiotype antibodies abrogated the anti-RNP IgG deposits. Vaccination with anti-idiotypes elicit antinuclear antibodies in adult BALB/c mice.

CONCLUSIONS

Anti-idiotype antibodies abrogate in vitro the antinuclear antibody deposition in neonatal BALB/c mice. Anti-idiotype antibodies elicit antinuclear antibodies in adult BALB/c mice.